AudioCircle

Audio/Video Gear and Systems => The Lab => Topic started by: wushuliu on 26 Feb 2010, 06:07 pm

Title: Nelson Pass B-1 preamp kit
Post by: wushuliu on 26 Feb 2010, 06:07 pm
EDIT: this was taken out of the Classdaudio amp thread in Cheap and Cheerful.

http://www.audiocircle.com/index.php?topic=76400.0

It's extremely easy to build and makes for a great project for anyone new to DIY. The price/performance ratio is hard to beat (~$150, and it's a Pass design for goodness sake!) and for the tweakers there are bunch of spin-off designs on diyaudio. Finally, it's a godsend for those of use who do not have hundreds or thousands of dollars to spend on a preamp (or anything else).

Bill of Materials

Board

http://www.passdiy.com/store.htm

Solder
(you can $4 10-50ft rolls of the primo stuff)

Cardas Quad (melts like butter at low temps)

seller: chaseii

http://cgi.ebay.com/CARDAS-Quad-Eutectic-Silver-Solder-20-feet_W0QQitemZ200438501940QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item2eab10d234

Digikey

(6) 1M
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CMF1.00MHFCT-ND (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CMF1.00MHFCT-ND)

(4)1k
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CMF1.00KHFCT-ND (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CMF1.00KHFCT-ND)

(2) 221k
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CMF221KHFCT-ND (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CMF221KHFCT-ND)

(2) 10k
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CMF10.0KHFCT-ND (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CMF10.0KHFCT-ND)

(1) 15k
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CMF15.0KHFCT-ND (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CMF15.0KHFCT-ND)

(1) 1ohm 3 Watt
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=P1.0W-3BK-ND (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=P1.0W-3BK-ND)

(1) 1uf bypass cap
http://search.digikey.com/scripts/DkSearch/dksus.dll?vendor=0&keywords=BC2076-ND (http://search.digikey.com/scripts/DkSearch/dksus.dll?vendor=0&keywords=BC2076-ND)

(2) 15000uf caps
http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=131081&k=P6890-ND (http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=131081&k=P6890-ND)

(1) 1n914 diode
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=1N914BCT-ND (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=1N914BCT-ND)

power jack
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CP-037A-ND (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CP-037A-ND)
alternate
http://www.radioshack.com/product/index.jsp?productId=2102486 (http://www.radioshack.com/product/index.jsp?productId=2102486)

wall wart
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=T987-P5P-ND (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=T987-P5P-ND)

(2) 1uf Polyprop Cap
http://www.parts-express.com/pe/pshowdetl.cfm?PartNumber=027-910&DID=7 (http://www.parts-express.com/pe/pshowdetl.cfm?PartNumber=027-910&DID=7)

(2) 10uf PP Cap
http://www.parts-express.com/pe/pshowdetl.cfm?PartNumber=027-932&DID=7 (http://www.parts-express.com/pe/pshowdetl.cfm?PartNumber=027-932&DID=7)

20 - 25k Volume pots (there are tons out there, these are just some inexpensive but good quality
options)

Mono

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=RV4N253C-ND (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=RV4N253C-ND)

Stereo

Alps pots, and more.

http://www.partsconnexion.com/controls_pot_alps.html (http://www.partsconnexion.com/controls_pot_alps.html)


Ebay DACT-Type Stepped Attenuator - $15 shipped
Even better AND cheaper
You can find values for 20k and higher. These are frickin' great for the money.


http://cgi.ebay.com/DACT-Type-21-Stepped-Attenuator-Volume-20K-for-PreAmp_W0QQitemZ200437532132QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item2eab0205e4#ht_1476wt_1202 (http://cgi.ebay.com/DACT-Type-21-Stepped-Attenuator-Volume-20K-for-PreAmp_W0QQitemZ200437532132QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item2eab0205e4#ht_1476wt_1202)

DPDT Toggle Switch for Input

Mini (1/4" hole)

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=060-083 (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=060-083)

(1/2" hole)

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=360-1829-ND (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=360-1829-ND)


Optional for zee thrifty audiophile connoisseurs:

May I recommend zee PRP:

http://www.hndme.com/productcart/pc/viewCategories.asp?idCategory=189 (http://www.hndme.com/productcart/pc/viewCategories.asp?idCategory=189)

and zee Dayton film/foil (parallel 2 to make 1uf, so get 4):

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=027-458 (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=027-458)

Enclosures

Ebay seller: fan_computer
Aluminum 8"x5.7"x2.7"

Ebay seller: gkphotonics
Alumimum, different colors/sizes

Par-metal.com
Aluminum, Desktop 20 series
http://par-metal.com/product-ttp-20series.php (http://par-metal.com/product-ttp-20series.php)





hope this helps

ainsley

Title: Re: Nelson Pass B-1 preamp kit
Post by: Mariusz on 26 Feb 2010, 08:47 pm
Here you go. Topic has been split so you can discuss this preamp and it's build in new thread.

Have fun.
 

Regards
Mariusz 
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 27 Feb 2010, 01:53 am
Good idea for this thread.

Does anyone here have experience building the Pass B1?
Title: Re: Nelson Pass B-1 preamp kit
Post by: Bemopti123 on 27 Feb 2010, 03:14 am
It would be interesting to have someone building step by step with pictures involved, how difficult or time consuming would it be?
Title: Re: Nelson Pass B-1 preamp kit
Post by: Mariusz on 27 Feb 2010, 03:25 am
I would be interesting to have someone building step by step with pictures involved, how difficult or time consuming would it be?

+1

I thought it would be best to move it here where more experienced DIY-ers can  keep their hand on the pulse.


If the kit was manageable for "junior" DIY-er or novice, I would have kept it in Cheap & Cheerful hifi.

Best
Mariusz

Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 27 Feb 2010, 04:21 am
It would be interesting to have someone building step by step with pictures involved, how difficult or time consuming would it be?

It's extremely easy to build.  Really. Perhaps the component list seemed daunting, but I just wanted to make it as easy as possible for people. It should take all of an 1 hour or 2 to solder, and the rest is making the input/output/volume connections in whatever way you like. If you can put a classdaudio amp together, you can put a B1 together for sure. :thumb: The pcb shows you were each component goes. Nelson's pcb is spacious, so there's no squinting or tight spaces.

Face has a great pic of his B1. Note that he opted for a toroid instead of a simple wallwart. But you can see how simple the board is and the connections.


(http://www.cleanandquiet.com/upload/store/Pass%20B1.jpg)


The hardest part would probably be figuring out how to do the volume pot, like if you want to do stereo or separate L/R and then matching the appropriate input/output/gnd. An Alps pot is a good way to go (see pic).

I am not an electronics expert by any stretch of the imagination, but I'll do my best to answer questions related to the build. Diyaudio has a huge thread on the B1, but some may find it daunting.

http://www.diyaudio.com/forums/pass-labs/124889-b1-buffer-preamp.html (http://www.diyaudio.com/forums/pass-labs/124889-b1-buffer-preamp.html)



Title: Re: Nelson Pass B-1 preamp kit
Post by: xecluded on 27 Feb 2010, 09:28 am
Do you have part list for the toroid transformer and where to buy. Thanks
Title: Re: Nelson Pass B-1 preamp kit
Post by: mightym on 27 Feb 2010, 01:37 pm
Wushuliu,

Thanks for the BOM!

This passive pre is so simple, powering with a couple of 9V batteries in series would last a looong time.

NP recommends a simple 18V wallwart ( regulated ).  This too should be available from Mouser, or Digikey.

I bought my B-1 last year, but haven't assembled it yet, I should be doing that in the near future.

I would like to know more about that Alps pot you mentioned......

John
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 27 Feb 2010, 01:38 pm
Thanks for the photo, the diyaudio link, and the reassurance about building the buffer.  I've looked for 25K Alps pots, and haven't been able to find one.  Is it okay to use a higher or lower value?  Also, any recommendation for the toggle switch to flip between one input and the other?  Seems like it should be nothing special (Rat Shack okay?), but would love to hear from someone with experience.

And I agree that it would be great to have a step by step build description, and some close up shots of the board as it is getting stuffed.  I assembled a Daniels DAC kit once based purely on how the board was labeled for the parts, and didn't realize that I'd inserted the power supply caps backwards until I powered it up and they got REALLY hot really fast.  Oops!  So reading a schematic or a board isn't second nature for me yet.


Thanks for all the help and support!

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: kukiman on 27 Feb 2010, 02:01 pm
I'm just wondering, does it take a very high quality volume dial to make this sound good? As I know, the volume dial can vary significantly in price...

Also, anyone has tried a nelson pass b1 buffer with a LDR attenuator?
Title: Re: Nelson Pass B-1 preamp kit
Post by: HAL on 27 Feb 2010, 02:55 pm
The Alps Blue volume control in the picture is a very good unit.  That is what I have for my B1 kit to build.

Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 27 Feb 2010, 06:04 pm
I'm just wondering, does it take a very high quality volume dial to make this sound good? As I know, the volume dial can vary significantly in price...

Also, anyone has tried a nelson pass b1 buffer with a LDR attenuator?

No, you don't have to shell out cash for a volume pot. Nelson sold the retail version with PEC volume pots that run for about $6 I think. I will add some more links for volume pot, etc.

On diyaudio there are folks using the LDR w/ the B1, so check the Pass Labs forum there. I just ordered the LDR kit myself, but probably won't build for a while.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 27 Feb 2010, 06:11 pm
Thanks for the photo, the diyaudio link, and the reassurance about building the buffer.  I've looked for 25K Alps pots, and haven't been able to find one.  Is it okay to use a higher or lower value?  Also, any recommendation for the toggle switch to flip between one input and the other?  Seems like it should be nothing special (Rat Shack okay?), but would love to hear from someone with experience.

And I agree that it would be great to have a step by step build description, and some close up shots of the board as it is getting stuffed.  I assembled a Daniels DAC kit once based purely on how the board was labeled for the parts, and didn't realize that I'd inserted the power supply caps backwards until I powered it up and they got REALLY hot really fast.  Oops!  So reading a schematic or a board isn't second nature for me yet.


Thanks for all the help and support!

Neil

You can go as high as 100k I believe for the volume pot. You can also use 20k. I'll add some links in the BOM, including switch.

Hm. Maybe I'll order a pcb and do a step by step w/ pics and then sell the completed build at cost...
Title: Re: Nelson Pass B-1 preamp kit
Post by: Mariusz on 27 Feb 2010, 06:17 pm
You can go as high as 100k I believe for the volume pot. You can also use 20k. I'll add some links in the BOM, including switch.

Hm. Maybe I'll order a pcb and do a step by step w/ pics and then sell the completed build at cost...

I will add a bottle of Scotch if you do.

Mariusz
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 27 Feb 2010, 07:37 pm
I will add a bottle of Scotch if you do.

Mariusz

Order'sgoinginfirstthingmonday!  :drool:
Title: Re: Nelson Pass B-1 preamp kit
Post by: Mariusz on 27 Feb 2010, 08:10 pm
Order'sgoinginfirstthingmonday!  :drool:


Very exited!!!! :drool:

Your contribution will help a lot of folks here at AC (but not only).

P.S

I'll contact you via PM later tonight (am on the way to work right now)


Thanks
Mariusz
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 27 Feb 2010, 10:06 pm
Do you have part list for the toroid transformer and where to buy. Thanks

No I don't, Face did his own thing w/ the PS, you may want to ask him.
Title: Re: Nelson Pass B-1 preamp kit
Post by: sts9fan on 27 Feb 2010, 10:17 pm
Just go to antek. They are cheap and easy.
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 28 Feb 2010, 01:48 pm
I would just like to confirm that building the B1 is nice and easy - and at the end very rewarding.

I power mine using 3 x 6volt SLA batteries wired in series - OK it is a bit more fiddly as every now and again you have to recharge the three of them.

As to the pot I did not use one, instead I grafted a Lightspeed Attentuator (early kit version) - for more details of this go to DIY Audio.

I am not a great believer in cases for certain items - I have attached (I hope  :?) an image warts and all showing my effort.

If anyone wants to know how I modified the B1 to fit the LSA please say so and I will post in this thread if that is OK with everyone.

(http://www.audiocircle.com/image.php?id=27280)
Title: Re: Nelson Pass B-1 preamp kit
Post by: mightym on 28 Feb 2010, 02:04 pm

As to the pot I did not use one, instead I grafted a Lightspeed Attentuator (early kit version) - for more details of this go to DIY Audio.

If anyone wants to know how I modified the B1 to fit the LSA please say so and I will post in this thread if that is OK with everyone.

I for one would like to have any details you wish to share.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Bemopti123 on 28 Feb 2010, 02:11 pm
Wow, grafting a LSA kit onto the B-1 kit, it is getting complicated quite fast.  Still, I am simply waiting for someone stuffing the regular B-1 PCB with some nice explanations...as someone else said here, even though parts counts are low and you can "sort" of stuff parts according to schematics, there are pitfalls, as polarity issues with components and other so "common sense" procedure for people familiar with DIYng but it is still "black matter" for people who do not have much experience.   :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 28 Feb 2010, 03:08 pm
I for one would like to have any details you wish to share.
OK - what I will do is first is to get my spare board and give details of what I did to build the B1 then follow up with LSA grafting.

Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 28 Feb 2010, 06:04 pm
OK - what I will do is first is to get my spare board and give details of what I did to build the B1 then follow up with LSA grafting.

Alan

Hi Alan, to keep things simple how about after or parallel to my step by step build you show how you integrated the LSA? 2 how-to builds of the board at the same time may end up confusing to follow (although I will be taking a basic by-the-book approach, maybe you're setup will be different).
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 28 Feb 2010, 07:14 pm
Sorry :oops: - I meant I would build the B1 and document it - when finished only then would I describe the LSA.

Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 28 Feb 2010, 11:29 pm
Hi couple of questions pertaining to mating the B1 with the ClassD. I realize it doesnt have gain but i am running the signal thru my HK avr right now with decent results and when i run direct from Paradisea and using SB3 for volume control i get better detail but lose alot of bass and volume. Does anyone know if i would get better results with the buffer in between? And could i still use the remote on the SB3 for volume with B1 installed?  Thanks.....
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 1 Mar 2010, 01:27 am
Sorry :oops: - I meant I would build the B1 and document it - when finished only then would I describe the LSA.

I just ordered the LSA pcb last week so I'm looking forward to your setup.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 1 Mar 2010, 01:41 am
Hi couple of questions pertaining to mating the B1 with the ClassD. I realize it doesnt have gain but i am running the signal thru my HK avr right now with decent results and when i run direct from Paradisea and using SB3 for volume control i get better detail but lose alot of bass and volume. Does anyone know if i would get better results with the buffer in between? And could i still use the remote on the SB3 for volume with B1 installed?  Thanks.....

There's probably no way to know for sure unless you try it out. It certainly will outperform the HK as a preamp, and you should probably have some sort of pre/buffer between the dac and amp.

Yes you can still use the SB3 volume, just turn the B1 volume all the way and leave it. Or adjust to whatever sounds best to you.

hth
Title: Re: Nelson Pass B-1 preamp kit
Post by: LejfK on 1 Mar 2010, 01:42 am
At the risk of sounding like an idiot, what is the LSA kit?
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 1 Mar 2010, 01:54 am
At the risk of sounding like an idiot, what is the LSA kit?

http://diyaudioprojects.com/Solid/DIY-Lightspeed-Passive-Attenuator/ (http://diyaudioprojects.com/Solid/DIY-Lightspeed-Passive-Attenuator/)


Light Speed Attenuator. It's a volume control that's all the rage and just got a stellar review in Stereophile. Supposedly better than DACT, TVC, etc. And cheap to build. It may seem daunting for some however. Alan will tackle that for those that are interested.
Title: Re: Nelson Pass B-1 preamp kit
Post by: gitarretyp on 1 Mar 2010, 01:59 am
Hi couple of questions pertaining to mating the B1 with the ClassD. I realize it doesnt have gain but i am running the signal thru my HK avr right now with decent results and when i run direct from Paradisea and using SB3 for volume control i get better detail but lose alot of bass and volume. Does anyone know if i would get better results with the buffer in between? And could i still use the remote on the SB3 for volume with B1 installed?  Thanks.....

The buffer will improve the bass because it has larger output coupling caps than the Paradisea, but it will not increase the overall volume because it provides no gain. You could still use the SB volume if you either turn the B1's volume all the way up or install a HT bypass type function, which would basically just require a switch and a couple of resistors.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 1 Mar 2010, 02:00 am
I will be ordering parts tonight and tomorrow for the B1; Pass Labs is only a few hours north of me so hopefully I'll have everything by the end of the week to start the tutorial.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Mariusz on 1 Mar 2010, 02:15 am
Sounds good.
Lot of guys will appreciate your effort.
 :thumb:

Mariusz
Title: Re: Nelson Pass B-1 preamp kit
Post by: mightym on 1 Mar 2010, 02:57 am
Sounds good.
Lot of guys will appreciate your effort.
 :thumb:

Mariusz

+1
Title: Re: Nelson Pass B-1 preamp kit
Post by: LejfK on 1 Mar 2010, 03:01 am
http://diyaudioprojects.com/Solid/DIY-Lightspeed-Passive-Attenuator/ (http://diyaudioprojects.com/Solid/DIY-Lightspeed-Passive-Attenuator/)


Light Speed Attenuator. It's a volume control that's all the rage and just got a stellar review in Stereophile. Supposedly better than DACT, TVC, etc. And cheap to build. It may seem daunting for some however. Alan will tackle that for those that are interested.

Thanks.  Since I'm on a roll, let me ask another basic question. 

I've looked at a lot of commercial preamps and see that a lot of them have "home theater bypass" which apparently allows them to be used with a home theater receiver.  I also remember reading somewhere that an old fashioned tape loop on a preamp does the exact same thing.

Would the B-1 need to be modified in order to be used with a receiver like this?  I'm thinking about building one of the ClassDs to go with my Pioneer receiver on the L/R channels and I would be interested in a preamp and a dac for two-channel.  Namely, for two channel it would be dac -> preamp -> amps, but with home theater the reciever's L/R signals just pass through the preamp to the amps.  Make sense?  :scratch:
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 1 Mar 2010, 03:30 am
Thanks.  Since I'm on a roll, let me ask another basic question. 

I've looked at a lot of commercial preamps and see that a lot of them have "home theater bypass" which apparently allows them to be used with a home theater receiver.  I also remember reading somewhere that an old fashioned tape loop on a preamp does the exact same thing.

Would the B-1 need to be modified in order to be used with a receiver like this?  I'm thinking about building one of the ClassDs to go with my Pioneer receiver on the L/R channels and I would be interested in a preamp and a dac for two-channel.  Namely, for two channel it would be dac -> preamp -> amps, but with home theater the reciever's L/R signals just pass through the preamp to the amps.  Make sense?  :scratch:

hopefully gitarretyp will weigh in on what resistors you would need and switch for the bypass. If you were to use the second set of inputs for the receiver however (1st being your dac, if i understand you correctly) it should work fine. This is how I use my receiver, and I think it sounds better through the B1 to my amp than without.

hth
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 1 Mar 2010, 03:39 am
Well I've ordered everything but the pcb/jfets, including a cheap but functional enclosure.

Total cost for everything incl. shipping will be ~ $150.
Title: Re: Nelson Pass B-1 preamp kit
Post by: gitarretyp on 1 Mar 2010, 04:54 am
hopefully gitarretyp will weigh in on what resistors you would need and switch for the bypass. If you were to use the second set of inputs for the receiver however (1st being your dac, if i understand you correctly) it should work fine. This is how I use my receiver, and I think it sounds better through the B1 to my amp than without.

hth

Sorry, you don't need additional resistors for a HT style bypass. All you need is a DPDT switch that bypasses the potentiometer.
Title: Re: Nelson Pass B-1 preamp kit
Post by: LejfK on 1 Mar 2010, 05:44 am
Sorry, you don't need additional resistors for a HT style bypass. All you need is a DPDT switch that bypasses the potentiometer.

That sounds doable.  Cool.
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 2 Mar 2010, 12:55 am
Thanks to all the tech contributors here. I'm looking forward to the builds.
Title: Re: Nelson Pass B-1 preamp kit
Post by: HAL on 2 Mar 2010, 01:08 am
You can also use the DPDT switch to bypass the entire buffer setup if you are running a preamp as input for HT bypass.  A seperate HT input can go to one side of the switch and the buffer output to the other.  The center terminal goes to the output connector. 
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 7 Mar 2010, 01:18 am
Well got part of the build done and plenty of pics. Still waiting for a bunch of stuff from Digikey. I'll get the first set of pics and commentary up soon! :eyebrows:
Title: Re: Nelson Pass B-1 preamp kit
Post by: shadowlight on 7 Mar 2010, 01:21 am
Anyone planning to put a remote control and ht bypass?  Any pointers on where you can pickup a remote control?
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 7 Mar 2010, 01:39 am
Anyone planning to put a remote control and ht bypass?  Any pointers on where you can pickup a remote control?

A remote control setup would certainly complicate things, but if you are so inclined. You
could try:

http://www.partsconnexion.com/product13983.html (http://www.partsconnexion.com/product13983.html)

http://diyclub.biz/catalog/product_info.php?products_id=247 (http://diyclub.biz/catalog/product_info.php?products_id=247)
Title: Re: Nelson Pass B-1 preamp kit
Post by: shadowlight on 7 Mar 2010, 01:42 am
A remote control setup would certainly complicate things, but if you are so inclined. You
could try:

http://www.partsconnexion.com/product13983.html (http://www.partsconnexion.com/product13983.html)

http://diyclub.biz/catalog/product_info.php?products_id=247 (http://diyclub.biz/catalog/product_info.php?products_id=247)


Thanks for the links.  I will try the non-remote version first and gradually make my way up :)
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 7 Mar 2010, 03:54 am
Just for everyone's information. I ordered one of those Chinese diy kits from eBay to make a Pass pre. It's going on three weeks and no kit yet. Parts from Canada arrived before the Hong Kong kit.

Also, what's an "ht bypass"?


The LSA installed into the Pass pre would be VI (Very Interesting). See there, I can do initials. A how-to follow-up on the LSA/Pass pre would be appreciated. I've got time on my hands, so....

Title: Re: Nelson Pass B-1 preamp kit
Post by: shadowlight on 7 Mar 2010, 04:19 am

Also, what's an "ht bypass"?


My system is dual purpose system.  It is both 2-channel and home theater.  HT Bypass basically allows me to by pass the pre from my receiver directly into the amp.
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 7 Mar 2010, 04:22 am
Aaahhhh... ht = home theater.  DUH   :duh: :duh: :duh:

Thanks!
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 7 Mar 2010, 05:05 am
Just for everyone's information. I ordered one of those Chinese diy kits from eBay to make a Pass pre. It's going on three weeks and no kit yet. Parts from Canada arrived before the Hong Kong kit.

Also, what's an "ht bypass"?


The LSA installed into the Pass pre would be VI (Very Interesting). See there, I can do initials. A how-to follow-up on the LSA/Pass pre would be appreciated. I've got time on my hands, so....

Looks like you ordered during the chinese holiday, hence the delay.
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 7 Mar 2010, 01:36 pm
I ordered one of the Chinese kits about 2 weeks ago, and it arrived day before yesterday.  The packaging was rather limited... a bubble enevelope with the board stuffed insided (wrapped in very thin bubble wrap) and a bag o' parts... but everything appears to have survived the journey.  Now I'm waiting for assembly details from those kind and generous sorts who've been successful at this already.  Note that there is no switch for selecting inputs with the kit, and the volume pot looks pretty so-so, although at least it appears that one could mount/solder it directly to the board.

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 7 Mar 2010, 02:53 pm
Thanks guys!

I've got Alps pot around here somewhere that I intend to use until the LSA situation is worked out.

Walkern, you imply that there are no instructions with the kit. Rats! I have the schematic they emailed to me, but I cannot read a schematic. I can read instructions and diagrams so we are in the same boat, waiting for others to provide a paddle.
Title: Re: Nelson Pass B-1 preamp kit
Post by: HAL on 7 Mar 2010, 04:12 pm
Here is my Pass B1 board with parts installed before soldering.  Two different views.


(http://www.audiocircle.com/image.php?id=27497)

(http://www.audiocircle.com/image.php?id=27498)

The B1 Board has silk screened parts numbers on it for stuffing.

Edit:  The Alps Blue Pot, 100Kohm version for input volume control.


(http://www.audiocircle.com/image.php?id=27501)
 
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 7 Mar 2010, 04:59 pm
Hi,

I have also built up the board with loads of photos - hopefully I can get them loaded on Monday - I have to reduce them in size before posting.

Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: schubert on 7 Mar 2010, 05:16 pm
Here's my Pass B-1 for anyone who is interested.

(http://www.audiocircle.com/image.php?id=27502)

(http://www.audiocircle.com/image.php?id=27503)

(http://www.audiocircle.com/image.php?id=27504)

(http://www.audiocircle.com/image.php?id=27505)

(http://www.audiocircle.com/image.php?id=27506)

It's powered by a TREAD and uses PEC carbon pots, which sound nice but introduce some operational awkwardness.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 7 Mar 2010, 06:00 pm
Ok kids, here we go. I hope the pics are good enough, but I will also provide a link to the full rez pictures so you can zoom in if you need to.

Now I will assume that the builder will have soldered at some point in their life. If, however you need a refresher or will be taking the leap for the first time, then I highly recommend the first 2 tutorials on the following page:

http://tangentsoft.net/elec/movies/ (http://tangentsoft.net/elec/movies/)


Below is Nelson's PCB.

(http://www.audiocircle.com/image.php?id=27511)

As you can see it is nice and spacious and very well laid out, no parts will be interfering other parts. The Part numbers are on the board as you can see, but you will need to refer the pdf to see what values correspond to what number.

http://www.passdiy.com/pdf/B1%20Buffer%20Preamp.pdf (http://www.passdiy.com/pdf/B1%20Buffer%20Preamp.pdf)

I printed out the sheet and placed it behind the board for easy reference.

R= resistor, C=Capacitor, Q = JFET, D= diode, led



(http://www.audiocircle.com/image.php?id=27513)


As a general rule of thumb, it is best to start populating a pcb with smallest/shortest height components first.

So that means the resistors.  So just pop one in and start solderin'!


(http://www.audiocircle.com/image.php?id=27515)


(http://www.audiocircle.com/image.php?id=27518)


(http://www.audiocircle.com/image.php?id=27519)


(http://www.audiocircle.com/image.php?id=27520)


(http://www.audiocircle.com/image.php?id=27521)


(http://www.audiocircle.com/image.php?id=27522)


Alright. Almost done!

Ok, not quite. But the resistors make up a bulk of the soldering, take a break and rub hands together in wicked glee. :icon_twisted:




Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 7 Mar 2010, 06:04 pm
Next up are the four matched JFETS that come with Nelson's board.


(http://www.audiocircle.com/image.php?id=27530)

Be sure it is oriented the right way when soldering. As you can see from the outline on the board, the 3-pronged jfet has a flat back and curved front - so be sure to put them in the right way.

(http://www.audiocircle.com/image.php?id=27531)

Another good reason to buy Nelson's directly is it can be difficult to source the JFETs and since his are matched you can be assured you're getting the best out of them. Or whatever. I don't really know what they do.

let's melt some lead!

(http://www.audiocircle.com/image.php?id=27532)

Gettin' closer!



Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 7 Mar 2010, 06:04 pm
Now we come to the input and output capacitors.

(http://www.audiocircle.com/image.php?id=27533)

This where you have some room to experiment and show off your audiophile cred/bling. Nelson designed his with regular Axon polypropylene caps similar to the Dayton's I have below. Good enough for him, then that'll be good enough for you, but if you want to season your B1 to get that certain flavor you may find a big payoff to swapping caps (let's leave the arguments in another thread, this is strictly a suggestion, nothing more).

(http://www.audiocircle.com/image.php?id=27536)


The one thing the Chinese ebay pcb has which Nelson's does not is a set of different lead spacings to accomadate different sized capacitors. With the Dayton's I had to bend the leads in a little on one side
to get them in on Nelson's board. No big deal, just be sure you don't block any upcoming parts.

(http://www.audiocircle.com/image.php?id=27534)


(http://www.audiocircle.com/image.php?id=27535)


(http://www.audiocircle.com/image.php?id=27538)


(http://www.audiocircle.com/image.php?id=27539)


Lookin' good! 8)





Title: Re: Nelson Pass B-1 preamp kit
Post by: Bemopti123 on 7 Mar 2010, 06:07 pm
 :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 7 Mar 2010, 06:15 pm
Now we'll take on the input switch.

(http://www.audiocircle.com/image.php?id=27540)

We have a DPDT for 2 source inputs. It has 6 solder lugs as you can see. The center two are the L/R outputs. The outer two are Source 1 L/R and Source 2 L/R. Hopefully the pics convey what goes where easily.

Source 1 Right

(http://www.audiocircle.com/image.php?id=27541)

Source 1 Left

(http://www.audiocircle.com/image.php?id=27542)


Now into the appropriate holes

(http://www.audiocircle.com/image.php?id=27543)

As you can guess, the center two will go the middle, and the Source 2 L/R will be soldered to the bottom two on the board.

(http://www.audiocircle.com/image.php?id=27544)


That's it for today. The Digikey stuff comes in tomorrow (I used spare resistors for this build), and I'll continue then.




Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 7 Mar 2010, 06:15 pm
Up next is the 3W 1 0hm resistor.

(http://www.audiocircle.com/image.php?id=27661)


And now the generic diode...

(http://www.audiocircle.com/image.php?id=27662)

Note that the diode has a stripe on one side.

Be sure that the striped side of your diode matches the stripe on the pcb.

(http://www.audiocircle.com/image.php?id=27664)

(http://www.audiocircle.com/image.php?id=27665)

Sorry, had a hard time getting a clear shot, but you get the, uh, picture


Now the 1uf PS bypass cap.

(http://www.audiocircle.com/image.php?id=27666)


(http://www.audiocircle.com/image.php?id=27667)









Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 7 Mar 2010, 06:15 pm
Next up, PEC volume pots.

(http://www.audiocircle.com/image.php?id=27668)



Btw: CW=input W=output CCW=ground


Inputs first


(http://www.audiocircle.com/image.php?id=27671)


(http://www.audiocircle.com/image.php?id=27670)


And there we be.

If your are using a stereo Alps pot, the wiring is as below:


(http://www.audiocircle.com/image.php?id=29367)






Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 7 Mar 2010, 06:24 pm
Thanks for the pics and instructions!

schubert, nice looking build. Mine's going into a cigar box, I suppose. Maybe I should use some grounded copper screen to shield it.

wushuliu, you da man, you da man! I see you intend to keep it coming.

Now, I just need the kit to arrive.

By the way, what is the cost of the kit and parts from Pass diy, Digikey and Mouser? I've seen $80 and $150. Does anyone know?

EDIT: Okay, just did a bit of homework on electrical schematic symbols. They are straightforward enough. Also, looking at the kit's parts list, there is an alphanumeric designator for each part that corresponds to an alphanumeric notation on the pcb. This should be no problem for me, aside from the nerve damage effects on my soldering skills. I'll quit whining now.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 7 Mar 2010, 06:43 pm
My $80 dollar estimate was wrong. $150 would be the total for the BOM I listed including shipping, rca connectors and enclosure I believe. Obviously you can save about $20 going w/ the ebay pcb, and you can save more going w/ a cheaper potentiometer, cheaper enclosure etc.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 7 Mar 2010, 07:09 pm
Wushuliu thanks for all the pics and instruction. So the only item that requires a certain orientation is the j fets? The resistors and caps are omni directional?
Thanks....... :eyebrows:

P.S. If you decide to put the unit on tour please count me in.  :drool:
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 7 Mar 2010, 07:15 pm
Wushuliu thanks for all the pics and instruction. So the only item that requires a certain orientation is the j fets? The resistors and caps are omni directional?
Thanks....... :eyebrows:

P.S. If you decide to put the unit on tour please count me in.  :drool:

The jfets, diode, led, and Power Supply caps require correct orientation. I will cover the power supply and all other parts that require specific orientation when they arrive.
Title: Re: Nelson Pass B-1 preamp kit
Post by: atroder on 7 Mar 2010, 07:53 pm
Wushuliu - Excellent - above and beyond !
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 7 Mar 2010, 08:54 pm
Wushuliu - you have done the same as I have except that you have shown the circuit along with the components - a very nice idea.

I will forget about posting my photos etc - duplication. I had thought about going through the build of the Lighter Note (Uriah's version of the LSA) but there is a document available from Uriah (see DiyAudio), so instead I will just explain how and why I modified the B1 to include the LSA.

Keep up the excellent work.

Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: Mariusz on 7 Mar 2010, 09:41 pm
Excellent 1•2•3 step-by-step instructions Wushuliu.
Wish other guys steped up with projects like this.

Thumbs way up

Mariusz
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 7 Mar 2010, 10:03 pm
Hal what is the purpose of using 1.5 sonicap intead of the parts list of 1.0?
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 7 Mar 2010, 10:11 pm
Excellent 1•2•3 step-by-step instructions Wushuliu.
Wish other guys steped up with projects like this.

Thumbs way up

Mariusz

Thanks Marius. Just my way of giving back to the audio community. :beer:
Title: Re: Nelson Pass B-1 preamp kit
Post by: HAL on 7 Mar 2010, 11:54 pm
Hal what is the purpose of using 1.5 sonicap intead of the parts list of 1.0?

I already had them from another project.  They are matched units, and close enough in value to the originals for input coupling caps to work well.
Title: Re: Nelson Pass B-1 preamp kit
Post by: peranders on 8 Mar 2010, 09:42 pm
I had a group buy of these boards (with permission from Mr. pass) but they are all gone, sorry. Red nice pcb's (http://sjostromaudio.com/joomla/index.php?option=com_content&task=view&id=131&Itemid=41) with gold pads.

It's a good design and I'll hope my pcb's will be used.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Sonny on 8 Mar 2010, 10:21 pm
Where can one get the boards to start this project? :drool:
Title: Re: Nelson Pass B-1 preamp kit
Post by: sts9fan on 8 Mar 2010, 10:23 pm
Check over at diyaudio for some groupbiysnor I think passdiy may still have em
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 8 Mar 2010, 10:44 pm
Where can one get the boards to start this project? :drool:

2 Links are in the first post. If the ebay link does not work, just search 'B1 Buffer'. Buying from
Pass himself is preferable.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Bemopti123 on 8 Mar 2010, 11:31 pm
Where can one get the boards to start this project? :drool:

Need to download an order form from PassDIY, fill, scan and send to their email.  NEVER send CC info in this email form.  They will reply with a phone number, you call and give them info over the phone. 

Even though the Ebay kit is cheaper, as you can already tell, Pass gets 0 anything from it.  It is unjust, so I ordered mines through this website.  $45 per board shipped with 4 matched Jfets. 

The list of items that Wushuliu provided is like trekking across the world, especially with Digitkey which wants to to buy some items at numbers as large as 10X what you need, but hey, we are talking cents worth per items.  Not biggie. 

I ordered the Digitkey pack.  I also ordered some stuff through PartsExpress...but I wonder, the toggle switch is for on and off or was it for source selection? 

BTW:  Remember to order at least 3 pairs of female chassis mount RCAs, along with a knob for what volume pot you choose.  I had to call Canada, prior to their submitting the internet order.  Got my volume pot and RCAs from my favorite people, PartsconneXion. 
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 8 Mar 2010, 11:39 pm
 

The list of items that Wushuliu provided is like trekking across the world, especially with Digitkey which wants to to buy some items at numbers as large as 10X what you need, but hey, we are talking cents worth per items.  Not biggie. 
 

Thanks for mentioning this bit. I reviewed the BOM and caught the mistake with the 1 ohm resistor. I thought I corrected that already. Otherwise I believe each item is available as a single unit.
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 9 Mar 2010, 03:00 am
To those who know,

My amp has an 100k input impedence. For the B1, the Alps pot I have is a 100k pot. Are these values acceptable of good performance of the B1 with my amp?
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 9 Mar 2010, 04:37 am
First official boo-boo. The PS caps I listed in the BOM are too wide for the Nelson Pass PCB. They should be fine for the Ebay PCB, but I have updated the BOM with ones that will fit both.

Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 11 Mar 2010, 03:46 am
To those who know,

My amp has an 100k input impedence. For the B1, the Alps pot I have is a 100k pot. Are these values acceptable of good performance of the B1 with my amp?

I think Nelson's response to the 100k pot question was basically 'give it a shot'.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 11 Mar 2010, 03:52 am
This is continued from the reserved spaces on Page 3, so for those currently following right now you'll want to head back there.

Power jack

(http://www.audiocircle.com/image.php?id=27672)


Black wire = Negative White = Positive center

Obviously white wire goes to '+' on the pcb to the left.

(http://www.audiocircle.com/image.php?id=27674)

(http://www.audiocircle.com/image.php?id=27675)

(http://www.audiocircle.com/image.php?id=27676)


Waiting for the new PS caps to come in and then this is pretty much done!






Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 11 Mar 2010, 05:26 am
Power supply Caps.

The white stripe = Negative So do not have the white stripe facing the '+' on the PCB.

If you are using the Jim's Audio Ebay PCB, the white stripe on his pcb = negative

(http://www.audiocircle.com/image.php?id=27855)


(http://www.audiocircle.com/image.php?id=27856)


(http://www.audiocircle.com/image.php?id=27857)




well for all intents and purposes the build is done. All that's left is wiring the input as you see fit and using the enclosure of your choice.


(http://www.audiocircle.com/image.php?id=28609)


(http://www.audiocircle.com/image.php?id=28610)


(http://www.audiocircle.com/image.php?id=28611)







Battery Power

There are many ways to configure batteries for the B1.

For some overview on wiring batteries in series or parallel.

http://www.zbattery.com/Connecting-Batteries-in-Series-or-Parallel (http://www.zbattery.com/Connecting-Batteries-in-Series-or-Parallel)

Here's one way using 9v batteries.

2 9v in series for a total of 18v.

(http://www.audiocircle.com/image.php?id=27859)

(http://www.audiocircle.com/image.php?id=27860)

Note the wiring of positive (red) to negative (black) from one 9v to the next
to make the necessary 18v.


With batteries you'll certainly want a switch. So wire the positive lead from the 9v to the
switch. And then from the switch to the '+' positive on the pcb. The negative black
lead from the 2nd 9v is then wired to the negative on the pcb.

Since I am not using batteries or a switch in my build, here's a mockup of the wiring.

(http://www.audiocircle.com/image.php?id=27861)

 

Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 11 Mar 2010, 05:26 am
reserved
Title: Re: Nelson Pass B-1 preamp kit
Post by: Mariusz on 11 Mar 2010, 03:43 pm
Looking good sir. 


What are the basic spects of Nelson Pass B-1 buffer?

For those curious minds.  :lol:

.......and, is it possible to implement battery power supply into this DIY project?
If so, how can one go about it?


Cheers
Mariusz
Title: Re: Nelson Pass B-1 preamp kit
Post by: peranders on 11 Mar 2010, 03:50 pm
For data of the design, please go to Nelson Pass' website.

This design consumes rather little power so it's quite possible to use batteries.
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 11 Mar 2010, 04:08 pm
Looking good sir. 


What are the basic spects of Nelson Pass B-1 buffer?

For those curious minds.  :lol:

.......and, is it possible to implement battery power supply into this DIY project?
If so, how can one go about it?


Cheers
Mariusz

Mariusz,

I use 3 SLA (Sealed Lead Acid) batteries each of 6volts and about 7ah (Amp Hours)and connect them in series, they do tend to last - especially if you turn them off when not using!

I keep two sets so that when one is exhausted I plug the charged ones in and re-charge the tired ones - I normally charge them overnight so 3 evenings before they can be re-used.

I also use batteries (2 SLAs for the LSA) using the same method.

Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: Mariusz on 11 Mar 2010, 05:16 pm
Mariusz,

I use 3 SLA (Sealed Lead Acid) batteries each of 6volts and about 7ah (Amp Hours)and connect them in series, they do tend to last - especially if you turn them off when not using!

I keep two sets so that when one is exhausted I plug the charged ones in and re-charge the tired ones - I normally charge them overnight so 3 evenings before they can be re-used.

I also use batteries (2 SLAs for the LSA) using the same method.

Alan

Thanks Alan
and was the difference noticeable?
Did you had a chance to compare?


Mariusz
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 11 Mar 2010, 09:05 pm
Looking good sir. 


What are the basic spects of Nelson Pass B-1 buffer?

For those curious minds.  :lol:

.......and, is it possible to implement battery power supply into this DIY project?
If so, how can one go about it?


Cheers
Mariusz

I have some battery holders that I used for my Hagerman Bugle. I can swap out the power jack and show the battery holder wiring for those who want to try that. I'll post pics later tonight.
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 12 Mar 2010, 10:06 am
Thanks Alan
and was the difference noticeable?
Did you had a chance to compare?


Mariusz
Mariusz

I had used a wallwart psu and then a small linear psu, after I changed to batteries I never went back - so I cannot say that it sounded better only that I felt happier with the sound.

Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 12 Mar 2010, 12:32 pm
I have a question about adding a second set of outs to the B1 for a sub. Since the B1 is an impedance matcher will an extra set of out mess things up?
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 12 Mar 2010, 01:29 pm
Some photos of my battery setup.


(http://www.audiocircle.com/image.php?id=27713)

(http://www.audiocircle.com/image.php?id=27714)

(http://www.audiocircle.com/image.php?id=27715)
Title: Re: Nelson Pass B-1 preamp kit
Post by: Mariusz on 12 Mar 2010, 02:24 pm
What is the 2nd BPS for?
Cool setup.  :drool:

Mariusz
Title: Re: Nelson Pass B-1 preamp kit
Post by: jtwrace on 12 Mar 2010, 02:26 pm
It may be one battery setup for the PS and one for the remote.  Maybe?
Title: Re: Nelson Pass B-1 preamp kit
Post by: avionic on 12 Mar 2010, 02:31 pm
What is the 2nd BPS for?
Cool setup.  :drool:

Mariusz

Lightspeed Attentuator
Title: Re: Nelson Pass B-1 preamp kit
Post by: Mariusz on 12 Mar 2010, 02:36 pm
Looks like it.  :scratch:
Very nice work.  :thumb:

Mariusz
Title: Re: Nelson Pass B-1 preamp kit
Post by: avionic on 12 Mar 2010, 02:42 pm
I soldered up one of the Chinese versions ( Jim's Audio)last night.
 Trying to upload a pic, but my camera just froze up  :(  Got it to load
(http://www.audiocircle.com/image.php?id=27716)
Title: Re: Nelson Pass B-1 preamp kit
Post by: Mariusz on 12 Mar 2010, 05:18 pm
I have some battery holders that I used for my Hagerman Bugle. I can swap out the power jack and show the battery holder wiring for those who want to try that. I'll post pics later tonight.

Awesome.
Surely there must be at least few fellow members speculating about this option.
Having owned (still using) few components with BPS, I can see why someone would like to explore this option or even implementing it into basic design.


That is probably what I like about this project.

- you can start with basic design
- refine it as you get better and more comfortable with DIY essentials
- spend as much (or as little) as you like/can afford



Mariusz

       
 
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 12 Mar 2010, 05:40 pm
I have a question about adding a second set of outs to the B1 for a sub. Since the B1 is an impedance matcher will an extra set of out mess things up?

Someone asked Nelson Pass this question at the DIY forum and his reply seemed to indicate that all you'd need to do is connect the second set of outputs parallel with the first, and you'd be good to go.  I'm intending to do this myself, (although it may be a little while... I haven't even stuffed my board yet) so I'll let you know if it works.

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 12 Mar 2010, 07:33 pm
Mariusz

I had used a wallwart psu and then a small linear psu, after I changed to batteries I never went back - so I cannot say that it sounded better only that I felt happier with the sound.

Alan

Rarely do I have an opportunity to contribute, but this is one of them. Others have probably read this from me, but here goes.

I had a Trends amp back when and I tried it with a SLAB supply. It made the sound smoother. Then I tried it with the old wall wart, but with a cap across the input lines. It made the sound more dynamic, but just as smooth as the SLABs.

My 3 cents (devalued dollar).
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 12 Mar 2010, 09:08 pm
Rarely do I have an opportunity to contribute, but this is one of them. Others have probably read this from me, but here goes.

I had a Trends amp back when and I tried it with a SLAB supply. It made the sound smoother. Then I tried it with the old wall wart, but with a cap across the input lines. It made the sound more dynamic, but just as smooth as the SLABs.

My 3 cents (devalued dollar).

I tried the battery option with a Trends as well, and found I liked it better than the wall wart... but never tried the cap across the input lines of the wall wart.  What value cap did you find worked best?

Neil

Oh, and hey Avionic... thanks for posting your photo of your Jims Audio board.  I've got one, and am about to get busy populating it.
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 12 Mar 2010, 09:19 pm
I tried the battery option with a Trends as well, and found I liked it better than the wall wart... but never tried the cap across the input lines of the wall wart.  What value cap did you find worked best?

I don't remember the value of the cap. I do not understand electronics and don't know why this works. I can say that the cap was physically large, but a wide range of values was acceptable, according to my sources.

Just put a cap across the power inputs, as if to short them, and voila! Clear and clean and dynamic. This was a noticeable difference, well, to my ears anyhow. The batteries made the sound slightly smoother. The dynamism imparted by the wall wart + cap was more noticeable.

Oh, I had jumpered the volume pot in the Trends. That clarified the sound a great deal and was probably responsible for me hearing the differences as well as I did.
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 12 Mar 2010, 09:22 pm
I finished the B1 kit from Jim's last night. It might be my eyes, but the color-coding of the resistor values was difficult to distinguish. Anyone else with this problem?
Title: Re: Nelson Pass B-1 preamp kit
Post by: avionic on 12 Mar 2010, 09:27 pm
I finished the B1 kit from Jim's last night. It might be my eyes, but the color-coding of the resistor values was difficult to distinguish. Anyone else with this problem?

 Yes.                                                                                       I think that the 6 holes on the jim's board marked S100 and S200 are the switch inputs? Is this correct?
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 12 Mar 2010, 09:53 pm
Yes.                                                                                       I think that the 6 holes on the jim's board marked S100 and S200 are the switch inputs? Is this correct?

Well, if you are asking me, I could only answer in the same way I assembled the kit... by guess and by God.

I haven't powered it up yet, so you certainly would want a better opinion than mine.

Some of the things placements can be deduced from the number of parts, but a few are just my guess. I was going to write "Jim" to tell him that pictures of a completed kit would help, but that wouldn't completely solve the Mystery of the Color-Coding.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 12 Mar 2010, 09:58 pm
Yes.                                                                                       I think that the 6 holes on the jim's board marked S100 and S200 are the switch inputs? Is this correct?

Yes those are the switch inputs.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 12 Mar 2010, 10:01 pm
Well, if you are asking me, I could only answer in the same way I assembled the kit... by guess and by God.

I haven't powered it up yet, so you certainly would want a better opinion than mine.

Some of the things placements can be deduced from the number of parts, but a few are just my guess. I was going to write "Jim" to tell him that pictures of a completed kit would help, but that wouldn't completely solve the Mystery of the Color-Coding.

Part of the reason why I recommend only gettting the pcb from them. Full kits from China/HK usually have poor documentation, dicey quality components, and yeah, tiny resistors with hard to read color coding...
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 12 Mar 2010, 10:46 pm
Well, if you are asking me, I could only answer in the same way I assembled the kit... by guess and by God.

I haven't powered it up yet, so you certainly would want a better opinion than mine.

Some of the things placements can be deduced from the number of parts, but a few are just my guess. I was going to write "Jim" to tell him that pictures of a completed kit would help, but that wouldn't completely solve the Mystery of the Color-Coding.

I asked for a photo of a completed board before I ordered mine, and was told (in a very prompt and polite response) that the board was very clearly marked, and that I would have no trouble identifying exactly where everything should go.  Now if ONLY i had memorized those color codes for resistors!  Oops.  None of the parts are clearly labeled or marked, and I'm sure they MUST have newbies who throw the power supply caps in backwards (not realizing the orientation is marked on the board), or the diode in backwards, etc.  And I wonder why he doesn't include a selector switch in with the rest of the parts mix?  Oh well... it was a cheap and cheerful way to check out the potential for a B1.

Neil

Title: Re: Nelson Pass B-1 preamp kit
Post by: avionic on 13 Mar 2010, 12:02 am
Thanks guys.
  This site has some really good electronics info including resistor calculators and explanations. Just click on the link and scroll through the different topics on the right.
   http://www.bcae1.com/
Title: Re: Nelson Pass B-1 preamp kit
Post by: mgalusha on 13 Mar 2010, 03:08 am
Cool thread. I've had one of the B1 boards and FET's for some time now, this makes me want to do something with it. :)

On a related note, http://www.electronics2000.co.uk has a lot of good info and a very handy and very free electronics calculator.

mike
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 13 Mar 2010, 09:56 am
Although it is an extra cost I think that everyone should have a DMM - Digital Multimeter - this would help to identify easily which resistors are which.

Even when I know what a resistor is meant to be I usually check before putting them into the board.

If you want to do more than just put the B1 together (e.g building your own power supply) or go on to other projects then this is a must-have piece of kit.

If anyone has the chinese kit up and running then I think a photo would help fellow builders.
Title: Re: Nelson Pass B-1 preamp kit
Post by: strobistray on 14 Mar 2010, 03:44 pm
Greetings Everyone

I'm new to this forum and have just recently stumbled upon this thread, a little late unfortunately. I say this because I've already purchased a couple of the Chinese B1 buffer kits and so far it's not been a great experience, you definitely get what you pay for! On the surface the kit looks ok but once you put it together it's obvious there's problems. The top end is tissy and smeared the bass is thin and muted and it just sounds bad.
For starters I think I'll replace the caps and maybe the FETs.

Great thread I'm really enjoying the comments.
Ray
Title: Re: Nelson Pass B-1 preamp kit
Post by: Bemopti123 on 14 Mar 2010, 03:57 pm
I have received a pair of legal Pass DIY boards with the matching FETs.  The board of really high quality, clearly labeled.  I received some parts of PartsExpress and I am currently waiting for the final items from PartsconneXion and also Digitkey. 

I must have dished out around $40 for the board along with FET, $56 for PartsConneXion, ~50 for PartsExpress and another $35 for DigitKey.  In no way is this comparable to the $35 price for the Chinese board, but at least I know what I am getting. 

I have been interested on other kits that the HK outfitter sells, but after hearing from the problems with his kits, I will think twice before ordering anything from there.   :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: jmc207 on 14 Mar 2010, 04:16 pm

On a related note, http://www.electronics2000.co.uk has a lot of good info and a very handy and very free electronics calculator.

mike

Great site Mike! Thanks!
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 14 Mar 2010, 04:54 pm
Greetings Everyone

I'm new to this forum and have just recently stumbled upon this thread, a little late unfortunately. I say this because I've already purchased a couple of the Chinese B1 buffer kits and so far it's not been a great experience, you definitely get what you pay for! On the surface the kit looks ok but once you put it together it's obvious there's problems. The top end is tissy and smeared the bass is thin and muted and it just sounds bad.
For starters I think I'll replace the caps and maybe the FETs.

Great thread I'm really enjoying the comments.
Ray
Ray - could I suggest that if the B1 sounds that bad then changing bits and pieces may not be the best route - what is that saying "You cannot make a silk purse out of a sows ear". :eyebrows: :eyebrows:

Although it costs more getting the proper board and components I think it is best. I have one last spare B1 board partly populated - resistors / caps / fets - it is the one I was going to show on this thread but wushuliu is doing a great job. Please PM me if you are interested.

Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: avionic on 14 Mar 2010, 05:34 pm
I to fell for the low price of the chinese b1 kit. Let's just say I am not happy with it at all. On the bright side it was fun soldering all the components onto the board :lol:
  I will now order a board from pass like I should have done in the first place. Live and learn thats DIY.
Title: Re: Nelson Pass B-1 preamp kit
Post by: strobistray on 15 Mar 2010, 03:50 pm
Thank guys for all the offers of help! Like any newbee I'm afraid I was a little hasty and posted before checking for obvious problems. The B1 likes to see the full 18 V. and doesn't tolerate anything lower without degradation. Once I replaced the power supply things improved dramatically.

Ray
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 15 Mar 2010, 07:07 pm
Neither picture nor detailed instructions would help much with the Chinese B1, nor the ability to identify color codes. The problem is that you cannot reliably read the colors on the resistors.

That said, I am not completely sure of copyright laws, but the Chinese seller may be quite legally reproducing and selling these boards. If so, I'm not sure that the ethical questions about selling such a board have much standing. It's an interesting question and before I throw mud at someone....

Anyhow, there may be other causes of the Chinese board sounding badly that parts quality or am I wrong? I am especially thinking of assembly issues.   :scratch:
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 15 Mar 2010, 07:29 pm
This is one of the B1 clones against the Nelson Pass original; I am not sure if this was legal but I do not remember any problems. I am trying to see if they are available.


(http://www.audiocircle.com/image.php?id=27832)
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 15 Mar 2010, 07:44 pm
Neither picture nor detailed instructions would help much with the Chinese B1, nor the ability to identify color codes. The problem is that you cannot reliably read the colors on the resistors.

That said, I am not completely sure of copyright laws, but the Chinese seller may be quite legally reproducing and selling these boards. If so, I'm not sure that the ethical questions about selling such a board have much standing. It's an interesting question and before I throw mud at someone....

Anyhow, there may be other causes of the Chinese board sounding badly that parts quality or am I wrong? I am especially thinking of assembly issues.   :scratch:

Why don't you post a pic of your build.

I have one of the ebay B1 pcb's. I like that it's more accomodating of different cap sizes. I think any ethical debates about clones vs. direct order should be set aside. I'd like to hear more about people's builds and impressions!
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 15 Mar 2010, 09:39 pm
wushuliu,

I published a few photos of my B1 / LSA build a few days ago specifically to show how I used batteries. I had started building another B1 for this thread but stopped because of your excellent contribution. :thumb:

As far as sound quality is concerned I think the B1 is excellent, as far as a simple 'pre-amp' is concerned the B1 takes a lot of beating. I have used valve pre-amps and switched to a Promitheus TVC (Transformer Volume Control) Pre-Amp - I found the B1 better (using ALPs pots) and the LSA/B1 even better.

The sound is open, detailed (but not agressively so) with a wide and fairly deep soundstage. Neither the B1 nor the LSA seem to add anything to the signal. A good test is to listen to some music through headphones and then insert the B1 into the signal path with the volume at maximum (the signal should be roughly what is was before) and listen again - you will be surprised at the very small change (if any) that there is.

The B1 without a potentiometer is very useful as a pure buffer - as far as I am aware (but I could be wrong) Nelson Pass designed the B1 for use with the original LightSpeed Attenuator - which may explain why they go together so well.

Sorry to push the LSA but I think once people have built the B1 and are feeling adventurous then it is the next logical step. I will start another thread for this shortly.

I have not seen the Ebay board - do you have a link?

Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 15 Mar 2010, 09:57 pm
as far as I am aware (but I could be wrong) Nelson Pass designed the B1 for use with the original LightSpeed Attenuator - which may explain why they go together so well.


Interesting, did not know that. Yes, please do a tutorial on the LSA!

Thanks for sharing your thoughts on the B1.

And I linked to the Jims audio pcb in my first post...
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 16 Mar 2010, 04:30 am
Awesome.
Surely there must be at least few fellow members speculating about this option.
Having owned (still using) few components with BPS, I can see why someone would like to explore this option or even implementing it into basic design.


That is probably what I like about this project.

- you can start with basic design
- refine it as you get better and more comfortable with DIY essentials
- spend as much (or as little) as you like/can afford



Mariusz

       
 

Absolutely. There are now spin-off designs based on the B1 on diyaudio that are suppose to
sound even better. Many thanks to Nelson Pass for making this design 'open source'.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Mariusz on 16 Mar 2010, 04:42 am
Quote
Many thanks to Nelson Pass for making this design 'open source'.

Obviously his contributions to DIY audience and forums are priceless.... literally.

P.S
you're doing great job with your tutorial  :thumb:


Cheers
Mariusz :P
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 16 Mar 2010, 05:31 am
PS caps and battery power now covered in the reserved on page 5...
Title: Re: Nelson Pass B-1 preamp kit
Post by: yammy1688 on 17 Mar 2010, 02:02 am
I've built this exact combination and it is indeed excellent.  Used one of the ebay B1 kits, but bypassed the POT, and using the LDR /LSA kit from udailey.  The B1 fleshes out the sounds and the LSA just helps keep things nice and clear.


wushuliu,

I published a few photos of my B1 / LSA build a few days ago specifically to show how I used batteries. I had started building another B1 for this thread but stopped because of your excellent contribution. :thumb:

As far as sound quality is concerned I think the B1 is excellent, as far as a simple 'pre-amp' is concerned the B1 takes a lot of beating. I have used valve pre-amps and switched to a Promitheus TVC (Transformer Volume Control) Pre-Amp - I found the B1 better (using ALPs pots) and the LSA/B1 even better.

The sound is open, detailed (but not agressively so) with a wide and fairly deep soundstage. Neither the B1 nor the LSA seem to add anything to the signal. A good test is to listen to some music through headphones and then insert the B1 into the signal path with the volume at maximum (the signal should be roughly what is was before) and listen again - you will be surprised at the very small change (if any) that there is.

The B1 without a potentiometer is very useful as a pure buffer - as far as I am aware (but I could be wrong) Nelson Pass designed the B1 for use with the original LightSpeed Attenuator - which may explain why they go together so well.

Sorry to push the LSA but I think once people have built the B1 and are feeling adventurous then it is the next logical step. I will start another thread for this shortly.

I have not seen the Ebay board - do you have a link?

Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: atroder on 17 Mar 2010, 02:49 am
... and using the LDR /LSA kit from udailey.

Can you please provide a link to the udailey kits? - Thanks.
Title: Re: Nelson Pass B-1 preamp kit
Post by: mgalusha on 17 Mar 2010, 02:52 am
Can you please provide a link to the udailey kits? - Thanks.

Uraih's site (http://www.buildanamp.com/main.sc)
Title: Re: Nelson Pass B-1 preamp kit
Post by: xecluded on 17 Mar 2010, 04:38 am
Used one of the ebay B1 kits, but bypassed the POT, and using the LDR /LSA kit from udailey..
How do you bypass the pot.  I have the LDR from udailey as well and want to do the same.  Do you feel that the sound would be a lot better for not using the pot. Thanks.
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 17 Mar 2010, 09:52 am
How do you bypass the pot.  I have the LDR from udailey as well and want to do the same.  Do you feel that the sound would be a lot better for not using the pot. Thanks.
There are two ways to 'bypass' the pot on the B1, firstly you can put the LDR-based circuit in the same position as the pot, secondly you can effectively short the pot and put the LDR-based circuit at the input to the B1.
I did the latter as I wanted to switch more than two sources. I think it is defintely time to start a new thread on the LDR-based attentuator.
I will do so this evening - I had been waiting for some new parts to arrive and to start new builds but I think that a new thread will allow people to post without taking up space in this B1 thread.

To answer your other question - yes either using an LDR-based attenuator or no pot at all will sound better - I built the B1 originally in the same way as wushuliu had demonstrated and liked it a lot but the LDR-based version is better.

Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: xecluded on 17 Mar 2010, 06:15 pm
Great.  I will try the "short the pot and put the LDR-based circuit at the input to the B1" way  too.  Thanks Alan.
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 17 Mar 2010, 06:26 pm
Great.  I will try the "short the pot and put the LDR-based circuit at the input to the B1" way  too.  Thanks Alan.
I will quickly draw a diagram and send it - please wait!
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 17 Mar 2010, 06:55 pm
xecluded,

If you do as you say then you can only use one input, on the board the volume control is after the input selector, so shorting the pot means that both inputs are running full tilt, the one with the LDR-based attentuator will function normally.

As a temporary measure this is OK - just connect one input.

By shorting I mean take the wire on the output leg of the pot (the one that goes to W on the pcb) and move it to the input leg on the pot (the one that goes to CW on the pcb) so now you have two wires on the input leg of the pot - you have to do it this way rather than simply connecting input to output on the pot. I am not sure what would happen if the pot is still in circuit and you twiddle it.

The alternative is to change the pot to a resistor - detail in the new thread - when I can it together!

Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 17 Mar 2010, 07:07 pm
diagram: -


(http://www.audiocircle.com/image.php?id=27902)
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 17 Mar 2010, 08:06 pm
Please note that I have started a new thread 'Optocoupled Attenuator Build' in which I will try to answer the various questions relating the much mentioned LSA.

Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: xecluded on 18 Mar 2010, 04:25 am
xecluded,

If you do as you say then you can only use one input, on the board the volume control is after the input selector, so shorting the pot means that both inputs are running full tilt, the one with the LDR-based attentuator will function normally.

As a temporary measure this is OK - just connect one input.

By shorting I mean take the wire on the output leg of the pot (the one that goes to W on the pcb) and move it to the input leg on the pot (the one that goes to CW on the pcb) so now you have two wires on the input leg of the pot - you have to do it this way rather than simply connecting input to output on the pot. I am not sure what would happen if the pot is still in circuit and you twiddle it.

The alternative is to change the pot to a resistor - detail in the new thread - when I can it together!

Alan
Thanks Alan.  I will try that this weekend.  :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 18 Mar 2010, 09:46 am
Please note that I have started a new thread 'Optocoupled Attenuator Build' in which I will try to answer the various questions relating the much mentioned LSA.

Alan
I have asked that this thread be deleted whilst I am trying to resolve some (non-technical) issues.
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 24 Mar 2010, 08:06 pm
So, can I hook up in series a 12v SLAB and a 6v SLAB to use as a 18v source?
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 24 Mar 2010, 08:12 pm
So, can I hook up in series a 12v SLAB and a 6v SLAB to use as a 18v source?
Yes, no problem with doing that.

Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 24 Mar 2010, 09:22 pm
OOOPS! That's bad!

The resistor at C2, the big one adjacent the power input, just blew smoke when I powered the unit. Is that resistor polarized?
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 24 Mar 2010, 09:41 pm
OOOPS! That's bad!

The resistor at C2, the big one adjacent the power input, just blew smoke when I powered the unit. Is that resistor polarized?

?

C should stand for capacitor. What board are you using ebay or Pass?

Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 24 Mar 2010, 09:46 pm
Well, maybe it is a capacitor, but it looks like a resistor to me. It's color coded like a resistor.

I'm using the ebay kit. There is no other component that fits the layout. I'm dizzled!
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 24 Mar 2010, 09:51 pm
Well, maybe it is a capacitor, but it looks like a resistor to me. It's color coded like a resistor.

I'm using the ebay kit. There is no other component that fits the layout. I'm dizzled!

Ok, C2 is for the power supply cap, but you must be referring to R1. This is for a 1 ohm 3 watt resistor.

Can you post a pic of your board?
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 24 Mar 2010, 09:53 pm
Well, maybe it is a capacitor, but it looks like a resistor to me. It's color coded like a resistor.

I'm using the ebay kit. There is no other component that fits the layout. I'm dizzled!

also, it is not polarized.
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 24 Mar 2010, 09:56 pm
Yeah, that's it! It's easily seen in avionic's post on page 5. It's the grey resistor on the far right.

Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 24 Mar 2010, 09:58 pm
Maybe my batteries are too large... too powerful. I'm just guessing.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 24 Mar 2010, 10:01 pm
Maybe my batteries are too large... too powerful. I'm just guessing.

The B1 can handle up to 40v I believe. Are you sure the batteries are wired correctly? A pic would be aaawful helpful!

Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 24 Mar 2010, 10:05 pm
The B1 can handle up to 40v I believe. Are you sure the batteries are wired correctly? A pic would be aaawful helpful!

Totally agree - pictures always help.
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 24 Mar 2010, 10:14 pm
The batteries are wired in series. 

(neutral) > (-/+) > (-/+) > (load in)

No cam handy.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 24 Mar 2010, 10:47 pm
The batteries are wired in series. 

(neutral) > (-/+) > (-/+) > (load in)

No cam handy.

and the + is wired correctly, right? (+ is closest to R1 resistor)

regardless, you should replace the resistor with a decent one from digikey, etc. there's a link on the first page BOM.

Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 24 Mar 2010, 11:02 pm
Running out to the local Rat Shack now. Will report back asap!
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 24 Mar 2010, 11:35 pm
Rat Shack no got. Further events must await digikey. Will report when I can. Thanks for everything.
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 25 Mar 2010, 03:04 pm
 :oops: :oops: :oops: :duh: :duh: :duh:

My bad! Thanks to all who tried to help me, but I fear I may be beyond help.

I looked at my battery connections in the morning light and found that I had reversed + and -. This resulted in the neutral side of the B1 receiving 18v and, I presume, cooking the 1ohm, 3watt resistor and who knows what else.

I couldn't get the digikey site to work correctly so I moved on to Mouser and ordered three 1ohm, 3watt resistors. They are Vishay Dale so the quality is assured. If I smoke them, then I'll know it was me... again!

So, a quick question: would reversing the power cause the resistor to smoke?

Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 29 Mar 2010, 06:53 pm
Okay, the new 1ohm, 3watt Vishay-Dale resistor arrived today. I soldered it in and turned on the power.This time the led glowed, but no smoke was emitted. A good sign, but when I installed the preamp into the system, it remained silent. No hum, hiss or pop from either channel.

Now, I'm thinking something else is cooked. I guess I'll have to get out the multi-meter and read the instructions... if I can still find them.

Any ideas for likely suspects?
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 29 Mar 2010, 08:55 pm
Okay, the new 1ohm, 3watt Vishay-Dale resistor arrived today. I soldered it in and turned on the power.This time the led glowed, but no smoke was emitted. A good sign, but when I installed the preamp into the system, it remained silent. No hum, hiss or pop from either channel.

Now, I'm thinking something else is cooked. I guess I'll have to get out the multi-meter and read the instructions... if I can still find them.

Any ideas for likely suspects?

Most likely suspects are the active devices i.e. the 2SK170 (370) and the zener diode, try the zener first - it is the cheapest to replace.

One thing - if you have a DMM do not connect the buffer to your system without checking the dc levels on the outputs of the B1 - better safe than sorry.
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 29 Mar 2010, 10:44 pm
I tested the zener diode. That took a bit of doing, but found a site on using DMM's that was helpful to me, a rank beginner.

Now, I believe I have a problem with the diode because I get a reading in both directions. Not a null or 1 reading, but something up in the high hundreds.

I presume that this kind of reading in both directions indicates a problem. Is this right?

Don't know how to test a jfet, yet. Can someone direct me to a site that would tell me how to do that process? I'm willing to try to learn!

UPDATE: Replaced the zener diode and checked all solder joints. Still no sound of any kind.  :(

Are the jfet's next?
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 1 Apr 2010, 03:51 pm
Hey Earplay...

This may be a really rude question, but since the board comes with no instructions, and the provider does not include a switch, nor does he label the board where the input selector switch would go, I'm wondering if you found a switch on your own and made all the necessary connections to route each input to the active sectons of the board?  The Pass boards all have the same accommodations for the input selector switch, and if you don't connect it then there is no way any input signal actually makes it to the active sections of the board.

Just a thought.  And if you've already connected the switch, and you are still getting no output, please accept my apologies for questioning your skills.  No offense intended.

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 1 Apr 2010, 04:28 pm
walkern,

Not rude at all! I'm laughing at myself, anyhow. Thanks for the suggestion. I was trying my wings on the Chinese B1 before I went the American route. In other words, I mean to build a second Pass pre as you suggest. Great minds, I suppose.

I'll add this for everyone's amusement. sondale has been holding my hand from across the pond and guiding me through my troubles. It seems that the Chinese kit, in fact, does not include all the board components to make this thing work. The connection of a dpdt switch is necessary. So I learned from sondale and, I think, that fact is mentioned earlier in this thread. This morning, I ran out and got a dpdt switch. It has six leads, 3x2. The board has six holes, 3x2. So, I just connected the three leads from each side to the three leads on each side of the board. What did I get? I get the left channel in position one, I get the right channel in position two. They sound great individually, but I hope sondale doesn't give up on me.

Lance
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 1 Apr 2010, 06:26 pm
walkern,

Not rude at all! I'm laughing at myself, anyhow. Thanks for the suggestion. I was trying my wings on the Chinese B1 before I went the American route. In other words, I mean to build a second Pass pre as you suggest. Great minds, I suppose.

I'll add this for everyone's amusement. sondale has been holding my hand from across the pond and guiding me through my troubles. It seems that the Chinese kit, in fact, does not include all the board components to make this thing work. The connection of a dpdt switch is necessary. So I learned from sondale and, I think, that fact is mentioned earlier in this thread. This morning, I ran out and got a dpdt switch. It has six leads, 3x2. The board has six holes, 3x2. So, I just connected the three leads from each side to the three leads on each side of the board. What did I get? I get the left channel in position one, I get the right channel in position two. They sound great individually, but I hope sondale doesn't give up on me.

Lance

Hey... at least you've got SOUND!  Now all you gotta do is figure out how the heck that switch should be wired in and everything will be hunky dunky.  Good luck.

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 1 Apr 2010, 07:03 pm
Neil,


Yeah, I've got sound, true enough. That tells me some things are right. I'm stuck with a partial system. sondale it trying to help me. I may be beyond hope, here.

How complicated can the switch wiring be? I mean, two rows of three on the board, two rows of three on the switch. One to one correspondence. I can figure that out! But, nooooooo! When wired the way that makes sense, it doesn't work correctly. Is there something wrong with the board?


(http://www.audiocircle.com/image.php?id=28482)


The switch is wired up as I described, so that's a given. It plays, so that's a given. Both channels play, so that's a given. They don't play simultaneously, so that's a given.  :scratch: :scratch: :scratch: :scratch:
Title: Re: Nelson Pass B-1 preamp kit
Post by: ebag4 on 1 Apr 2010, 07:13 pm
It certainly sounds as if you have the switch wired incorrectly.  Typically a DPDT switch will wire something like this:
                                         
                 Left input 1-------        --------Right Input 1
   Common to Buffer Left-------        --------Common to Buffer Right
                 Left input 2-------        --------Right Input 2

Your symptoms sound like you either hav the common and input swopped on one side or you have the two inputs swopped on one side.

Good luck!
Ed
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 1 Apr 2010, 07:25 pm
It certainly sounds as if you have the switch wired incorrectly.  Typically a DPDT switch will wire something like this:
                                         
                 Left input 1-------        --------Right Input 1
   Common to Buffer Left-------        --------Common to Buffer Right
                 Left input 2-------        --------Right Input 2

Your symptoms sound like you either hav the common and input swopped on one side or you have the two inputs swopped on one side.

Good luck!
Ed

I think it is the board - if you look at the left/right inputs for 1 the left goes to the bottom pin on S100 and the right goes to the top pin of S200!

Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 1 Apr 2010, 07:26 pm
Thanks ebag4,

But I did exactly as your diagram suggests. I was hoping to get this done tonight. sondale has probably gone to bed, by now because he lives in the UK.

I'm not well-informed about electronics, but I don't think I'm giving myself too much credit when I believe that even I can figure out a one-to-one correspondence. It's disheartening!

The thing that has me going is that both channels will play, just not simultaneously. I conclude then, that both channels of the board are assembled correctly. The problem must be with the switch.

sondale and you suggested I swap a couple of leads. I swapped S100a with S200a, but that caused the sound to come out of only the right channel when the switch was in either position.

I've concluded I need professional help. I don't mean electronic help, either!

EDIT: Alan, just got your message. Which is the bottom in your view? I'll rewire according to your plan. The behaviour does suggest that mere swapping straight across will not solve the problem, IMHO.

EDIT 2: Alan, just got your diagram. Will report back.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 1 Apr 2010, 07:34 pm
I believe its


R2           L1
OUTR      OUTL
R1           L2
Title: Re: Nelson Pass B-1 preamp kit
Post by: ebag4 on 1 Apr 2010, 07:36 pm
I think it is the board - if you look at the left/right inputs for 1 the left goes to the bottom pin on S100 and the right goes to the top pin of S200!

Alan

I agree with Sondale.  Looking at the switch connections on your board it appears that the S100 side uses the bottom (as the pic is oriented) to switch input 2 and S200 uses the top top to switch input 2.  If you take one side and move the top wire to the bottom and bottom to top you might fix your problem.  A meter to check continuity from the input to the switch connection would be very beneficial.

edit: Just like Wishuliu is showing in his post above.

Best,
Ed
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 1 Apr 2010, 07:52 pm
Healed!!!   :thumb:

Indeed, as sondale suggested, the board is laid out incorrectly. When I swapped the switch's leads so they were not in one-to-one correspondence, everything worked as advertised.  :beer: :banana piano:

How can I thank you. sondale, you da' man!  :notworthy:

And everyone else who helped, thanks to you, too.  :notworthy:
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 1 Apr 2010, 07:54 pm
Healed!!!   :thumb:

Indeed, as sondale suggested, the board is laid out incorrectly. When I swapped the switch's leads so they were not in one-to-one correspondence, everything worked as advertised.  :beer: :banana piano:

How can I thank you. sondale, you da' man!  :notworthy:

And everyone else who helped, thanks to you, too.  :notworthy:

As we say over here - Bloody Good Show - now sit back and enjoy!

Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 1 Apr 2010, 09:37 pm
Healed!!!   :thumb:

Indeed, as sondale suggested, the board is laid out incorrectly. When I swapped the switch's leads so they were not in one-to-one correspondence, everything worked as advertised.  :beer: :banana piano:

How can I thank you. sondale, you da' man!  :notworthy:

And everyone else who helped, thanks to you, too.  :notworthy:

Sweet...
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 2 Apr 2010, 12:29 am
Being unable to endure what can be changed, especially if it can be changed cheaply, I removed the blue input and output connectors and soldered the wires directly to the board. Then I bypassed the 10uf caps with VISHAY-RODERSTEIN MKP-1837 Caps I had lying around. Well, those changes helped things in terms of clarity and detail. Not that the stock Chinese B1 did not improve the clarity and detail of my system. I must say though, that the B1 is smooth, too. Very smooth!

Also, I'll probably install the Alps Blue I have setting around. That may help matters. The tonality of this thing is great already, though.

Thanks again to everyone. Now I'll try to piece together an American-sourced B1.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 2 Apr 2010, 12:46 am
Being unable to endure what can be changed, especially if it can be changed cheaply, I removed the blue input and output connectors and soldered the wires directly to the board. Then I bypassed the 10uf caps with VISHAY-RODERSTEIN MKP-1837 Caps I had lying around. Well, those changes helped things in terms of clarity and detail. Not that the stock Chinese B1 did not improve the clarity and detail of my system. I must say though, that the B1 is smooth, too. Very smooth!

Also, I'll probably install the Alps Blue I have setting around. That may help matters. The tonality of this thing is great already, though.

Thanks again to everyone. Now I'll try to piece together an American-sourced B1.

If you're going to put another one together, go for some better quality caps and resistors if you can. The  (2)1uf Input caps at least. The B1 is simple enough that any of those changes are reflected in the sound in a big way. So there's no where to go but up... :eyebrows:

Angela's Instruments sells Takman, Riken, etc. resistors for cheap and they ship first class so you wont get hit w/ shipping costs. The (4) 1k resistors are the ones you will want to upgrade. Or even just 2 of them, to prevent 'too much of a good thing'. The rest you can go digikey per the BOM (including TS-HA for the PS caps!).

http://angela.com/rikenohmresistors.aspx (http://angela.com/rikenohmresistors.aspx)



Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 2 Apr 2010, 01:31 am
Whoops! What's this?

The right channel fades out after about a minute of play. If I turn the B1 off for a few seconds, then repower it, both channels sound fine until the right channel fades out. I've done this five times now. Any ideas?
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 2 Apr 2010, 10:45 am
Whoops! What's this?

The right channel fades out after about a minute of play. If I turn the B1 off for a few seconds, then repower it, both channels sound fine until the right channel fades out. I've done this five times now. Any ideas?
Oh dear!

Did it do this before you changed the inputs and added the bypass caps?

I would think there are two things could be wrong, firstly a cap is misbehaving - normally this would be an electrolytic - but if that was the case then it would be both channels fading. The other is that the jfets were damaged by the reverse voltage.

Recheck the solder joints on your latest work.

Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 2 Apr 2010, 01:47 pm
I must admit that I didn't attend closely enough to know when this happened. As I said, it takes about a minute. In that time, I would listen for a short period, then shift my attention to something else and let the B1 break-in. So, I don't know which change caused the problem.

The B1 has two electrolytics, so I was thinking one per channel. In that case, I thought, an electrolytic could go bad and not affect the other channel. But, I know I could be wrong in my assumptions there.

I do suspect my soldering of the volume pot because I can't see the rear connections very well. The legs did not align precisely with the holes, so I had to bend the legs somewhat. The rear legs do not protrude through the holes, so I may have a problem there.

I'll remove the pot and try to rejoin it to the board. Also, my afternoon is committed elsewhere, so I may not be able to fix this until tomorrow, when I have good light. I'll wire the pot to the board instead of soldering it directly. Then I can be sure my joints are good.

Will report back. Thanks again! Have a sunny day.
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 2 Apr 2010, 02:21 pm
I must admit that I didn't attend closely enough to know when this happened. As I said, it takes about a minute. In that time, I would listen for a short period, then shift my attention to something else and let the B1 break-in. So, I don't know which change caused the problem.

The B1 has two electrolytics, so I was thinking one per channel. In that case, I thought, an electrolytic could go bad and not affect the other channel. But, I know I could be wrong in my assumptions there.

I do suspect my soldering of the volume pot because I can't see the rear connections very well. The legs did not align precisely with the holes, so I had to bend the legs somewhat. The rear legs do not protrude through the holes, so I may have a problem there.

I'll remove the pot and try to rejoin it to the board. Also, my afternoon is committed elsewhere, so I may not be able to fix this until tomorrow, when I have good light. I'll wire the pot to the board instead of soldering it directly. Then I can be sure my joints are good.

Will report back. Thanks again! Have a sunny day.
It cannot be the electrolytics as they supply both channels, if it is a dodgy joint then something would have to get fairly hot for it to have an effect.

A Sunny Day? In England?? In Spring??? :lol: :lol:

Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 2 Apr 2010, 05:02 pm
Some electrolytics are polarized, and you could have one in backwards?  I did this once with a dac kit, and the backwards cap would get SUPER hot fairly quickly and then give out.  As soon as I installed it correctly everything worked like a champ.  Just a thought.

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 3 Apr 2010, 11:01 pm
Well, heat build-up could explain the problem, but everything stays cool. Plus, now the distortion is immediate. I did remove the pot and resoldered it with wire leads to assure that the connections are good.

Of the few things I know, I did get the electrolytics installed correctly by aligning the stripe on the cap to the stripe on the board.

Thanks, all. I may have blown a jfet. So I've been told. I wouldn't know and I don't have high confidence in my cheap DMM. Maybe too little confidence. Plus, it is hard for me to get a reliable check because I cannot hold the leads steadily enough. Nerve damage in my hands causes them to be too unsteady at this small scale.

Maybe I should just order a couple or four and get it over with. Well, get that part of the hunt over with.   :weights:
Title: Re: Nelson Pass B-1 preamp kit
Post by: xecluded on 4 Apr 2010, 04:34 am
What is the minimum voltage requirement for the (2) 10uf caps and (2) 1uf caps.  Would 63VDC be to low? 
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 4 Apr 2010, 05:41 pm
What is the minimum voltage requirement for the (2) 10uf caps and (2) 1uf caps.  Would 63VDC be to low?
No - more than adequate - the psu should be delivering no more than 18vdc.
Title: Re: Nelson Pass B-1 preamp kit
Post by: xecluded on 4 Apr 2010, 06:58 pm
Cool.  It's all done now.  Much easier than I thought and the best part is it works beautifully the first time i plugged it in.  This is my first built ever.  Many thanks everyone who helped to make this build happened.  :thumb: :eyebrows:
(http://)

(http://)


Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 5 Apr 2010, 08:14 pm
final build pics w/ enclosure on page 5...
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 5 Apr 2010, 08:15 pm
Cool.  It's all done now.  Much easier than I thought and the best part is it works beautifully the first time i plugged it in.  This is my first built ever.  Many thanks everyone who helped to make this build happened.  :thumb: :eyebrows:


Sexy!
Title: Re: Nelson Pass B-1 preamp kit
Post by: Mariusz on 5 Apr 2010, 08:46 pm
final build pics w/ enclosure on page 5...

Very nice.

Great project.

Hope that many guys will benefit from this build.


Mariusz  :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 7 Apr 2010, 05:20 pm
Grounding Question

I read it somewhere that you need to do chassis grounding.  From wushuliu's build pictures, I did not know if there is a "grounding" step in there.  If I plan to build the case using scrap MDF, how should I "ground" it?
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 7 Apr 2010, 05:25 pm
Grounding Question

I read it somewhere that you need to do chassis grounding.  From wushuliu's build pictures, I did not know if there is a "grounding" step in there.  If I plan to build the case using scrap MDF, how should I "ground" it?
The short answer is - you cannot! However if you want to shield the buffer you could spray the insides with a metal paint designed for RFI.
However I have run my B1 open - sitting on a block of wood - no problems.
I do remember that some people on DIYAudio had suggested that the grounding on the board is not optimal and that tracks could be cut and everything wired to the -ve on the psu cap. This again I have not done.
So another short answer - dont worry about it!
Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 7 Apr 2010, 05:36 pm
That's certainly great to hear.  I read someone is hearing "hum" and they suspect it's grounding issue.  However, what if I line sheet metal at the bottom of the chasis - would I be able to ground it in this case? if so how?

The short answer is - you cannot! However if you want to shield the buffer you could spray the insides with a metal paint designed for RFI.
However I have run my B1 open - sitting on a block of wood - no problems.
I do remember that some people on DIYAudio had suggested that the grounding on the board is not optimal and that tracks could be cut and everything wired to the -ve on the psu cap. This again I have not done.
So another short answer - dont worry about it!
Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 7 Apr 2010, 05:44 pm
That's certainly great to hear.  I read someone is hearing "hum" and they suspect it's grounding issue.  However, what if I line sheet metal at the bottom of the chasis - would I be able to ground it in this case? if so how?
I do not think that you will get hum - try the buffer first.

Are the people reporting the hum using the Nelson Pass boards or the Ebay ones?

I know of no problems with the NP boards.

Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 9 Apr 2010, 10:46 pm
wushuliu,

Would you mind sharing where you got the enclosure?  (the only thing not on your BOM  :D)

How did you drill the holes?

Thanks!

Power supply Caps.


Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 9 Apr 2010, 11:12 pm
wushuliu,

Would you mind sharing where you got the enclosure?  (the only thing not on your BOM  :D)

How did you drill the holes?

Thanks!

From seller 'Tedss' on ebay. Search under Pactec. For the holes I just used my drill with a 3/8" wood boring bit for the volume pots and rca's. Regular 1/4" bit for the switch and power supply. My enclosure skills are pretty weak and I'm too impatient (and broke!) to get any fancier.

hth
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 10 Apr 2010, 03:16 am
That helps.  Another question: is there any benefit of using two volume pots? 

Hate to answer my own question - I just figured if I use Stereo volume I only need one.  ;)

From seller 'Tedss' on ebay. Search under Pactec. For the holes I just used my drill with a 3/8" wood boring bit for the volume pots and rca's. Regular 1/4" bit for the switch and power supply. My enclosure skills are pretty weak and I'm too impatient (and broke!) to get any fancier.

hth
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 10 Apr 2010, 03:32 am
The wall wart has a lead time until 6/1/2010.  Any other option over digi-key?

wall wart
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=T987-P5P-ND
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 10 Apr 2010, 04:58 am
The wall wart has a lead time until 6/1/2010.  Any other option over digi-key?

wall wart
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=T987-P5P-ND

here you go!

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=T986-P5P-ND (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=T986-P5P-ND)

Title: Re: Nelson Pass B-1 preamp kit
Post by: xecluded on 10 Apr 2010, 04:59 am
I am running my B-1 without any 1uf bypass cap. Does it hurt anything and which cap does it bypass. 
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 10 Apr 2010, 05:08 am
I am running my B-1 without any 1uf bypass cap. Does it hurt anything and which cap does it bypass.

It bypasses the power supply, and no I don't believe it's absence causes harm.
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 10 Apr 2010, 01:59 pm
here you go!

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=T986-P5P-ND (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=T986-P5P-ND)
Thanks!
I am amazed on how fast you can find another one.  All parameters on the Digi-Key is like crypto.  Any advises on how to decipher them?
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 10 Apr 2010, 05:51 pm
Thanks!
I am amazed on how fast you can find another one.  All parameters on the Digi-Key is like crypto.  Any advises on how to decipher them?

I just use the search function, never the directory. I just type in 'potentiometer' or 'switch' or 'capacitor', etc. and go from there. Practice makes perfect. And I have had a LOT of practice.
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 10 Apr 2010, 11:03 pm
I just use the search function, never the directory. I just type in 'potentiometer' or 'switch' or 'capacitor', etc. and go from there. Practice makes perfect. And I have had a LOT of practice.

Quick question, why choose output of 6A? 
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 10 Apr 2010, 11:31 pm
Quick question, why choose output of 6A?

Do you mean 6W? the wall wart has .33A...
Title: Re: Nelson Pass B-1 preamp kit
Post by: Mariusz on 10 Apr 2010, 11:40 pm
Hi Wushu
A quick thank you
Recieved the package
looks great
Will try it early next week

Awesome job :thumb:

Best
Mariusz :)
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 11 Apr 2010, 12:50 am
My bad, yes 6W.  My challenge in Digi-Key has been how do I know it's 6W, not 4W or something else.

Do you mean 6W? the wall wart has .33A...
Title: Re: Nelson Pass B-1 preamp kit
Post by: xecluded on 11 Apr 2010, 10:10 am
It bypasses the power supply, and no I don't believe it's absence causes harm.
Thanks.  I will put in a bypass cap when i have a chance to monkey with it.  It sounds so good that i did not feel like doing anything.

Would using battery power improve the sound even more.  If it is, i may build another one with battery power.  Not that i need anymore preamp but for the cost of putting one together, i can hardly go wrong  :green:
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 11 Apr 2010, 05:51 pm
Thanks.  I will put in a bypass cap when i have a chance to monkey with it.  It sounds so good that i did not feel like doing anything.

Would using battery power improve the sound even more.  If it is, i may build another one with battery power.  Not that i need anymore preamp but for the cost of putting one together, i can hardly go wrong  :green:

Some people on Diyaudio think battery power sounds better. If you could build one and compare that would be great!
Title: Re: Nelson Pass B-1 preamp kit
Post by: xecluded on 11 Apr 2010, 05:54 pm
Some people on Diyaudio think battery power sounds better. If you could build one and compare that would be great!
Great idea.  I will do it if you would show me how to connect it with SLA battery instead of those 9V batteries.  :green:
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 13 Apr 2010, 03:18 am
I want to buy this volume pot suggested by wushuliu

Ebay DACT-Type Stepped Attenuator - $15 shipped
Even better AND cheaper
You can find values for 20k and higher. These are frickin' great for the money.

http://cgi.ebay.com/DACT-Type-21-Stepped-Attenuator-Volume-20K-for-PreAmp_W0QQitemZ200437532132QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item2eab0205e4#ht_1476wt_1202

Could you suggest a knob that would fit this through Digi-Key? What are the key filters that would ensure the knob will fit the pot?  (I can do the search, just need to know the right filters.)

Thanks!
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 13 Apr 2010, 04:38 am
Thanks for mentioning this. Since using them I have learned there is one caveat: as they only have 21 steps and are in fact linear I believe, there is a larger volume increase from step to step - it's not a 'smooth' increase in volume. So unless you're familiar w/ these kind of pots, I would recommend getting the Alps pot or similar from the Partsconnexion link. There are knobs for them on ebay. just search 'alps knob'.


 
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 13 Apr 2010, 03:21 pm
I am definitely not familiar into this and I was surprised to learn that volume pot could cost $300.  Geez.. Learn something new everyday.

Would this Apls work? http://www.partsconnexion.com/product7387.html (http://www.partsconnexion.com/product7387.html) 100K

How do you tell whether it is linear or not?  Would this one work better?

http://www.partsconnexion.com/product7386.html (http://www.partsconnexion.com/product7386.html)  250K

I don't know what makes the 100K and 250K different.

Thanks for mentioning this. Since using them I have learned there is one caveat: as they only have 21 steps and are in fact linear I believe, there is a larger volume increase from step to step - it's not a 'smooth' increase in volume. So unless you're familiar w/ these kind of pots, I would recommend getting the Alps pot or similar from the Partsconnexion link. There are knobs for them on ebay. just search 'alps knob'.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 13 Apr 2010, 04:01 pm
I am definitely not familiar into this and I was surprised to learn that volume pot could cost $300.  Geez.. Learn something new everyday.

Would this Apls work? http://www.partsconnexion.com/product7387.html (http://www.partsconnexion.com/product7387.html) 100K

How do you tell whether it is linear or not?  Would this one work better?

http://www.partsconnexion.com/product7386.html (http://www.partsconnexion.com/product7386.html)  250K

I don't know what makes the 100K and 250K different.

Go for the 50k...
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 13 Apr 2010, 04:11 pm
Go for the 50k...

I think the cost from Partsconnex is expensive adding handling and shipping fee.  I'll look for eBay...
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 13 Apr 2010, 07:27 pm
I think the cost from Partsconnex is expensive adding handling and shipping fee.  I'll look for eBay...

Yeah, but it's a 'safe' option if you're not experienced w/ using potentiometers. The problem w/ ebay is there are a LOT of fake Alps pots out there (like anything from HK/China probably), and the first link I had actually I think may be fake so I deleted it. If you feel confident in your soldering skills I can give you a link to the VERY cheap ($3?) Panasonic EVJ pots on digikey - they are very good for the money, they just don't have too much wiggle room to solder the wire...


(http://www.audiocircle.com/image.php?id=28975)


oh dear, AC's very flexible upload size can be a blessing and a curse. sorry!
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 13 Apr 2010, 07:34 pm
No, I'd not bet my solder skill to be good. ;)

How about this one from PE:

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=023-650

The shaft might be too short and I am not sure about its quality.  They have 25K too.

Yeah, but it's a 'safe' option if you're not experienced w/ using potentiometers. The problem w/ ebay is there are a LOT of fake Alps pots out there (like anything from HK/China probably), and the first link I had actually I think may be fake so I deleted it. If you feel confident in your soldering skills I can give you a link to the VERY cheap ($3?) Panasonic EVJ pots on digikey - they are very good for the money, they just don't have too much wiggle room to solder the wire...

Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 13 Apr 2010, 07:45 pm
No, I'd not bet my solder skill to be good. ;)

How about this one from PE:

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=023-650

The shaft might be too short and I am not sure about its quality.  They have 25K too.

Here you go: Amb is a good site.

http://www.amb.org/shop/ (http://www.amb.org/shop/)

The Alps 50k is listed near the bottom, just scroll down. $16 bucks and I think he
does regular usps.
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 13 Apr 2010, 07:57 pm
Wow, very impressive on finding this.  I know AMB and have one of their DAC.  Now off to find a volume knob, probably from AMB if they also have one. 

Here you go: Amb is a good site.

http://www.amb.org/shop/ (http://www.amb.org/shop/)

The Alps 50k is listed near the bottom, just scroll down. $16 bucks and I think he
does regular usps.
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 14 Apr 2010, 09:38 pm
I want to buy this volume pot suggested by wushuliu

Ebay DACT-Type Stepped Attenuator - $15 shipped
Even better AND cheaper
You can find values for 20k and higher. These are frickin' great for the money.

http://cgi.ebay.com/DACT-Type-21-Stepped-Attenuator-Volume-20K-for-PreAmp_W0QQitemZ200437532132QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item2eab0205e4#ht_1476wt_1202

Could you suggest a knob that would fit this through Digi-Key? What are the key filters that would ensure the knob will fit the pot?  (I can do the search, just need to know the right filters.)

Thanks!

I browsed through the DIY Audio forum and found a digikey link for a knob that VERY closely matches older Nelson Pass gear knobs.  I ordered one, and it fits on the stepped potentiometer that I got via Ebay from Valab... not sure if it would fit the one you are considering.

Here is the digikey link:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=226-3016-ND

Hope this helps.

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: whoaru99 on 16 Apr 2010, 12:49 pm
Anyone tried these Carli caps in the B1 for C101/C201?   http://www.madisound.com/manufacturers/carli/index.php

Also, I'm looking at these pots from DigiKey.   http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=381N503-ND

Thoughts on either/both?
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 16 Apr 2010, 04:07 pm
Anyone tried these Carli caps in the B1 for C101/C201?   http://www.madisound.com/manufacturers/carli/index.php

Also, I'm looking at these pots from DigiKey.   http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=381N503-ND

Thoughts on either/both?

Those are polyester caps. Perfectly usable, but as a general rule are considered inferior to polypropylene caps. Given the simplicity of the B1 design (and thus the greater influence of cap choice to sound quality), I would not recommend them.

Don't know anything about the Honeywell. The PEC pot recommended in the BOM are well regarded, and were used by Nelson for the retail B1.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 16 Apr 2010, 04:19 pm
I browsed through the DIY Audio forum and found a digikey link for a knob that VERY closely matches older Nelson Pass gear knobs.  I ordered one, and it fits on the stepped potentiometer that I got via Ebay from Valab... not sure if it would fit the one you are considering.

Here is the digikey link:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=226-3016-ND

Hope this helps.

Neil

Very cool! Thanks Neil...
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 20 Apr 2010, 02:33 am
Quick question on soldering PCB board.

When I solder crossover components, I'll use arligator clips as heat sinks to protect the capacitors.  I haven't seen people use this practice when soldering components onto a PCB board.  Is that b/c it's easier to heat up at PCB?

The idea should be similar so you heat up the joint and let the joint melt the solder, not the soldering iron, right?
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 20 Apr 2010, 05:55 am
Quick question on soldering PCB board.

When I solder crossover components, I'll use arligator clips as heat sinks to protect the capacitors.  I haven't seen people use this practice when soldering components onto a PCB board.  Is that b/c it's easier to heat up at PCB?

The idea should be similar so you heat up the joint and let the joint melt the solder, not the soldering iron, right?

No, there should be no need for alligator clips at all. Yes, the heated joint melts the solder. Eutectic solder is best like the Cardas I linked in the BOM or Kester 60/40, etc. as they melt very easily. Regardless of what solder, clips should not be necessary for this application.

hth
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 20 Apr 2010, 07:32 pm
How did you mount the power jack?  From the picture, you seem to use glue to fix it and leave a small hole for external plug in.  How big the hole it is, like 1/4"?
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 21 Apr 2010, 03:31 am
How did you mount the power jack?  From the picture, you seem to use glue to fix it and leave a small hole for external plug in.  How big the hole it is, like 1/4"?

Hot glue and 1/4" hole...
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 22 Apr 2010, 12:53 am
Any suggested place to source interconnect cables?  I never though I'd need these but with the preamp, I need one more set. ;)

The wires from Apex Jr are excellent!
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 22 Apr 2010, 01:18 am
Any suggested place to source interconnect cables?  I never though I'd need these but with the preamp, I need one more set. ;)

The wires from Apex Jr are excellent!

alas, I roll my own interconnects, so I don't really have a recommendation for anything retail.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Mariusz on 22 Apr 2010, 01:36 am
I have one question:

- what would be the single, most influential (sound characteristic wise) part in this circuit ?


Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 22 Apr 2010, 01:49 am
alas, I roll my own interconnects, so I don't really have a recommendation for anything retail.

How did you do that?  Could I use regular wires and put them in plugs?  I bought quite some 20 awg apex jr wires and that would be a fantastic idea if I can use these to make interconnects.  Where to source RCA plugs?
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 22 Apr 2010, 07:05 pm
Question about the input switch.  How do we know which lug is right and which lug is left output? Which side is source 1 and which one is source 2?  Or it doesn't matter as long as I am consistent with L and R - like all Ls on one row and all Rs on one row?

Btw, for the Alps Pot, is the G O I the same layout as PEC pot?  like from left to right, G -> O -> I when the shafe facing me.

Thx!

Now we'll take on the input switch.

(http://www.audiocircle.com/image.php?id=27540)

We have a DPDT for 2 source inputs. It has 6 solder lugs as you can see. The center two are the L/R outputs. The outer two are Source 1 L/R and Source 2 L/R. Hopefully the pics convey what goes where easily.

Source 1 Right

(http://www.audiocircle.com/image.php?id=27541)

Source 1 Left

(http://www.audiocircle.com/image.php?id=27542)


Now into the appropriate holes

(http://www.audiocircle.com/image.php?id=27543)

As you can guess, the center two will go the middle, and the Source 2 L/R will be soldered to the bottom two on the board.

(http://www.audiocircle.com/image.php?id=27544)


That's it for today. The Digikey stuff comes in tomorrow (I used spare resistors for this build), and I'll continue then.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 22 Apr 2010, 08:26 pm
Or it doesn't matter as long as I am consistent with L and R - like all Ls on one row and all Rs on one row?
Thx!

correct

Btw, for the Alps Pot, is the G O I the same layout as PEC pot?  like from left to right, G -> O -> I when the shafe facing me.

Thx!


(http://www.audiocircle.com/image.php?id=29366)
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 22 Apr 2010, 09:18 pm
correct


(http://www.audiocircle.com/image.php?id=29366)

Thanks!!!!!!!
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 22 Apr 2010, 11:33 pm
I have one question:

- what would be the single, most influential (sound characteristic wise) part in this circuit ?

whoa, sorry Mariusz I totally missed your post. I would say the input/output caps, followed by the 1k output resistors. A good test for flavoring would be the 2 1uf input caps. I was tempted to ask you what kind of tonality you prefer, lean/neutral or warm/neutral and then swap in (hopefully) appropriate caps/resistors but I figured I would KISS and just go straight no chaser.

My guess is your B1 would be sounding on the lean, clinical side? Maybe a little forward with the dale resistors. I have found Claritycaps to smooth things out, add warmth and some space.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Mariusz on 22 Apr 2010, 11:51 pm
Got ya. 
Planing to roll some caps just for fun and personal curiosity.
Thanks again Wusu.

Cheers
Mariusz  :wink:
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 23 Apr 2010, 04:36 am
"Hum..."  Ground Noise?

So I hook it up tonight.  It works!  However, the right channel has big "hum" sound.  I put the board open.  No boxes, laying on the carpet.  Interesting enough, when I touched the power caps - the hum lowered or disappeared.  When I lift the board, the hum sound would decrease.  When my hand touching the back of the board, resistors and JEFTs, left channel will have hum sound and noise will increase. 

Not sure what to do.  Any advises are appreciated!
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 23 Apr 2010, 04:42 am
How did you do that?  Could I use regular wires and put them in plugs?  I bought quite some 20 awg apex jr wires and that would be a fantastic idea if I can use these to make interconnects.  Where to source RCA plugs?

If the apex jr wire is stranded, then sure why not. But don't you have a couple different projects on your plate right now?  :lol:
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 23 Apr 2010, 04:45 am
"Hum..."  Ground Noise?

So I hook it up tonight.  It works!  However, the right channel has big "hum" sound.  I put the board open.  No boxes, laying on the carpet.  Interesting enough, when I touched the power caps - the hum lowered or disappeared.  When I lift the board, the hum sound would decrease.  When my hand touching the back of the board, resistors and JEFTs, left channel will have hum sound and noise will increase. 

Not sure what to do.  Any advises are appreciated!

? just laying on the carpet? How about getting it on a proper surface of some kind instead of static-y carpet and pics are always a big big plus...
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 23 Apr 2010, 12:49 pm
? just laying on the carpet? How about getting it on a proper surface of some kind instead of static-y carpet and pics are always a big big plus...

Carpet is static-y oh- So that's the same reason with my hands I guess.  I put them on a MDF and had similar results but that could be twisted when I move the board around.  I'll check all the joints again and post pictures.  I think I have very bad soldering skill too.
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 23 Apr 2010, 02:10 pm
So I rechecked all solder joints and fixed some - the situation is the same.  I put the board on a MDF and lift it so no direct contacts with the board from the bottom (picture below) - no changes.

The situation is now like this:  When I hook it up (Class D amp), I turn the volume to minimum, input switch to the correct input (either 1 or 2), and there will be "Buzz or Hums" from the right channel.  When I turn the volume to maximum, "Buzz and Hums" will come out from both channels.  If I touch the bottom of the left most resistor, there will be big hum/buzz from the left channel (regardless of whether there is input signal or not).

When music is coming from Input 1 and I set the input switch to "Middle" or "input 2", if I turn the volume all the way to maximum, I can hear the music playing in low volume along with big hum/buzz.  I feel like the sound is "leaking".  Is that normal?

I added the LED and it is working correctly - it will light up when the power is on.

(http://www.audiocircle.com/image.php?id=29379)

(http://www.audiocircle.com/image.php?id=29380)

(http://www.audiocircle.com/image.php?id=29381)
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 23 Apr 2010, 04:39 pm
So I rechecked all solder joints and fixed some - the situation is the same.  I put the board on a MDF and lift it so no direct contacts with the board from the bottom (picture below) - no changes.

The situation is now like this:  When I hook it up (Class D amp), I turn the volume to minimum, input switch to the correct input (either 1 or 2), and there will be "Buzz or Hums" from the right channel.  When I turn the volume to maximum, "Buzz and Hums" will come out from both channels.  If I touch the bottom of the left most resistor, there will be big hum/buzz from the left channel (regardless of whether there is input signal or not).

When music is coming from Input 1 and I set the input switch to "Middle" or "input 2", if I turn the volume all the way to maximum, I can hear the music playing in low volume along with big hum/buzz.  I feel like the sound is "leaking".  Is that normal?


The middle position for the switch should be 'off' so there should be no noise/sound at all. My guess is the switch/pot wiring is off. Could you take a closer pic or draw a diagram of how you wired the switch and alps?
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 23 Apr 2010, 10:36 pm
My half-pence... I am glad and grateful this thread continues to add technical info. I will be building a PassDIY B1 soon, having slaughtered a Chinese board. My bad. No pictures will be forthcoming.   :oops:

Sondale helped me a lot and now I'm on track, I think, to a great pre. It's that kind of assistance that creates a good feeling for this hobby.  :thumb:

Tried to order the Pass board today, but found that the DIY site was down. Seems it was hacked to install malware on visitors' PC's. You might want to check your machine.

 
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 24 Apr 2010, 06:14 pm
Well, the verdict is in.  It's the ground issue.  I put the PCB in inside an old DVD player (metal enclosure) and did a chassis ground from four corners of the PCB.  The noise disappeared.  So my plan of using a MDF box is gone.  Need to find a alumninum enclosure.  This design will attract lots of noise without enclosure / shielding / grounding.  To be safe, metal enclosure is the way to go.  So what would be an economical alumninum enclosure? :)

The middle position for the switch should be 'off' so there should be no noise/sound at all. My guess is the switch/pot wiring is off. Could you take a closer pic or draw a diagram of how you wired the switch and alps?
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 25 Apr 2010, 12:43 am
RCA Jacks.

I bought RCA jacks from Parts Express.  I found out that my jacks are not shielded from the chassis. 

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=090-278

However, since the touching part of the RCA jacks to the chassis are grounds, it should be better that way.  Right?

Thx!
Title: Re: Nelson Pass B-1 preamp kit
Post by: avionic on 25 Apr 2010, 03:55 am

(http://www.audiocircle.com/image.php?id=29452)


  Finally got my b1 up and running in a temporary enclosure. I can't believe how good this sounds. I am using cheap pots from radio shack until the stepped dact type attenuator gets here. Even so the sound is fantastic and dead silent. Many thanks to Wushuliu for starting this thread and all the work including the parts list. Also thanks to Mr. Pass for bringing this to the DIY community. I can't wait to get the attenuator and permanent enclosure and finish this up. Just a heads up for those that are going to use only one source. The inputs can be jumpered as I did so you don't have to buy a switch and wire it up.
   Thanks again everyone  :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 25 Apr 2010, 03:57 am
What enclosure would you use?

(http://www.audiocircle.com/image.php?id=29452)


  Finally got my b1 up and running in a temporary enclosure. I can't believe how good this sounds. I am using cheap pots from radio shack until the stepped dact type attenuator gets here. Even so the sound is fantastic and dead silent. Many thanks to Wushuliu for starting this thread and all the work including the parts list. Also thanks to Mr. Pass for bringing this to the DIY community. I can't wait to get the attenuator and permanent enclosure and finish this up. Just a heads up for those that are going to use only one source. The inputs can be jumpered as I did so you don't have to buy a switch and wire it up.
   Thanks again everyone  :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: avionic on 25 Apr 2010, 04:03 am
 Still looking for the enclosure Parodielin. I may end up making one myself. There is a place online that sells aluminum sheet up to an inch thick and they will cut to size.
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 25 Apr 2010, 04:05 am
Still looking for the enclosure Parodielin. I may end up making one myself. There is a place online that sells aluminum sheet up to an inch thick and they will cut to size.

Where is it?  How much will they charge?  I am eyeing on a Hammond chassis + bottom (1441-24BK3) around $45 shipped. 
Title: Re: Nelson Pass B-1 preamp kit
Post by: avionic on 25 Apr 2010, 04:08 am
  Let me see if I can find the place and then post a link. I have a hard time finding it on my home computer but it pops right up at work. Different search engine I guess.
    Found it      http://www.onlinemetalstore.com/
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 25 Apr 2010, 04:21 am
  Let me see if I can find the place and then post a link. I have a hard time finding it on my home computer but it pops right up at work. Different search engine I guess.
    Found it      http://www.onlinemetalstore.com/

Glad to know such store exists.  Do you need to order six sheets and put them together as a box? 
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 4 May 2010, 03:21 am
So I used a Hammond Chassis.  Magically - all noise are gone and the match with Class D is like heaven.  The combination clearly trump my old HK 635.  Wow - I never thought a preamp would make such a big difference.  The noise almost killed my confidence.  Hey the simple metal box and proper grounding solve all previous issues.  It's dead silent, crystal clear and the image is huge.

Thanks wushuliu for suggesting such a nice preamp.  Love it!!!
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 4 May 2010, 04:25 am
So I used a Hammond Chassis.  Magically - all noise are gone and the match with Class D is like heaven.  The combination clearly trump my old HK 635.  Wow - I never thought a preamp would make such a big difference.  The noise almost killed my confidence.  Hey the simple metal box and proper grounding solve all previous issues.  It's dead silent, crystal clear and the image is huge.

Thanks wushuliu for suggesting such a nice preamp.  Love it!!!


 8) :eyebrows: :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 4 May 2010, 04:47 am
Really, I am very very impressed of the combination of B1 and Class D.  Unbelievable...  I have client work tomorrow and I am still listening to the music.

Now tell me what to upgrade on DAC!!!


 8) :eyebrows: :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 4 May 2010, 03:41 pm
VERY encouraging!  I've been trying to combine the China based Pass board with a Class D amp in the same chassis for a while now with no luck.  One channel of the China board won't work, and the one channel that does kept giving me hum issues... so I've finally given up on the combo and have ordered a real Pass board, all the necessary parts, and a dedicated chassis.  Glad to hear that this combo is a winner.  In the mean time, I am enjoying the Class D amp, which IMHO is a genuine bargain and an awesome performer.

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: avionic on 4 May 2010, 04:55 pm
I spent the $15.00 to buy 2 sets of 9volt batts and the terminals from radio shack just to try the pass b1 on battery power. It is more clean and clear than run off the small plug in power supply.
   I have been listening for 3 days now on the same batteries. Very impressive for the small investment.
Title: Re: Nelson Pass B-1 preamp kit
Post by: 1MOR on 10 May 2010, 02:53 am
N.P.  states that "...D2 is a generic LED for indicating power...".  I see that LEDs are available with different voltage ratings.  Does N.P. indicate that any LED would be appropriate for use?  I have a few blue LEDs rated for 24 volts.  Would those work in the B1?
Title: Re: Nelson Pass B-1 preamp kit
Post by: 1MOR on 11 May 2010, 11:17 pm
So no one used a LED?
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 11 May 2010, 11:23 pm
So no one used a LED?

Your 24v LEDs will be fine...
Title: Re: Nelson Pass B-1 preamp kit
Post by: 1MOR on 12 May 2010, 01:53 am
Thanks wushuliu! 

Pass boards and chips are here, Obligato caps are somewhere between HK and here, I hope, and Digikey has shipped.  Hope to get started soon!
Title: Re: Nelson Pass B-1 preamp kit
Post by: HAL on 16 May 2010, 02:48 pm
Ok, today is B1 solder day.  Need to go to RS and get the input channel selector switch.  The 100K Alps Blue Velvet pot is here, but need a chassis at some point.

Just ordered a pair of Li Ion rechargable 9V batteries and matching battery charger. They should last 20-30 hours on a charge and should be good for 700 charges.  That should be good for awhile. 

Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 16 May 2010, 05:42 pm
Ok, today is B1 solder day.  Need to go to RS and get the input channel selector switch.  The 100K Alps Blue Velvet pot is here, but need a chassis at some point.

Just ordered a pair of Li Ion rechargable 9V batteries and matching battery charger. They should last 20-30 hours on a charge and should be good for 700 charges.  That should be good for awhile.

keep us posted and post pics when yer done!
Title: Re: Nelson Pass B-1 preamp kit
Post by: HAL on 17 May 2010, 08:10 pm
Here are the pictures of the Pass DIY B1 Buffer kit in an old DIY preamp chassis that I had available. 


(http://www.audiocircle.com/image.php?id=30522)


(http://www.audiocircle.com/image.php?id=30523)


(http://www.audiocircle.com/image.php?id=30524)



(http://www.audiocircle.com/image.php?id=30525)


The batteries are Li Ion Rechargeables.  Charging them now for use this evening! :)
Title: Re: Nelson Pass B-1 preamp kit
Post by: grubyhalo on 18 May 2010, 07:07 am
Neat!  :)
Title: Re: Nelson Pass B-1 preamp kit
Post by: HAL on 18 May 2010, 12:51 pm
Thanks!

Have to swap the volume pot leads on the left channel.  I wired it backwards and have a great balance control instead of a volume control.  DOH!  :duh:

Will rewire it today and have some fun.  :)
Title: Re: Nelson Pass B-1 preamp kit
Post by: HAL on 18 May 2010, 02:08 pm
Ok, the B1 is rewired and sounding very good!   :thumb:

The setup is my Gateway MP8708 laptop with Foobar 2000 driving a Musiland Monitor 01 Mini 24bit/192KHz Asynchronous DAC via kernel streaming mode and the HDCD DSP plug-in.  This drives the B1, which drives an AV123 X-Head HPA for my Sennheiser HD-650 phones.

This is my favorite way to check out equipment as you hear any noise or distortion easily over phone.

Music is the Reference Recordings HRx 24bit/176.4KHz of Exotic Dances.  This is a very nice recording!

Frequency response and dynamic range are outstanding with this setup.   I like what I am hearing so far and will give it some time for burn-in.  Then off to the ssytem.  :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: jtwrace on 18 May 2010, 02:09 pm
HAL

You're building one of these as well?  I'll look forward to your comparison between this and the other buffer.
Title: Re: Nelson Pass B-1 preamp kit
Post by: HAL on 18 May 2010, 02:18 pm
I have had the B1 kit for about 2 years and wanted something until the Dodd battery buffer arrives and is built.   My Dodd battery preamp has to much gain for the setup so a buffer is a very good way to go. 

Tonight will be the battery DAC driving the battery B1 driving the battery PA for the Super-V's!  This should be interesting! :)
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 19 May 2010, 12:56 am
I have had the B1 kit for about 2 years and wanted something until the Dodd battery buffer arrives and is built.   My Dodd battery preamp has to much gain for the setup so a buffer is a very good way to go. 

Tonight will be the battery DAC driving the battery B1 driving the battery PA for the Super-V's!  This should be interesting! :)

Do you have a wall wart to compare battery B1 vs. regular? I think I may test that out tonight.

And for the record, if I have to read another 100+ page thread on diyaudio just to build a project my brain will explode. After 2 years I am DONE.
 :shake:
Title: Re: Nelson Pass B-1 preamp kit
Post by: Lyndon on 19 May 2010, 01:28 am
Wushuliu said:
Quote
And for the record, if I have to read another 100+ page thread on diyaudio just to build a project my brain will explode. After 2 years I am DONE.
 :shake:

I hear ya!  I am waiting, waiting, waiting for those Pearl 2 boards to drop.  Gots' to have my Pass Phono!
Lyndon
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 19 May 2010, 04:58 pm
Gave a couple things a whirl last night with the B1.

1. Battery power does have a very smooth delivery and lower noise. Not sure if it was enough
   of an improvement for me to invest in batteries at this time, because I have several AC filter tweaks in place in my system already. For those who don't I think it's worth people's time to give them a listen  on batteries. Also, some people have reported liking the way it sounds with only 9v as opposed to 18v, 24v, etc. So there is room for experimentation. I may order a 9v wallwart for kicks.

2. My B1 pcb is actually the one that was sold on ebay (I consider this tutorial my 'penance'). So my fets were regular unmatched from Mouser. Last night I swapped in some matched fets I got from diyaudio. Oops, such have done this sooner! I guess Nelson selling them w/ his boards should have been a hint :lol: I do believe the B1 performs much better. More coherent, lower noise. Smoother, cleaner. So for those of you who did not get matched fets, I recommend it.

3. Output cap size. I threw in 22ufs for kicks just to hear. Little swollen in the low frequencies, but
still sounds good. I have some russian 10uf K73-16 dry polyester caps coming so we'll see how those stack up.

bottom line is there is much to experiment with with the B1.

end o' report


 
Title: Re: Nelson Pass B-1 preamp kit
Post by: HAL on 19 May 2010, 07:32 pm
Do you have a wall wart to compare battery B1 vs. regular? I think I may test that out tonight.

And for the record, if I have to read another 100+ page thread on diyaudio just to build a project my brain will explode. After 2 years I am DONE.
 :shake:

No 9V wall wart, but could always jumper one battery holder to run off a single 9V battery.

The kit here was from Nelson Pass with the matched JFETs. 
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 20 May 2010, 07:07 am
Well I pulled out the 22ufs. They were too bloated, but hey it was worth a try. I dropped in the 10uf Russian PETP caps that arrived today, and what can I say, I think they sound pretty. freakin'. good. Right off the bat. Not what I was expecting. They're kind of sweet, good detail. Tingly. My B1 has never sounded better. I think it's mainly due to the matched fets and my AC choke filters, those really improved the performance several notches.

I was going to build the DC Coupled B1 on diyaudio next because it's supposed to be better, but I like what I hear so much now I think I'll call it a day. My tweaks on this 'r done. :smoke:


(http://www.audiocircle.com/image.php?id=30625)




 
Title: Re: Nelson Pass B-1 preamp kit
Post by: bigaudioscotto on 22 May 2010, 05:21 pm
 Hey Walkern
 Did you try the sub out hookup on B1,and did it work.
   Thanks Scott
Someone asked Nelson Pass this question at the DIY forum and his reply seemed to indicate that all you'd need to do is connect the second set of outputs parallel with the first, and you'd be good to go.  I'm intending to do this myself, (although it may be a little while... I haven't even stuffed my board yet) so I'll let you know if it works.

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 22 May 2010, 05:27 pm
Quote
    My tweaks on this 'r done. 

Ya right! :eyebrows:

Good work, i am using some russian pio's with excellent results also.
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 25 May 2010, 09:35 pm
Hey Walkern
 Did you try the sub out hookup on B1,and did it work.
   Thanks Scott

Just finished drilling all the chassis holes for my B1... and I've got the board stuffed, so am ready to begin making input and output connections... but it was so hot and sticky in the garage yesterday (my one day off per week) that I couldn't bring myself to solder anything!

I'll keep you posted.  Theoretically though, it should work just fine.  The unit should drive an amp in a subwoofer just as easily as any other power amp.  Fingers crossed.

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: 1MOR on 26 May 2010, 04:51 am
Finished the board and doing front and rear panel layouts.  I should be making chips and mounting pots and jacks by the weekend. 

(http://img88.imageshack.us/img88/2458/fna2andpassb1buffer004.jpg)

(http://img62.imageshack.us/img62/2509/fna2andpassb1buffer013.jpg)

(http://img163.imageshack.us/img163/1557/fna2andpassb1buffer002.jpg)

(http://img96.imageshack.us/img96/4449/fna2andpassb1buffer043.jpg)

Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 27 May 2010, 11:35 pm
Will using a high end stepped attenuator like the Elma/Goldpoint or DACT CT2 in the B1 buffer result in superior sonics as compared to the recommended ALPs blue velvet 25k stereo pot?

I'd rather not tear up my Goldpoint passive if I don't have to...  :icon_lol:

Anyone know?
Title: Re: Nelson Pass B-1 preamp kit
Post by: poseidonsvoice on 30 May 2010, 12:48 pm
For those interested I have a pair of partially built Nelson Pass B1 boards with matched Jfets, Mundorf and Obbligato capacitors, and Caddock MK132 resistors with an uber power supply for sale here (http://www.audiocircle.com/index.php?topic=81874.0).

Sorry about intruding on the thread, just thought somebody could grab a good deal.

Anand.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 30 May 2010, 06:04 pm
Will using a high end stepped attenuator like the Elma/Goldpoint or DACT CT2 in the B1 buffer result in superior sonics as compared to the recommended ALPs blue velvet 25k stereo pot?

I'd rather not tear up my Goldpoint passive if I don't have to...  :icon_lol:

Anyone know?

Hi Roy, yes, probably. The B1 does not negate the performance of a volume pot. So the better pot, the better it will sound.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 30 May 2010, 06:22 pm
Thanks AC,appreciate the answer.  I assume the need for the buffer is to match with the very low input impedance of the Class D CDA series amps?   :scratch:
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 30 May 2010, 06:34 pm
Thanks AC,appreciate the answer.  I assume the need for the buffer is to match with the very low input impedance of the Class D CDA series amps?   :scratch:

While presenting high impedance to a source, yes. Ideally. For any amp for that matter. Or it could be you need a pre with different inputs. Or both. Some also feel that an active preamp sounds better than passive. From what I've read there's no cut and dry answer. The Class D amp doesn't need the B1.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 30 May 2010, 06:41 pm
My Elma 20K stepped attenuator seems to work great with my amplifier of about 50K input impedance.  So I'm assuming that the SDS series amps (47K) would be a better match for my passive than the CDA series amp with their 7K input impedance.  Am I right about that?
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 30 May 2010, 07:09 pm
My Elma 20K stepped attenuator seems to work great with my amplifier of about 50K input impedance.  So I'm assuming that the SDS series amps (47K) would be a better match for my passive than the CDA series amp with their 7K input impedance.  Am I right about that?

Yes, it would be a better match.
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 1 Jun 2010, 10:30 pm
Finished my B-1 today, and it is working like a champ.  Went with all the "standard" parts including dual PEC volume controls (not sure if I'll like that, but I do appreciate having a balance control of sorts).  And I set mine up with two outputs, one for my main amp (Class D) and another for my sub amp (Rhythmic) and both outputs work just fine together... no hum issues or noise... and plenty of drive. 

I installed everything in as small a chassis as I could, and I wouldn't do that if I was starting again from scratch.  Although the wiring is very short, getting all the inputs, outputs, and the volume controls and the selector switch wired up and then squeezing the board into the chassis was pretty tricky.  If someone can explain how to upload photos I'll do my best to throw some up here.

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 1 Jun 2010, 10:49 pm
Quote
      And I set mine up with two outputs, one for my main amp (Class D) and another for my sub amp (Rhythmic) and both outputs work just fine together... no hum issues or noise... and plenty of drive.                                                             

Thanks for the update, have you tried the output with and without the sub connected and confirmed no ill effect?
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 1 Jun 2010, 11:00 pm
Yup.  Ran the little bugger with only my Class D amp first just to get a sense for the sound, and then ran the second set of outputs to my sub.  No ill effects what so ever.  No hum or noise from my Class D, and no hum or noise from the sub either.   Connecting the sub did not affect the overall volume level either (thought I might notice a decrease... but didn't).  I know some subs have grounding issues with some preamps and other amps all wired together in one system, but in my set up I've never had any ground loop hum issues with either the Class D or the Rhythmik.  Up 'til now though I've been using a passive TVC, so I was a bit concerned... but without reason.

Really glad it worked as expected.  How often does that happen?

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 2 Jun 2010, 11:45 pm
Yup.  Ran the little bugger with only my Class D amp first just to get a sense for the sound, and then ran the second set of outputs to my sub.  No ill effects what so ever.  No hum or noise from my Class D, and no hum or noise from the sub either.   Connecting the sub did not affect the overall volume level either (thought I might notice a decrease... but didn't).  I know some subs have grounding issues with some preamps and other amps all wired together in one system, but in my set up I've never had any ground loop hum issues with either the Class D or the Rhythmik.  Up 'til now though I've been using a passive TVC, so I was a bit concerned... but without reason.

Really glad it worked as expected.  How often does that happen?

Neil

So you have 1 B1 and you split the outputs to feed both your amp and sub?
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 4 Jun 2010, 10:12 pm
That's correct.  Basically, I daisy chained from each left and right output to the other pair (as was suggested by Nelson Pass in the VERY long thread at DIY audio).  I thought about directly connecting each set of connectors (both pairs) to the board with their own dedicated wires, but the holes in the board did not accommodate me... the gauge of wire I was using wouldn't allow me to double up the stripped ends of the wire in the holes in the board.

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 5 Jun 2010, 01:41 pm
Here are some photos of my B1.  The chassis is a "wrap around" style, so the board is mounted to the bottom, all the wiring was done to all the connectors, and then the connectors were inserted into the chassis, and then bottom was secured to the chassis.  The second set of outputs (for my sub) were wired to the first set of outputs, and everything else was wired to the board directly.

Neil

(http://www.audiocircle.com/image.php?id=31218)

(http://www.audiocircle.com/image.php?id=31219)

(http://www.audiocircle.com/image.php?id=31220)
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 5 Jun 2010, 03:02 pm
If someone can explain how to upload photos I'll do my best to throw some up here.
Neil

Glad you learned how to post pics.  Very nice job on the B1... looks great!  Thanks for posting your impressions.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 5 Jun 2010, 03:05 pm
Love the case (linky?). Looks great!  :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 5 Jun 2010, 03:07 pm
Love the case (linky?). Looks great!  :thumb:

I think it's a hammand chassis.  I used the same one. :)
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 5 Jun 2010, 03:35 pm
You are quite correct.. that is a Hammond chassis.

I got it via Partsconnexion.  You need to order the chassis and the bottom cover separately.
Here is a link to the chassis I used: http://www.partsconnexion.com/product10259.html

As I noted before, I would not recommend this size to anyone unless you've got long skinny fingers, plenty of patience, and REALLY need something this small.  If I had it to do all over again I would have gotten a taller chassis (3 or 4 inches instead of 2), and maybe 8 inches deep instead of only 6.  Something like this would have certainly been worth the extra $10 to me: http://www.partsconnexion.com/product10262.html

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 5 Jun 2010, 05:11 pm
Here are some photos of my B1.  The chassis is a "wrap around" style, so the board is mounted to the bottom, all the wiring was done to all the connectors, and then the connectors were inserted into the chassis, and then bottom was secured to the chassis.  The second set of outputs (for my sub) were wired to the first set of outputs, and everything else was wired to the board directly.

Neil


Very cool!
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 5 Jun 2010, 05:16 pm
I'll have a couple extra sets of 1k and 220 ohm PRP resistors for $7 for anyone who wants to upgrade their resistors and/or lower their ouput impedance w/ the 220. This way you don't have to shell out minimum fees and ups shipping, etc. just to get them...  8)
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 5 Jun 2010, 08:20 pm
Although the B1 buffer is ZERO gain, I've read several who commented that it had plenty of drive.  And, the B1 buffer review in Enjoy the Music.com stated the following:

"Lots of kinetic energy.  But more than anything else, rising from below the threshold of conscious perception, a single word began to form: wow! A sensation of extreme clarity and transparency took hold of the soundstage. The sonic presentation was spectacularly open and spacious. It was as if my sonic window received the Windex treatment. Transients unfolded with speed and control. Image outlines were nicely focused. Massed voices were readily resolvable, thus enhancing the spatial impression of large choral works."


That's a lot of performance from a ZERO gain device using inexpensive volume pots and walwart power supply.

Wushuliu and others, can you share some insight on this?  Thanks!  :o

Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 5 Jun 2010, 08:44 pm
The review is more or less on the money. The B1 is not a warm and fuzzy buffer/pre. If you're asking how it accomplishes this sonic feat. Heck if I know. Nelson's pdf (article is also on ETM site) is a good start as well as all the armchair discussions on diyaudio. It's all in his design...
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 11 Jun 2010, 10:29 pm
Before I get my feet wet again on a B1 build or should I say, my fingers burned, I would like to know if 20 gauge hookup wire is sufficient.  :scratch:

I'm getting parts together for the effort and have fifty feet of 20 gauge wire.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 11 Jun 2010, 10:32 pm
Before I get my feet wet again on a B1 build or should I say, my fingers burned, I would like to know if 20 gauge hookup wire is sufficient.  :scratch:

I'm getting parts together for the effort and have fifty feet of 20 gauge wire.

20 gauge stranded should be fine...
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 11 Jun 2010, 10:36 pm
I'll have a couple extra sets of 1k and 220 ohm PRP resistors for $7 for anyone who wants to upgrade their resistors and/or lower their ouput impedance w/ the 220. This way you don't have to shell out minimum fees and ups shipping, etc. just to get them...  8)

The PRPs have arrived. I have about 3 or 4 sets (set=4) of 1k and 2 sets of the 220. Shoot me a PM if interested...
Title: Re: Nelson Pass B-1 preamp kit
Post by: bigaudioscotto on 12 Jun 2010, 12:30 pm
Do any of you guys know how to wire B1
without using the input switch,using volume controls only.
Title: Re: Nelson Pass B-1 preamp kit
Post by: avionic on 12 Jun 2010, 12:39 pm
Do any of you guys know how to wire B1
without using the input switch,using volume controls only.

 See page 12 of this thread near the bottom.
Title: Re: Nelson Pass B-1 preamp kit
Post by: bigaudioscotto on 12 Jun 2010, 04:18 pm
See page 12 of this thread near the bottom.
Just what I needed.
  Thanks,
Title: Re: Nelson Pass B-1 preamp kit
Post by: bigaudioscotto on 12 Jun 2010, 04:42 pm
 I am using an all wood enclosure,do I need to ground the unit somehow.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 12 Jun 2010, 06:24 pm
I am using an all wood enclosure,do I need to ground the unit somehow.

No you don't.  Many users put them in wooden enclosures with no hum or noise.
Title: Re: Nelson Pass B-1 preamp kit
Post by: bigaudioscotto on 12 Jun 2010, 09:51 pm
No you don't.  Many users put them in wooden enclosures with no hum or noise.
Great,Thanks for the feedback.
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 13 Jun 2010, 01:39 am
20 gauge stranded should be fine...


Thanks, Wushuliu,

As I've said before, tu est l'homme!
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 13 Jun 2010, 10:42 am
20 gauge stranded should be fine...

Does 20ga fit into the board, holes seem pretty small. I was going to get some 24ga just to be safe but i like bigger.  :eyebrows:
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 13 Jun 2010, 05:56 pm
Does 20ga fit into the board, holes seem pretty small. I was going to get some 24ga just to be safe but i like bigger.  :eyebrows:

I use 24 awg solid core myself. You don't need more than that for low level audio signals unless like earplay you have some wire lying around.
 
Dunno about the hole size. That's why I do prefer the ebay board to the pass board (sorry Nelson). The ebay board has bigger input/output holes and is much more accommodating of cap sizes.
Title: Re: Nelson Pass B-1 preamp kit
Post by: xecluded on 13 Jun 2010, 08:53 pm
Finished my B-1 today, and it is working like a champ.  Went with all the "standard" parts including dual PEC volume controls (not sure if I'll like that, but I do appreciate having a balance control of sorts). 
Neil
Neil,

Can i ask what is the part # for the dual pec volume controls and where do you get them at. I am looking to upgrade the pots on mine. Thanks
Title: Re: Nelson Pass B-1 preamp kit
Post by: poseidonsvoice on 13 Jun 2010, 09:05 pm
Looks like this (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=RV4N253C-ND) may be the one. You would need a pair of course.

(http://media.digikey.com/photos/Precision%20Elec%20Comp%20Photos/RV4N%20SERIES.jpg)



Anand.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 13 Jun 2010, 09:13 pm
Anand i have seen this link used before also. I like your price point better, but whats the difference between the two??

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=KB2531S28-ND
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 13 Jun 2010, 10:51 pm
I was wondering the same thing???

There can't be much difference in the two... you'd think.  :scratch:
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 13 Jun 2010, 11:48 pm
Anand i have seen this link used before also. I like your price point better, but whats the difference between the two??

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=KB2531S28-ND

Military v. Commercial.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 13 Jun 2010, 11:50 pm
Military v. Commercial.

Any reason to spend the extra money??
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 14 Jun 2010, 05:50 am
Any reason to spend the extra money??

Nope!
Title: Re: Nelson Pass B-1 preamp kit
Post by: daniloreyes on 14 Jun 2010, 07:14 pm
Which one would be better for the ClassdAudio amps, this B-1 or the lightspeed?  anyone has tried adding the lightspeed to this preamp?
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 14 Jun 2010, 07:59 pm
Which one would be better for the ClassdAudio amps, this B-1 or the lightspeed?  anyone has tried adding the lightspeed to this preamp?

LSA integrated into the B1 would be great.  Lightspeed alone would not work with the CDA series amps given their very low input impedance of 3K.  However, the SDS series amps should be good using the Lightspeed given an input impedance of 47K.  SDS-254 would be my preference.

I recommend you give the B1 a try first, then decide whether investing in the LSA is necessary.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 15 Jun 2010, 04:17 am
wushuliu, I've got a question... surprise!  :D

Using the standard PS, is it necessary to use a power switch (on/off) with the B1?

Battery power is a different matter of course.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 15 Jun 2010, 04:41 am
wushuliu, I've got a question... surprise!  :D

Using the standard PS, is it necessary to use a power switch (on/off) with the B1?

Battery power is a different matter of course.

I don't. It barely draws any power.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 15 Jun 2010, 05:00 am
I don't. It barely draws any power.

Yes, less than 0.02 amps is not much current.  The reason I asked is I noticed that the Burson Audio Buffer has a power switch on the rear, and NP did not mention it in his paper on the B1.  Thanks!
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 15 Jun 2010, 06:51 am
If all goes well I may be selling my B1 soon.  :wink:  :eyebrows:
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 15 Jun 2010, 11:58 am
If all goes well I may be selling my B1 soon.  :wink:  :eyebrows:

Would you possibly be building a hot rodded B1?  :drool:
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 15 Jun 2010, 12:59 pm
If all goes well I may be selling my B1 soon.  :wink:  :eyebrows:

AC, wassup?  You can tell us... we won't tell anyone!  :D
Title: Re: Nelson Pass B-1 preamp kit
Post by: xecluded on 15 Jun 2010, 03:30 pm
Looks like this (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=RV4N253C-ND) may be the one. You would need a pair of course.

(http://media.digikey.com/photos/Precision%20Elec%20Comp%20Photos/RV4N%20SERIES.jpg)



Anand.
Thanks Anand.  I will put in my order.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 15 Jun 2010, 03:39 pm
Looks like this (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=RV4N253C-ND) may be the one. You would need a pair of course.

(http://media.digikey.com/photos/Precision%20Elec%20Comp%20Photos/RV4N%20SERIES.jpg)



Anand.

You forgot to mention that this is the actual size...
Title: Re: Nelson Pass B-1 preamp kit
Post by: poseidonsvoice on 15 Jun 2010, 05:12 pm
You forgot to mention that this is the actual size...
:lol:
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 15 Jun 2010, 08:43 pm
from wushuliu,
A good test for flavoring would be the 2 1uf input caps.

How about using the Digi-Key BC2076-ND that Nelson P recommended instead of the Jantzen 1.0uF 400V Crosscap listed in the BOM?

Looks like they would also fit better on the board.  Any difference in the quality of sound?  :scratch:
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 15 Jun 2010, 08:55 pm
from wushuliu,
A good test for flavoring would be the 2 1uf input caps.

How about using the Digi-Key BC2076-ND that Nelson P recommended instead of the Jantzen 1.0uF 400V Crosscap listed in the BOM?

Looks like they would also fit better on the board.  Any difference in the quality of sound?  :scratch:

As far as stock goes, Nelson's pick is fine. I really, really do recommend stepping up a notch with that cap and the resistors. The B1 is very responsive to the components. Though it's better to upgrade later I suppose if you're not convinced what difference it will make and want to hear it for yourself.

Title: Re: Nelson Pass B-1 preamp kit
Post by: daniloreyes on 15 Jun 2010, 10:12 pm
Well I ordered it. along with the lightspeed and a second set of upgraded components.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 15 Jun 2010, 11:54 pm
As far as stock goes, Nelson's pick is fine. I really, really do recommend stepping up a notch with that cap and the resistors. The B1 is very responsive to the components.

OK, I'll stick with your BOM choices.  Thanks!
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 15 Jun 2010, 11:56 pm
Well I ordered it. along with the lightspeed and a second set of upgraded components.

Which Class D amp did you order? Did you get the LS from George or buy the one available on Audiogon?  Either way you should be pleased.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 16 Jun 2010, 12:02 am
OK, I'll stick with your BOM choices.  Thanks!

Just to be clear I doubt the PE Jantzen Cap is better than Nelson's, so if it's between those two pick whichever is most convenient (certainly Nelson's will fit better).
Title: Re: Nelson Pass B-1 preamp kit
Post by: daniloreyes on 16 Jun 2010, 12:33 am
Which Class D amp did you order? Did you get the LS from George or buy the one available on Audiogon?  Either way you should be pleased.
I ordered the CDA-1000 amp. Also ordered the LS full kit from their website. I have a few Cardas and Black Gates parts that need to be used :)

Title: Re: Nelson Pass B-1 preamp kit
Post by: daniloreyes on 16 Jun 2010, 01:21 am
Just to be clear I doubt the PE Jantzen Cap is better than Nelson's, so if it's between those two pick whichever is most convenient (certainly Nelson's will fit better).
In the BOM I think it should specify pot qty and switch qty.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 16 Jun 2010, 02:21 am
In the BOM I think it should specify pot qty and switch qty.

? I have Mono recommendations and Stereo recommendations. As for switches, not everyone wires their stuff the same way.
Title: Re: Nelson Pass B-1 preamp kit
Post by: daniloreyes on 16 Jun 2010, 03:20 am
I'm sorry I meant you had quantities for all other parts, and if they decide to use a mono then qty 2, for an ALPs qty 1 etc.

This thread rocks, thanks for all the information you have provided. We, the poor audiophiles really needed these articles.
Title: Re: Nelson Pass B-1 preamp kit
Post by: bigaudioscotto on 18 Jun 2010, 08:17 pm
 Do any of you guys know if you leave out the LED
 do you need to jumper that circuit.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 18 Jun 2010, 08:45 pm
Do any of you guys know if you leave out the LED
 do you need to jumper that circuit.

no
Title: Re: Nelson Pass B-1 preamp kit
Post by: bigaudioscotto on 18 Jun 2010, 08:54 pm
no
Thanks,
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 18 Jun 2010, 08:56 pm
Will any led work or do you need a high power one? This one okay?

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=P467-ND&itemSeq=87343920&uq=634124733550327198

Title: Re: Nelson Pass B-1 preamp kit
Post by: bigaudioscotto on 18 Jun 2010, 09:05 pm
Will any led work or do you need a high power one? This one okay?

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=P467-ND&itemSeq=87343920&uq=634124733550327198
Use this one.http://mouser.com/ProductDetail/Chicago-Miniature/5100H6/?qs=xVwIPGMSSakO3a%2fGNp5%252b2g%3d%3d
Title: Re: Nelson Pass B-1 preamp kit
Post by: bigaudioscotto on 18 Jun 2010, 09:09 pm
Will any led work or do you need a high power one? This one okay?

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=P467-ND&itemSeq=87343920&uq=634124733550327198
Or from Digikey
http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=US&WT.z_homepage_link=hp_go_button&KeyWords=5100H6+&x=22&y=13
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 19 Jun 2010, 12:50 am
Will any led work or do you need a high power one? This one okay?

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=P467-ND&itemSeq=87343920&uq=634124733550327198

Any. Run to Radio Shack.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 21 Jun 2010, 03:18 am
Well here's the next step up: The DC Coupled B1. This is not designed by Nelson Pass, but by folks over at diyaudio. Pass designed the simple B1 circuit to foster and encourage experimentation, so it has his blessing. The difference between this and the standard B1 is the elimination of input and output caps and the inclusion of a much praised shunt regulated power supply. So I can chuck the battery power and go back to good old ac.

Many thanks to Salas, Tea-Bag, and all the other extraordinary minds and helping hands over at diyaudio - the two B1 threads there are the few that actually stay on-topic and don't try my patience.

Be warned: These threads are loooong.

http://www.diyaudio.com/forums/pass-labs/145201-building-symmetrical-psu-b1-buffer.html (http://www.diyaudio.com/forums/pass-labs/145201-building-symmetrical-psu-b1-buffer.html)

http://www.diyaudio.com/forums/group-buys/147075-gb-dc-coupled-b1-buffer-shunt-psus.html (http://www.diyaudio.com/forums/group-buys/147075-gb-dc-coupled-b1-buffer-shunt-psus.html)

The cost to build is slightly cheaper to much cheaper - mostly due to the very cheap pcb ($7) and depending on the quality of caps, etc. you use for the standard B1. On the other hand, there is some tricky component matching involved like the fets and the LEDs and a larger parts count.

These PCBs are no longer available but a larger and more accomodating (and twice as expensive) PCB is planned for the end of July. If interested you'll have to sign up in the DC Coupled B1 Group Buy thread in the Group Buy section of diyaudio linked above.

Too early for serious opinion, but given the lower quality connectors and slap-dash nature of the build it sounds very impressive. The overall signature of the standard B1 remains, transparent and clean - but kicked up a couple notches.


(http://www.audiocircle.com/image.php?id=31883)

(http://www.audiocircle.com/image.php?id=31884)

(http://www.audiocircle.com/image.php?id=31885)





Title: Re: Nelson Pass B-1 preamp kit
Post by: daniloreyes on 22 Jun 2010, 10:19 pm
wushuliu,
Can you put links for nice cases that fit the B1? That would be added to the BOM also.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 22 Jun 2010, 11:40 pm
wushuliu,
Can you put links for nice cases that fit the B1? That would be added to the BOM also.

I don't have any. I suppose there's always Par-Metal or Pac-tec. If you know of some nice enclosures
please let us know.
Title: Re: Nelson Pass B-1 preamp kit
Post by: avionic on 23 Jun 2010, 06:56 am
This is what I used:  http://cgi.ebay.com/Aluminum-Project-Box-Enclousure-Case-Electronic-DIY-Big-/250597855778?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item3a58cbd222

  Fits a little snug. He also has them in silver. I will post some pics tomorrow of my b1 mounted in this enclosure.
(http://www.audiocircle.com/image.php?id=31958)

(http://www.audiocircle.com/image.php?id=31960)
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 23 Jun 2010, 07:07 am
This is what I used:  http://cgi.ebay.com/Aluminum-Project-Box-Enclousure-Case-Electronic-DIY-Big-/250597855778?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item3a58cbd222

  Fits a little snug. He also has them in silver. I will post some pics tomorrow of my b1 mounted in this enclosure.

Now that's what I'm talkin' about. Bloody brilliant. I can NEVER find stuff like that on ebay...
Title: Re: Nelson Pass B-1 preamp kit
Post by: 1MOR on 23 Jun 2010, 04:39 pm
This is what I used, but in the 8 inch length size. 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270583727179&ru=http%3A%2F%2Fshop.ebay.com%3A80%2F%3F_from%3DR40%26_trksid%3Dp4712.m570.l1313%26_nkw%3D270583727179%26_sacat%3DSee-All-Categories%26_fvi%3D1&_rdc=1 (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270583727179&ru=http%3A%2F%2Fshop.ebay.com%3A80%2F%3F_from%3DR40%26_trksid%3Dp4712.m570.l1313%26_nkw%3D270583727179%26_sacat%3DSee-All-Categories%26_fvi%3D1&_rdc=1)
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 23 Jun 2010, 06:07 pm
Another nice option.  I will put the size and seller for these in the BOM but no links because they are finite. I will also add pactec and parmetal.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 23 Jun 2010, 06:12 pm
Also if someone wants to foot the bill and there is interest I will order a dcb1 board and do a tutorial on that and on The condition that there is a tour before payer gets it.
Title: Re: Nelson Pass B-1 preamp kit
Post by: daniloreyes on 23 Jun 2010, 06:49 pm
PM :P
Title: Re: Nelson Pass B-1 preamp kit
Post by: mightym on 23 Jun 2010, 11:04 pm
I'm getting ready to finally construct my B-1. ( Pass board, and matched transistors )

The info posted here is proving to be invaluable to someone who hasn't driven a soldering iron in over 20 yrs.

What are the thoughts concerning the substitution of the DPDT sw, for the input selection, with a rotary switch to give the possibility of additional inputs?

Any Idea where I would go about sourcing such a switch?  Would a double pole rotary work, or would it require an additional pole for the signal ground?  What is "Shorting" vs "Nonshorting" when I look at the # and variety of rotary's available at someplace like Mouser, my eyes glaze over and I want to take a nap....

Opinions, answers, or suggestions are welcome...

John
Title: Re: Nelson Pass B-1 preamp kit
Post by: rtate on 23 Jun 2010, 11:42 pm
hey avionic, what are those by-pass caps and what values did you use??
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 24 Jun 2010, 12:01 am
hey avionic, what are those by-pass caps and what values did you use??

Also how much difference in the cap swap to Sonicaps, i opted for 1uf Sonicaps and for the 10uf went with Daytons 1% precision. I hope i am not disappointed but the 10uf Sonicap was pricey.  :duh:
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 24 Jun 2010, 12:16 am

My 10 uf caps are MIA, just for the record NEVER opt for the Smartpost at Parts Express. It takes forever, i went for the low price ship since it was only 2 caps but i have been waiting a whole week and still not here :(

I went with a wood case since i had a little walnut veneer left over, PRP resistors and Takman resistors for the output.

(http://i59.photobucket.com/albums/g295/mrnick_2006/Picture829.jpg)

(http://i59.photobucket.com/albums/g295/mrnick_2006/Picture830.jpg)
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 24 Jun 2010, 12:36 am
Oh bummer, yeah smartpost sucks. I've got 10uf Erse and the Russion K73-16. lmk if you want me to drop some in the mail...
Title: Re: Nelson Pass B-1 preamp kit
Post by: avionic on 24 Jun 2010, 12:37 am
hey avionic, what are those by-pass caps and what values did you use??
Vitamin Q's and I believe they are .022 These were NOS (new old stock)that a guy on ebay had.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 24 Jun 2010, 12:38 am
Also how much difference in the cap swap to Sonicaps, i opted for 1uf Sonicaps and for the 10uf went with Daytons 1% precision. I hope i am not disappointed but the 10uf Sonicap was pricey.  :duh:

The general feedback on Sonicaps have been the Gen I can sound on the lean/bright side - hence the Gen II as a warmer bypass. So those with the Daytons may make for a more analytical delivery...
Title: Re: Nelson Pass B-1 preamp kit
Post by: avionic on 24 Jun 2010, 12:41 am
Also how much difference in the cap swap to Sonicaps, i opted for 1uf Sonicaps and for the 10uf went with Daytons 1% precision. I hope i am not disappointed but the 10uf Sonicap was pricey.  :duh:
  This is actually another complete b1 with the sonicaps. The other one has the dayton 1% caps and for the $ in this application I think the daytons would be hard to beat. Try bypassing the dayton 1% with the dayton film/foil caps if you want to experiment later.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 24 Jun 2010, 12:42 am
I'm getting ready to finally construct my B-1. ( Pass board, and matched transistors )

The info posted here is proving to be invaluable to someone who hasn't driven a soldering iron in over 20 yrs.

What are the thoughts concerning the substitution of the DPDT sw, for the input selection, with a rotary switch to give the possibility of additional inputs?

Any Idea where I would go about sourcing such a switch?  Would a double pole rotary work, or would it require an additional pole for the signal ground?  What is "Shorting" vs "Nonshorting" when I look at the # and variety of rotary's available at someplace like Mouser, my eyes glaze over and I want to take a nap....

Opinions, answers, or suggestions are welcome...

John

A 2 pole should work fine. As for sourcing, it depends on how many inputs you are looking to use. I like high quality selectors like Grayhill... you can do a search on digikey for Grayhill rotary switches...
Title: Re: Nelson Pass B-1 preamp kit
Post by: avionic on 24 Jun 2010, 12:44 am
The general feedback on Sonicaps have been the Gen I can sound on the lean/bright side - hence the Gen II as a warmer bypass. So those with the Daytons may make for a more analytical delivery...
  Exactly right. Adding the vitamin Q's really helped soften things up a little. I also added riken resistors for the 1k values.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 24 Jun 2010, 12:57 am
  This is actually another complete b1 with the sonicaps. The other one has the dayton 1% caps and for the $ in this application I think the daytons would be hard to beat. Try bypassing the dayton 1% with the dayton film/foil caps if you want to experiment later.

Thanks for the input, i have some small value russian pio's i might try as bypass's
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 24 Jun 2010, 12:58 am
  Exactly right. Adding the vitamin Q's really helped soften things up a little. I also added riken resistors for the 1k values.

Yes, I like Vit Qs. Had them in my speakers.

Good resistors like riken, prp, shinkoh, etc. I think are a must for the B1.
Title: Re: Nelson Pass B-1 preamp kit
Post by: mightym on 24 Jun 2010, 11:07 am
A 2 pole should work fine. As for sourcing, it depends on how many inputs you are looking to use. I like high quality selectors like Grayhill... you can do a search on digikey for Grayhill rotary switches...

Thank you :D
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 24 Jun 2010, 07:34 pm
Its ALIVE! Wushuliu you hatched another one, many thanks for your support.  :thumb: :thumb:

Right out of the box it sounds really good, already getting very good bass and clean sound. Cant wait to put a few hours on it.  :eyebrows:
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 24 Jun 2010, 11:14 pm
Its ALIVE! Wushuliu you hatched another one, many thanks for your support.  :thumb: :thumb:

Right out of the box it sounds really good, already getting very good bass and clean sound. Cant wait to put a few hours on it.  :eyebrows:

Excellent!  :rock: Now where are the pics !  :D
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 25 Jun 2010, 03:08 pm
Would these PNP 1K resistors be a good choice?  :scratch:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=PNP100JR-52-1R-ND
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 25 Jun 2010, 03:42 pm
Would these PNP 1K resistors be a good choice?  :scratch:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=PNP100JR-52-1R-ND

Never heard of PNP. Also It appears the quantity available is zero. If ordering resistors from digikey then the Dale resistors linked in the BOM are about as good as you can get...
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 25 Jun 2010, 03:53 pm
Thanks, sorry I was confused.  I looked up the wrong ones, should have been PRP.  I there anywhere that sells them that uses parcel post and doesn't have a minimum order?

Which series of PRP?  The have several.  Thanks!
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 26 Jun 2010, 01:55 am
Thanks, sorry I was confused.  I looked up the wrong ones, should have been PRP.  I there anywhere that sells them that uses parcel post and doesn't have a minimum order?

Which series of PRP?  The have several.  Thanks!

No, all the PRP sellers have some sort of catch which is why I grabbed an extra dozen on my last buy. So $7 and I'll ship the 4 1ks you need  :wink:. 1/4 watt or 1/2 watt are fine. I have the 1/2 watt.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 26 Jun 2010, 03:24 pm
Excellent!  :rock: Now where are the pics !  :D

The first 25 hrs were a little rough and congested but now its sounding much better. I am trying out a couple of Russian k40y pio's and they are looking like a great pick for bypass.  :eyebrows:


(http://i59.photobucket.com/albums/g295/mrnick_2006/Picture833.jpg)

(http://i59.photobucket.com/albums/g295/mrnick_2006/Picture829.jpg)
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 26 Jun 2010, 07:47 pm
Keep us posted.  What your impression of the B1/SDA-254 combo?
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 26 Jun 2010, 07:56 pm
Its ALIVE! Wushuliu you hatched another one, many thanks for your support.  :thumb: :thumb:

Right out of the box it sounds really good, already getting very good bass and clean sound. Cant wait to put a few hours on it.  :eyebrows:

Oh dude sorry, I forgot your pics were posted right above when I asked for pics. Duh. Too many forums, too many projects, too many beers. :jester:
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 26 Jun 2010, 08:31 pm
Hi folks - long time no post. Good to see that more and more people are building B1s and enjoying them.

Earplay - how are you getting on?

Wushuliu - The Hypnotize is a nice project - I built one of the prototypes and I should use it in my system but the LSA/B1 keeps playing music. So I will have to (finally) test my LSA point-to-point build and incorporate that into the Hypnotize.

Apart from the track lifting on the prototypes (not a problem with the GB boards as the tracks were made much thicker) the only fiddly bit was setting up the LED strings.

I agree with you about the DCB1 sound - it is like the B1 but more open and detailed - but the B1 is not in any way shamed.

Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: bigaudioscotto on 27 Jun 2010, 03:17 pm
  This is actually another complete b1 with the sonicaps. The other one has the dayton 1% caps and for the $ in this application I think the daytons would be hard to beat. Try bypassing the dayton 1% with the dayton film/foil caps if you want to experiment later.
Hey Avionic
 Are you saying you are liking the sound of the Daytons over Sonicaps.
 

  Regards,
   Scott

 
Title: Re: Nelson Pass B-1 preamp kit
Post by: avionic on 27 Jun 2010, 03:31 pm
Hey Avionic
 Are you saying you are liking the sound of the Daytons over Sonicaps.
 

  Regards,
   Scott

 
Not necessarily. What I meant was that the daytons sound damn good and I think for the money spent on daytons you can not beat them $ for $. I am speaking of the dayton 1% bypassed with the film&foil daytons.
Title: Re: Nelson Pass B-1 preamp kit
Post by: daniloreyes on 28 Jun 2010, 04:02 pm
This is what I used:  http://cgi.ebay.com/Aluminum-Project-Box-Enclousure-Case-Electronic-DIY-Big-/250597855778?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item3a58cbd222

  Fits a little snug. He also has them in silver. I will post some pics tomorrow of my b1 mounted in this enclosure.
(http://www.audiocircle.com/image.php?id=31958)

(http://www.audiocircle.com/image.php?id=31960)
What pot did you use? and that knob is awesome...
Thanks
Title: Re: Nelson Pass B-1 preamp kit
Post by: avionic on 28 Jun 2010, 06:03 pm
  Search for this one on ebay  DACT Type 21 Stepped Attenuator 20K FOR PASS B1 DIY  and the knob is from Valab also from ebay.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 2 Jul 2010, 01:23 am
Just an update on the DC Coupled B1: The sound has settled into a very open, easy going delivery. As sondale mentioned it is more open and transparent than the regular B1. Audibly, audibly so. It is also more engaging - maybe the term is musical? - than my battery run B1, which itself is terrific. I find myself having a hard time analyzing it as my mind wanders and I forget to skip to other demo tracks. Get lost in it pretty easily. Really involving. Not really sure how to describe the improvement except that it's absolutely worth it. I would love a comparison with higher priced gear...
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 2 Jul 2010, 01:25 am
Hi folks - long time no post. Good to see that more and more people are building B1s and enjoying them.

Earplay - how are you getting on?

Wushuliu - The Hypnotize is a nice project - I built one of the prototypes and I should use it in my system but the LSA/B1 keeps playing music. So I will have to (finally) test my LSA point-to-point build and incorporate that into the Hypnotize.

Apart from the track lifting on the prototypes (not a problem with the GB boards as the tracks were made much thicker) the only fiddly bit was setting up the LED strings.

I agree with you about the DCB1 sound - it is like the B1 but more open and detailed - but the B1 is not in any way shamed.

Alan

LSA, LSA, LSA... I'm waiting!
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 2 Jul 2010, 01:27 am
  Search for this one on ebay  DACT Type 21 Stepped Attenuator 20K FOR PASS B1 DIY  and the knob is from Valab also from ebay.

Does that knob come with a set screw?
Title: Re: Nelson Pass B-1 preamp kit
Post by: avionic on 2 Jul 2010, 05:46 am
Does that knob come with a set screw?

  Yes sir
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 2 Jul 2010, 11:20 am
avionic,

Are you still using DacT mono's on your other B1 board?  How do they compare to the ebay stepped attenuator?

Your project looks good, well done.  Bet it sounds great!   :eyebrows:
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 3 Jul 2010, 07:40 pm
Just an update on the DC Coupled B1: The sound has settled into a very open, easy going delivery. As sondale mentioned it is more open and transparent than the regular B1. Audibly, audibly so. It is also more engaging - maybe the term is musical? - than my battery run B1, which itself is terrific. I find myself having a hard time analyzing it as my mind wanders and I forget to skip to other demo tracks. Get lost in it pretty easily. Really involving. Not really sure how to describe the improvement except that it's absolutely worth it. I would love a comparison with higher priced gear...

Wushuliu thanks for the update on the dcB1, im sure it has to sound better or it wouldnt exist but this B1 is absoluely blowing me away. It has taken over 150 hrs to finally open up which has been very fustrating but worth the wait. I used carbon resistors in the signal path and i kept wanting to remove 2 if not all cause it sounded so lifeless and muted. Well i heard from several buddies that carbon resistors can take 300 hrs to break in so i decided to stick it out and i am glad i did. What i am hearing now is a VERY smooth warm yet detailed presentation that feels like an expensive tube preamp. I am in love, this little simple design rocks. Thanks again Wush for sharing, i would not have attempted it without your tutorial.   :thumb:  :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 3 Jul 2010, 08:19 pm
Wushuliu thanks for the update on the dcB1, im sure it has to sound better or it wouldnt exist but this B1 is absoluely blowing me away. It has taken over 150 hrs to finally open up which has been very fustrating but worth the wait. I used carbon resistors in the signal path and i kept wanting to remove 2 if not all cause it sounded so lifeless and muted. Well i heard from several buddies that carbon resistors can take 300 hrs to break in so i decided to stick it out and i am glad i did. What i am hearing now is a VERY smooth warm presentation that feels like an expensive tube preamp. I am in love, this little simple design rocks. Thanks again Wush for sharing, i would not have attempted it without your tutorial.   :thumb:  :thumb:

Right on!!! Congrats!!!

 :beer: :drums: :rock: :weights: :smoke:
Title: Re: Nelson Pass B-1 preamp kit
Post by: avionic on 4 Jul 2010, 04:05 am
avionic,

Are you still using DacT mono's on your other B1 board?  How do they compare to the ebay stepped attenuator?

Your project looks good, well done.  Bet it sounds great!   :eyebrows:

  Thanks Roy. I went with a stepped pot from valab on the other board and would have used one on this one ,but it's diameter is to large for the way I mounted the pot in this small enclosure.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 7 Jul 2010, 07:45 pm
I put together an integrated amp: Hot Rodded DC Coupled B1 Mezmerize board with 3 inputs, and my CDA-254.

I am a big believer in reducing connections as much as possible and this seemed the best way to do between the two components. Also GF will hopefully be less irritated with having to turn on this and turn off that. Messy wiring will be cleaned up later. May also get an extension rod for the volume pot.

(http://www.audiocircle.com/image.php?id=32482)

(http://www.audiocircle.com/image.php?id=32483)



Well I am just about wrapped up w/ big audio projects for a while. Time to enjoy the fruits of my labors.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 7 Jul 2010, 07:53 pm
I didn't do a tutorial for the DCB1, but I will do a small one for matching the LEDs and fets as this is probably the biggest stumbling block for the build to a beginner. Very easy, just need a multimeter.

Also, I will do a tour of the first DCB1 I built. I will also try to hot-rod it. I just need to get a proper enclosure first.

Title: Re: Nelson Pass B-1 preamp kit
Post by: daniloreyes on 7 Jul 2010, 09:18 pm
Nice Build. That case looks awesome, whats the brand?
I like the idea of the integration, while trying to solder the RCA connectors was wondering the same, too many connections, welding etc and then adding interconnects (which by themselves have more connections)  when it can be done one time and for all.
I'll probably end my two projects and then will do an integrated one. My B1 is looking cool, will put pics soon too.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 8 Jul 2010, 04:51 am
Nice Build. That case looks awesome, whats the brand?
I like the idea of the integration, while trying to solder the RCA connectors was wondering the same, too many connections, welding etc and then adding interconnects (which by themselves have more connections)  when it can be done one time and for all.
I'll probably end my two projects and then will do an integrated one. My B1 is looking cool, will put pics soon too.

It's a gold alodine Par-Metal enclosure...
Title: Re: Nelson Pass B-1 preamp kit
Post by: earplay on 8 Jul 2010, 05:41 am
sondale,

I just saw your post asking how I was getting on. I've got too many irons in the fire right now to do the B1 build. I will keep you posted, though, as I said I would. I see my reminder every day to do just that. Thanks for asking, though. I haven't forgotten.

Besides being busy, I'm kind of waiting for the many modification ideas to percolate in the thread.

I really don't need the B1 until cooler weather returns to south Florida. That will probably be in mid-October or November. I will use the B1 to drive my tube amp which puts out a lot of heat. The cozy glow of tubes is nice in cool and overcast climes, but the last thing I need in south Florida is one more reminder of the ^%$&*(^ heat. Just to give you an idea, the heat index (temp x humidity) will be over 100 degrees Fahranheit for five months.

In hot weather, I use my massaged Sonic Impact Super t-amp. Frankly, I'm surprised at its performance. Compared to "giant killers" I have owned (Glow Amp One w/NOS Mullards, MiniWatt w/upgraded tubes and the cap mod, Kingrex with full Audiomagus mods) it's no contest. I stumbled onto a formula that kills the giant killers. So it's cool runnings for me. I only wish I could get my hands on another one because there are a few other tricks I want to try.

I'll stop. I think I getting off topic. My mind wanders in the heat!

Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 8 Jul 2010, 07:27 pm
A little off topic, but I wonder what the unused secondaries (the taped off ones) are on the Class D amp torroid, and whether or not they could be used to power the DC B1?  If there were a couple of 12V to 15V secondaries there, you might be able to get rid of the second (B1) transformer, and clean things up.

Just a thought?

Neil

Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 9 Jul 2010, 08:38 am
A little off topic, but I wonder what the unused secondaries (the taped off ones) are on the Class D amp torroid, and whether or not they could be used to power the DC B1?  If there were a couple of 12V to 15V secondaries there, you might be able to get rid of the second (B1) transformer, and clean things up.

Just a thought?

Neil

The classdaudio toroids come w/ unused secondaries now?
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 9 Jul 2010, 03:43 pm
Wushuliu thanks for the update on the dcB1, im sure it has to sound better or it wouldnt exist but this B1 is absoluely blowing me away. It has taken over 150 hrs to finally open up which has been very fustrating but worth the wait. I used carbon resistors in the signal path and i kept wanting to remove 2 if not all cause it sounded so lifeless and muted. Well i heard from several buddies that carbon resistors can take 300 hrs to break in so i decided to stick it out and i am glad i did. What i am hearing now is a VERY smooth warm yet detailed presentation that feels like an expensive tube preamp. I am in love, this little simple design rocks. Thanks again Wush for sharing, i would not have attempted it without your tutorial.   :thumb:  :thumb:

UPDATE:
Well i decided to give this close to 300hrs break in as several subjested but it remained to warm and syrupy for my taste. I removed the 2 carbon input resistors and replaced with prp metal fim and it sounds much more lively. A real good balance for anyone looking for a slightly warmer presentation.  :green:

Should have heeded Wushilui's warning of potentially to much of a good thing. hehe
Installing just a pair of carbon's on the output is a nice touch though.
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 9 Jul 2010, 04:03 pm
The classdaudio toroids come w/ unused secondaries now?

Mine came with the blue and green wires (which were used for the Class D power supply board) and 2 or 3 additional wires (were brown if memory serves) which were NOT to be used, and needed to be clipped or taped up so they didn't short out or bump into anything conductive.  I vaguely recall some folks asking about them early on in the Cheap and Cheerful Class D amp thread.  I wouldn't even begin to know how to measure them... and hence my inquiry. 

Okay, I re-read the Class D thread, and on page 13 they get mentioned, and on page 14 apparently Tom indicated that they are 12V secondaries which could be used for a secondary project, but are NOT used for the Class D amp.  Apparently the early Antec transformers did not come with these, and the later 400VA models did.  Sorry for the confusion.

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 9 Jul 2010, 04:36 pm
Mine came with the blue and green wires (which were used for the Class D power supply board) and 2 or 3 additional wires (were brown if memory serves) which were NOT to be used, and needed to be clipped or taped up so they didn't short out or bump into anything conductive.  I vaguely recall some folks asking about them early on in the Cheap and Cheerful Class D amp thread.  I wouldn't even begin to know how to measure them... and hence my inquiry. 

Okay, I re-read the Class D thread, and on page 13 they get mentioned, and on page 14 apparently Tom indicated that they are 12V secondaries which could be used for a secondary project, but are NOT used for the Class D amp.  Apparently the early Antec transformers did not come with these, and the later 400VA models did.  Sorry for the confusion.

Neil

Interesting. If the secondaries are 12-0-12, then they can be used with for a DCB1.
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 9 Jul 2010, 06:52 pm
That's exactly what I was thinking... which is often quite dangerous.  :o

Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 13 Jul 2010, 03:12 am
I realized today my DCB1, which had an output impedance of 220 ohm was probably causing slight oscillation in the HF (persistent treble sizzle, reduced bass). My regular B1 had 330 and I had no problems with my classdaudio amp, but just an FYI to listen for that if you decide to go that low. In my case it was slight but prominent enough that I spent all day hunting down the cause.

And I thought it sounded good before... :o
Title: Re: Nelson Pass B-1 preamp kit
Post by: daniloreyes on 14 Jul 2010, 05:51 am


Ok almost done,

Only issue is that the LED does not lit, no voltage.

How ever the sound is ok, very very clean and smooth.

used Cardas connectors, Cardas solder, western electric wires, Elna 12,000 uf 65v caps, Janzen MKP caps, and Alps 100k pot.


(http://www.audiocircle.com/image.php?id=32758)

(http://www.audiocircle.com/image.php?id=32759)

(http://www.audiocircle.com/image.php?id=32757)

Big Elnas :-)
(http://www.audiocircle.com/image.php?id=32773)
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 14 Jul 2010, 08:14 am
Ok almost done,

Only issue is that the LED does not lit, no voltage.

How ever the sound is ok, very very clean.

used Cardas connectors, Cardas solder, western electric wires, Elna 12,000 uf 65v caps, Janzen MKP caps, and Alps 100k pot.



Another one down! Looks great!

Why did you choose the 100k pot?
Title: Re: Nelson Pass B-1 preamp kit
Post by: daniloreyes on 14 Jul 2010, 02:46 pm


I used the 100k because Nelson Pass recommended anything from 25k to 100k. I just found  100k easier to get at the moment.
Sound should be the same, only percentage of volume will change, right?

I have another set of components (with PRP and Daytons caps) and will load them to a PassDIY (original) board to see the differences.

One detail I don't like is we cant adjust for bass and treble like a normal preamp, yes, I know we want pure sound, but aren't we changing caps and resistor brands to massage the sound to our liking?  LOL

Note: don't use solid core wiring as it seems they break easily, I used stranded western electric NOS wiring.

Now to complete my classdaudio amp (using Cardas wires!!!).

current gear- Music Hall 25.2 cd player/Pass B1/Denon POA2200/Monitor Audio RS6= sweet sound!!!
Title: Re: Nelson Pass B-1 preamp kit
Post by: face on 14 Jul 2010, 11:29 pm
Just an update on the DC Coupled B1: The sound has settled into a very open, easy going delivery. As sondale mentioned it is more open and transparent than the regular B1. Audibly, audibly so. It is also more engaging - maybe the term is musical? - than my battery run B1, which itself is terrific. I find myself having a hard time analyzing it as my mind wanders and I forget to skip to other demo tracks. Get lost in it pretty easily. Really involving. Not really sure how to describe the improvement except that it's absolutely worth it. I would love a comparison with higher priced gear...
The best cap is no cap.   :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 15 Jul 2010, 12:03 am
The best cap is no cap.   :thumb:

I want to know how the heck you fit those massive 10uf Clarity MR's into your B1.

Have you heard the DCB1?
Title: Re: Nelson Pass B-1 preamp kit
Post by: Bemopti123 on 15 Jul 2010, 01:16 am
Is there something special about the WE cables that were used for the wiring above?  There is plenty of NOS/used WE cables in Ebay and I wonder if there is something to be gained  by using such wire.  It is a mystery to me....asides from the fact that it is covered with cotton or some cloth material....a la JPS. 
Title: Re: Nelson Pass B-1 preamp kit
Post by: face on 15 Jul 2010, 02:31 am
I want to know how the heck you fit those massive 10uf Clarity MR's into your B1.

Have you heard the DCB1?
They barely fit.  :D 

No, I haven't heard the DC yet.  Maybe I'll get in on one of the GP's.
Title: Re: Nelson Pass B-1 preamp kit
Post by: daniloreyes on 15 Jul 2010, 07:26 am
They barely fit.  :D 

No, I haven't heard the DC yet.  Maybe I'll get in on one of the GP's.

HEHEHE those caps have a nice B1 sticked to it!!!
Title: Re: Nelson Pass B-1 preamp kit
Post by: porfido on 15 Jul 2010, 01:36 pm
Hi everybody!
First of all, sorry for my terrible english, I'm writing from Italy.... :oops:
Second, thank you so much for this very useful thread!  :thumb:
I finished my B1 some months ago and I'm very satisfied, but I would ask you if someone tried batteries psu with this buffer and if this kind of supply gives any advantage on, for example, switching supply like the one I'm using....
Thank you very very much! :)

P.S. Some pics of my B1:


(http://www.audiocircle.com/image.php?id=32795)


(http://www.audiocircle.com/image.php?id=32796)


(http://www.audiocircle.com/image.php?id=32797)


(http://www.audiocircle.com/image.php?id=32798)

Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 15 Jul 2010, 05:08 pm
I just got my battery set up done yesterday, and spent some time listening to it this morning.  I had been using a 24V wall wart (per the BOM).  I chose 2 12V Powersonic SLA batteries (wired in series) and picked up a cheap 12 V Battery Tender Jr from Amazon for recharging purposes (although I'll need to disconnect the batteries from one another to charge them... I couldn't find a cheap 24V charger).

Here is what I noticed in terms of sonic shifts.  First off, the decay associated with instruments seems more obvious, and lasts and lasts beyond what it did before.  There is an increase in clarity with the battery power that makes lyrics easier to understand, and background instruments or singers easier to pick out or listen to.  The dynamics (one thing I really admire about the B1) remain more or less unchanged, with the possible exception that very soft passages are more clearly articulated (maybe due to less grunge or background noise?).  Bass, midrange and treble balance seems very much like before, but each range's details seem a little clearer.  I also noticed that the soundstage seems a little more precise, and layered from front to back.  The only "down side" to the change is that the battery powered B1 seems a little less forgiving of marginal recordings.  Cymbals that are spitty or gritty in the recording are simply and clearly revealed that way.  Raspy violins, glaring brass, and lumpy one note bass are all also more clearly revealed.  Mediocre recordings don't sound worse than they are.  Their faults are more obviously laid bare... but the music can still be involving and enjoyable.   I found it even more difficult than usual to pull myself away from listening to come to work... which is always a good sign.

Hope this helps folks who are considering battery power for their B1s.  I found the whole process of switching over to batteries pretty simple and reasonably inexpensive (total cost under $60).  I don't know how long the batteries will hold a decent charge (my B1 has no on/off switch), but I can always get in the habit of unplugging the connector if they won't hold a charge for a good stretch of time.

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: porfido on 15 Jul 2010, 06:39 pm
Thank you very much, Walkern!
Your feedback tells me that this is the way to go, then....
I'm feeding 18v to my B1 and so I want to link in serie 3 6v sla batteries....
I already made an "automatic charging" unit for my class T amps, using sla battery and an automatic charger coming from house alarm system, but I can't find a 18v charger in Italy....
I will keep searching and will try.... :D
Title: Re: Nelson Pass B-1 preamp kit
Post by: mightym on 16 Jul 2010, 11:30 am
IIRC from calculations I did last year ( and I've slept since then ) A pair of 9V Alkaline batteries would last around 420 hrs ( I think ). An On/Off Switch, and a couple of battery connectors is all that is required to try it out.

That being said, there may be something to the capacity of the SLA batteries that would affect the resultant sound too.....

John
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 16 Jul 2010, 07:14 pm
IIRC from calculations I did last year ( and I've slept since then ) A pair of 9V Alkaline batteries would last around 420 hrs ( I think ). An On/Off Switch, and a couple of battery connectors is all that is required to try it out.

That being said, there may be something to the capacity of the SLA batteries that would affect the resultant sound too.....

John

?

9Vs typically only have about 500-600mA. With a current draw of 20mA, that only gives you about 25 hours...
Title: Re: Nelson Pass B-1 preamp kit
Post by: mightym on 16 Jul 2010, 09:25 pm
My bad Wushuliu,  You are of course right.

I think that most of the capacity I was able to find for plain 9V were 420 MA.

You can however, still purchase 2 Nimh 9V's and a charger for less than $ 25 from Amazon.... It'll even charge them both at the same time.

John
Title: Re: Nelson Pass B-1 preamp kit
Post by: HAL on 16 Jul 2010, 09:30 pm
Or you can get the two Hi Tech Li Ion 9VDC/600mAh batteries and dual charger from Batterymart for $37
Title: Re: Nelson Pass B-1 preamp kit
Post by: daniloreyes on 16 Jul 2010, 09:56 pm
Or you can get the two Hi Tech Li Ion 9VDC/600mAh batteries and dual charger from Batterymart for $37
wow that is a beautiful find:
http://www.batterymart.com/p-c-rli-9600-9v-lithium-ion-charger.html

Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 19 Jul 2010, 04:53 am
FYI, I still plan on doing the DCB1 tour for those that are interested. Just waiting for the enclosure to arrive (from HK, so probably a couple of weeks).
Title: Re: Nelson Pass B-1 preamp kit
Post by: porfido on 22 Jul 2010, 04:41 am
I'm for sure VERY INTERESTED! :D
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 24 Jul 2010, 01:52 pm
I am wondering were most folks picked up their RCA connectors from? Thanks.

Added info:
I found these in the B1 thread at diyaudio which look good and do not cost that much.

http://www.futurlec.com/RCA-ChassIns.shtml

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: porfido on 26 Jul 2010, 09:52 am
I am wondering were most folks picked up their RCA connectors from? Thanks.

Added info:
I found these in the B1 thread at diyaudio which look good and do not cost that much.

http://www.futurlec.com/RCA-ChassIns.shtml

James

I took mine from ebay sellers in HK....
Like these:
http://cgi.ebay.com/Lot10-RCA-female-connector-chassis-socket-amplifier-/280537287363?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item4151534ac3
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 26 Jul 2010, 12:13 pm
Thanks for the information.

The other thing I m looking for is the led. I saw some green leds at Radio Shack, are those the kind that I need? Thanks.

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: rtate on 26 Jul 2010, 07:02 pm
Question for all those using 24v to power their B1,

Did you upgrade the voltage rating on the power supply caps from the spec'd 25v??

Also is there a sonic benefit to using 24v instead of Nelson's 18v?

I'm trying to decide between 18 or 24v for my project...  :scratch:
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 26 Jul 2010, 08:21 pm
Nelson has talked about there being a sweet spot, from what i have read most think that is closer to the 18v mark. I am using an old HP supply rated at 18.5v that is working nicely.
Title: Re: Nelson Pass B-1 preamp kit
Post by: mightym on 26 Jul 2010, 10:39 pm
I used this guy on the 'Bay:http://stores.ebay.com/chanler-young?_rdc=1

Quick service, paid shipping, combined orders, quality looks good.  I'll use him again.

John
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 27 Jul 2010, 03:57 pm
Question for all those using 24v to power their B1,

Did you upgrade the voltage rating on the power supply caps from the spec'd 25v??

Also is there a sonic benefit to using 24v instead of Nelson's 18v?

I'm trying to decide between 18 or 24v for my project...  :scratch:

I never tried 18V compared to 24V so I can't speak to any net sonic benefit either way.
I did not upgrade the voltage rating on the power supply caps, and so far have had no issues running either a 24V wall wart or 2X 12V batteries in series (started off at 25.3V).  Maybe I'm pushing my luck? 
I think if I had it to do over again I'd be tempted to go with the 9V rechargeable battery set up mentioned earlier.  After all, the board is spec'd for 18V, and that way you can be sure that you are not overloading the power supply caps.  Just my $.02.

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 28 Jul 2010, 02:33 am
Well I have ordered everything except the case, RCA connectors (which I will get from the location mighty linked) and the 1uf and 10uf caps (I will be trying the Clarity ESA ones). I do need to say thanks to wushuliu for putting the parts list in such a nice cut and paste format for folks like me. I am very interested in getting this made and see how it sounds.

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: bundee1 on 28 Jul 2010, 02:59 am
Would this preamp work with my Red Dragon Amp-1 that have 10k input impedance?
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 28 Jul 2010, 04:22 am
Would this preamp work with my Red Dragon Amp-1 that have 10k input impedance?

Yes
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 28 Jul 2010, 01:48 pm
OK, I just got my Clariity caps ordered for C100-200, C101-201. Just a few more things to order up and than just wait till everything arrives.

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 28 Jul 2010, 02:38 pm
I have found that the 4-1k resistors have quite an effect with the B1. Im surprized it isnt mentioned a whole lot, seems to be a bigger issue on the dcb1 thread. Im sure it is somewhat system dependant but good parts in this location should be considered.

I have tried several different resistors so far and awaiting some naked Vishays now.

Takman carbon film- great bass and dynamics, warm and smooth but lack transparency
Prp metal film- smooth and transparent but lacks dynamics
Riken carbon film- great resistor with good transparency, smooth, awesome bass and dynamics. I think i could live with all 4 Rikens but some say use in moderation.
Naked Vishay(TX2575)- report back

I am going to try the Vishays as the input resistor and have the Rikens on the output right now, hoping that will be a good balance with awesome transparency. I will also note these results are based upon 330r.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 28 Jul 2010, 06:12 pm

I think if I had it to do over again I'd be tempted to go with the 9V rechargeable battery set up mentioned earlier. 
Neil

The B1 sips very little current.  Nelson Pass said, "The preamp typically draws fewer than 0.02 Amps, so current is not much of an issue."

It's little wonder why the two 9V rechargeable setup would work great with the B1.  And, it wouldn't cost much to implement.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 28 Jul 2010, 07:43 pm
I have found that the 4-1k resistors have quite an effect with the B1. Im surprized it isnt mentioned a whole lot, seems to be a bigger issue on the dcb1 thread. Im sure it is somewhat system dependant but good parts in this location should be considered.

I have tried several different resistors so far and awaiting some naked Vishays now.

Takman carbon film- great bass and dynamics, warm and smooth but lack transparency
Prp metal film- smooth and transparent but lacks dynamics
Riken carbon film- great resistor with good transparency, smooth, awesome bass and dynamics. I think i could live with all 4 Rikens but some say use in moderation.
Naked Vishay(TX2575)- report back

I am going to try the Vishays as the input resistor and have the Rikens on the output right now, hoping that will be a good balance with awesome transparency. I will also note these results are based upon 330r.

Thanks for the report!  :thumb: Very interested in hearing about the Vishays...  :eyebrows:
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 1 Aug 2010, 10:38 pm
Well I just got the case and RCA’s ordered up. Now I am just waiting for everything to arrive and then I can start the process of assembly.

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 2 Aug 2010, 11:50 pm
Looksey what i got today! I am going to hold off on comment till i give'em and few hrs breakin but i will say they seem to live up to all the hype.


(http://i59.photobucket.com/albums/g295/mrnick_2006/Picture844.jpg)
Title: Re: Nelson Pass B-1 preamp kit
Post by: bigaudioscotto on 3 Aug 2010, 08:58 pm
 Hey guys
 Just thought I would post a couple shots of finished B1.


 Scott
 
(http://www.audiocircle.com/image.php?id=33509)

(http://www.audiocircle.com/image.php?id=33510)
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 3 Aug 2010, 09:40 pm
Guys i have to say switching from prp resistors in the signal path to premium resistors was no small subtle change, but i would say more like 20% jump in performance. I have dynamics thru the roof and the bass is now outstanding. The Riken add a small dose of warmth to the sound but still transparent and the Vishays are dead nuetral and very quiet with outstanding transparency. Cant reccomend premium resistors enough, my B1 is now a great audiophile piece of equipment.

Scott is currently trying the Rikens on my reccomendation, maybe he will give some input.
Scott great looking B1 by the way.  :thumb:

Rikens $4ea Angela.com
Vishay tx2575 $9.40ea Texas Componants

Edit: replaced riken with vishay, riken were a tad warm for my system. 4 vishays are very clean and nuetral.
Title: Re: Nelson Pass B-1 preamp kit
Post by: bigaudioscotto on 3 Aug 2010, 10:10 pm
 Guys
 Keith is correct,the 4 1k signal resistors are very critical
 in the B1,
  everything is system dependent,try various resistors until you find the
   right flavor.
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 4 Aug 2010, 01:46 pm
Here is my progress so far. Just resistors, jfets and some caps. I wanted to wait on getting the enclosure before running any of the wires for everything else. The picture is not the best so I apologize about that.

(http://i148.photobucket.com/albums/s3/exojam/DSCF1624.jpg)

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 7 Aug 2010, 10:19 am
Glad I dropped in on this thread again - as I am about to re-house my LSA / B1 into a case with the NP Pearl Phono I will have to try changing the resistors.

The increase in the level of performance seems to be well worth the effort and cost.

Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 7 Aug 2010, 12:37 pm
Hey Alan, how are things across the pond?  Hope you're doing well.  Be sure to post your finished project.

Hi Scott, very nice job on the completed B1.  Let us know which resistors work best for you.  Thanks!  :D
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 7 Aug 2010, 11:07 pm
Well I got some more done today. I made a few mistakes on this project but I do not think anything will impact the performance. I made the hole for the switch a little too big and drilled one hole for an RCA at a bad angle :duh: The RCA is tilting down because on the inside of the cover it is hitting a rib piece. I should be able to somehow file it down so it will be flat but it is also a little off center compared to the other.

Now all I need it to get the power receptacle (back order at this time), solder in the led and get a knob for the volume pot.

The picture just shows the PCB laying ion the housing, I have not secured it at this time, just wanted to take a picture real quick.

James

(http://i148.photobucket.com/albums/s3/exojam/B1inside.jpg)

(http://i148.photobucket.com/albums/s3/exojam/RCAs.jpg)
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 10 Aug 2010, 02:15 am
One more mistake I made was pointed out to me, that would be a mono pot I have installed instead of a stereo one :duh: :duh:
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 10 Aug 2010, 03:28 am
Looksey what i got today! I am going to hold off on comment till i give'em and few hrs breakin but i will say they seem to live up to all the hype.


(http://i59.photobucket.com/albums/g295/mrnick_2006/Picture844.jpg)

Nick,

Did those go in R105 and R205? Thanks.

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 10 Aug 2010, 11:43 am
Quote
      Nick,

Did those go in R105 and R205? Thanks.

James                                                                       

No, the Vishay's are in the input position R102 & R202.

I have Rikens in the output R104 & R204.

It should be noted that Scott tried Rikens in both positions and wasnt favorable results. They seem to only play well in the output, use in moderation seems to apply. Having a good transparent neutral resistor like the TX2575 in the input seems to be key.

Edit: replaced riken with vishay, riken were a tad warm for my system. 4 vishays are very clean and nuetral.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 10 Aug 2010, 11:48 am
Any noticeable audible difference?  :|
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 10 Aug 2010, 11:53 am
Any noticeable audible difference?  :|

As i stated earlier the bump in performance over the prp's was quite substantial and in the neighborhood of 20% increase in performance. Mainly dynamics and bass and better resolution.
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 10 Aug 2010, 11:56 am
No, the Vishay's are in the input position R102 & R202.

I have Rikens in the output R104 & R204.

It should be noted that Scott tried Rikens in both positions and wasnt favorable results. They seem to only play well in the output, use in moderation seems to apply. Having a good transparent neutral resistor like the TX2575 in the input seems to be key.

Nick,

OK so those are just the 1K ohm ones. Thanks for your reply.

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 10 Aug 2010, 11:59 am
Nick,

OK so those are just the 1K ohm ones. Thanks for your reply.

James

Yes the 1k resistors are the ones in the signal path and one should consider premium parts in this position. Again my results are using 330r instead of 1k.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 10 Aug 2010, 12:16 pm
Yes the 1k resistors are the ones in the signal path and one should consider premium parts in this position. Again my results are using R330 instead of 1k.

Sorry, what does R330 refer to?
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 10 Aug 2010, 12:21 pm
Sorry, what does R330 refer to?

Sorry typo, 330r.
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 10 Aug 2010, 12:22 pm
I believe me means that he changed to a 330 ohm value instead of a 1K ohm, but I am sure Nick will clarifiy this.

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 10 Aug 2010, 12:24 pm
Keith, what is the benefit of making this change?
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 10 Aug 2010, 12:25 pm
I believe me means that he changed to a 330 ohm value instead of a 1K ohm, but I am sure Nick will clarifiy this.

James

Correct, the boys over at diyaudio concluded you get a little better clairty and bass with lower value resistor.

Wushilui recommended them to me, i never tried 1k.
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 10 Aug 2010, 12:33 pm
Nick,

Thank you again. Looks like i have another purchase to make :D

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: vantagesc on 10 Aug 2010, 05:18 pm
I just ordered all the parts that wushuliu posted on the first page.  So the 4 1K resistors are Dale/Vishay type.  1% tolerance, 50 ppm.  Are these decent parts?
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 10 Aug 2010, 06:02 pm
Welcome to the forum, im sure they will be fine, just depends on what your looking for.

http://www.altavistaaudio.com/resistors.html

Title: Re: Nelson Pass B-1 preamp kit
Post by: vantagesc on 10 Aug 2010, 07:09 pm
Thanks.  I will try it out with the parts I have and then get to tinkering down the road.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 10 Aug 2010, 09:22 pm
I just ordered all the parts that wushuliu posted on the first page.  So the 4 1K resistors are Dale/Vishay type.  1% tolerance, 50 ppm.  Are these decent parts?

I wouldn't be too concerned.  I'm pretty sure that Nelson Pass used the Vishay RN55D type 1K resistors in his stock design.  And, plenty of guys used the BOM list that Wushuliu suggested and are very happy with the result.
Title: Re: Nelson Pass B-1 preamp kit
Post by: turkey on 11 Aug 2010, 05:43 pm
I wouldn't be too concerned.  I'm pretty sure that Nelson Pass used the Vishay RN55D type 1K resistors in his stock design.  And, plenty of guys used the BOM list that Wushuliu suggested and are very happy with the result.

I've had almost a dozen components that used these resistors. Originally they were Corning, then Dale. They're very high quality.

I've also used them in some things I built and I was very satisfied.

Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 11 Aug 2010, 06:51 pm
HT COZ POSTED THIS IN GR RESEARCH. IF YOU WANT TO RUN YOUR B1 W/ BATTERIES THIS IS AN AWESOME DEAL!!!! EVEN IF YOU ALREADY HAVE A WALLWART THIS IS WORTH IT!!!

Just noticed this today www.woot.com Maybe this would be an option for battery power?

Energizer Universal 8000mAh Rechargeable Battery Pack
$39.99
Specifications:

Power Capacity: 8000 mAh @ 5V
Battery Cell: Lithium Polymer
Rated Input: DC 19V
Rated Output: DC 5V~1000mA; DC 12V~2000mA; DC 19V~2000mA
Store and operate between: 32 degrees F – 113 degrees F
Dimensions: 4.3" x 2.9" x .9" (LxWxH)
Weight: 7.9oz  
Title: Re: Nelson Pass B-1 preamp kit
Post by: rtate on 11 Aug 2010, 07:22 pm
Too bad they won't ship to Canada.... :x
Title: Re: Nelson Pass B-1 preamp kit
Post by: vantagesc on 12 Aug 2010, 04:22 am
BTW, what gauge hookup wire do you guys recommend? Parts express has 18awg and 24awg.
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 13 Aug 2010, 12:24 pm
Does anyone know where I can find a substitute for this power jack? I all ready have the wall wart below. I checked mouser but could not find one. Thanks.

Power jack:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CP-037A-ND

Wall wart:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=T987-P5P-ND

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 13 Aug 2010, 12:25 pm
BTW, what gauge hookup wire do you guys recommend? Parts express has 18awg and 24awg.

I used 24awg from Radio Shack..

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 13 Aug 2010, 01:37 pm
BTW, what gauge hookup wire do you guys recommend? Parts express has 18awg and 24awg.

I dont think 18ga will fit.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 13 Aug 2010, 02:18 pm
Does anyone know where I can find a substitute for this power jack? I all ready have the wall wart below. I checked mouser but could not find one. Thanks.
James

This one will fit flush and was recommended to me by another AC member.

http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=US&WT.z_homepage_link=hp_go_button&KeyWords=CP-011A-ND&x=19&y=21
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 13 Aug 2010, 02:29 pm
This one will fit flush and was recommended to me by another AC member.

http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=US&WT.z_homepage_link=hp_go_button&KeyWords=CP-011A-ND&x=19&y=21

Cool. Thank you very much.

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: vantagesc on 13 Aug 2010, 03:29 pm
Does anyone know where I can find a substitute for this power jack? I all ready have the wall wart below. I checked mouser but could not find one. Thanks.

Power jack:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CP-037A-ND

Wall wart:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=T987-P5P-ND

James

I just ordered the high current version of the same jack:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CP-037AH-ND

I haven't tried it out yet though.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 13 Aug 2010, 05:18 pm
It's just easier to drill a hole and attach.  :)
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 13 Aug 2010, 05:23 pm
Has anyone compared the B1 buffered pre to a quality non-buffered passive?  Since both are passive and have no gain, I suspect the B1 provides drive and dynamics that a non-buffered passive can't produce, at least not as well.
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 13 Aug 2010, 06:09 pm
It's just easier to drill a hole and attach.  :)

That was my thought when I saw the picture of it.

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 13 Aug 2010, 06:19 pm
Has anyone compared the B1 buffered pre to a quality non-buffered passive? 

BTW, anyone have any good ideas how to label RCA jacks, etc, cheaply yet not too ugly? 

Anyway, I have been comparing my B1 with Jentzen Superior Z caps and Alps Blue Velvet  to highly modded grounded grid, EVS ultimate attenuators, and source-direct (digital volume attenuator), and while B-1 definitely provides better bass dynamics and punch compared to direct or passive, there is some cost in terms of pure transparency in mid/highs, not surprising given the large caps, resistors, wires, pot, buffer, etc, that the signal must go through..
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 13 Aug 2010, 07:25 pm
I just ordered the high current version of the same jack:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CP-037AH-ND

I haven't tried it out yet though.

You can also find panel/chassis mountable jacks at Radio Shack. Much easier to deal with.

http://www.radioshack.com/product/index.jsp?productId=2102486 (http://www.radioshack.com/product/index.jsp?productId=2102486)


(http://www.audiocircle.com/image.php?id=33928)
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 13 Aug 2010, 07:40 pm
BTW, anyone have any good ideas how to label RCA jacks, etc, cheaply yet not too ugly? 

Anyway, I have been comparing my B1 with Jentzen Superior Z caps and Alps Blue Velvet  to highly modded grounded grid, EVS ultimate attenuators, and source-direct (digital volume attenuator), and while B-1 definitely provides better bass dynamics and punch compared to direct or passive, there is some cost in terms of pure transparency in mid/highs, not surprising given the large caps, resistors, wires, pot, buffer, etc, that the signal must go through..

Jon i cant deny your fault with the design but i cant help but wonder if you had a 4 pack of naked Visays in the signal path if you would have the same conclusion.

I have certainly gotten some transparency i was looking for with premium resistors.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 13 Aug 2010, 07:49 pm
Jon i cant deny your fault with the design but i cant help but wonder if you had a 4 pack of naked Visays in the signal path if you would have the same conclusion.

I have certainly gotten some transparency i was looking for with premium resistors.

I will get to the naked Vishays (perhaps others) eventually, but don't get me wrong.  B-1 is as transparent of a preamp as I have ever heard really, except maybe for McCormack VRE-1 J-Fet buffered preamp. Many high $$$ big-name active preamps, especially ones with many tubes, would sound quite additively colored in comparison.   

But what I'm doing is, instead of my DAC driving the system directly, inserting another set of interconnects (same as others in system), another preamp (B-1), as well as another power cord.  I would actually be stupefied if the preamp setup sounded just as transparent  :o
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 13 Aug 2010, 07:54 pm
I will get to the naked Vishays (perhaps others) eventually, but don't get me wrong.  B-1 is as transparent of a preamp as I have ever heard really, except maybe for McCormack VRE-1 J-Fet buffered preamp. Many high $$$ big-name active preamps, especially ones with many tubes, would sound quite additively colored in comparison.   

But what I'm doing is, instead of my DAC driving the system directly, inserting another set of interconnects (same as others in system), another preamp (B-1), as well as another power cord.  I would actually be stupefied if the preamp setup sounded just as transparent  :o

Gotcha! I am certainly with ya on the bass and dynamics, they are off the charts.  :thumb:

I would sure like to hear your's with those caps.  :wink:
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 13 Aug 2010, 08:23 pm
BTW, anyone have any good ideas how to label RCA jacks, etc, cheaply yet not too ugly? 

Anyway, I have been comparing my B1 with Jentzen Superior Z caps and Alps Blue Velvet  to highly modded grounded grid, EVS ultimate attenuators, and source-direct (digital volume attenuator), and while B-1 definitely provides better bass dynamics and punch compared to direct or passive, there is some cost in terms of pure transparency in mid/highs, not surprising given the large caps, resistors, wires, pot, buffer, etc, that the signal must go through..

Hi Jon, one suggestion if you have not already tried is to replace the Blue Velvet w/ the gigawork SMT 20k attenuator mentioned in the BOM. They are $10 on ebay, seller is Gigawork, and are very popular. They are much more transparent than the Blue Velvet I had and general consensus is that they are very high value. I've had occasion to switch back and forth between the two and the Gigawork is very, very clean and clear particularly in the mids and up. No contest.

http://cgi.ebay.com/DACT-Type-21-Stepped-Attenuator-20K-PASS-B1-DIY-/120502791204?pt=LH_DefaultDomain_0 (http://cgi.ebay.com/DACT-Type-21-Stepped-Attenuator-20K-PASS-B1-DIY-/120502791204?pt=LH_DefaultDomain_0)

As for the ultimate transparency denied by all the caps, well, that's what the DCB1 is for!
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 13 Aug 2010, 08:58 pm
Hi Jon, one suggestion if you have not already tried is to replace the Blue Velvet w/ the gigawork SMT 20k attenuator mentioned in the BOM. They are $10 on ebay, seller is Gigawork, and are very popular. They are much more transparent than the Blue Velvet I had and general consensus is that they are very high value. I've had occasion to switch back and forth between the two and the Gigawork is very, very clean and clear particularly in the mids and up. No contest.

http://cgi.ebay.com/DACT-Type-21-Stepped-Attenuator-20K-PASS-B1-DIY-/120502791204?pt=LH_DefaultDomain_0 (http://cgi.ebay.com/DACT-Type-21-Stepped-Attenuator-20K-PASS-B1-DIY-/120502791204?pt=LH_DefaultDomain_0)

As for the ultimate transparency denied by all the caps, well, that's what the DCB1 is for!

Yes, I hope to try a DCB1 at some point, also LDR.  Preamp is the bane of many audiophiles these days it seems. 

I've seen those ebay attenuators before and sure looks good.  It actually looks good enough to go in my Almarro, actually..

For B-1, my system gain is such that I actually can bypass the volume pot and not use too much digital attentuation.  I'll try that next I think.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 13 Aug 2010, 09:30 pm
Wushuliu, I read somewhere that the stock PEC attenuators sounded better than the Alps.  What did you think?

No doubt a SMT stepped attenutor would sound much better.
Title: Re: Nelson Pass B-1 preamp kit
Post by: parodielin on 13 Aug 2010, 09:41 pm
I used the pot too.  I have Blue Velvet too.  The resistance of both channels on my blue velvet is not exactly the same, which created a shifted image problem for me.  The Gigawork pot, measured exactly 50K on both channels, and that's what I use right now.  I care less to compare the sound quality but to me, the shifted image is a bigger issue.

Hi Jon, one suggestion if you have not already tried is to replace the Blue Velvet w/ the gigawork SMT 20k attenuator mentioned in the BOM. They are $10 on ebay, seller is Gigawork, and are very popular. They are much more transparent than the Blue Velvet I had and general consensus is that they are very high value. I've had occasion to switch back and forth between the two and the Gigawork is very, very clean and clear particularly in the mids and up. No contest.

http://cgi.ebay.com/DACT-Type-21-Stepped-Attenuator-20K-PASS-B1-DIY-/120502791204?pt=LH_DefaultDomain_0 (http://cgi.ebay.com/DACT-Type-21-Stepped-Attenuator-20K-PASS-B1-DIY-/120502791204?pt=LH_DefaultDomain_0)

As for the ultimate transparency denied by all the caps, well, that's what the DCB1 is for!
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 13 Aug 2010, 10:24 pm
Wushuliu, I read somewhere that the stock PEC attenuators sounded better than the Alps.  What did you think?

No doubt a SMT stepped attenutor would sound much better.

I haven't heard the mono PECs except briefly when building the tutorial version. I prefer a stereo pot. Got enough buttons and knobs to push/pull/turn/break!
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 13 Aug 2010, 11:33 pm
All right, I have ordered the resistors Nick mentioned (will not ship till the 19th though) and the jack that Roymail pointed me to. I should be up and running within a week hopefully. Just in time for me to go back in and put in the new resistors.

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 14 Aug 2010, 12:19 am
All right, I have ordered the resistors Nick mentioned (will not ship till the 19th though) and the jack that Roymail pointed me to. I should be up and running within a week hopefully. Just in time for me to go back in and put in the new resistors.

James

Nice work, what caps will you be running?
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 14 Aug 2010, 01:22 am
Nick,

I will be using Clarity ESA's.

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 14 Aug 2010, 02:34 pm
Has anyone compared the B1 buffered pre to a quality non-buffered passive?  Since both are passive and have no gain, I suspect the B1 provides drive and dynamics that a non-buffered passive can't produce, at least not as well.

I've replaced a Promitheus TVC with a standard issue battery powered B1 (and I have a DCB1 that I'm beginning to build) and here are the differences I noticed as a result of the change:
1) The B1 has better dynamics, both micro and macro.  Subtle changes in volume as well as large ones are more effortlessly communicated by the B1.
2) The overall imaging of both units were quite comparable.  Both seem capable of rendering nice depth, width, (occasionally height) and a 3D character to instruments and groups and vocalists.
3) Background noise level is also comparable.  I expected the B1 to have a little residual hiss or hum, but it is dead quiet, as was the TVC.
4) The B1 has better bass extension, power, authority, and definition.  The TVC sounds ever so slightly softer with less oomph in the mid and deepest bass areas, and also with slight less transient snap or speed (the leading whack of a bass drum for example).
5) The mids on my B1 are a little recessed compared to the TVC.  This works well with some recordings, and not so well with others.  Not sure which I prefer here.
6) The treble range (particularly after shifting to battery power) seems a little cleaner and clearer on the B1 (cymbals sound more realistic... less like white noise).  This difference is quite small.

Hope this helps.

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 14 Aug 2010, 03:09 pm
Neil, thanks for that comparison.  I'm sure it will be helpful to many readers of this thread.  Much appreciated.  :thumb:

And, please keep us updated on your DCB1 project.
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 14 Aug 2010, 03:43 pm
Actually, I was kind of hoping someone here with more E.E. or tech skills would do a "step by step" build tutorial for the latest DCB1 Blue Board.  It has lots of options for various components, and has lots of stuff on it that I'm not familiar with.  I had no trouble with my Nelson Pass board assembly thanks to all the help and support earlier in this thread.

Anyone else committed to a DCB1 who'd be willing to take photos along the way, and offer up advice for folks who (for example) don't know which side of a diode is + and which is the -?

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 14 Aug 2010, 07:03 pm
Actually, I was kind of hoping someone here with more E.E. or tech skills would do a "step by step" build tutorial for the latest DCB1 Blue Board.  It has lots of options for various components, and has lots of stuff on it that I'm not familiar with.  I had no trouble with my Nelson Pass board assembly thanks to all the help and support earlier in this thread.

Anyone else committed to a DCB1 who'd be willing to take photos along the way, and offer up advice for folks who (for example) don't know which side of a diode is + and which is the -?

Neil

Actually the board has directional markings to match the diodes, so you'll be fine  :wink:

If no one steps up to the plate, we'll walk you through it. It seems more complicated than it is.
Title: Re: Nelson Pass B-1 preamp kit
Post by: poseidonsvoice on 14 Aug 2010, 07:08 pm
I just ordered a pair of DCB1's. I'm trying to build a balanced/differential version, and I like the fact that it is direct coupled and shunt regulated, which has advantages over cap coupling seen in the standard B1. I'm most likely going to be using some uber quality resistors with this one, like the naked Vishays for example. I'm aiming for extreme neutrality, whatever that means! Mundorf Electrolytics, etc...

I'll keep my eyes peeled for any pics on this forum...

Anand.

Title: Re: Nelson Pass B-1 preamp kit
Post by: Lyndon on 14 Aug 2010, 07:18 pm
wushuliu,
Has anyone on this thread or the other one on diyaudio compared the sound of the B-1
to a tubed preamp, such as the Grounded Grid, or the 12b4 linestage?  I am considering building a newer version of the Grid, but was wondering if I could find some feedback.
Lyndon
Title: Re: Nelson Pass B-1 preamp kit
Post by: poseidonsvoice on 14 Aug 2010, 07:34 pm
Do what I am doing, build both and make your own decision.

I have a differential parafeed 6N6P preamp I am building with switchable 6dB/12dB of overall gain.

And I'll be building a differential direct coupled B1 w/shunt regulation with 0dB overall gain.

It's diy, have fun. They all sound good, great, bad, and different.

Anand.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 14 Aug 2010, 08:07 pm
Lyndon, you might contact Jon L, Walkern or Anand with a PM.  They should be able to answer your questions.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 14 Aug 2010, 09:37 pm
wushuliu,
Has anyone on this thread or the other one on diyaudio compared the sound of the B-1
to a tubed preamp, such as the Grounded Grid, or the 12b4 linestage?  I am considering building a newer version of the Grid, but was wondering if I could find some feedback.
Lyndon

I believe someone compared theirs to a grounded grid on diyaudio. You may want to do a search there or post in the B1 Buffer Preamp thread.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 14 Aug 2010, 09:58 pm
compared the sound of the B-1
to a tubed preamp, such as the Grounded Grid, or the 12b4 linestage? 

My grounded grid is not stock, but I have compared it to B-1. 

First of all, as nice as stock grounded grid is, it simply does not compare with B-1 in terms of transparency and impact.  After doing much of everything possible to my GG as described here, it's a different story, though.
http://www.audiocircle.com/index.php?topic=72652.0

Now we have two VERY different sound paths, but one could argue he prefers one over the other for very valid reasons.  B-1 is still more transparent and "straight with gain" while giving great defined bass and dynamic impact.

Tweaked GG still has that expansive, richly harmonic, warm yet clear sound that simply tugs at your ear more.  Depending on one's tastes and system configuration, I can appreciate somebody preferring one over the other.  Just for reference, I've had Audible Illusions L1 tube pre and SAS Labs 10A tube pre in my system before (both wonderful preamps!), and I prefer the tweaked GG more. 

Of course, now I'm looking into improving the B-1 with better resistors, volume control, wire, etc, so we'll see.  I even found a pair of 1 uF teflon caps in my drawers, so I may even do that to even the playing field since my GG has teflon output caps  :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: Lyndon on 14 Aug 2010, 10:01 pm
Jon L,
Thanks so much for that.
And the link.
wushuliu, I'll check over at the other forum as well.
Don't have the time or resources to do both this fall.
Lyndon
Title: Re: Nelson Pass B-1 preamp kit
Post by: poseidonsvoice on 14 Aug 2010, 10:05 pm
My grounded grid is not stock, but I have compared it to B-1. 

First of all, as nice as stock grounded grid is, it simply does not compare with B-1 in terms of transparency and impact.  After doing much of everything possible to my GG as described here, it's a different story, though.
http://www.audiocircle.com/index.php?topic=72652.0

Now we have two VERY different sound paths, but one could argue he prefers one over the other for very valid reasons.  B-1 is still more transparent and "straight with gain" while giving great defined bass and dynamic impact.

Tweaked GG still has that expansive, richly harmonic, warm yet clear sound that simply tugs at your ear more.  Depending on one's tastes and system configuration, I can appreciate somebody preferring one over the other.  Just for reference, I've had Audible Illusions L1 tube pre and SAS Labs 10A tube pre in my system before (both wonderful preamps!), and I prefer the tweaked GG more. 

Of course, now I'm looking into improving the B-1 with better resistors, volume control, wire, etc, so we'll see.  I even found a pair of 1 uF teflon caps in my drawers, so I may even do that to even the playing field since my GG has teflon output caps  :thumb:

This is what I found true to the nature of diy and why it is so gratifying. You can somewhat tailor the sound. I have found, in recent years, that properly designed differential/balanced circuits are out of this world, even though I am not running hundreds of feet of cables...

Anand.
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 15 Aug 2010, 12:16 am
I believe someone compared theirs to a grounded grid on diyaudio. You may want to do a search there or post in the B1 Buffer Preamp thread.

I built a Ground Grid several years ago shortly after they came out, and was quite happy with it (stock) until I got a chance to listen to some far more expensive tube and SS preamps.  By comparison the stock unit was a little rough around the edges, although it had terrific speed and articulation.  It lacked a bit of finesse, and didn't have the bass slam or definition that my B1 has.  I was kind of hoping it would have a more classically tube kind of character... a little warm and forgiving, so it would match up well with a SS amp I was using at the time... but it was not warm or forgiving (nor was it cold or clinical... just pretty neutral).  In any case, I sold it and bought the TVC and was happy until I built a B1.  I'm sure (as noted above) that the GG can be tweaked and improved beyond stock, and adjusted to be an ideal fit for a given system... but the B1 is less expensive, and equally flexible (again, as noted above... one of the advantages of DIY).

Best of luck with your decision,

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: Lyndon on 15 Aug 2010, 01:46 am
Thanks, Neil
I just finished the 261 pages of the original thread at diyaudio, and that is not adding the other variations!
I guess I will think more on this option, but will want to include the remote volume control
(yeah, I know, I know) that I bought from some Dutch guy on diyaudio a few years ago.
Lyndon
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 17 Aug 2010, 06:46 pm
The B1 without a potentiometer is very useful as a pure buffer.
Alan

Hi Alan,

Can you tell me how to wire the B1 as a buffer only, using RCA's in place of the attenuators?

CW - input
W - wiper
CCW - ground

I wire the RCA with input and ground, but what about the wiper?  I'm thinking the W (wiper) is only for attenuating or resisting the signal.  Do I just leave it open?

I don't know a lot about electronics, but I can solder pretty well if I know what goes where.  Please explain but keep it simple.  Thanks.

I'll place the B1 buffer between my diy Goldpoint/Elma 20K stepped attenuator and amplifier.

I appreciate your help,
Roy in TX
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 17 Aug 2010, 07:40 pm
Roy,

Connect CW to W, then solder a 25K resistor between W and CCW.

Effectively you have a potentiometer which is fully open.

Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 17 Aug 2010, 11:38 pm
This provides still another option for the B1 buffer.  For me, since I already have a nice passive stepped attenuator, adding the B1 buffer to control any impedance mismatches is a great option.  I'm really looking forward to trying it.

Yes, I can integrate the GP/Elma SMT 20K stepped attenuator into the B1, and I may do that later.  But for now, I'm going to configure the Pass B1 buffer in the same way that Burson does their buffer.

Alan, thanks for the helpful information.  Much appreciated.
Title: Re: Nelson Pass B-1 preamp kit
Post by: HAL on 18 Aug 2010, 12:08 am
If you are putting a passive attenuator in front of the B1, you would not need a low value resistor like 25K.  In this situation that would load the other passive attenuator depending on it's value.

Another idea would be to put a 1 meg ohm resistor in instead of the 25K ohm and then this will load the input attenuator very little, but keep the input terminated for DC offset incase the attenuator is ever disconnected.

Just a thought.
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 19 Aug 2010, 12:14 pm
Hal,

Thanks for that - I will try 1Meg in that position.

Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 19 Aug 2010, 08:20 pm
Vishay tx2575 resistors and eBay 20K SMT attenuator have been ordered  :green:
Title: Re: Nelson Pass B-1 preamp kit
Post by: toxteth ogrady on 19 Aug 2010, 08:45 pm
I just picked up two dcb1 blue boards from the diyaudio group buy. Is anyone in the process of building one of these? Looks to be quite a bit more challenging than the original b1 build.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 19 Aug 2010, 08:56 pm
I just picked up two dcb1 blue boards from the diyaudio group buy. Is anyone in the process of building one of these? Looks to be quite a bit more challenging than the original b1 build.

stay tuned...  :wink:
Title: Re: Nelson Pass B-1 preamp kit
Post by: toxteth ogrady on 19 Aug 2010, 09:46 pm
 :D
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 19 Aug 2010, 10:35 pm
Vishay tx2575 resistors and eBay 20K SMT attenuator have been ordered  :green:

Has anyone tried Caddock 132's or 020's?
Title: Re: Nelson Pass B-1 preamp kit
Post by: Russellc on 20 Aug 2010, 01:08 pm
wushuliu,
Has anyone on this thread or the other one on diyaudio compared the sound of the B-1
to a tubed preamp, such as the Grounded Grid, or the 12b4 linestage?  I am considering building a newer version of the Grid, but was wondering if I could find some feedback.
Lyndon

I have.  I have the B-1, but for speakers with less efficiency, the F-5 needs a little gain.  I switch in the Audio by Van Alstein Super Pass III.  wonderful combination, sometimes I think maybe it gives up a little transparency to the B-1, but then again it adds its tubey goodness.  Very nice combo.

Russellc
Title: Re: Nelson Pass B-1 preamp kit
Post by: Russellc on 20 Aug 2010, 01:09 pm
I just picked up two dcb1 blue boards from the diyaudio group buy. Is anyone in the process of building one of these? Looks to be quite a bit more challenging than the original b1 build.

I just picked up the same boards.   Will be watching.

russellc
Title: Re: Nelson Pass B-1 preamp kit
Post by: Russellc on 20 Aug 2010, 01:13 pm
You can also find panel/chassis mountable jacks at Radio Shack. Much easier to deal with.

http://www.radioshack.com/product/index.jsp?productId=2102486 (http://www.radioshack.com/product/index.jsp?productId=2102486)


(http://www.audiocircle.com/image.php?id=33928)

I used that jack, not too bad of quality, cant say the same for the plug they have to go with it, it is a piece of poo.

Russellc
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 20 Aug 2010, 06:39 pm
Digi-key has this one, CP-5-ND.

(http://)
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 22 Aug 2010, 02:56 pm
This one will fit flush and was recommended to me by another AC member.

http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=US&WT.z_homepage_link=hp_go_button&KeyWords=CP-011A-ND&x=19&y=21

Can anyone tell me if I only need to use one of the ground tabs from this connector? If you look at the picture in the link it has three tabs. I can see which one is for power but I am not sure if I can use either of two other ones for the ground connection. Thanks.

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 22 Aug 2010, 06:09 pm
Can anyone tell me if I only need to use one of the ground tabs from this connector? If you look at the picture in the link it has three tabs. I can see which one is for power but I am not sure if I can use either of two other ones for the ground connection. Thanks.
James

You only need to use one ground and one center.  The wire you are attaching only has 2 wires and one is a ground wire.  You can't really hurt anything since the power supply is such low voltage, 18v or 24v.
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 22 Aug 2010, 11:54 pm
Very good. I was just not sure why this had three tabs for only two wires.

Thanks,
James
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 23 Aug 2010, 02:27 am
FYI: DCB1 Build thread has started.
Title: Re: Nelson Pass B-1 preamp kit
Post by: HAL on 23 Aug 2010, 03:59 am
Very good. I was just not sure why this had three tabs for only two wires.

Thanks,
James
Usually the third wire is a switch terminal when the plug is inserted into the jack.   
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 26 Aug 2010, 09:14 pm
I've put my first B1 and DCB1 builds for sale. Just the boards, no enclosures. Need to clear out my projects.
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 26 Aug 2010, 11:10 pm
Well to say the least I am pretty bummed right now, my stereo pot came into today so I figured I would finally finish this up and be able to listen to it this week. BUT, the jack that I had ordered will not accept the wall wart plug :evil:. I ordered that jack since the original one I ordered was not in stock.

I went ahead and soldered in the new pot and new resistors I got for R102-202 and now just have to wait for the other jack to get in stock and shipped.

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 26 Aug 2010, 11:49 pm
Well to say the least I am pretty bummed right now, my stereo pot came into today so I figured I would finally finish this up and be able to listen to it this week. BUT, the jack that I had ordered will not accept the wall wart plug :evil:. I ordered that jack since the original one I ordered was not in stock.

I went ahead and soldered in the new pot and new resistors I got for R102-202 and now just have to wait for the other jack to get in stock and shipped.

James

I'm in a similar spot myself for something else, but that's what the alligator clips are for  :green:
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 26 Aug 2010, 11:51 pm
Well to say the least I am pretty bummed right now, my stereo pot came into today so I figured I would finally finish this up and be able to listen to it this week. BUT, the jack that I had ordered will not accept the wall wart plug :evil:. I ordered that jack since the original one I ordered was not in stock.

I went ahead and soldered in the new pot and new resistors I got for R102-202 and now just have to wait for the other jack to get in stock and shipped.

James

What's the size of your wall-wart? have you checked radio shack? (assuming youre in the states).
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 27 Aug 2010, 12:14 am
Well to say the least I am pretty bummed right now, my stereo pot came into today so I figured I would finally finish this up and be able to listen to it this week. BUT, the jack that I had ordered will not accept the wall wart plug :evil:. I ordered that jack since the original one I ordered was not in stock.
James

2.1mm I.D. x 5.5mm O.D. should be correct since that what it has for both the Digi-key wall PS plug (T987-P5P-ND) and the DC jack (CP-5-ND).

As Wushuliu asked, what part numbers did you order?  And, have you checked at Radio Shack for a DC jack that will fit your wall plug?
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 27 Aug 2010, 12:56 am
Guys,

Thanks for the replies. After I found my magnifying glass I found the issue. Digikey sent me the wrong wall wart (I had ordered the one wushuliu had listed on the first page). I am using the jack you pointed me to roymail.

The box was marked with the correct part number but in super small writing I found the unit itself had a different part number. I called and spoke with Digikey and they are sending me another one out. Their customer support was great to deal with. They even offered to send the new one out over night but everyone makes mistakes so I just had them ship regular mail.

I am also going to try and get a picture or two up and see if someone can lok at the wiring from the pot to the board to see if I made any mistakes. I believe it is correct but another set of eyes never hurts.

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 27 Aug 2010, 04:17 am
I am also going to try and get a picture or two up and see if someone can lok at the wiring from the pot to the board to see if I made any mistakes. I believe it is correct but another set of eyes never hurts.
James

I assume you're referring to the 3 wires (in-out-gnd) that connect from the volume pot to the board for each channel.  It should be easy to tell whether it's wired correctly.

CW = input
W = wiper
CCW = ground


Sure we'll be glad to look at some pics for you.  Hope you get things worked out soon.  You should be nearly done.  We'll be happy to hear your impressions of the B1.
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 27 Aug 2010, 11:49 am
Roymail,

Thanks for the response. I did use a post earlier in the thread as a guide for the pot hook up.  I just figured with my luck it will be better to see if anyone sees an issue with it.

I am really ready to get this preamp finished and see how it sounds. I thought that would have been tonight but now I am looking at next week sometime.

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: Chris Adams on 28 Aug 2010, 12:01 am
Hi everyone! My first post. I read the whole thread, bought the parts and put it together. My first build except for a Hafler amp and pre that I put together in the '80s. Thanks for all the pics and terrific information. Here's a couple of pics of mine.

(http://i80.photobucket.com/albums/j200/massagevermont/B1front.jpg)
(http://i80.photobucket.com/albums/j200/massagevermont/B1rear.jpg)
(http://i80.photobucket.com/albums/j200/massagevermont/B1inside.jpg)
Title: Re: Nelson Pass B-1 preamp kit
Post by: toxteth ogrady on 28 Aug 2010, 12:19 am
Outstanding Chris. Really well done! That last pic looks like a work of art. Now tell us how it sounds.


Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 28 Aug 2010, 12:31 am
Hi everyone! My first post. I read the whole thread, bought the parts and put it together. My first build except for a Hafler amp and pre that I put together in the '80s. Thanks for all the pics and terrific information. Here's a couple of pics of mine.

Wow. Nice.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 28 Aug 2010, 01:36 am

(http://i80.photobucket.com/albums/j200/massagevermont/B1inside.jpg)

Nice work.  I don't know how you came about choosing Audiocap Theta's, but Great choice.  However, Audiocap Theta is one of the caps that REALLY improve when bypassed with some Russian teflon caps.  I could try a Russian FT-1 on the 1 uF cap and larger FT-2 or 3 on the 10 uF cap. 

On the Audiocap, the teflon bypass truly improves the "air" and extend high treble while making low-treble/upper-mid much smoother and organic IME.
Title: Re: Nelson Pass B-1 preamp kit
Post by: poseidonsvoice on 28 Aug 2010, 01:50 am
Hi everyone! My first post. I read the whole thread, bought the parts and put it together. My first build except for a Hafler amp and pre that I put together in the '80s. Thanks for all the pics and terrific information. Here's a couple of pics of mine.

Nice work. Looks like a Context engineering chassis. Is that right?

Anand.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Chris Adams on 28 Aug 2010, 02:28 am
Thanks, guys! I am running a break in disc as we speak. Listened to it cold earlier today and it is smoother and much more of an open window then the clone P1.0 that I had been using, and that piece was no slouch. I'm all solid state. Modified Teradak Chameleon, B1, Bill Thalmann modded Sonographe SA-400, modded Maggie MMGs.

Jon L, I picked those caps after a lot of reading and some experimenting. I happen to have some FT-1s already and some FT-3s on the way. :)

Anand, it is indeed a Context engineering chassis. Nicely made and nice people to work with.
Title: Re: Nelson Pass B-1 preamp kit
Post by: kingnubian on 28 Aug 2010, 02:50 am
I have found that the 4-1k resistors have quite an effect with the B1. Im surprized it isnt mentioned a whole lot, seems to be a bigger issue on the dcb1 thread. Im sure it is somewhat system dependant but good parts in this location should be considered.

I have tried several different resistors so far and awaiting some naked Vishays now.

Takman carbon film- great bass and dynamics, warm and smooth but lack transparency
Prp metal film- smooth and transparent but lacks dynamics
Riken carbon film- great resistor with good transparency, smooth, awesome bass and dynamics. I think i could live with all 4 Rikens but some say use in moderation.
Naked Vishay(TX2575)- report back

I am going to try the Vishays as the input resistor and have the Rikens on the output right now, hoping that will be a good balance with awesome transparency. I will also note these results are based upon 330r.

I'd like to request direct retail links, if possible Canadian links in addition to U.S. links would also be appreciated, to the Riken & Naked Vishay resistors used in your build. I've found the Naked Vishay's but at almost $16 a pop CAD at Parts Connexion, I'm looking for alternate sources.
Title: Re: Nelson Pass B-1 preamp kit
Post by: kingnubian on 28 Aug 2010, 02:56 am
Hi everyone! My first post. I read the whole thread, bought the parts and put it together. My first build except for a Hafler amp and pre that I put together in the '80s. Thanks for all the pics and terrific information. Here's a couple of pics of mine.

(http://i80.photobucket.com/albums/j200/massagevermont/B1inside.jpg)

Wow!! This is exactly what I am after................100% beautiful build. Please post a link to the case retailer & I really hope they ship to Canada.
Title: Re: Nelson Pass B-1 preamp kit
Post by: mightym on 28 Aug 2010, 04:22 am
Chris:  Niiice.... :D

Title: Re: Nelson Pass B-1 preamp kit
Post by: poseidonsvoice on 28 Aug 2010, 04:55 am
I'd like to request direct retail links, if possible Canadian links in addition to U.S. links would also be appreciated, to the Riken & Naked Vishay resistors used in your build. I've found the Naked Vishay's but at almost $16 a pop CAD at Parts Connexion, I'm looking for alternate sources.

Google is your friend.

Context engineering desktop enclosures like the 175/350dt. (http://contextengineering.com/desktop_enclosures.html)

Texas Components TX2575. Just call them or e-mail them request: resistorinfo@texascomponents.com. They are usually $9 per resistor (http://www.texascomponents.com/)

Anand.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 28 Aug 2010, 10:47 am
I'd like to request direct retail links, if possible Canadian links in addition to U.S. links would also be appreciated, to the Riken & Naked Vishay resistors used in your build. I've found the Naked Vishay's but at almost $16 a pop CAD at Parts Connexion, I'm looking for alternate sources.

Im actually waiting on another pair of naked Vishays, the Riken is wonderfully colored but for my system is a tad warm. If your looking to warm things up its a great resistor.
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 28 Aug 2010, 11:29 am
Chris,

Very nice and clean looking build you have there.

I wish mine was going to be that nice looking, but…

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: Chris Adams on 28 Aug 2010, 11:50 am
Google is your friend.

Context engineering desktop enclosures like the 175/350dt. (http://contextengineering.com/desktop_enclosures.html)

Texas Components TX2575. Just call them or e-mail them request: resistorinfo@texascomponents.com. They are usually $9 per resistor (http://www.texascomponents.com/)

Anand.

The contact at Context is Lucy and at Texas Components it's Janet Alcebo. I called both and they were very pleasant and easy to deal with. I have some TX2575 in my dac and I'm going to try some in the B1. The difference in the dac was amazing. :o
Title: Re: Nelson Pass B-1 preamp kit
Post by: rtate on 28 Aug 2010, 04:20 pm
Chris, what type of volume pot did you use??
Is that a PEC?
What are you powering your B1 with?
Also where did you source the nichon electrolytics??

Thanks
Great build by the way :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: Chris Adams on 28 Aug 2010, 04:59 pm
rtate,

Thanks for the compliment!
The pot is from gigawork on ebay 120502791204, 20k stereo 21 step. Inexpensive build quality but great sound, $15 shipped. Got the Gold Tune Nichicons from Parts Connection. Using the PS from Digikey at the moment but I intend to try batteries when it's broken in.
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 28 Aug 2010, 05:03 pm
Here is my correct pot connected. I believe the wiring is correct but if anyone wants to take a pick that would be great (hopefully the picture is clear enough). Thanks.

James

(http://i148.photobucket.com/albums/s3/exojam/wiring.jpg)
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 28 Aug 2010, 05:16 pm
James, the pot wiring appears to be right in the picture.  Looks like you're close to being done.  But, what's the deal with those humongous caps?  :wink:
Title: Re: Nelson Pass B-1 preamp kit
Post by: kingnubian on 28 Aug 2010, 05:18 pm
rtate,

Thanks for the compliment!
The pot is from gigawork on ebay 120502791204, 20k stereo 21 step. Inexpensive build quality but great sound, $15 shipped. Got the Gold Tune Nichicons from Parts Connection. Using the PS from Digikey at the moment but I intend to try batteries when it's broken in.

I got an email from Gigawork stating that their pot is a Linear type. I was after a logarithmic so I'm inclined to pick up one of these.

http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&item=270617059671&ssPageName=STRK:MEWAX:IT#ht_4926wt_911
http://cgi.ebay.ca/Assemble-Dale-23-Step-Attenuator-Volume-Control-50k-/270311270532?pt=LH_DefaultDomain_0#ht_2154wt_911
http://parts.digikey.com/1/parts/737959-pot-10k-ohm-2w-dual-log-taper-kka1031s28.html
 
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 28 Aug 2010, 05:30 pm
James, the pot wiring appears to be right in the picture.  Looks like you're close to being done.  But, what's the deal with those humongous caps?  :wink:

Roymail,

Thanks for taking the time to look of the wiring. The caps were recommended so I figured I would give them a try and see where it takes me.

Yeah, I am almost there. I used some JB Weld to fix up one RCA hole and the switch hole. The housing will not look nearly as good as some I am seeing but for now it will work. I will have to place this next to my TT so the smaller the better at this time.

The thing I am waiting for most of all is to see how this sounds in my setup. I have never done anything DIY like this so it will be interesting to hear the results.

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: kingnubian on 28 Aug 2010, 05:33 pm
Roymail,

Thanks for taking the time to look of the wiring. The caps were recommended so I figured I would give them a try and see where it takes.

Yeah, I am almost there. I used some JB Weld to fix up one RCA hole and the switch hole. The housing will not look nearly as good as some I am seeing but for now it will work. I will have to place this next to my TT so the smaller the better at this time.

The thing I am waiting for most of all is to see how this sounds in my setup. I have never done anything DIY like this so it will be interesting to hear the results.

James

What caps did you use? I was looking at using Sonicaps Gen 1 (1uf & 10uf)
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 28 Aug 2010, 05:58 pm
Those are the Clarity ESA's.

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: rtate on 28 Aug 2010, 06:05 pm
Kingnubian , I have the digikey pot for my build but have not completed it yet so I can't coment on the sound....
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 28 Aug 2010, 06:05 pm
I got an email from Gigawork stating that their pot is a Linear type. I was after a logarithmic so I'm inclined to pick up one of these.

http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&item=270617059671&ssPageName=STRK:MEWAX:IT#ht_4926wt_911
http://cgi.ebay.ca/Assemble-Dale-23-Step-Attenuator-Volume-Control-50k-/270311270532?pt=LH_DefaultDomain_0#ht_2154wt_911
http://parts.digikey.com/1/parts/737959-pot-10k-ohm-2w-dual-log-taper-kka1031s28.html

I would still go with the Gigawork. Despite being linear, it is smoother and easier to use than the others you have linked and there's a lot of good feedback on it, not just on this forum. I do not care for the switch quality of the Dale. And you don't want to get that PEC stereo pot, they are not reliable for matching. Only use their mono pots.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 28 Aug 2010, 06:07 pm
I got an email from Gigawork stating that their pot is a Linear type. I was after a logarithmic so I'm inclined to pick up one of these.

Huh?  The Gigawork 20K pot I ordered says clearly log type in the ad:
"Up for sale is one (1) piece Brand New 21-stepped attenuator 20K Type A (Log)  STEREO using SMT resistors.  Knurled shaft supplied with a nut and a star washer"

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=120502791204&ssPageName=STRK:MEWAX:IT#ht_4201wt_907
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 28 Aug 2010, 06:09 pm
Kingnubian , I have the digikey pot for my build but have not completed it yet so I can't coment on the sound....

Hi rtate, as I just said above the dual-gang PEC pots are not recommended. There have been serious issues reported w/ L/R volume matching in the past.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 28 Aug 2010, 06:10 pm
Huh?  The Gigawork 20K pot I ordered says clearly log type in the ad:
"Up for sale is one (1) piece Brand New 21-stepped attenuator 20K Type A (Log)  STEREO using SMT resistors.  Knurled shaft supplied with a nut and a star washer"

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=120502791204&ssPageName=STRK:MEWAX:IT#ht_4201wt_907

That's what I thought too. I know they used to be linear, but mine sure operates like log...

EDIT: I see that I describe them as linear in the BOM. I'll change that.
Title: Re: Nelson Pass B-1 preamp kit
Post by: rtate on 28 Aug 2010, 06:12 pm
wushuliu, thanks for the heads up I wish I would have known this before I spent the 32$ on it.
Where did you read about the unreliability??
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 28 Aug 2010, 06:20 pm
wushuliu, thanks for the heads up I wish I would have known this before I spent the 32$ on it.
Where did you read about the unreliability??

It's come up several time on diyaudio.com. Doesn't mean yours won't be fine, but better safe than sorry. If you haven't used them yet, it's easy to do returns w/ digikey...

http://www.diyaudio.com/forums/chip-amps/40676-so-i-did-try-all-those-different-potentiometers-25.html#post807128 (http://www.diyaudio.com/forums/chip-amps/40676-so-i-did-try-all-those-different-potentiometers-25.html#post807128)
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 28 Aug 2010, 06:33 pm
Here's a post from stereo.au that maybe of some help.

http://www.stereo.net.au/forums/showthread.php/21593-Dirt-cheap-stepped-attenuators-available?s=6d14852c87a8634f8b471a3a28111cba&p=326222&viewfull=1#post326222 (http://www.stereo.net.au/forums/showthread.php/21593-Dirt-cheap-stepped-attenuators-available?s=6d14852c87a8634f8b471a3a28111cba&p=326222&viewfull=1#post326222)


Just to report my findings regarding these attenuators.

- Build quality is excellent. Nicely made gold plated spring brushes sliding over gold plated pads. I lubricated mine with Caig ProGold to start with. It is an open construction which may cause some dirt accumulation over time but it also makes cleaning a breeze.

- The log profile is more a dual-linear. I can post an graph to illustrate this - but essentially starts with almost a perfect linear transition with a slow slope from 0 to 10th step and then changes to a steeper linear curve from 10th to 21st step. I find this very useful because it gives more control at low levels.

- Precision is very good. Overall difference between channels is around 0.2% but never larger then 0.4%. To be accurate, on 4 attenuators (2x10K and 2x50K) that I bought I found only 3 steps on each of them to have larger channel difference then 0.1%.

- Physical size is also good because they are 1/3 smaller then standard Alps Blue and can be fitted anywhere in the case. Feeling when rotating the shaft is very smooth with very soft but distinct steps. Rotation resistance is just right to give a good control but also to allow a fast change.

- Listening test: the real benefit with steppers is always precision and control on low volume levels. This one is no different. When compared to Alps blue that it replaced - it brought more clarity as my first impression, on top of already anticipated (and achieved) improvements. In my case it was also the size that mattered since it allowed me to bring the pot closer to the selector relays at the back of the case (with an extension shaft) and shorten the signal path considerably.

- Bad things - none. Simply as that. That being said - yes they do have "only" 21 steps. I did not find that restrictive in any way simply because of the nicely designed pseudo-log curve. On top of that - standard steppers are all around 24steps and that is not a big difference. For more then that one has to go towards digitally controlled volume controllers like the one from Twisted Pear, but they do cost a lot and they need a PSU.

- The best thing - price! For $10 this is a steal. Who ever has Alps pots should think seriously about replacing them with these.
Title: Re: Nelson Pass B-1 preamp kit
Post by: rtate on 28 Aug 2010, 06:37 pm
Thanks again wushuliu   :thumb:
If I measue the pot with a couple of meters would I be able to see if the pec pot is ok??
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 28 Aug 2010, 06:38 pm
Thanks again wushuliu   :thumb:
If I measue the pot with a couple of meters would I be able to see if the pec pot is ok??

Dunno 'bout that. Maybe someone else can chime on the best way to assess matching accuracy.
Title: Re: Nelson Pass B-1 preamp kit
Post by: kingnubian on 28 Aug 2010, 06:46 pm
That's what I thought too. I know they used to be linear, but mine sure operates like log...

EDIT: I see that I describe them as linear in the BOM. I'll change that.

I'm sold. I've sent in an order for the pots that you recommend.
Thanks as usual for the heads up.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 28 Aug 2010, 06:53 pm
wushuliu, thanks for the heads up I wish I would have known this before I spent the 32$ on it.

I'm not doubting wushuliu or the posts on other forums, but I got a chance to audition a passive shunt attenuator using a dual gang PEC and a Caddock 132 resistor on each channel.  I have to say it sounded awesome in my system, beautifully musical to my ears.

So as previously stated, yours may sound just fine.  Don't despair just yet.  :wink:
Title: Re: Nelson Pass B-1 preamp kit
Post by: kingnubian on 28 Aug 2010, 07:55 pm
I'm not doubting wushuliu or the posts on other forums, but I got a chance to audition a passive shunt attenuator using a dual gang PEC and a Caddock 132 resistor on each channel.  I have to say it sounded awesome in my system, beautifully musical to my ears.

So as previously stated, yours may sound just fine.  Don't despair just yet.  :wink:

Good to hear as I also ordered the PEC for another upcoming project.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 29 Aug 2010, 10:18 pm
Guess what came in the mail today  :green: The lovely and expensive Vishay TX2575's.

(http://a.imageshack.us/img291/8278/img5483h.jpg) (http://img291.imageshack.us/i/img5483h.jpg/)

Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 29 Aug 2010, 10:36 pm
BEFORE

(http://a.imageshack.us/img413/5990/img5490y.jpg) (http://img413.imageshack.us/i/img5490y.jpg/)

AND AFTER

(http://a.imageshack.us/img405/1404/img5500a.jpg) (http://img405.imageshack.us/i/img5500a.jpg/)

I have my burn-in music going, but I couldn't resist so took a listen anyway.  So far, even before solder is dry, there's a feeling I went from tap water to a really good bottled water due to the gentle clarity.  A little bit of grit and grain I used to hear on certain vocal tracks are clean and clear. 

Will let'em burn for a gazillion years and report back. 

Too bad the SMT volume control is stuck at the post office.  I was home, but they must have rang the bell once and took off, with that pick-up notice stuck to my door  :roll:
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 29 Aug 2010, 11:10 pm
Jon L, thanks for posting the pics.  What B1 board are you using?  Doesn't appear to be a standard Pass B1 board.  Did I miss something?

What's the benefit of using 330R value?

Thanks!
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 29 Aug 2010, 11:11 pm
Quote
  Guess what came in the mail today   The lovely and expensive Vishay TX2575's.

Nice work Jon, I have another pair of the Vishays on the way. How long did your order take?
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 30 Aug 2010, 07:59 pm
Well, the 20K SMT volume control is here from Hong Kong.  It sure is tiny compared to Alps it is replacing.  After only about half an hour, jury is still out on whether sound quality actually improved or just changed.

(http://a.imageshack.us/img101/2937/img5512r.jpg) (http://img101.imageshack.us/i/img5512r.jpg/)

Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 30 Aug 2010, 08:23 pm
I just installed a second pair of naked Vishays TX2575 in place of a pair of Rikens in the output position. I now have 2 pairs of the naked Vishays in the signal positions. The clairty has gone thru the roof, I lost a little bass and dynamics/volume, i think i have confused dynamics with noise created by using carbon/riken resistor. Anyway thru trial and error i can say if you can afford the Vishays you will be rewarded with awesome transparency and tight clean bass. This is using 330r Vishays and Sonicaps your results may vary depending on how revealing your system is.  :wink:
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 30 Aug 2010, 09:14 pm
Well, the 20K SMT volume control is here from Hong Kong.  It sure is tiny compared to Alps it is replacing.  After only about half an hour, jury is still out on whether sound quality actually improved or just changed.

(http://a.imageshack.us/img101/2937/img5512r.jpg) (http://img101.imageshack.us/i/img5512r.jpg/)

I would have thought that the SMT stepped attenuator would be noticeably superior to an Alps Blue pot.  Any thoughts as to what's going on with this? 

Please keep us updated.  Thanks!
Title: Re: Nelson Pass B-1 preamp kit
Post by: kingnubian on 31 Aug 2010, 12:51 am
I just installed a second pair of naked Vishays TX2575 in place of a pair of Rikens in the output position. I now have 2 pairs of the naked Vishays in the signal positions. The clairty has gone thru the roof, I lost a little bass and dynamics/volume, i think i have confused dynamics with noise created by using carbon/riken resistor. Anyway thru trial and error i can say if you can afford the Vishays you will be rewarded with awesome transparency and tight clean bass. This is using 330r Vishays and Sonicaps your results may vary depending on how revealing your system is.  :wink:

Thanks for the update. This is the exact route I will be taking.

I have one question though. I will be using my B1 build in front of a ClassDaudio SDS-254 diy build. Anyone with experience with this setup or driving another class D amp?
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 31 Aug 2010, 02:05 am
Thanks for the update. This is the exact route I will be taking.

I have one question though. I will be using my B1 build in front of a ClassDaudio SDS-254 diy build. Anyone with experience with this setup or driving another class D amp?

Thats the exact setup i am running, the match up is impeccable. Highly reccomend!!  :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 31 Aug 2010, 03:19 am
I would have thought that the SMT stepped attenuator would be noticeably superior to an Alps Blue pot.  Any thoughts as to what's going on with this? 

It probably is superior, but I had to adjust my system a bit.  SMT does sound more solid and resolute through mids to bass, but it seemed a tad too "controlled" AKA "darker" up top compared to Alps.  SMT may in fact be more accurate here and Alps injecting its own splash and "air" perhaps by making you notice the treble more due to less solid mids/bass possibly. 

Anyway, I changed out my Stereovox XV2 for a UPOCC solid silver digital cable and that seemed to have rebalanced things just right...

I do want to compare both volume controls to *no pot," meaning bypass the volume.  Do I just connect input wire to output wire (bypassing pot)? What do I do with the ground wire that goes to the vol pot?
Title: Re: Nelson Pass B-1 preamp kit
Post by: rtate on 31 Aug 2010, 11:07 pm
Just to report back on the dual pec pot, I took some measurments and the results are a bit concerning to say the least    :scratch:

At 200 ohms there was a difference of 60 ohms
At 1K there was a difference of  250 ohms
At 20k there was a difference of almost 3k

I can't imagine that this wouldn't be audible!!!!
At this point I think I will order one of the stepped volume controls.....
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 1 Sep 2010, 12:00 am
It's absolutely crazy, but I seemed to have bought yet another preamp, the Diyparadise Eva LDR  :scratch:

(http://a.imageshack.us/img696/2613/evauu.jpg) (http://img696.imageshack.us/i/evauu.jpg/)

Now I have my tweaked-out Transcendant Grounded Grid tube preamp, almost-tweaked-out Pass B-1, and a LDR preamp, which I assume will not have much to tweak. 

It's crazy because I run my system source-direct most of the time without a preamp, and so far preampless sounds "best" to me.  I guess I can have fun having my own preamp shoot-outs after each parts upgrade  :duh:
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 1 Sep 2010, 12:10 am
Jon L, thanks for posting the pics.  What B1 board are you using?  Doesn't appear to be a standard Pass B1 board.  Did I miss something?

What's the benefit of using 330R value?

Thanks!

Lower outpuit resistance has been found to increase clarity and dynamics. However you don't want to go too low or you risk oscillating your amp. The stock DCB1 recommends 220 ohms for instance; 330 ohms is the lowest I've tried and therefore the lowest i recommended at the beginning of this thread.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 1 Sep 2010, 01:26 am
Lower outpuit resistance has been found to increase clarity and dynamics. However you don't want to go too low or you risk oscillating your amp. The stock DCB1 recommends 220 ohms for instance; 330 ohms is the lowest I've tried and therefore the lowest i recommended at the beginning of this thread.

AC, the (4) 1K ohm resistors on the B1?
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 1 Sep 2010, 01:50 am
AC, the (4) 1K ohm resistors on the B1?

Yeppers
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 1 Sep 2010, 07:21 am
It's absolutely crazy, but I seemed to have bought yet another preamp, the Diyparadise Eva LDR  :scratch:

(http://a.imageshack.us/img696/2613/evauu.jpg) (http://img696.imageshack.us/i/evauu.jpg/)

Now I have my tweaked-out Transcendant Grounded Grid tube preamp, almost-tweaked-out Pass B-1, and a LDR preamp, which I assume will not have much to tweak. 

It's crazy because I run my system source-direct most of the time without a preamp, and so far preampless sounds "best" to me.  I guess I can have fun having my own preamp shoot-outs after each parts upgrade  :duh:

Nice price on that too...
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 1 Sep 2010, 10:42 pm
Nice price on that too...

I know.  I can sort of see LDR volume-control integrated with B1 or DCB buffer in one box for REALLY nice preamp  :thumb:

BTW.  Do you think just bypassing the volume pot in B-1 and soldering together input wire with output wire would be OK?
Title: Re: Nelson Pass B-1 preamp kit
Post by: Russtafarian on 2 Sep 2010, 12:09 am
Quote
BTW.  Do you think just bypassing the volume pot in B-1 and soldering together input wire with output wire would be OK?

That'll work Jon.  But keep in mind you may be changing the input impedance of the circuit by removing the pot.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 2 Sep 2010, 02:31 am
I know.  I can sort of see LDR volume-control integrated with B1 or DCB buffer in one box for REALLY nice preamp  :thumb:

BTW.  Do you think just bypassing the volume pot in B-1 and soldering together input wire with output wire would be OK?

Hey Jon,  I raised the same question back on page 25, post 489.  But, I'm still not real sure about it.  The Burson Buffer doesn't have a volume pot, just rca's.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 2 Sep 2010, 03:22 am
That'll work Jon.  But keep in mind you may be changing the input impedance of the circuit by removing the pot.

That's why I ask, Russ.  Wondering if I need to solder on some resistors instead of pot, and what do I do with the green ground wire soldered to the pot?  Leave it on the pot or solder it on to some random ground point on the board or chassis?
Title: Re: Nelson Pass B-1 preamp kit
Post by: Russellc on 2 Sep 2010, 06:14 pm
It's come up several time on diyaudio.com. Doesn't mean yours won't be fine, but better safe than sorry. If you haven't used them yet, it's easy to do returns w/ digikey...

http://www.diyaudio.com/forums/chip-amps/40676-so-i-did-try-all-those-different-potentiometers-25.html#post807128 (http://www.diyaudio.com/forums/chip-amps/40676-so-i-did-try-all-those-different-potentiometers-25.html#post807128)

Just exchange for the mono pots from PEC, they work fine. It's what Nelson uses in the commercial version.

Russellc
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 3 Sep 2010, 12:42 pm
Well the wall wart should be arriving today. Then I will find out if I hooked everything up correctly.

One thing has me thinking though. Right now my speakers are different length away from my listening position due to room layout. With the Onkyo I have the trims a little different to get 75db at the listening position. I hope that one side will not sound louder than the other through the pre amp.

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: sondale on 3 Sep 2010, 01:50 pm
Hey Jon,  I raised the same question back on page 25, post 489.  But, I'm still not real sure about it.  The Burson Buffer doesn't have a volume pot, just rca's.
Roy - have you tried it yet?

Alan
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 3 Sep 2010, 02:17 pm
Alan,  I haven't tried it yet, just one of many things I haven't gotten around to doing. :?
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 3 Sep 2010, 08:55 pm
Well I got the wall wart in and hooked up the B1. No left channel! Took it back out to the garage and found the left wire had come off of the RCA. Fixed.

First up were Robert Plant and Alison Krauss “Raising Sand”. On this album I noticed the vocals had even more separation than before, also the instruments were more defined. Next up was Willie Nelson. This also sounds very clear and all vocals and instruments were available to listen to separately or “all together” if that makes sense.  I suck at describing what I hear so I apologize about that.

What I found interesting is that I could tell a difference in the material, not an absolutely huge difference but a change for the better none the less, but my mother in law yelled out to me while listening to the WN album and asked why I turned it down. I called her out to show her the B1 and she commented on how she was able to listen to every instrument in the band and the vocals and thought it was fantastic.

The one bad thing about the way I made mine is that the sound from the right speaker gets to my listening position before the left due to the way the speakers sit in the room. With the B1 (as I have it) I cannot control this since I am using a single pot.  This was something I did not think of before going this route, so I guess I will just have to change the area I sit in while jamming.

All in all very happy.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Russtafarian on 3 Sep 2010, 09:21 pm
@JonL: If the pot is hooked up in the usual way (not as a shunt volume control) you can replace it with a resistor of the same value as the pot.  So if it's the 10k Alps pictured below, replace the pot with a 10k resistor for each channel.  You don't need to do anything with the ground wire other than make sure it doesn't touch and potentially short anthing else in the circuit to ground.  if you're not going to use a pot at all, remove the ground wire from the board.

Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 3 Sep 2010, 09:35 pm
@JonL: If the pot is hooked up in the usual way (not as a shunt volume control) you can replace it with a resistor of the same value as the pot.  So if it's the 10k Alps pictured below, replace the pot with a 10k resistor for each channel.  You don't need to do anything with the ground wire other than make sure it doesn't touch and potentially short anthing else in the circuit to ground.  if you're not going to use a pot at all, remove the ground wire from the board.

Thanks Russ.  Will try that, but I'm beginning to think what's stopping me from soldering some good wire from my soon-to-arrive LDR attenuator's output right onto the B-1 board.  Bet that sounds fantastic  :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 3 Sep 2010, 09:47 pm
Riddle me this Joker....whats GREEn with envy, cant get hard and loves taking a stiff horse cock in the arse? Why John R it be! Aaaargh hes a faggy pirate. Aaaargh!
haha John R u loser tigtey whitey tight ass!

The Man

Matt, you should soon see the inside of the intergalatic wastebin, a place for all those who don't play nicely!  Real men know when to behave.  :nono:
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 3 Sep 2010, 10:00 pm
Here is a picture of the final outcome. I like the small foot print of it now but once that last hermit crab on the other shelf goes to see Davey Jones than I will make a better housing.

I also forgot to say thanks to Pass Labs for making this available and to all those who helped me get a finished B1!

(http://i148.photobucket.com/albums/s3/exojam/FinishedB1.jpg)

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 3 Sep 2010, 10:42 pm

(http://i59.photobucket.com/albums/g295/mrnick_2006/Picture869.jpg)


(http://i59.photobucket.com/albums/g295/mrnick_2006/Picture877.jpg)


Well i just i would post a couple of pic's since i am totally finished with this B1 project. Cleaned up some wireing and installed Gen2 bypasses and with the new naked Vishays it rocks!!
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 3 Sep 2010, 11:17 pm
Nice job, Keith.  I don't have to ask how it sounds.  :D
Title: Re: Nelson Pass B-1 preamp kit
Post by: Chris Adams on 3 Sep 2010, 11:48 pm
Nick77,

That is gorgeous! :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: poseidonsvoice on 4 Sep 2010, 12:13 am
Well i just i would post a couple of pic's since i am totally finished with this B1 project. Cleaned up some wireing and installed Gen2 bypasses and with the new naked Vishays it rocks!!

Whew! Finally...you are done! :banana piano:

Anand.
Title: Re: Nelson Pass B-1 preamp kit
Post by: kingnubian on 4 Sep 2010, 03:56 am

Well i just i would post a couple of pic's since i am totally finished with this B1 project. Cleaned up some wireing and installed Gen2 bypasses and with the new naked Vishays it rocks!!

Excellent! Thanks for the tips btw.
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 4 Sep 2010, 02:27 pm
Nick,

Do you have other caps paralleled off of both the 1 and 10 caps in there? If so, what was the purpose of that? Thanks.

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 4 Sep 2010, 03:06 pm
Quote
   The Sonicap Gen I is basically a fairly balanced capacitor.  However, some find our "balanced" slightly thin and bright compared to the more lush "colored" capacitors which would include the Gen II.  While the Gen II has a nice Midrange bloom, Gen I has a slight advantage on the freq extremes (top and bottom).  In many applications, larger values of Gen I bypassed with smaller values of Gen II yield a very favorable result.

                                                                 
The bypass added a little extra detail and lushness.
Title: Re: Nelson Pass B-1 preamp kit
Post by: exojam on 4 Sep 2010, 03:43 pm
Interesting...

James
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 7 Sep 2010, 03:27 am
Jeez, that Hong Kong SMT volume control turned out to be very flimsy.  The shaft and nut became loose, so I tightened the nut just a little bit more...and bam! the whole shaft separated off of the body  :duh:

Luckily, I think I prefer the sound of Blue Velvet more anyway.  It's more organic yet more sparkly IMO. 

I finally replaced the 1 uF input cap to my secret-weapon, Penta Labs teflon caps which are well-used already.  Very niice... I then replaced the wiring with solid-core silver in teflon/air.  Nicer..  My camera is MIA but photos to come later.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 8 Sep 2010, 10:05 pm
(http://a.imageshack.us/img64/2231/img3577o.jpg) (http://img64.imageshack.us/i/img3577o.jpg/)

These 1uF Penta Labs teflon caps (white) are HUGE!  Unfortunately, I can't close the lid anymore, but at least I have a DAC with huge caps I can't close the lid, either, so at least they'll match..
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 8 Sep 2010, 10:13 pm
So how is it sounding??
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 9 Sep 2010, 03:52 am
Jon, those MONSTER caps got me looking and reading, and  I came across your articles in Enjoy the Music.  Very nice reading, descriptions and pictures.  Nice job!

For those who may be interested, here you go.  It's two parts.

http://www.enjoythemusic.com/diy/0708/capacitor1.htm
http://www.enjoythemusic.com/diy/1108/capacitor1.htm

Maybe next you could try SLA battery power and a Goldpoint/Elma 20K stepped attenuation.  WOW!  :D
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 9 Sep 2010, 04:01 am
Jon, those MONSTER caps got me looking and reading, and  I came across your articles in Enjoy the Music.  Very nice reading, descriptions and pictures.  Nice job!

For those who may be interested, here you go.  It's two parts.

http://www.enjoythemusic.com/diy/0708/capacitor1.htm
http://www.enjoythemusic.com/diy/1108/capacitor1.htm

Maybe next you could try SLA battery power and a Goldpoint/Elma 20K stepped attenuation.  WOW!  :D

I do have a Goldpoint in my grounded grid, so I may "borrow" that for a while, but a proper, really transparent volume control at reasonable prices is a dilemma.

Ebay SMT volume control guys have agreed to send me another 20K one after I told them the shaft broke at the body, so at least that's good.  There's a small protrusion on these SMT to prevent it from spinning around the shaft, but how are you guys making the opening on the chassis? 
Title: Re: Nelson Pass B-1 preamp kit
Post by: avionic on 9 Sep 2010, 06:23 am
Hey Jon, I just took the wire cutters to that "small protrusion" and drilled a single hole. The nut holds the pot plenty tight with the lock washer and I have a nice flush mount.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 9 Sep 2010, 05:21 pm
Hey Jon, I just took the wire cutters to that "small protrusion" and drilled a single hole. The nut holds the pot plenty tight with the lock washer and I have a nice flush mount.

That's what I did initially, and the SMT was nice and tight.  But after some use, the volume control became looser and looser, rotating past the stop when turned. That's when I tried tightening the nut, which broke the shaft  :scratch:

If I decide to use the SMT again, I may try a power drill to make an opening for that protrusion to stick into.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Chris Adams on 9 Sep 2010, 05:52 pm
Jon, I did just that with a drill and it works fine. Your front panel looks a tad thicker than mine so it should work fine. In order to go deep enough on mine, I ended up with a small nipple on the front of the panel from the tip of the drill bit. :duh: The volume knob covers it up just fine. :wink:
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 9 Sep 2010, 09:37 pm
Jon, I did just that with a drill and it works fine. Your front panel looks a tad thicker than mine so it should work fine. In order to go deep enough on mine, I ended up with a small nipple on the front of the panel from the tip of the drill bit. :duh: The volume knob covers it up just fine. :wink:

Are you happy with your SMT's sound quality (compared to?). 

Since I haven't tried the SMT since the teflon cap upgrade, I will give it another shot when the replacement SMT arrives.  I plan to let the teflons run in for a gazillion years before making up my mind, but already there is a removal of compression and a lot more dynamic freedom and energy.  If I could only get some 10 uF teflon capacitors  :o
Title: Re: Nelson Pass B-1 preamp kit
Post by: poseidonsvoice on 9 Sep 2010, 11:14 pm
  If I could only get some 10 uF teflon capacitors  :o

You can get close. There is no reason why you have to settle on a 10uf cap value, if you have a high impedance amplifier you are driving (like something with an input impedance of 50K). The RC constant will still be plenty low with something like 4.7uf. In fact, VH Audio sells a 3.3uf TFTF which will settle you back a nice $700 each  :P And when the cap starts getting really large, then all you've got is an antenna to pick RF up... :scratch:

But at that point I would ask myself, wouldn't a transformer coupled or a direct coupled design be better? Like the DCB1?

Anand.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Chris Adams on 10 Sep 2010, 02:13 am
Are you happy with your SMT's sound quality (compared to?). 

Since I haven't tried the SMT since the teflon cap upgrade, I will give it another shot when the replacement SMT arrives.  I plan to let the teflons run in for a gazillion years before making up my mind, but already there is a removal of compression and a lot more dynamic freedom and energy.  If I could only get some 10 uF teflon capacitors  :o

I've only had the SMT in it so far. Still burning the FT-1/3. I want to wait 'till they settle down before I do anything else. I do have Blue Velvet in another pre but it's 10k and the SMT is 20k. I don't know how much SQ difference the impedance change will make.
Title: Re: Nelson Pass B-1 preamp kit
Post by: kingnubian on 15 Sep 2010, 03:59 pm
Here are some pics of my build. This is my first diy build of any kind and I had not picked up a soldering iron in years. Some things stay with you though & I remember my dad teaching me how to solder when I was still in primary school. The leads are still there in case I needed to remove & reseat any components but will be clipped off when the build is complete.

The build is obviously not complete. I'm still waiting on the Sonicaps & the naked Vishay resistors, got the invoice but no resistors.....strange.
I'm also toying with ideas of how to power the B1. Using batteries is very doable but not at the top of my list which also includes classic Toroid, mini SMPS or just a wall wart.

(http://www.audiocircle.com/image.php?id=35784)

(http://www.audiocircle.com/image.php?id=35785)

Title: Re: Nelson Pass B-1 preamp kit
Post by: Chris Adams on 16 Sep 2010, 02:17 am
kingnubian, That's looking good. I presume you're getting Gen 1. Are you going to bypass them with anything? I ask because I had some 4.7 Gen 1s in a dac and when I bypassed with a .1 Gen 2, it smoothed out the top end nicely. Good luck.
Title: Re: Nelson Pass B-1 preamp kit
Post by: kingnubian on 16 Sep 2010, 03:43 am
kingnubian, That's looking good. I presume you're getting Gen 1. Are you going to bypass them with anything? I ask because I had some 4.7 Gen 1s in a dac and when I bypassed with a .1 Gen 2, it smoothed out the top end nicely. Good luck.

As per a suggestion I received by a member here, I will be bypassing the Gen 1's with .1 Gen 2's. Hopefully I will get them next week & will also look into ordering a case as well.
Title: Re: Nelson Pass B-1 preamp kit
Post by: kingnubian on 27 Sep 2010, 02:44 pm
Almost finished with the build. Just waiting on the caps & chassis.

There seems to be a number of ways disused on how to power the B1. The 3 I am looking at are

1) Wall wart (18-20v)
2) Batteries (2x9v) {Onece in my audio stand battery replacement would be a chore unless they were mounted externally)
3) SMPS like this one (http://cgi.ebay.com/DC-18V-2A-Universal-Regulated-Switching-Power-Supply_W0QQitemZ270617463458QQcategoryZ58288QQcmdZViewItemQQ_trksidZp3286.m263QQ_trkparmsZalgo%3DSIC%26itu%3DUCI%252BIA%252BUA%252BFICS%252BUFI%252BDDSIC%26otn%3D5%26pmod%3D170390359079%26po%3DLVI%26ps%3D63%26clkid%3D5387978462761763319#ht_2557wt_1011)

What are the advantages & disadvantages of each approach physically & with respect to sonics?
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 2 Oct 2010, 01:12 am
I let the B-1 "cook" for a long while since the last set of mods (1 uF Penta Labs Teflon cap and silver/teflon wires) before messing around again, and it has come a long way. 

The transparency and the straight-wire quality definitely improved a great deal.  It's gotten so darn good, I figured it's only a few % away from becoming a true world-beater Monster preamp.  So I threw the kitchen sink at it.  I bypassed the 1 uF Penta Labs teflon with 0.1 uF Aura-T Teflon caps and the 10 uF Jantzen Superior-Z with 0.22 uF FT-3 Teflon caps (awesome in bypass duty). 

I'll let it burn in a lot more, but already, I can't stop grinning  :green:

(http://img828.imageshack.us/img828/2928/img3693k.jpg) (http://img828.imageshack.us/i/img3693k.jpg/)


Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 2 Oct 2010, 01:28 am
I let the B-1 "cook" for a long while since the last set of mods (1 uF Penta Labs Teflon cap and silver/teflon wires) before messing around again, and it has come a long way. 

The transparency and the straight-wire quality definitely improved a great deal.  It's gotten so darn good, I figured it's only a few % away from becoming a true world-beater Monster preamp.  So I threw the kitchen sink at it.  I bypassed the 1 uF Penta Labs teflon with 0.1 uF Aura-T Teflon caps and the 10 uF Jantzen Superior-Z with 0.22 uF FT-3 Teflon caps (awesome in bypass duty). 

I'll let it burn in a lot more, but already, I can't stop grinning  :green:

(http://img828.imageshack.us/img828/2928/img3693k.jpg) (http://img828.imageshack.us/i/img3693k.jpg/)



 :beer:
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 2 Oct 2010, 01:56 am
Jon L, you should email that pic to Nelson Pass along with a description of the caps.  I wonder if he ever envisioned such a B1 super mod?  AWESOME!  :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: Jon L on 2 Oct 2010, 05:22 pm
Jon L, you should email that pic to Nelson Pass along with a description of the caps.  I wonder if he ever envisioned such a B1 super mod?  AWESOME!  :thumb:

I wouldn't want Nelson Pass to think I'm a total nutjob!

Seriously though, every time I have to embark on one of these capacitor exercises for audio gear, it takes a lot of time and effort and makes me long for a capacitor-less world.  I guess I'm lucky (?) I have all these capacitors laying around already, so at least I have a shot at ending up with something that fits my needs  :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: kingnubian on 7 Oct 2010, 04:55 pm
Got these in the mail today, 20 (10x10) K73-16 Russian Caps of both 10uf & 1uf rating. I will be pairing these up with some Obbligato Premiums that I have on the way in my B1 build.  From everything I've been reading these may be a good mix n match with the Obbligatos. As usual, the proof will be in the pudding.

P.S. If anyone is in the Montreal area, it looks like I may have a few extra K73-16caps that I can part with as I now have more than I will need.

(http://www.audiocircle.com/image.php?id=36742)
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 7 Oct 2010, 06:02 pm
I may have a few extra K73-16caps that I can part with as I now have more than I will need.

(http://www.audiocircle.com/image.php?id=36742)

Really, you think?   :thumb:

Let us know how those work for you.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Russellc on 8 Oct 2010, 06:26 pm
Got these in the mail today, 20 (10x10) K73-16 Russian Caps of both 10uf & 1uf rating. I will be pairing these up with some Obbligato Premiums that I have on the way in my B1 build.  From everything I've been reading these may be a good mix n match with the Obbligatos. As usual, the proof will be in the pudding.

P.S. If anyone is in the Montreal area, it looks like I may have a few extra K73-16caps that I can part with as I now have more than I will need.

(http://www.audiocircle.com/image.php?id=36742)



Similarly, I thought I ordered 3 Similac 100uF, 35 volt and inadvertantly ordered 30 if anyone is looking.  I have no use for 30 of these, only needed 3. Obviously, they are not expensive!

Russellc
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 10 Oct 2010, 08:51 pm
I saw this mentioned on htguide. I hear Obbligato are good caps and the discount plus US domestic shipping is a great deal:

http://www.hawthorneaudio.com/forums/viewtopic.php?f=18&t=3716 (http://www.hawthorneaudio.com/forums/viewtopic.php?f=18&t=3716)

Title: Re: Nelson Pass B-1 preamp kit
Post by: kingnubian on 11 Oct 2010, 02:24 am
I saw this mentioned on htguide. I hear Obbligato are good caps and the discount plus US domestic shipping is a great deal:

http://www.hawthorneaudio.com/forums/viewtopic.php?f=18&t=3716 (http://www.hawthorneaudio.com/forums/viewtopic.php?f=18&t=3716)

Sounds like a great deal!
I hope that they will be a good compliment to the K73-16's as well.
Title: Re: Nelson Pass B-1 preamp kit
Post by: rtate on 11 Oct 2010, 04:09 pm
Great people over there at Hawthorne !!!
Great speakers too...    :green:
Title: Re: Nelson Pass B-1 preamp kit
Post by: 1MOR on 13 Oct 2010, 04:36 am
Finally got the B1 to make music! Its powered by a 18 volt wall wart.


(http://www.audiocircle.com/image.php?id=37029)

(http://www.audiocircle.com/image.php?id=37030)

(http://www.audiocircle.com/image.php?id=37031)

(http://www.audiocircle.com/image.php?id=37032)

Its a tube kinda thing!  :lol: :thumb:
(http://www.audiocircle.com/image.php?id=37034)

Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 13 Oct 2010, 12:45 pm
Finally got the B1 to make music! Its powered by a 18 volt wall wart.

(http://www.audiocircle.com/image.php?id=37029)

(http://www.audiocircle.com/image.php?id=37032)

Congrats on a very nice B1 build.

What caps did you use, they actually appear to fit the B1 board.

Thanks for posting the pics.  :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: kingnubian on 13 Oct 2010, 12:56 pm
Finally got the B1 to make music! Its powered by a 18 volt wall wart.


(http://www.audiocircle.com/image.php?id=37029)


Congrats on the build! How does it sound so far?
Title: Re: Nelson Pass B-1 preamp kit
Post by: 1MOR on 13 Oct 2010, 03:25 pm
Congrats on a very nice B1 build.

What caps did you use, they actually appear to fit the B1 board.

Thanks for posting the pics.  :thumb:
Caps are Erse Pulse X.  Aexon caps are no longer available.  Erse/Aexon/Solen appear to be quite similar. So far, B1 sounds quite nice.  Will need a few days to have the caps settle in.  I also have a 24 Volt wall wart that I will try for sonic comparison. 
Title: Re: Nelson Pass B-1 preamp kit
Post by: 1MOR on 13 Oct 2010, 03:41 pm
No exotic parts were used, will do that for the DCB1 build. Case is a tight fit, but I made it work.  Seller has larger cases. Pots are the PECs. Case came from here:

http://stores.ebay.com/gkphotonics/Aluminum-Enclosure-Boxes-/_i.html?_fsub=1668375016&_sid=79834146&_trksid=p4634.c0.m322 (http://stores.ebay.com/gkphotonics/Aluminum-Enclosure-Boxes-/_i.html?_fsub=1668375016&_sid=79834146&_trksid=p4634.c0.m322)
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 13 Oct 2010, 06:46 pm
Case is a tight fit, but I made it work.  Seller has larger cases.
http://stores.ebay.com/gkphotonics/Aluminum-Enclosure-Boxes-/_i.html?_fsub=1668375016&_sid=79834146&_trksid=p4634.c0.m322 (http://stores.ebay.com/gkphotonics/Aluminum-Enclosure-Boxes-/_i.html?_fsub=1668375016&_sid=79834146&_trksid=p4634.c0.m322)

What size is the case you used?  Thanks!
Title: Re: Nelson Pass B-1 preamp kit
Post by: 1MOR on 13 Oct 2010, 08:01 pm
What size is the case you used?  Thanks!

8" X 8" X3"  I should have used the 4" or 5" deep box instead of the 3" box.
Make sure you measure your board, caps, pots, switch, in/out hardware before you order this product.  Mine was a tight fit, very tight fit.  I used the optional bottom plate to mount the pc board on, using standoffs.  Contact the seller, he was great to do business with.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 13 Oct 2010, 08:40 pm
OK, thanks for the heads up on that.  :D
Title: Re: Nelson Pass B-1 preamp kit
Post by: kingnubian on 14 Oct 2010, 01:30 pm
A delivery from DiyHifiSupply came today! The Obbligato Premium 1uf matched pair.

(http://www.audiocircle.com/image.php?id=37074)

Things are getting close to the final build. Got the naked Vishay's and both my Russian & Obbligato caps as well as the Gigaworks attenuator. Now just need a toggle switch, wall wart with matching power input jack, volume knob & enclosure. I was going for the ProjectX Enclosures from DiyHifiSupply but with an advertised internal height of only 63mm (~2.5"), it would be too tight a squeeze for the Panasonic caps that are on the board, unless I wire them to their connections instead of having them sit on the board directly. (Opinions??).

1More's case selection seems pretty good & I could easily go for the 4" height model also, I just like the look of the Diyhifisupply chassis more but it isn't a deal breaker. I have to admit I have very little experience with drilling Aluminium so this is what is really bothering me right now. I want this project to look very clean.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 14 Oct 2010, 05:41 pm
I have to admit I have very little experience with drilling Aluminium so this is what is really bothering me right now. I want this project to look very clean.

Just remember to use painter's blue masking tape over the area where you want to drill the holes.  Mark them on the tape, then drill small pilot holes.  Be patient and work up to the proper size hole.  Once the holes are drilled, clean off the debis, then remove the tape.  Should be very nice and clean.

Since you're going top end on parts, consider using a Goldpoint/Elma stepped attenuator if you ever decide to upgrade your volume control.  Absolutely first rate!  :thumb:

When you get it up and running, please let us know how it sounds in your system.
Title: Re: Nelson Pass B-1 preamp kit
Post by: kingnubian on 14 Oct 2010, 06:22 pm
Just remember to use painter's blue masking tape over the area where you want to drill the holes.  Mark them on the tape, then drill small pilot holes.  Be patient and work up to the proper size hole.  Once the holes are drilled, clean off the debis, then remove the tape.  Should be very nice and clean.

Since you're going top end on parts, consider using a Goldpoint/Elma stepped attenuator if you ever decide to upgrade your volume control.  Absolutely first rate!  :thumb:

When you get it up and running, please let us know how it sounds in your system.

Thank you very much for the info!! After the final build I'll start tweaking stuff to get the recipe just right. :thumb: 
What kind of drill bits do you recommend? Carbide, Cobalt, step??

Just for size comparison's sake, here are from the top, Russian K73-16 10uf, Obbligato Premium 1uf & K73-16 1uf.

(http://www.audiocircle.com/image.php?id=37084)
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 14 Oct 2010, 07:51 pm
What kind of drill bits do you recommend? Carbide, Cobalt, step??

I use standard Craftsman or Black & Decker drill bits, nothing special necessary since you're only drilling through aluminum.  Be sure to use the tape and start with the small holes first, then work up to the desired size hole.

It's not difficult, just take your time.  Remember the old saying, "measure twice, cut once."
Title: Re: Nelson Pass B-1 preamp kit
Post by: kingnubian on 14 Oct 2010, 08:30 pm
I use standard Craftsman or Black & Decker drill bits, nothing special necessary since you're only drilling through aluminum.  Be sure to use the tape and start with the small holes first, then work up to the desired size hole.

It's not difficult, just take your time.  Remember the old saying, "measure twice, cut once."

Lol, that old saying is very true.
Do you use some type of oil or as some have mentioned, WD40, for the drill bit?
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 14 Oct 2010, 08:33 pm
Do you use some type of oil or as some have mentioned, WD40, for the drill bit?

No, as aluminum is soft and it's not necessary.  Just a good bit is all it takes.
Title: Re: Nelson Pass B-1 preamp kit
Post by: sts9fan on 14 Oct 2010, 08:59 pm
Unibits are real nice to have.
Title: Re: Nelson Pass B-1 preamp kit
Post by: 1MOR on 16 Oct 2010, 04:50 am
I use a drill press.  Keep your spindle speed at less than 1/2 of the recommended speed when drilling aluminum panels. I use high speed drills from Enco.  I measure the diameters of the control shafts, rca barrel, etc, with a dial caliper.  Then select a drill just a tad larger than your measurement, for clearance.  Layout your panel on the backside, I use a good quality square combo and a small center punch.  Then I use a center drill to locate the center of the scribed location lines, to drill a small hole, much smaller than the size of the finished hole.  These work great and can be found in Grizzly, Harbor Freight, Enco etc. http://www.grizzly.com/products/4-pc-Center-Drill-Set-82-/H5931 (http://www.grizzly.com/products/4-pc-Center-Drill-Set-82-/H5931)
You are always better off, by drilling your holes too small and then opening them up, than to drill finish size first and find that your drill had some wobble and your hole is way too large or not round. Nice cap selection!

(http://www.audiocircle.com/image.php?id=37133)
Title: Re: Nelson Pass B-1 preamp kit
Post by: 1MOR on 16 Oct 2010, 05:11 am
I layout the panels on a piece of cardboard first, to check the appearance and the final dimensions of the holes.  Cardboard is scrap and zero cost, finish panels are not!


(http://www.audiocircle.com/image.php?id=37134)

(http://www.audiocircle.com/image.php?id=37135)
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 16 Oct 2010, 06:57 am
Can't do that (drill press) in a small 2br apartment. *sigh*  :(
Title: Re: Nelson Pass B-1 preamp kit
Post by: kingnubian on 16 Oct 2010, 01:48 pm
Can't do that (drill press) in a small 2br apartment. *sigh*  :(

These may be the ticket. They are small both in size & price. It looks to be exactly what the DIY'er could use for projects. I'm going to check both out today & I'll report back what I find.

http://www.homedepot.ca/webapp/wcs/stores/servlet/CatalogSearchResultView?D=930979&Ntt=930979&catalogId=10051&langId=-15&storeId=10051&Dx=mode+matchallpartial&Ntx=mode+matchall&N=0&Ntk=P_PartNumber

http://www.rona.ca/shop/~drill-10-in.-drill-press-with-table-haussmann-440068_!drill-press_shop

Any comments?

NOTE: The price quoted is in Canadian.
Title: Re: Nelson Pass B-1 preamp kit
Post by: 1MOR on 16 Oct 2010, 02:39 pm
RYOBI offers a quality product.  If you purchase the Ryobi, make sure HD will take it back/replace if you have excessive spindle play/slop. A small drill press is all that you will need for constructing cases for audio equipment.  Harbor Freight had a sale, I had a 20% off coupon. I got the larger DP for $149.  The used Craftsman stand came from Epay, $16.  All of these drill presses are made in China.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 16 Oct 2010, 03:16 pm
Drill presses are great if you have a shop or other dedicated room.  As stated, always start with a smaller bit.

Once, I asked my wife if I could turn our spare bedroom into a hobby room, you can guess the outcome...  :nono:
Title: Re: Nelson Pass B-1 preamp kit
Post by: 1MOR on 19 Oct 2010, 12:20 am
Update on the PS!  I started with a 18 volt wall wart, nice but a little dry, top to bottom. This afternoon, I switched in the 24 volt wall wart.  No smoke, no burning B1.  Just a noticeable improvement. Improved dynamics and bass response.  For the associated equipment and the listening space, this is a very worthwhile upgrade.  That is my story, and I am sticking to it! :singing:

I had paralleled the output jack to  allow use of a second set of output RCAs to attach a subwoofer.  Got that working this morning.  One of my pics shows that detail. 
Title: Re: Nelson Pass B-1 preamp kit
Post by: nodiak on 29 Oct 2010, 03:16 am
Just getting back to audio after summer break. Getting the B1 buzz, have read this thread and am getting ready to source B1 parts. Ordered the Pass pcb's/jfets and gigaworks 20K ebay pot.
Open to buying parts from anyone not finishing the project (been there...).
Have a CDA-254 amp now, hope it matches well. Speakers are 90db 4ohm.
Nice to have such quality available for such price! Thanks to NP, and yous guys too.
Don
Title: Re: Nelson Pass B-1 preamp kit
Post by: AUDFILE74 on 31 Oct 2010, 12:40 am
 what are the  voltages if i want to go with a transformer instead of a wall wart?
Title: Re: Nelson Pass B-1 preamp kit
Post by: 1MOR on 31 Oct 2010, 01:03 am
Its a bit more complicated than just using a transformer. You will need to convert the AC from the transformer to DC. You will also need to provide some type of regulation for the DC.  So, you can use batteries, you can use an existing cicruit that provides rectification and regulation or, you can follow the recommendations of the circuit's designer, Nelson Pass and use an appropriate wall wart. NP sells his commercial product with power supplied by a wall wart. And, you will pay about $1000 for that product!!  HTH  8) 8)
Title: Re: Nelson Pass B-1 preamp kit
Post by: AUDFILE74 on 4 Nov 2010, 06:58 pm
 good point 1MOR, http://www.amb.org/audio/sigma11/ next week i will be ordering this for my b-1 project. i tihinkit's time i get it in gear her. thanks wushuliu
Title: Re: Nelson Pass B-1 preamp kit
Post by: nodiak on 13 Nov 2010, 12:31 am
Am ordering the parts from wushuliu's list. Have a Pass pc

Don
Title: Re: Nelson Pass B-1 preamp kit
Post by: nodiak on 2 Jan 2011, 12:05 am
Worked on B1 board today. Soldered the small resistors. Serious appreciation to Wushuliu for the run through. I used the soldering demos he linked to, and they were very helpful. Made some classic poor joints and think/hope have redone them well...trying to get the hang of small soldering. May get a big magnifying glass as my eyesight isn't really good enough for this small work.
Have a good soldering station, but had to practice setting temperature and using best tip for the work. In college took jewelry/metalworking classes and one of the best things about it was working nights in the lab when everyone would help and encourage each other on our projects. Would be cool if my audio projects could be done that way, sure some folks arrange that with buddies.
So, will try to make more time to finish this up soon, it's a short project but have a busy 2 weeks ahead at work.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 2 Jan 2011, 02:18 am
Worked on B1 board today. Soldered the small resistors. Serious appreciation to Wushuliu for the run through. I used the soldering demos he linked to, and they were very helpful. Made some classic poor joints and think/hope have redone them well...trying to get the hang of small soldering. May get a big magnifying glass as my eyesight isn't really good enough for this small work.
Have a good soldering station, but had to practice setting temperature and using best tip for the work. In college took jewelry/metalworking classes and one of the best things about it was working nights in the lab when everyone would help and encourage each other on our projects. Would be cool if my audio projects could be done that way, sure some folks arrange that with buddies.
So, will try to make more time to finish this up soon, it's a short project but have a busy 2 weeks ahead at work.

cool. keep us posted!
Title: Re: Nelson Pass B-1 preamp kit
Post by: nodiak on 3 Jan 2011, 11:35 pm
Got a visor style magnifier with several magnification choices and I'm set. Now I can see what I'm doing! My solder joints from the other day look decent, shiny and conical. (Good to get this setup as my next project is a much smaller board - Ampslab LM60 amp.)
Today did the jfets. Large caps to go. Have some North Creek caps - 1uf Harmony, 10uf Zen, and four Sonicap .1uf g2 for bypasses. Probly try those combos.
Title: Re: Nelson Pass B-1 preamp kit
Post by: nodiak on 15 Feb 2011, 11:45 pm
Got it up and running. Will let it play a few days and see how we break in to each other. Have been using a tube pre which is clear, open and 3d. With the cda254 it's been a little thin sounding (was contemplating speaker tweaking) but otherwise nice.
B1 has much bigger and warmer bass (not a BIG bass guy, like depth but not too much weight/bloom). In fact the whole range has warm sq in my system. Surprised as didn't expect that from cda254 with their little PS.
edit: I had knocked the lead off one tweeter without knowing it. So there's better balance now, not as bass heavy. B1 sounds nice after a day, transparency coming through.
I don't want to swap out parts for sq except the 1 uF caps (maybe the 10uF too). Have North Creek Harmony 1uF caps in it now. Have gen II Sonicaps for bipassing. May try other 1uF known for clarity, like gen I Sonicaps. But will wait a bit and hear what happens.
Using 10K Bourns pot.
Using chassis from dvd player.
(http://www.audiocircle.com/image.php?id=42900)
   
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 16 Feb 2011, 12:41 am
Glad it's working for you.  Keep us posted of the changes and progress.
Title: Re: Nelson Pass B-1 preamp kit
Post by: yeldarb on 1 Mar 2011, 08:32 pm
Just curious, since some of you have modded for two outputs, will the B1 drive a fairly long sub cable (12 feet), in addition to a normal length?
Title: Re: Nelson Pass B-1 preamp kit
Post by: walkern on 1 Mar 2011, 08:49 pm
I'm driving 9 feet of cables without any problems what so ever.  I'm sure 12 feet will not be an issue.

Neil
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 1 Mar 2011, 10:43 pm
Yes, I agree.  Not a problem...  :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: nodiak on 2 Mar 2011, 04:07 pm
After a couple weeks of playing the B1 with cda254 the frequency response has evened out (only took ~ 20 hours) and it's sounding very nice. Clear, much more open than expected, room filling soundstage. Adds a sense of power, more like I'd expect a bigger amp would. Currently using 24v walwart, wiill get an 18v one to compare. Bass remains strong but cleaner than at first. Makes the cda254 sounds better, but am anxious to try B1 with other amps. B1/cda254 combo allows full use of volume control which I like. It plays as loud as I need at 2:00 mark and up, but 11:00 is getting loud.
I would say if you can build B1 it's very much worth having to compare other pre's/buffers to, and it could improve the rest of your system. Am not really missing out on the sense of space I like from tubes, but may try a Dodd buffer when able as I bet it's another goody.

Just wanted to add that the B1 cured my systems slight bass shyness. I was considering working on the speakers as it seemed the bass drivers weren't as loud as the mids and tweeters. But now frequencies are even spl wise. Bonus.
Title: Re: Nelson Pass B-1 preamp kit
Post by: roymail on 2 Mar 2011, 08:06 pm
Currently using 24v walwart, wiill get an 18v one to compare.

Although I have no plausible explanation, and for what it's worth, I've read that the 24v actually sounds better than the 18v.  I don't see any reason to try it unless you just want to, but doesn't cost much to try.  However, SLA battery power would definitely be a step up.  Thanks for sharing your impressions.
Title: Re: Nelson Pass B-1 preamp kit
Post by: sl_1800 on 3 Mar 2011, 01:03 pm
I just built a B1 and I'm running it on 24V AGM batteries, two 12's in series.  I also use it with a Class D Audio CDA 254, sounds like a good combination.  I was thinking of going with 18V batteries since I have a charging system for that from another older piece of gear but the 24V is sound so good I may just leave it alone.
Title: Re: Nelson Pass B-1 preamp kit
Post by: porfido on 15 Mar 2011, 11:27 pm
Hi everybody,
as usual, sorry for my english first of all....
Thank you very very much for this topic that helped me so much building also the second B1 buffer....
This time I wanted a remote controlled unit, so I decided to use a cheap ebay pcb with remote to control a motorized pot on the Lightspeed attenuator kit by Uriah Dailey....
These cheap remote pcb's are not so good for working on signal but using it only for controlling the 5v supply to the LDR's I don't risk any kind of noise....
This time I used k73 caps bypassed by teflon k40, only precision resistors on board and 0,01% res on signal...

(http://www.audiocircle.com/image.php?id=44260)

This time I use three 6v sla batteries for 18v B1 psu and a simple charging/mantaining circuit for charging them....
About Lightspeed attenuators everybody says that the 5v supply to the LDR's has to be the "cleanest" possible, so I used a JLH Ripple Eater after a simple 7805 regulator....
With a 24v switching PSU and a simple quadripolar switch, with one movement,  I can select between powering the charging/mantaining circuit or giving power to the 5v to LDR's, 18v to remote pcb and connecting batteries to B1...

(http://www.audiocircle.com/image.php?id=44261)

(http://www.audiocircle.com/image.php?id=44262)

The sound of battery powered B1 with Lightspeed is IMHO very very good and I'm really happy I finally can sit on sofa controlling volume with the remote! :)
I'm really becoming the italian version of Homer Simpson! :D

Thank you very very much again for this really useful thread! :thumb:

Title: Re: Nelson Pass B-1 preamp kit
Post by: Howie on 31 Mar 2011, 03:13 am
Greetings, I just finished my B1 a week ago and was inspired by all the posts. I had a nice idea for battery power and want to share it. I realized, after wondering how to build a battery PS, that I had one almost ready to go. The battery for my cordless drill is 18v Lithium. (Measures 19.2v) I have the charger. It should power the B1 for about 60 hours. Here are some self explanatory pics.
(http://www.audiocircle.com/image.php?id=44921)

(http://www.audiocircle.com/image.php?id=44922)

(http://www.audiocircle.com/image.php?id=44923)

(http://www.audiocircle.com/image.php?id=44924)

(http://www.audiocircle.com/image.php?id=44925)

(http://www.audiocircle.com/image.php?id=44926)

(http://www.audiocircle.com/image.php?id=44927)

(http://www.audiocircle.com/image.php?id=44928)

(http://www.audiocircle.com/image.php?id=44929)

(http://www.audiocircle.com/image.php?id=44930)

(http://www.audiocircle.com/image.php?id=44931)

I made the wood form to prevent polarity accidents. I will make a wood cap for the unit after glue up. You could also add a switch, but just removing the battery is easy. The large Ryobi battery has a power gauge, so you can monitor the charge. Battery does sound better.
-Howie
Title: Re: Nelson Pass B-1 preamp kit
Post by: toxteth ogrady on 31 Mar 2011, 05:04 am
Brilliant! That's thinking out of the box.
Title: Re: Nelson Pass B-1 preamp kit
Post by: yeldarb on 31 Mar 2011, 04:14 pm
Nice looking work.  Where did you get the case?  The battery dock is brilliant.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Howie on 31 Mar 2011, 05:18 pm
Thank you.

The case is from Context Engineering. I saw it on this thread.
http://contextengineering.com/desktop_enclosures.html (http://contextengineering.com/desktop_enclosures.html)

-Howie

Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 31 Mar 2011, 06:56 pm
Hi everybody,
as usual, sorry for my english first of all....
Thank you very very much for this topic that helped me so much building also the second B1 buffer....
This time I wanted a remote controlled unit, so I decided to use a cheap ebay pcb with remote to control a motorized pot on the Lightspeed attenuator kit by Uriah Dailey....
These cheap remote pcb's are not so good for working on signal but using it only for controlling the 5v supply to the LDR's I don't risk any kind of noise....
This time I used k73 caps bypassed by teflon k40, only precision resistors on board and 0,01% res on signal...


This time I use three 6v sla batteries for 18v B1 psu and a simple charging/mantaining circuit for charging them....
About Lightspeed attenuators everybody says that the 5v supply to the LDR's has to be the "cleanest" possible, so I used a JLH Ripple Eater after a simple 7805 regulator....
With a 24v switching PSU and a simple quadripolar switch, with one movement,  I can select between powering the charging/mantaining circuit or giving power to the 5v to LDR's, 18v to remote pcb and connecting batteries to B1...


The sound of battery powered B1 with Lightspeed is IMHO very very good and I'm really happy I finally can sit on sofa controlling volume with the remote! :)
I'm really becoming the italian version of Homer Simpson! :D

Thank you very very much again for this really useful thread! :thumb:

Thanks for sharing perfido. I think using the  motorized remote with the lightspeed is brilliant. I'm sure it sounds amazing!

Same to you Howie. It's great to see all these clever ways to get the best out of a component. 8)
Title: Re: Nelson Pass B-1 preamp kit
Post by: HAL on 1 Apr 2011, 01:32 pm
I'll have a couple extra sets of 1k and 220 ohm PRP resistors for $7 for anyone who wants to upgrade their resistors and/or lower their ouput impedance w/ the 220. This way you don't have to shell out minimum fees and ups shipping, etc. just to get them...  8)
wushuliu,

Do you still have the PRP resistors available?  The lower output impedance might solve my noise pickup issue.
Title: Re: Nelson Pass B-1 preamp kit
Post by: porfido on 1 Apr 2011, 06:57 pm
Thanks for sharing perfido. I think using the  motorized remote with the lightspeed is brilliant. I'm sure it sounds amazing!


Thanks to you, Wushuliu, for having opened this thread! Without it I don't think I could have built these two buffers! :)
For whom could be interested, here is a very simple circuit for charging and mantaining sla batteries:

(http://www.audiocircle.com/image.php?id=44981)

Ten minutes of work on a veroboard and it's done! With the transistor you can mantain the battery in charge 24h a day, allowing the charger to decrease the current till zero when the battery is charged, and changing the value of R4 you can set the desired charging current...
Simple and useful, IMHO... :)
I use it also for mantaining the battery of my motorbike.... :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: ik on 15 May 2011, 02:22 pm

Hi Washuliu

Thanks for this great posing!

I'm looking to build a B1 with more then 2 inputs.
On pg 18 you've mentioned "Grayhill rotary switches"
What is the deck # I need?
Which of these would you recomend?
http://search.digikey.com/scripts/DkSearch/dksus.dll

THanks
IK

Title: Re: Nelson Pass B-1 preamp kit
Post by: ruphen on 26 Dec 2011, 05:21 pm
Hi,

Sorry for bringing this post back. i wanted to ask what the minimum/maximum voltage everyone is using. Reason i ask, is i have a power supply with a switch but the voltages are 13/30. would this PS work?

thanks in advance,

Ruphen
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 5 Jan 2012, 06:21 pm
Hi,

Sorry for bringing this post back. i wanted to ask what the minimum/maximum voltage everyone is using. Reason i ask, is i have a power supply with a switch but the voltages are 13/30. would this PS work?

thanks in advance,

Ruphen

Not sure what kind of PS that is, but 13v should suffice.
Title: Re: Nelson Pass B-1 preamp kit
Post by: vinylb on 5 Feb 2012, 03:43 pm
Been awhile since anybody posted in this thread. I am about to embark on my B1 journey and will be using the BOM posted on 1st page but I have some questions:

1. is the B1 still the preamp to get in terms of value, sound quality and simple assembly steps or is there another that has taken the crown?
2. Apart from replacing the walwart with a battery solution and also replacing caps, is there anything else that folks are tweaking? I can  believe
    the battery would make a difference but is the cap replacement noticable?

Thanks to all that have posted their experiences here.
Title: Re: Nelson Pass B-1 preamp kit
Post by: 1MOR on 4 May 2012, 11:45 pm
Any one start a new build, finish a build or swapped in new parts on an existing build?  Just thought I would check?  I finished a diy Pass F5 amp build and have been using the B1 that I built off this thread.  I am gathering parts to upgrade the B1 resistors and caps. 

The B1 is quite impressive sounding with the F5. Excuse the test setup.


(http://img232.imageshack.us/img232/4347/p1010205c.jpg)
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 4 May 2012, 11:59 pm
What caps and resistors are ya gonna try. I just recently upgraded to the DCB1.
Title: Re: Nelson Pass B-1 preamp kit
Post by: 1MOR on 5 May 2012, 12:56 am
I have Russian Teflons for the 1 and 10uf caps, 1K Zfoils for input and output resistors, PRPs for the remaining resistors and have Mundorf electrolytics ordered for the power caps.  The LED is way too bright so that will be tamed with a 33K resistor.  May also do some mods to the case, new front panel to match the F5.  Thinking about a 1/4" piece of machined 6061 aluminum to replace the stock panel.

I have enough parts for a hot rod DCB1 Hypnotize build but wanted to take the B1 as far as I could before starting another project..
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 5 May 2012, 01:01 am
Sounds like great choices, you will be rewarded.

The B1 with upgraded parts is an excellent buffer, the dcb1 takes it up a few notches.  :green:
Title: Re: Nelson Pass B-1 preamp kit
Post by: 1MOR on 6 May 2012, 04:08 pm
Anyone else?  There seemed to be a great amount of interest when this project was first started?
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 7 May 2012, 07:13 am
Anyone else?  There seemed to be a great amount of interest when this project was first started?

This thread is over 2yrs old (!), which is a long time in diy years since then there's been the dcb1, dodd tube pre, and the optocoupler-based pre/buffer designs. Glad you are enjoying the B1.
Title: Re: Nelson Pass B-1 preamp kit
Post by: kevinh on 8 May 2012, 10:04 pm
Anyone else?  There seemed to be a great amount of interest when this project was first started?


Nelson is still selling the boards with a set of FET's for $40 @ the first watt website/
Title: Re: Nelson Pass B-1 preamp kit
Post by: sachu888 on 15 May 2012, 09:01 am
Hi,
I am using Pass B1 with LDR Volume control.I must say that B1's performance is quite impressive. Most important observation is the quietness of the system even at high volume. Soundstage improved a lot. Instruments became more defined & very very clear.
I have noticed the bass sounded very with B1 using LDR volume control.The Bass-power was reduced drastically.I get a better bass response If I put my LDR volume control at max position and control volume from my Technics integrated amp.I would like to ask other FM using B1 regarding their experience.
My system: TT--> DIY Phono--> B1--> Integrated amp

Regards,
Sachin
Title: Re: Nelson Pass B-1 preamp kit
Post by: voxxonline on 3 Jan 2013, 03:26 pm
Gents, hello

I am specifically registered on this forum due to very hq threads on B1 buffer.
I have my b1 ready, but since I have got salas sslv , I would like to ask for a help, if anybody has built psu specifically for b1 ?
If yes, can one to share how to 's for it , as I dont want to make a mistake :)

And one more thing- what is a suggested upgrade for b1 components ?


Thank you
Title: Re: Nelson Pass B-1 preamp kit
Post by: vinylb on 7 Apr 2013, 02:00 pm
Well after months of deciding what to do I ended up purchasing the PCB from Pass store and parts based on the BOM from first page. I know this thread has been dormant for a long time but thought I would share my pictures of my preamp.


(http://www.audiocircle.com/image.php?id=78371)


(http://www.audiocircle.com/image.php?id=78372)


(http://www.audiocircle.com/image.php?id=78373)


I followed pretty much all of the BOM but opted for ALPS pot and boutique caps which to me made a huge difference in the sound - better be for that price :) I originally had Solens  - Janzten caps
were night and day. In fact it was so good that I can easily say that this preamp now comes very close to my ARC SP6C tube preamp. I was concerned about the length of wiring to each of the 6 inputs
but so far have not had any crosstalk. Yes I do need 6 inputs :) DAC (SB Touch to external dac), Vinyl, CD player, Tape deck, Reel 2 reel and a spare. also added a HT bypass so my kids could still hear their games via front channel speakers without having to mess with the input and volume. Worked out good.

Thx again to all who have posted over the years.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 7 Apr 2013, 02:14 pm
Nice build, those signal resistors have a surprising effect on resolution also.  :thumb:
Title: Re: Nelson Pass B-1 preamp kit
Post by: vinylb on 7 Apr 2013, 02:58 pm
Thx Nick77. You referring to the 1K resistors? What did you use ? Were you able to compare to original?
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 7 Apr 2013, 03:09 pm
Thx Nick77. You referring to the 1K resistors? What did you use ? Were you able to compare to original?

Most felt lowering the value to 330r was best for sonics, so thats what i used.
Lots of comparison, best to worst.....

Vishay TX2575 Foil very resolute and neutral
Riken Carbon warm and fairly resolute
PRP Metal film good metal film
Takman Carbon, warm but conjested
Title: Re: Nelson Pass B-1 preamp kit
Post by: vinylb on 7 Apr 2013, 03:48 pm
Yeah I read that somewhere too. K, I will now have to get those resistors :) Thinking of getting another preamp/build together, maybe I should save it for that build with even better caps :)
I really would like to try the DCB1 kit but it looks a lot more complex and pcb's are hard to find.
Title: Re: Nelson Pass B-1 preamp kit
Post by: rif on 7 Apr 2013, 04:46 pm
I was concerned about the length of wiring to each of the 6 inputs
but so far have not had any crosstalk. Yes I do need 6 inputs :) DAC (SB Touch to external dac), Vinyl, CD player, Tape deck, Reel 2 reel and a spare. also added a HT bypass so my kids could still hear their games via front channel speakers without having to mess with the input and volume. Worked out good.

Thx again to all who have posted over the years.

What did you use for a selector switch?  Does it switch the signal and ground or just signal?

Title: Re: Nelson Pass B-1 preamp kit
Post by: vinylb on 7 Apr 2013, 07:08 pm
I used a 2P6T switch,  no ground was used. I would have preferred to have switched signal and ground but I could not find anything cheap and easy to wire up with 6 inputs.
So i grounded all inputs to the pcb which in turn was grounded to chassis.
Title: Re: Nelson Pass B-1 preamp kit
Post by: vinylb on 9 Apr 2013, 02:13 pm
Most felt lowering the value to 330r was best for sonics, so thats what i used.
Lots of comparison, best to worst.....

Vishay TX2575 Foil very resolute and neutral
Riken Carbon warm and fairly resolute
PRP Metal film good metal film
Takman Carbon, warm but conjested

Nick, I reread your posts earlier on in the thread and about how you replaced all 4 1K with these TX2575....Do you still believe that the DCB1 is better than your B1 with these TX2575?
I been thinking that at some point if I have not already, will be hitting diminishing returns on any more parts I throw at my B1. I think TeaBag over at diyaudio has new stock of DCB1 kits.
Did you buy the kit or did you buy exotic parts?

Thx
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 9 Apr 2013, 02:19 pm
Yes the DCB1 is a cut above the B1 even with TX2575 although I also use TX2575 in my DCB1. I purchased boards only and used exotic parts. Mine is the hotrodded version running at about 600mA.
Title: Re: Nelson Pass B-1 preamp kit
Post by: vinylb on 10 Apr 2013, 11:25 am
Yes the DCB1 is a cut above the B1 even with TX2575 although I also use TX2575 in my DCB1. I purchased boards only and used exotic parts. Mine is the hotrodded version running at about 600mA.

I put my order in for kit and pcb with Teabag for DCB1. I am also going to hotrod mine. Thanks for your comments. Do you mind if I pick your brain if I have questions?
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 10 Apr 2013, 11:41 am
Be happy to share my experiences with parts selection, but i relied on Wushilu's build tutorial.
Title: Re: Nelson Pass B-1 preamp kit
Post by: WireNut on 26 Jul 2013, 02:27 am
Hi wushuliu,

 Thanks for the build thread. I received most of the parts last week except for the case which has been the hardest thing to find so far. Par-metal only builds cases on an order by order basis and there's a 3-6 week waiting period. No cases are kept in stock I was told. Looks like I’m going to try a Lansing enclosure. Their twice as much as par-metal but Lansing keeps cases in stock.

 I think I’m going to mount all 5 Sonic Caps on a second board behind the B1 board due to their size and use small terminal strips to make it easy to try different caps in the future.

 Also, it looks like the 4 Jfet's might be a SMALL bear to solder in place. I can barely see the dam things and the eyelets on the board are very tiny and close together in all 4 locations. I bought the Jfet’s from NP so I don’t wanna screw those up.  :nono:
If you guy's have any suggestions/cautions about how to solder in those Jfet's let me know. I'm all ears.
I'm intimidated by these little things.

Thanks,
WN

(http://www.audiocircle.com/image.php?id=84170)


   Jfet's


(http://www.audiocircle.com/image.php?id=84173)


Title: Re: Nelson Pass B-1 preamp kit
Post by: vinylb on 26 Jul 2013, 11:07 am
Hey Wirenet, use a magnifying glass or one of those "helping hands" with a circular magnifying glass. Its not too bad, also make sure you use a small solder and the right iron size and you'll be ok.
Follow orientation that son board - flat side faces to left if you looking at pcb as in your pic posted.

Dont forget the 1K resistors are in the signal path and benefit from boutique part, but having said that, will work and sound fine with just a regular resistor :)

The holes for the caps are not much bigger than the resistors if I recall so you might have to put in left over cuts from trimming resistors in place and then solder cap leads onto them.
Title: Re: Nelson Pass B-1 preamp kit
Post by: djtw on 26 Jul 2013, 12:48 pm
I have also heard that JFET's can be sensitive to heat, so I would put a small clip on the lead to be soldered to absorb some of the heat during the soldering process.

Also, pre bend the leads and don't cut the leads too short, in case you have to remove the part later.

Hope this helps...


Title: Re: Nelson Pass B-1 preamp kit
Post by: Speedskater on 26 Jul 2013, 02:03 pm
With the exception of the 6 power supply resistors, all the other resistors are in the signal path. Just because one end of a resistor is connected to circuit ground doesn't take it out of the signal circuit.
Title: Re: Nelson Pass B-1 preamp kit
Post by: vinylb on 26 Jul 2013, 06:13 pm
These are all good pointers, one more thing if you are going to be swapping out resistors either make the legs/leads longer so they further away from the pcb or just use
those connectors commonly found in Arduino diy kits - stackable headers. they come in all different lengths.


(http://www.audiocircle.com/image.php?id=84184)


I trim mine so that I am able to put one pin in each resistor hole and yank out the pins in betweeen so that the header sits flat. This has saved me a lot of frustration when trying to get the right sound.
Title: Re: Nelson Pass B-1 preamp kit
Post by: WireNut on 26 Jul 2013, 08:23 pm
Hi djtw and vinylb,

 Thanks for all the tips. I like the idea of stackable headers. Think I’ll pick some up on digikey or mouser if I can find them. Your right about the eyelets for the 1UF caps, they are too small for the leads on my caps so using the scrap resistor leads was a good idea.

 I believe the resistors most folks change are R102 and R202. Not sure if any other locations are as critical. I may pick up some naked Vishay’s for those spots.

Title: Re: Nelson Pass B-1 preamp kit
Post by: vinylb on 28 Jul 2013, 12:01 pm
In an earlier post, Nick77 described resistors as:

Vishay TX2575 Foil very resolute and neutral
Riken Carbon warm and fairly resolute
PRP Metal film good metal film
Takman Carbon, warm but conjested

in my opinion he is 100% right with his description of each. In this project I settled on TX2575 (built 3 of these) and other projects I have used Riken.

If you only using one input then you dont need to buy all resistors for input1 and input 2. I compared my 2 builds (one with a switch and one without) and could not tell
the difference in sound.
Title: Re: Nelson Pass B-1 preamp kit
Post by: WireNut on 1 Aug 2013, 02:52 am
I know the B1 was not designed to drive 2 power amps, NP built the First Watt B2 for driving multiple amps. But If I'm running the output of the B1 into an active crossover (audio research ec22) that drive's two amps from it's own outputs, do you all think that will work?









Title: Re: Nelson Pass B-1 preamp kit
Post by: vinylb on 1 Aug 2013, 10:31 am
I have no experience with that ARC product but I dont see why not. Check to see the impedance is what the EC22 is wanting or in the range and i think you should be ok.
btw I love ARC products, had SP5,SP9,SP6.
Title: Re: Nelson Pass B-1 preamp kit
Post by: WireNut on 27 Aug 2013, 02:00 am

Can the B1 be built inside an all wood case or do you all think there will be a hum issue?

Thanks


Title: Re: Nelson Pass B-1 preamp kit
Post by: G Georgopoulos on 27 Aug 2013, 03:02 am
Can the B1 be built inside an all wood case or do you all think there will be a hum issue?

Thanks

wn there wont be hum issue in wood case...if all is done properly...go ahead and build it... :green:
Title: Re: Nelson Pass B-1 preamp kit
Post by: Kooka on 30 Dec 2014, 07:41 am
I think it is the board - if you look at the left/right inputs for 1 the left goes to the bottom pin on S100 and the right goes to the top pin of S200!

Alan

Sorry to revive an old topic but I have this Jim's board around with all the parts ready and was readind this: is it confirmed that that the chinese boards are WRONG? That would be very strange, actually.
If any one Can help, please...
Title: Re: Nelson Pass B-1 preamp kit
Post by: Speedskater on 30 Dec 2014, 03:50 pm
Now that it's just about 2015, almost any product (including lights) that you buy that plug's into the AC power has the possibility of generating EMI/RFI interference.  Wood cases and EMI/RFI interference don't get along well together.
Title: Re: Nelson Pass B-1 preamp kit
Post by: I.Greyhound Fan on 12 Nov 2015, 07:55 pm
I know that this is an old thread but I am going to build the B1 for my son Parasound A21 amp.

I am curious as to what caps people are using.  I want a slightly warm, detailed, tubey sound with good air and transparency.  I am using Vishay TX2575 1K resistors in the input section and Carbon Riken 1K resistors in the output section.

I would appreciate any comments on caps as well as resistor selection for the remaining 10K, 15K and 221K resistors.  I was considering trying some PIO caps but I am open to suggestions.

Has any one used a remote volume control?

Thanks!
Title: Re: Nelson Pass B-1 preamp kit
Post by: navi on 2 Dec 2015, 05:08 am

(http://www.audiocircle.com/image.php?id=132830)

Just completed mine.
Resistive Ladder attenuator off Ebay $38
Obligato capacitors
Silver plated RCAs
Sonic art silver plated PTFE cable, Oyaide and Mogami cable
Rubycon and Vishay parts from divi-key

Sounds great so much more bass and detail in the lower notes but I think midrange detail isn't as good.

Ivan.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Nick77 on 2 Dec 2015, 11:45 am
I know that this is an old thread but I am going to build the B1 for my son Parasound A21 amp.

I am curious as to what caps people are using.  I want a slightly warm, detailed, tubey sound with good air and transparency.  I am using Vishay TX2575 1K resistors in the input section and Carbon Riken 1K resistors in the output section.

I would appreciate any comments on caps as well as resistor selection for the remaining 10K, 15K and 221K resistors.  I was considering trying some PIO caps but I am open to suggestions.

Has any one used a remote volume control?

Thanks!

PRP resistors and Auricaps would be a good choice to meet your sound target. IMHO......
Title: Re: Nelson Pass B-1 preamp kit
Post by: I.Greyhound Fan on 3 Dec 2015, 01:08 am
Nice build Navi.

I just ordered most of the parts.  I went with Mundorf MCap Supreme's for the 1uF's and Clarity ESA's for the 10uF's.  I was going to go with the Obbligato's instead of the ESA's but I am leery about their bass being a little too thin.  I can always swap in the Obbligato's.

For resistors I went with the Tx 2575 for the input and Riken Carbon's for the output.  Other resistors are Audio Note Tantalums, Takman Rey's and Vishay-Dale's.

I am thinking about using one of these case's - the A28-A or the A28-C

http://diyclub.biz/catalog/index.php?cPath=1_284_298

And this Remote AlP's volume pot-

http://diyclub.biz/catalog/product_info.php?products_id=601


I would prefer a 20K or 50K pot but I can't find a decent kit for a similar price.
Title: Re: Nelson Pass B-1 preamp kit
Post by: navi on 7 Dec 2015, 12:49 am
Nice build Navi.

I just ordered most of the parts.  I went with Mundorf MCap Supreme's for the 1uF's and Clarity ESA's for the 10uF's.  I was going to go with the Obbligato's instead of the ESA's but I am leery about their bass being a little too thin.  I can always swap in the Obbligato's.

For resistors I went with the Tx 2575 for the input and Riken Carbon's for the output.  Other resistors are Audio Note Tantalums, Takman Rey's and Vishay-Dale's.

I am thinking about using one of these case's - the A28-A or the A28-C

http://diyclub.biz/catalog/index.php?cPath=1_284_298

And this Remote AlP's volume pot-

http://diyclub.biz/catalog/product_info.php?products_id=601


I would prefer a 20K or 50K pot but I can't find a decent kit for a similar price.


Have you tried the Obilgato's in the past and thought the bass was lacking? 
I tried the B1  board with old 10yr old slagle/intact audio autoformers  (AVC) and couldn't get enough bass from it. Maybe my stacking of the cores wasn't right but I could never get deep bass  from it in the past
Title: Re: Nelson Pass B-1 preamp kit
Post by: I.Greyhound Fan on 7 Dec 2015, 05:59 pm

Have you tried the Obilgato's in the past and thought the bass was lacking? 
I tried the B1  board with old 10yr old slagle/intact audio autoformers  (AVC) and couldn't get enough bass from it. Maybe my stacking of the cores wasn't right but I could never get deep bass  from it in the past

I am just going by the reviews of the Obbligato's.  I realize that it's all subjective and it will depend upon what electronic's you mix them with.  I may end up swapping my Clarity ESA's for them in the long run.  I should have my build done in about 2-3 weeks.

How many hours do you have on the preamp?  The caps definitely need time to burn in.  I had a friend replace all the Jensen PIO caps in my BAT preamp and it took about 20hrs for them to sound good and about another 100hrs for them settle in.

http://singaporehifi.blogspot.com/2010/09/capacitor-shoot-out.html


"Obbligato Gold Premium Cap

Initial impressions during burn in time were quite promising. A very even handed performer with a neutral balance and good detail throughout. Balance wise, this reminds me of the Auricap the most except that the Obbligato has more extended and wetter highs. Midrange is pleasingly smooth without being muffled and there is plenty of information being conveyed in a tidy and controlled fashion. The Achilles' heel of this cap is its bass which is slightly rounded and not particularly deep, especially compared to the Mundorf Supreme series. This results in a somewhat lighweight sounding presentation. That being said, this is a very good cap, especially considering its competitive price. Subjectively, I feel that except for the bass issue, the Obbligato is more pleasing than the Auricap at a much cheaper price."
Title: Re: Nelson Pass B-1 preamp kit
Post by: I.Greyhound Fan on 10 Jan 2016, 08:53 pm
I completed my B1 build a couple of weeks ago.  My jaw dropped when I first heard it.  It is stunningly good.  Bass is deep, powerful and controlled.  There is just a little bit of bloom which I like.  The sound stage is wide, airy and transparent.  The mid range is where it really shines.  It has very good depth with a lot of texture and a nice smooth yet detailed sound.  If I had to pick a weakness, it is the highs which are slightly pushed back and rolled off a bit on certain recordings.  Otherwise cymbals have good timbre.  Vocals, horns and piano are stunningly life like with a rich harmonic texture and musicality.  It has good attack and just a slightly forward mid range. The overall sound is just slightly warm and dark which was by design with the caps and resistors that I picked.  I built this for my son to use with my old Parasound A21 amp.  I did try it in my reference system with my Pass X250 amp and Maggie 1.6 speakers.  It did not sound as good as my BAT preamp but it certainly was not embarrassed.  Not bad for $300 worth of parts.  Next up is to get a remote volume pot and board and then add a real power supply instead of the walwart.

I will post pictures later today.
Title: Re: Nelson Pass B-1 preamp kit
Post by: Folsom on 10 Jan 2016, 09:08 pm
Don't use a Pot mate. They're not going to impress you. Instead of use an eBay chinese DACT, and then add a remote control for it if you must have remote. Switching from a pot to one of those is close to the difference your B-1 made in my experience.
Title: Re: Nelson Pass B-1 preamp kit
Post by: I.Greyhound Fan on 10 Jan 2016, 10:20 pm
Don't use a Pot mate. They're not going to impress you. Instead of use an eBay chinese DACT, and then add a remote control for it if you must have remote. Switching from a pot to one of those is close to the difference your B-1 made in my experience.

Thanks for the tip.  Do you know of any DACT type with a remote kit for $100 or less?   $100 is the budget.  Currently I am using an Alps Blue pot 50k.  I was considering one of these Kits with either a TKD or Blue Alps pot.  I don't know if the TKD will be any better than the Alps

http://www.hificollective.co.uk/catalog/potentiometer/tkd-2cp-2511-motorised.html

Title: Re: Nelson Pass B-1 preamp kit
Post by: Folsom on 10 Jan 2016, 10:56 pm
I do not. Perhaps you could link one to a motorized device? I'm not sure what would occur with the stepped part, but they are make before break so it's safe to try.
Title: Re: Nelson Pass B-1 preamp kit
Post by: I.Greyhound Fan on 14 Jan 2016, 05:05 am
Here are pics of my B1-

(http://www.audiocircle.com/image.php?id=135141)


(http://www.audiocircle.com/image.php?id=135142)

(http://www.audiocircle.com/image.php?id=135143)

(http://www.audiocircle.com/image.php?id=135144)

(http://www.audiocircle.com/image.php?id=135145)


I am going to add a Remote TKD volume pot and board along with a Torroidal power transfomer
Title: Re: Nelson Pass B-1 preamp kit- Help!
Post by: yardbird on 17 Apr 2016, 05:07 pm
Hey guys,
Newbie question. Am building the buffer and got a "Pass" small enclosure off of Ebay. It came with an AC in and an AC switch. I am going to use batteries or a wall wart to power the buffer. Can I use the AC power switch to turn off the power and eliminate a drain on the batteries? The Negative lead will still be "active" to the buffer. Will this hurt the buffer? Seems like I need a switch that will disconnect the positive and negative leads??? Any suggestions?
Thanks,
 Jeff
Title: Re: Nelson Pass B-1 preamp kit
Post by: yardbird on 18 Apr 2016, 10:52 am
Never mind. Saw in the build pics where a switch was included with batteries. Seems to work fine. I used Sonicaps with a gen 2 bypass, naked Vishay 320k in the 4 critical positions. I had to order 2 shorter Rubycon power caps to allow it to fit in the case I bought. Powering it with batteries. Sounds really nice with no break in. A substantial improvement in my system (Wadia 121 dac, Prima Luna Prologue 4 and Dennis Murphy designed ER-18s). Very happy. I'll try to post a pic. Now, can I build the F6 without killing myself?
Title: Re: Nelson Pass B-1 preamp kit
Post by: Coup36 on 14 May 2016, 03:18 pm
Hello DIYer's,

Wanted to say thank you to everyone that has contributed to this thread!  I just finished my very first DIY build which was a ton of fun but would have been impossible without this thread as a resource.  Check out the finished product below. 

Pass B-1 Dual Mono Integrated Amp:
 - Pass B-1 Buffer (BOM as listed by wushuliu) 
       - Mundorf MCap EVO 10uf
       - Jantzen Superior ZCap MKP 1uf
 - IcePower 50asx2 - mono X2
 - 25k Apls Pot
 - Velleman K1823 1A power supply
 - AnTek AN-0118 10VA Transformer
 - Aluminum amp enclosure WA11 (eBay)




(http://www.audiocircle.com/image.php?id=142971)
Title: Re: Nelson Pass B-1 preamp kit
Post by: I.Greyhound Fan on 30 Jun 2016, 06:18 pm
We just replaced  (with the help of a friend) the manual Alps Blue volume pot with a remote controlled TKD from Hi Fi Collective and the sound is noticeably better with greater clarity, air and detail.  Textures are improved as well.
Title: Re: Nelson Pass B-1 preamp kit
Post by: KR500 on 18 Nov 2016, 04:37 pm
just purchased the legitimate B-1 Board with matched jfets from Nelson Pass via the store and printed out the BOM from the first page
I am thinking about upgradeing  the resistors and caps, but after looking at the price of 4 Vishay tx 2575 resistors my fixed income budget got sticker shock.
At the bottom of the BOM post on page 1 it mentions PRP resistors. for the thrifty audio fan , but the link to the retailer is changed and I couldn't find resistors marked PRP at the new site . Are these for the 4 1K input resistors people suggest upgrading ?   I realize this is an older thread .
I posted here because the other one is huge in length.
Are the suggested bypass Dayton film/foil caps paralleled to get 1uF  suggested upgrades for the metallized polypropelene caps in the digi-key BOM ?
I use a couple of tube integrated amps, one a Class A and the other AB  along with some AB solid state amps . Does the B-1 work well with tube amps ?
thanks
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 18 Nov 2016, 08:21 pm
just purchased the legitimate B-1 Board with matched jfets from Nelson Pass via the store and printed out the BOM from the first page
I am thinking about upgradeing  the resistors and caps, but after looking at the price of 4 Vishay tx 2575 resistors my fixed income budget got sticker shock.
At the bottom of the BOM post on page 1 it mentions PRP resistors. for the thrifty audio fan , but the link to the retailer is changed and I couldn't find resistors marked PRP at the new site . Are these for the 4 1K input resistors people suggest upgrading ?   I realize this is an older thread .
I posted here because the other one is huge in length.
Are the suggested bypass Dayton film/foil caps paralleled to get 1uF  suggested upgrades for the metallized polypropelene caps in the digi-key BOM ?
I use a couple of tube integrated amps, one a Class A and the other AB  along with some AB solid state amps . Does the B-1 work well with tube amps ?
thanks

You can get PRP resistors from Sonicraft (who also have a circle here). They also have Takman metal film and carbon film resistors that are also very good.
yes the film/foil caps are an upgrade, but this is very subjective. I'd once again point to Sonicraft and their Sonicaps I and II as possible upgrade caps.
The B-1 should work with whatever amp you pair it with.
Title: Re: Nelson Pass B-1 preamp kit
Post by: wushuliu on 18 Nov 2016, 08:24 pm
Hello DIYer's,

Wanted to say thank you to everyone that has contributed to this thread!  I just finished my very first DIY build which was a ton of fun but would have been impossible without this thread as a resource.  Check out the finished product below. 

Pass B-1 Dual Mono Integrated Amp:
 - Pass B-1 Buffer (BOM as listed by wushuliu) 
       - Mundorf MCap EVO 10uf
       - Jantzen Superior ZCap MKP 1uf
 - IcePower 50asx2 - mono X2
 - 25k Apls Pot
 - Velleman K1823 1A power supply
 - AnTek AN-0118 10VA Transformer
 - Aluminum amp enclosure WA11 (eBay)

Nice!
Title: Re: Nelson Pass B-1 preamp kit
Post by: KR500 on 19 Nov 2016, 01:37 pm
thanks for the post Wush, heading over to SC right now
Title: Re: Nelson Pass B-1 preamp kit
Post by: Steve on 20 Nov 2016, 04:16 pm
We just replaced  (with the help of a friend) the manual Alps Blue volume pot with a remote controlled TKD from Hi Fi Collective and the sound is noticeably better with greater clarity, air and detail.  Textures are improved as well.

Yep, agree I.Greyound. I tested and used a 25mm TKD pot in my last few preamps and  it was unbelievably natural and accurate. That and Noble (not manufacturered anymore) were the best I have ever tested for accuracy and naturalness in every aspect of reproduction. And of course smoothness of rotation is a good thing.

I think you can now concentrate on other aspects, tweaks that you may be concerned with.

Cheers and all the best.
Steve
Title: Re: Nelson Pass B-1 preamp kit
Post by: KR500 on 19 Dec 2016, 02:46 pm
I'm ordering from Parts Express per Wush's BOM ( thank you for posting that ) and wondered if the Jantzen Z or Solen 10uF caps are any improvement over the recommended one ?
Will try the Jantzen Z caps

(2) 10uf PP Cap
Quote
http://www.parts-express.com/pe/pshowdetl.cfm?PartNumber=027-932&DID=7
Title: Re: Nelson Pass B-1 preamp kit
Post by: KR500 on 24 Dec 2016, 11:10 pm
I got the four .47uf Dayton bypass caps to parallel in pairs per page 1's suggestion and only one caps lead will fit through the pcb . They are bigger than the area for them on the PCB.
If I solder the leads from one cap to the other cap mounted on the board it's going to be pretty top heavy..... so I was thinking about mounting the cap off to the side of the board ?
Looking at the previous pages of this topic I see a couple of other folks did this on their project with larger caps so I'm glad they posted pictures .A shrink wrap on the cap leads to insulate any bare wire from touching something on the board .
The 10uF Jantzen Z cap is pretty big too, so I may move that off the board mounting also.

Do you ground the PCB to the chassis ?
Should the input jacks be insulated from the chassis, or the ground tabs on the jacks to another point ?

thanks
Title: Re: Nelson Pass B-1 preamp kit
Post by: I.Greyhound Fan on 25 Dec 2016, 04:50 pm
I used the insulating spacers with my RCA jacks.  We also used a star ground to the metal chassis.
Title: Re: Nelson Pass B-1 preamp kit
Post by: KR500 on 29 Dec 2016, 03:33 pm
thanks greyhound
On my amp project I grounded the earth center pin to the chassis.
The Pass B1 uses a wall wart jack with only positive and earth on the jack pin and outer shell,
I don't know if you use the negative pin of the jack as earth, and chassis ground , or something different ?
Title: Re: Nelson Pass B-1 preamp kit
Post by: KR500 on 15 Jan 2017, 02:17 pm
I don't need a volume control so will just put a resistor on each input as mentioned in an earlier post
Will any brand/type resistor work or is one type preferred for this use ?
thanks
Title: Re: Nelson Pass B-1 preamp kit
Post by: I.Greyhound Fan on 15 Jan 2017, 04:50 pm
I don't need a volume control so will just put a resistor on each input as mentioned in an earlier post
Will any brand/type resistor work or is one type preferred for this use ?
thanks


I used Audio Note Non-Metallic Tantalums and Shinkoh Tantalums in my B1 (along with Naked Z-foil at the input and Riken Carbon at the output) for their supposed more organic and warmer sound.  You can find them at parts connexion.
Title: Re: Nelson Pass B-1 preamp kit
Post by: KR500 on 9 Mar 2017, 01:51 pm
FWIW , I ordered the larger DPDT switch from the BOM on page 1 and it is on-on only for 2 inputs , the smaller DPDT switch linked on page one is on-on with center off
Title: Re: Nelson Pass B-1 preamp kit
Post by: cliffylfd on 3 Apr 2018, 05:18 pm
Hi,This thread seem to have gone quiet, but i wonder if  anyone from the UK  can help me source parts /
 I usually buy from RSwww.com , but they don't sell the Vishay  resistors in 1s or 2s and i am not sure what else to get.
 I will change the original 1k to the "naked 330r as recommended in the thread,(any other improved changes would be grateful.
  Also has people stop building the B1 and moved on?
 Thanks
CJ
Title: Re: Nelson Pass B-1 preamp kit
Post by: navi on 22 Jun 2018, 01:20 am
Hi,This thread seem to have gone quiet, but i wonder if  anyone from the UK  can help me source parts /
 I usually buy from RSwww.com , but they don't sell the Vishay  resistors in 1s or 2s and i am not sure what else to get.
 I will change the original 1k to the "naked 330r as recommended in the thread,(any other improved changes would be grateful.
  Also has people stop building the B1 and moved on?
 Thanks
CJ

I just completed my B1 with Intact audio auto former volume control. I changed the R204 & R104 to Amtrans 39R resistor, Linear power supply off eBay that I set to 15V & a SBooster DC filter.

Sounds great. I think the bass is meatier than before with no grain the the highs.
Title: Re: Nelson Pass B-1 preamp kit
Post by: turion64 on 6 Apr 2021, 12:52 pm
Very late into this game it seems.

Now that the part # for C1&2 appears to be obsolete, any recommendations for a replacement cap?  Anything 15000uF; 25V or higher, similar diameter & ESR rating?

Thanks!
Title: Re: Nelson Pass B-1 preamp kit
Post by: I.Greyhound Fan on 6 Apr 2021, 03:33 pm
Very late into this game it seems.

Now that the part # for C1&2 appears to be obsolete, any recommendations for a replacement cap?  Anything 15000uF; 25V or higher, similar diameter & ESR rating?

Thanks!

I can't remember the caps that I used for C1 and C2.  But Nichicon KG series would be fine.

https://www.partsconnexion.com/capacitors-ele-nichicon-kg-series.html

Title: Re: Nelson Pass B-1 preamp kit
Post by: turion64 on 30 Apr 2021, 11:25 am
Thanks for that.

Another question, the boards stand-off holes appear to be connected to the general ground. So, in mounting the board in a case I should use brass standoffs to connect the boards to the case earth grounding scheme or should the board be mounted with nylon standoffs to isolate it from such?