I want to do the "depth" mod on a Boss CE-2 pedal or, alternatively, Tonepad's clone (http://www.tonepad.com/project.asp?id=53) (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 (http://www.diystompboxes.com/smfforum/index.php?topic=43037.msg311507#msg311507).
So I have two questions:
1. Will something like this work (EDIT: the circle with three lugs is a pot)?
(https://s17.postimg.org/4izbwsx23/CE-2_Schematic_-_Lag_Mod.png) (https://postimg.org/image/4izbwsx23/)
2. If it will, which value and type of potentiometer would work best?
on off on toggle switch? with 3 cap options?
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.
http://www.smallbear-electronics.mybigcommerce.com/9mm-rotary-1p6t/
still not a pot
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.
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
???
Down in pF ranges, you can get actual variable capacitors. Maybe not too many these days that will panel mount and accept a knob.
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.
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.
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?