B1 Buffer Preamp

zingo
zingo Posts: 11,258
edited March 2013 in DIY, Mods & Tweaks
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.
Jake
Post edited by zingo on
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  • zingo
    zingo Posts: 11,258
    edited January 2009
    my.php?image=b1bufferpreampti0.pdf
    Jake
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  • strider
    strider Posts: 2,568
    edited January 2009
    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.
    Wristwatch--->Crisco
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  • zingo
    zingo Posts: 11,258
    edited January 2009
    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.
    Jake
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  • strider
    strider Posts: 2,568
    edited January 2009
    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.
    Wristwatch--->Crisco
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  • zingo
    zingo Posts: 11,258
    edited January 2009
    Ya, those threads were a little intimidating, but I figure that's the best way to learn. :D
    Jake
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  • Face
    Face Posts: 14,340
    edited January 2009
    Pass%20B1.jpg
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • Systems
    Systems Posts: 14,873
    edited January 2009
    I posted the B1 schem awhile back.http://www.polkaudio.com/forums/showthread.php?t=69722&highlight=PASS+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.
    Testing
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  • Face
    Face Posts: 14,340
    edited January 2009
    Btw, I would avoid using Jantzens that are in the picture above.
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • zingo
    zingo Posts: 11,258
    edited January 2009
    What was wrong with the Jantzen caps? I used them in my Monitor 5Jrs with good success.
    Jake
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  • zingo
    zingo Posts: 11,258
    edited January 2009
    GV#27 wrote: »
    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.

    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.
    Jake
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  • Face
    Face Posts: 14,340
    edited January 2009
    zingo wrote: »
    What was wrong with the Jantzen caps? I used them in my Monitor 5Jrs with good success.
    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.
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • Systems
    Systems Posts: 14,873
    edited January 2009
    zingo wrote: »
    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.
    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.
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  • zingo
    zingo Posts: 11,258
    edited January 2009
    Where did you get the chassis Face? Your completed product looks fantastic!
    Jake
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  • Systems
    Systems Posts: 14,873
    edited January 2009
    zingo wrote: »
    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.htm
    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.
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  • Face
    Face Posts: 14,340
    edited January 2009
    I bought mine used and I believe the case is unavailable.
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • Systems
    Systems Posts: 14,873
    edited January 2009
    Face wrote: »
    I bought mine used and I believe the case is unavailable.
    Too bad because they look great.


    What didn't you like about the Z caps?
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  • Systems
    Systems Posts: 14,873
    edited January 2009
    GV#27 wrote: »


    What didn't you like about the Z caps?
    Oooops,make that Jantzen caps.
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  • Gaara
    Gaara Posts: 2,415
    edited January 2009
    zingo wrote: »
    Where did you get the chassis Face? Your completed product looks fantastic!

    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.
    The Basement HT
    PC Rig
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  • Face
    Face Posts: 14,340
    edited January 2009
    GV#27 wrote: »
    Oooops,make that Jantzen caps.
    I found them rolled off up top and not very coherent.
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • ben62670
    ben62670 Posts: 15,969
    edited January 2009
    Face wrote: »
    I found them rolled off up top and not very coherent.

    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.
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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  • zingo
    zingo Posts: 11,258
    edited January 2009
    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.
    Jake
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  • strider
    strider Posts: 2,568
    edited January 2009
    Are the Jfet's hard to source for this thing, or am I remembering incorrectly?
    Wristwatch--->Crisco
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  • zingo
    zingo Posts: 11,258
    edited January 2009
    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
    Jake
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  • zingo
    zingo Posts: 11,258
    edited January 2009
    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
    Jake
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  • Face
    Face Posts: 14,340
    edited January 2009
    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.
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • zingo
    zingo Posts: 11,258
    edited January 2009
    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
    Jake
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  • zingo
    zingo Posts: 11,258
    edited January 2009
    Face wrote: »
    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.

    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.
    Jake
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  • Face
    Face Posts: 14,340
    edited February 2009
    Face wrote: »
    Pass%20B1.jpg
    B1%20MR.jpg
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • strider
    strider Posts: 2,568
    edited February 2009
    New wiring, Mike?


    Daytons in mine. Finally checked tonight.
    Wristwatch--->Crisco
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  • Face
    Face Posts: 14,340
    edited February 2009
    strider wrote: »
    New wiring, Mike?
    Kinda. ;)
    Daytons in mine. Finally checked tonight.
    Good! Be glad.
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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