Nelson Pass B-1 preamp kit

wushuliu · « **on:** 26 Feb 2010, 06:07 pm »

Mariusz · « **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 · « **Reply #2 on:** 27 Feb 2010, 01:53 am »

Good idea for this thread.

Does anyone here have experience building the Pass B1?

Bemopti123 · « **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 · « **Reply #4 on:** 27 Feb 2010, 03:25 am »

Quote from: Bemopti123 on 27 Feb 2010, 03:14 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 · « **Reply #5 on:** 27 Feb 2010, 04:21 am »

Quote from: 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?

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.

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

xecluded · « **Reply #6 on:** 27 Feb 2010, 09:28 am »

Do you have part list for the toroid transformer and where to buy. Thanks

mightym · « **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 · « **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 · « **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 · « **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 · « **Reply #11 on:** 27 Feb 2010, 06:04 pm »

Quote from: 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?

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 · « **Reply #12 on:** 27 Feb 2010, 06:11 pm »

Quote from: 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

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 · « **Reply #13 on:** 27 Feb 2010, 06:17 pm »

Quote from: wushuliu on 27 Feb 2010, 06:11 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 · « **Reply #14 on:** 27 Feb 2010, 07:37 pm »

Quote from: Mariusz on 27 Feb 2010, 06:17 pm

I will add a bottle of Scotch if you do.

Mariusz

Order'sgoinginfirstthingmonday!

Mariusz · « **Reply #15 on:** 27 Feb 2010, 08:10 pm »

Quote from: wushuliu on 27 Feb 2010, 07:37 pm

Order'sgoinginfirstthingmonday!

Very exited!!!!

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 · « **Reply #16 on:** 27 Feb 2010, 10:06 pm »

Quote from: xecluded on 27 Feb 2010, 09:28 am

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 · « **Reply #17 on:** 27 Feb 2010, 10:17 pm »

Just go to antek. They are cheap and easy.

sondale · « **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 · « **Reply #19 on:** 28 Feb 2010, 02:04 pm »

Quote from: sondale on 28 Feb 2010, 01:48 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.