I am going to start point-to-pointing the Pass Labs B1 Buffer Preamp in a week or two when I get some time. I have attached the schematics with transposed part specs for anyone else who wants the information.
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I am going to start point-to-pointing the Pass Labs B1 Buffer Preamp in a week or two when I get some time. I have attached the schematics with transposed part specs for anyone else who wants the information.
Did you give up on waiting on the PCB? I've been checking the site every once in a while and haven't seen them become available again.
I'll look forward to your updates.
I did get tired of waiting for the board... And since it has so few parts anyway, I'll just get a breadboard and do it myself.
I ended up buying one from Tim Rawson instead of trying to build one without the board. Even though there's a low parts count and it seemed pretty straight forward, I got intimidated/confused reading the threads on diyaudio.com.
Ya, those threads were a little intimidating, but I figure that's the best way to learn. :D
I posted the B1 schem awhile back.http://www.polkaudio.com/forums/show...S+PREAMP.Looks like a great little pre,if I didn't already have a Pass Jfet clone then I would probably build one of these or the B3.If I where to build it I think I would use the bipolar 9 volt power supply so as to eliminate the need for costly output caps.
Btw, I would avoid using Jantzens that are in the picture above.
What was wrong with the Jantzen caps? I used them in my Monitor 5Jrs with good success.
I was looking at running it off a pair of 9v batteries to totally avoid A/C. Am I missing something with the bipolar power supply? The specs sheet says it required between 18-24v.Quote:
Originally Posted by GV#27
IMO, I thought they sounded terrible in the B1. I replaced them with Sonic Caps and there was a large improvement. They may not be as bad in a speaker crossover.Quote:
Originally Posted by zingo
You can use a single 18 volt supply or a +-9 volt.I haven't checked the thread at DiyAudio in awhile but I think some builders intended to use batteries.Quote:
Originally Posted by zingo
Where did you get the chassis Face? Your completed product looks fantastic!
If you are looking for a nice chassis for your B1 one of these Hammonds would do nicely.http://www.hammondmfg.com/1455ptbla.htmQuote:
Originally Posted by zingo
They come in several sizes and with either plastic or metal fronts. I have used them for several projects.I used a small one for this passive pre.
I bought mine used and I believe the case is unavailable.
Too bad because they look great.Quote:
Originally Posted by Face
What didn't you like about the Z caps?
Oooops,make that Jantzen caps.Quote:
Originally Posted by GV#27
For my last couple projects Tim went with Diyenclosure. Not sure if it is the same company but it looks similar to my BPA200 and 200asc, just smaller.Quote:
Originally Posted by zingo
I found them rolled off up top and not very coherent.Quote:
Originally Posted by GV#27
Thats what I got doing my cap shoot out on speakers. Solen's were too hot brittle, Jantzen's were better, but kinda lifeless, and Dayton's came out on top.Quote:
Originally Posted by Face
I'm kind of surprised that I liked them then in my 5Jrs, because I really like the Sonicaps in my 4.1TLs. Or maybe they just work well with those speakers. I will be building this with Daytons however since I have had good results with them in electronics before.
Are the Jfet's hard to source for this thing, or am I remembering incorrectly?
I believe that the 2SK370 can be hard to find, but here is a link to the also approved LSK170:
http://www.ka-electronics.com/FETS/FET.htm
FYI: The 2SK170 is also approved to be used
Parts List:
2SK370 Transistor 4x
1N914 Diode
Generic LED
15000 uF 2x
10 uF 2x
1 uF 3x
1 ohm
1k ohm 4x
10k ohm 2x
15k ohm
25k ohm 2x
221k ohm 2x
1M ohm 6x
2 way switch
RCA jack 6x
I remember reading that if you contact Pass Labs, they may be able to sell you a board. They're leaving the "out of stock" message up on their page due to them not being able to meet demand.
I may actually grab a second one.
Updated Parts List:
2SK370 N channel JFET Transistor 4x (GR or BL grades)
1N914 Diode
Generic LED
15000 uF 2x Electrolytic 25v
10 uF 2x Film
1 uF 3x Film
1 ohm 3w
1k ohm 4x .25w
10k ohm 2x .25w
15k ohm .25w
25k ohm 2x .25w
221k ohm 2x .25w
1M ohm 6x .25w
2 way switch
RCA jack 6x
Linear Taper Pots 25k 2x
The first time I contacted them, they said they were out. I contact them back a month later a few times but haven't received any updated responses. I figured since there were so few parts and it's not high voltage, point-to-point would be a good route.Quote:
Originally Posted by Face
http://face.cleanandquiet.com/store/B1%20MR.jpgQuote:
Originally Posted by Face
New wiring, Mike?
Daytons in mine. Finally checked tonight.