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CV to EXP circuit.

Posted: Thu May 06, 2010 7:22 am
by smile_man
Anyone know how to make one? Would it be difficult to do? TSP made something like this but I'd rather just build my own.

Re: CV to EXP circuit.

Posted: Thu May 06, 2010 10:34 am
by multi_s
Image

If your using a pot, you could just do this^^.

You can use a TRS (stereo) jack to connect the pedal or whatever to the expresion pedal. 3 terminals on teh jack, 3 terminals on the pot...

The main difference is the expression pedal does not generate its own voltage, as CV would. So you send it a voltage to one lug of the pot and it sends back a fraction of that voltage via the middle lug (wiper). and then the third lug will go to ground presumably.

Re: CV to EXP circuit.

Posted: Thu May 06, 2010 6:32 pm
by smile_man
thanks, would it work the other way around? I'm meaning to put CV into an expression pedal input.

Re: CV to EXP circuit.

Posted: Thu May 06, 2010 11:14 pm
by multi_s
ya you should be able yo go from one to the other pretty easily.

if its an expression input i would assume it is a TRS jack CV's usually just have TS jacks (mono, 2 terminal). So what you need to do i s disconnect the terminal corresponding to the voltage being sent to teh expression pedal. The CV will replace the voltage the expression pedal was sending back.

I guess there could be an issue if you plug a CV with a higher voltage out than the expression pedal would have returned but thats fixable too.

I dont know for sure but i think usually in expression pedal on a TRS, tip is the returning voltage that you can adjust, ring is the voltage sent out by the pedal and sleeve is ground. In CV with TS tip is again teh alternating voltage supplied by teh .. well whatever is making your CV/LFO and sleeve is ground.

so you probably can see that it should not be that hard to flip form one to the other (since tip and sleeve serve teh same functon in both setups). You have to remove the voltage on teh ring connector though because otherwise a mono plug would short that voltage to ground (mono in a stereo jack ends up connecting ring and sleeve).