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.

Monday, November 9, 2015

TubeSound Overdrive

Here's a simple one-knob drive that's ripe for modification. It uses an interesting combination of one NPN and one PNP silicon transistor stacked together. There are a few different values you can tweak to taste. Here's a schematic for reference:



  • The input capacitor (C1) could be increased for more bass.
  • C2 could be increased to 47-100µF for more drive.
  • The output capacitor (C3) could be decrease for more treble.
  • R5 could be replaced by a 10-20k pot, lug 1 going to ground. C2 could then be moved between lugs 1 and 2. This would act as a gain control (much like in a Fuzz Face).
  • R3 (trimmer) could be moved off-board as an alternative bias/gain control.
I haven't tried these modifications, but they should do something interesting. YMMV



6 comments:

  1. Agradable sonido! C1= 33uf. C2= 6,8nf. Trimmer 22k. De esta forma me parece mas metálico y valvular. Verificado en Benavidez, Argentina.

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  2. Perdon! C1: 6,8 nf. C2: 33 uf.

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  3. Hey! Is there a place where i can find more info about this layout-schematic?
    Maybe a video where i can hear this pedal?
    thanks in advance

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  4. If anyone wants to try this circuit.., remove 10k and 22uf from emitter to ground or else this circuit will not work
    Connect the emitter pin directly to the ground!!

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    Replies
    1. Hi Rosang. For me, it worked with the 10k resistor and 22uF capacitor, but the biasing is a bit hard to get done. Once you get the bias trimmer on the right spot, it gets a very good overdrive sound.

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