This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Thursday, December 19, 2019

VFE Distortion 3

Always a fan of the MXR Distortion+/DOD 250 as you all have probably figure out by now. Here's VFE's take on the classic circuit. Bunch of extra controls and mods including soft clipping, along with bass and tone controls. Schematic here for reference.


15 comments:

  1. Those W taper pots... Very hard to find. Any sources?
    I do not see why it uses a W200k pot as it is not "standard" in both value as in taper type.It is only used as a warp control like described by AMZ (http://www.muzique.com/lab/warp.htm). Wouldn't a W20k be enough?

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    1. Aside from the usual W20k and W100k, I'm not finding much out there.
      We could try with a linear pot instead. It's just going to have a different feel at both ends of the pot rotation.
      (Or is it less play in the middle of the rotation?)

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    2. Are you gonna to the Boston tea party?

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    3. I would think a linear taper would work well enough.

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    4. Peter from VFE has previously said on other forums that you can sub a "W pot with a "B" of one tenth the size, so try B20k & B100k. Since it's for clipping, I've found other values I prefer when experimenting with other VFE builds.

      On my build of this one, I just used on/off/on switches instead of pots. The earlier version of this pedal did just that.

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  2. You can get W Taper (Anti-Log) pots from here

    https://www.futurlec.com/PotRot.shtml

    Thou they only have a 220k W not 200k
    But probably as close as you will get

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    1. Nope only A, B and C tapers there. It mentions 1/2W, but that is 0,5 Watt, not W taper. The 220k is a C taper. I also think we can best use linear (B) type pots and a B250k for the "hard" pot this does change the values a bit, but I doubt it will be noticable. You couls also use a A250k with a 1M between lug 1 and 3. It will make the taper more linear but still keeps a bit of the A taper feel.
      And lastly, a B1M for the "soft" pot.

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  3. Ahh sorry confused myself between C and W types.
    Too many Xmas drinks ��

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  4. verified! Used: A1m,B10k(norm working),B1m,B200k,A100k,A100k, everything working, mosfet used 2n7000.Germanium soviet D9. Chip used OP07.

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  5. AlexS was rigt, better take b20k& b100k!

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  6. Howdy! Love this cicuit! It came out pretty good. I subbed BAT41 for the 1n34a, and a tl071 for the LM741. Used B25k for the Hard pot and B100k for the soft. Lot's of sustain, gain and distortion. Couple questions though.
    Seems like the soft doesn't do much prolly cuase of the pot switch, but the real issue is the fat pot. Turning it higher than 1/2 way and it whistles pretty good, and then the filter pot changes the pitch a little. It works really well otherwise, but I'm curious if there's anything I can look at to address these problems.
    Any suggestions would be greatly appreciated. Oh I used your etch pattern and made a pcb...
    pg

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  7. Is this ok to replace the 1N5817 with 1N4002?

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    1. You'll get a tiny bit more voltage drop with the 4002, but it should still work fine.

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  8. Hi - is the schematic available?

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