Nelson Pass B-1 preamp kit

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wushuliu

Nelson Pass B-1 preamp kit
« 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

(4)1k
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

(2) 10k
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

(1) 1ohm 3 Watt
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

(2) 15000uf caps
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

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

wall wart
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

(2) 10uf PP Cap
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

Stereo

Alps pots, and more.

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

DPDT Toggle Switch for Input

Mini (1/4" hole)

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


Optional for zee thrifty audiophile connoisseurs:

May I recommend zee PRP:

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

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





hope this helps

ainsley

« Last Edit: 28 Aug 2010, 06:12 pm by wushuliu »

Mariusz

Re: Nelson Pass B-1 preamp kit
« Reply #1 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 

earplay

  • Full Member
  • Posts: 300
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Re: Nelson Pass B-1 preamp kit
« Reply #2 on: 27 Feb 2010, 01:53 am »
Good idea for this thread.

Does anyone here have experience building the Pass B1?

Bemopti123

  • Full Member
  • Posts: 1995
Re: Nelson Pass B-1 preamp kit
« Reply #3 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?

Mariusz

Re: Nelson Pass B-1 preamp kit
« Reply #4 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


wushuliu

Re: Nelson Pass B-1 preamp kit
« Reply #5 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.





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



« Last Edit: 7 Mar 2010, 08:25 pm by wushuliu »

xecluded

Re: Nelson Pass B-1 preamp kit
« Reply #6 on: 27 Feb 2010, 09:28 am »
Do you have part list for the toroid transformer and where to buy. Thanks

mightym

Re: Nelson Pass B-1 preamp kit
« Reply #7 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

walkern

Re: Nelson Pass B-1 preamp kit
« Reply #8 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

kukiman

  • Jr. Member
  • Posts: 5
Re: Nelson Pass B-1 preamp kit
« Reply #9 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?

HAL

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Re: Nelson Pass B-1 preamp kit
« Reply #10 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.


wushuliu

Re: Nelson Pass B-1 preamp kit
« Reply #11 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.

wushuliu

Re: Nelson Pass B-1 preamp kit
« Reply #12 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...

Mariusz

Re: Nelson Pass B-1 preamp kit
« Reply #13 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

wushuliu

Re: Nelson Pass B-1 preamp kit
« Reply #14 on: 27 Feb 2010, 07:37 pm »
I will add a bottle of Scotch if you do.

Mariusz

Order'sgoinginfirstthingmonday!  :drool:

Mariusz

Re: Nelson Pass B-1 preamp kit
« Reply #15 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

wushuliu

Re: Nelson Pass B-1 preamp kit
« Reply #16 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.

sts9fan

Re: Nelson Pass B-1 preamp kit
« Reply #17 on: 27 Feb 2010, 10:17 pm »
Just go to antek. They are cheap and easy.

sondale

Re: Nelson Pass B-1 preamp kit
« Reply #18 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.



mightym

Re: Nelson Pass B-1 preamp kit
« Reply #19 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.