PNP to NPN Layout Changes

Discussion in 'Burnt Fingers DIY Effects' started by Neener, Oct 9, 2019 at 7:46 AM.

  1. Neener

    Neener Tele-Meister

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    Hello,

    This is my first DIY project, haven't burned the house down yet...

    I'm attempting to build a "Fuzz 69" with NPN Germaniums. I have a PCB kit from GGG, but would like to make my own and use perfboard or euroboard.

    Having trouble finding a layout for NPN, what changes do I have to make to the PNP layout below?

    As i said, first time, I'm sure it's an obvious answer so please forgive Fulltone 69.png ..
     
  2. Digital Larry

    Digital Larry Tele-Afflicted

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    Flip the polarity of the battery input and the electrolytic capacitors.
     
  3. Neener

    Neener Tele-Meister

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    I'm also swapping some components out based on a youtuber's build. Here's all the info I could gather from what he says and some of the video comments. If anyone can help me translate I'd appreciate it.

    "This build doesn't have the resistance in series with the fuzz cap but I did go with 15uf instead of 20uf..."

    "The 8k2 is a trimmer and the 33k is more like 22k"

    "trimmer - bias 4.53 - 5"
     
  4. Wyatt

    Wyatt Tele-Afflicted

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    Is there a schematic? Layout drawings are great for building, but are all but useless for designing/studying the circuit.
     
  5. edvard

    edvard Tele-Afflicted

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    There's a bit of Voodoo involved with swapping pnp for npn; it's not always cut and dried "flip the polarity". I would advise you to look up Pinkjimiphoton's latest posts on the subject at diystompboxes.com. He came up with something that works without the risk of runaway oscillation and other problems that can arise from swapping, though I can't remember what it was at the moment, and right now I'm on my phone with a dodgy data connection or else I'd give you a direct link. :(
     
  6. Neener

    Neener Tele-Meister

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    schematics.jpg
     
  7. Digital Larry

    Digital Larry Tele-Afflicted

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    Yeah, I probably should have said "at the very least flip the polarity". Pinkjimi is really very experienced and a great resource. I've never built one of these. Caveat lector.
     
    Neener likes this.
  8. sirbergersworth

    sirbergersworth Tele-Holic

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    Why not use the GGG board? I built a 69 on on one a few years back and it performs great?
     
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  9. awasson

    awasson Poster Extraordinaire Gold Supporter

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    Neener and zippofan like this.
  10. Neener

    Neener Tele-Meister

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    I’d like do a handwired, so I can call my own I guess.
     
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