Digital Octave Fuzz (Stupid CMOS) question.

[digi2t]

Hi all,
I recently build a DOF, and there's just one thing that has me wondering. When I turn the "Fundamental" down, I lose volume. Not completely mind you, but it's significant. Here's my layout;


Component values are as per Mr, Escobedo's diagram;


Massive square wave, you bet. Mosquito-like octave, not really. Unless I'm missing something here....

Cheers,
Dino

[Earthscum]

It's pretty simple, actually... your pulse width is getting smaller, thus less overall signal. It's spending more time at one side and eventually only blipping to the other side for a moment.

To expand on that a bit farther, a smaller pulse width, say 25%, means that you have half of one note higher and half of one note that is lower (the other 75%), and the total of the 2 make up the signal that we hear. The 'higher pitch' half will be more easily affected by any low pass filtering happening downstream, i.e. the softer your amp is, the more apparent volume loss you will have when you turn towards the FUND side.

[digi2t]

Aw geez... that's happens when I'm up past my bedtime. Like the flow of the schematic wasn't clear enough  .

Thanks Earthscum. Maybe I can amplify that side somehow. Maybe use a dual gang pot, one half for the fund, and the other half for volume for that loop (post some gain circuit).

Cheers,
Dino

[Earthscum]

Unfortunately thats just the nature of the type of wave it produces. In easiest form you may be able to use a dual ganged pot to increase or decrease volume as you turn to one wave or the other. Otherwise it would take quite a bit more circuitry to make that compensation.

Or you just work with it like an MXR Blue Box.

[digi2t]

Maybe just a clean boost, like this;



and a dual gang to run the signal through the booster at one end, or not, at the other end.