Boss CE-2 "Depth" Mod on a Pot

Started by Fael, March 14, 2018, 08:58:21 PM

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Fael

I want to do the "depth" mod on a Boss CE-2 pedal or, alternatively, Tonepad's clone (schematic in link). What this mod does is increase the delay time of the wet signal by increasing the C22 cap (from 47pF to higher values). Most resources suggest implementing a switch to alternate between two (or more) caps. My goal is to be able to simulate a variable capacitor by doing something like this.

So I have two questions:

1. Will something like this work (EDIT: the circle with three lugs is a pot)?


2. If it will, which value and type of potentiometer would work best?

njkmonty

on off on toggle switch?  with 3 cap options?

Fael

Quote from: njkmonty on March 14, 2018, 09:46:36 PM
on off on toggle switch?  with 3 cap options?

I'm aware of this option but the mod I'm inquiring about would essentially be like having a variable capacitor.


Fael

Quote from: njkmonty on March 14, 2018, 10:43:11 PM
http://www.smallbear-electronics.mybigcommerce.com/9mm-rotary-1p6t/

still not a pot

Thanks, I'm aware of those too. I am explicitly asking about whether the layout I posted in the OP would work or not.

njkmonty

by using a 1 meg pot?

you may need to use 2 caps , so when the pot has maximum resistance then there is still a bypass cap supplying the minimum  cap preference
???

thermionix

#6
Down in pF ranges, you can get actual variable capacitors.  Maybe not too many these days that will panel mount and accept a knob.

Rob Strand

You will find the RC oscillators used for clocks and VCO's don't work so well with you have a resistor in series with a cap. 
A switch might work but you don't really want to run wires to caps with those high frequencies on them.
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Danich_ivanov

#8
I'm not sure, but maybe adding a pot wired as a variable resistor across the cap might do the trick, i would start with something like 1m, and watch what happens. Or perhaps a pot before/after the cap? I don't know exactly what's happening there, since i only had a brief look, but these are first things that come to mind.

Fender3D

You won't change capacity with just a resistor....

But the real deal here is the change of the clock frequency, then why don't you simply add a potentiometer at pins 6 and 7, how it should be done?
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