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previous: Dave Thanks for that guys :-) -- 1/14/2001 3:15 AM View Thread

Re: Switching between three effects?

1/14/2001 7:19 PM
R.G. in Austin for the momentRe: Switching between three effects?
"Can't anyone decipher the page? I've saved it to my PC and read it 20 times and I still don't quite get it!!!"
What, my description isn't a marvel of lucidity???? *<8-)  
You'd think that as a native speaker of English with some years of experience, I'd be better at this.  
To select between three distortion devices, yes, you need at least a 2P3T switch setup, just as you thought.  
Here's the poop. The footswitch circuit is a quick and dirty way to "capture" which of a number of momentary switches was pressed. You can use it directly for a one-of-three by just not putting momentary switches on the inputs above three. It's also possible to eliminate those inverters and junk by some judicious tying of inputs.  
You probably want a fourth setting "none of the distortions" too, right?  
If you're doing **ONLY** selection of one of three distortions, you are trying to solve a different problem than the massive any-effect-any-order-programmable thing. You can get by with only some CD4066 switches.  
Basically, you put a switch in series with the input and output of each distortion pedal, so there are three "paths" through the distortion pedals. Each output from the footswitch turns on the input and output switch for one of the distortions. The fourth "none of the distortions" switch is in parallel with the distortions. The fourth footswitch signal turns it on to bypass all of the distortions.  
There are some places where you need finesse, such as biasing the switches into the middle of the power supply to get rid of switch pop, but that's not needed until you understand what's happening.  
So - which part of this does not make sense now, and we'll work from there.

Dave Too cool! An answer from the myan h... -- 1/14/2001 8:04 PM