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.

Tuesday, November 12, 2019

Morula Auto Wah

Here's a simple auto wah circuit with a pretty low parts count I thought was interesting. Not a lot out there on it, but it uses a single CD4049UBE to create an LFO and wah audio path. The depth of the effect is controlled by the LFO. Should fit nicely in a 1590B. Here's the schematic for reference.


  1. Has anyone ever seen a working version of this circuit? The reason I ask is a few years ago I tried breadboarding something very similar to this and while it worked, I could never keep the oscillator from "ticking"... The only thing that helped was using a separate chip for the oscillator.

    1. That was my concern with this circuit as I was laying it out. I think this vero layout is verified and there was no mention of tick so I went ahead and laid it out.

    2. Did it had ticking noise?
      Anyone verfied it?

  2. Well - the PCB does not want to work - I etched it and soldered it, but to no avail - what I do get is the signal from my bass unaltered plus the LFO bleed/click. Checked for shorts - found none.