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Andy_H's Pass B1 Build

Andy_H

Andy_H

Behind the Wall of Sleep
After having the board for a few months, I finally got started on my Pass DIY B1 buffer preamp yesterday. I'm keeping it pretty basic component-wise. Resistors are the standard Vishay Dale RN55D from Pass's instructions, C100, 101, 200 & 201 are Dayton 1% metalized polypropylene. I've worked on perfboard before but this was actually the first PCB I've soldered, but it all went together fine. The trickiest part, as everyone else who's built this has noted, is fitting the bigger caps on the board. Also I had to ream out the holes for C100 & 200 as the leads on the Dayton caps were too thick.

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It will live in a red oak box. I got the pieces for that rough cut yesterday. Finish will be something along the lines of tung oil or Danish oil. (Top not pictured)

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I'm still waiting on RCA jacks, Alps Blue Velvet pot and fancy knob to arrive from Parts Connexion. I'm really looking forward to hearing what this pre can do.
 

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i can only tell you good things about B1, transparent...very transparent, music sounds even better through it than plugin tube phono preamp direct to amp!!!

and i feel great when turning up volume pot to 2 or 3 o'clock position!!!!
 
looking good so far! if you like it half as much as i like my DC-B1, you are in for a treat.
 
I too have read tons of good things. It's nice and simple which I like from a sonic standpoint plus its simplicity makes it a very doable build for me to hone my skills on.

Now I'm just waiting on the Parts Connexion order to arrive. I can't continue any further until that gets here, and since it's coming from Canada I suppose this project will be on hold for a week or two. But that's OK; I have other things to tinker with :D.
 
I used the Alps pots, too, from Partsconnexion. They work well. The standard B1 is probably the easiest kit build I've done. What are you using for a power supply?
 
I got one of these 24VDC 250 mA wall warts. I'll use that for now. I also have an old laptop power supply that would work too, can't recall the exact rating.
 
Andy_H said:
I got one of these 24VDC 250 mA wall warts. I'll use that for now. I also have an old laptop power supply that would work too, can't recall the exact rating.
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Nelson used similar when he was introducing the B1, I believe his was a medical rated supply. The B1 seems to work OK across a range of voltages, I power mine at around 20v., IIRC. Most of the laptop supplies I have around here are around 19v. so you shuold be fine with that, also.
 
The enclosure is starting to come together. Dry fitting parts before glue-up (The flashlight is just there to prop up the front panel):

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And now, glue time:

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Whenever I glue something like this, I always worry that I'll remove the clamps and find that I put it together all wrong and now it's stuck like that. Hopefully I got it right.
 

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Lookin' good!
Man, you even took the time to tape cardboard on the clamp faces, that is serious detality.:D
 
westend said:
Lookin' good!
Man, you even took the time to tape cardboard on the clamp faces, that is serious detality.:D
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I've learned that one from experience. :D What you can't see in the photo is that the corner pieces of the band clamp are all lined with masking tape as well. After spending the last couple evenings sanding everything to a nice smooth finish I'd hate to have the surface get marred by the clamps.

I removed the clamps this morning before I left for work. It went together pretty well. The joints are not quite perfect due to some warps in the thinner wood sections, but it's passable. Tonight I'll do the last finish sanding to clean up a few little glue drips and get the finish applied - Watco Medium Walnut Danish Oil. I should have it completed Thursday night or Friday (I have Friday off work, woohoo!) and then it's listening time. :music:
 
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Nice build! I have a board & matched transistors sitting here- I should get off my butt & build it. Could you estimate what the componants for the board cost? (less the alps pot.)
 
Approximate costs:
$45 for the board & jfets from Pass
$20 for the Dayton caps from Parts Express
$32 for resistors, diode, switch, remaining caps, wall wart, etc. from Digi-key (I bought larger quantities of resistors and diodes than necessary, but they were all super cheap, like $0.09 apiece)
$50 for RCAs, pot, and knob from Parts Connexion
$15 for wood from Lowe's
for a total of $162.

If you already have the board, jfets and exclude the Alps pot and the wood, that would be ~$85. The cost of the signal caps can vary widely; I went for relatively inexpensive with good specs but there are tons of options for fancy boutique caps. On the other hand, you could go even cheaper for the caps if you really wanted to rein in your budget.
 
Another productive evening on the B1 project! I sanded all the joints nice and flush and applied the Danish oil finish. I have to say, I am really pleased with how the finish is looking. It's the first rubbed oil finish I've done, and if I may be so bold as to say I think it looks great :D

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I just have to let it dry overnight and then get all the connections and controls wired up and then :music:
 

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Looks great, Andy! Although I probably would have chosen different feet. :D
 
Thanks Ray! The feet are still in the prototype stage and may be subject to further refinement. :scratch2:
 
My local hardware store used to stock a whole line of rubber furniture bumpers like these. They came in different colors and sizes and were really good for gear cases. They now only stock a few sizes and colors are limited but the price is still very good and they are easy to install.
 
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