Delay pedal (china) - Expression mod

[soundcityec]

Hello friends, I want to mess up a pedal haha.
Is a digital delay - analog voiced, and playing with the time control it gives really cool sounds, but it lacks of an output for an expression pedal and that is what I want to add.

I have disassembled the pedal and found that it has a 100k Ohm pot (B104).
I was just thinking in solder wires from the pot, to a new TRS jack and drill the case.
How can I export it to an expression pedal, if almost all pedals are between 10 to 25 k ohms?? (my expression pedal is 20K I think, is the pigtronix dual EXP)

Do I have to make a type of circuit or something?

Thank you.

[soundcityec]

BUMP

[Nocentelli]

Figure 2 here shows a way to use an expression pedal to control an led that controls an LDR which could replace the time pot using a switching jack for the expression input:
http://tech.thetonegod.com/rockncontrol/rock.html

[phatt]

Thanks "Nocentelli" interesting concept and good info on leds.
But if looking for a simple way you just need a pedal with the same value as the 100k internal pot.

Hard to see but looks like the pot in question is wired as a resistor so you may only need 2 wires.

The down side of taking wiring direct out like this is that if you short the wires it might kill the pedal. yes I'm talking from experience
Phil.

[Nocentelli]

Thanks "Nocentelli" interesting concept and good info on leds.
But if looking for a simple way you just need a pedal with the same value as the 100k internal pot

How can I export it to an expression pedal, if almost all pedals are between 10 to 25 k ohms?? (my expression pedal is 20K I think, is the pigtronix dual EXP)

Do I have to make a type of circuit or something?

20k expression pedal would give a good range of brightness for an Led, put a 1k resistor in series to prevent burning it out at minimum resistance on the exp pot.

[soundcityec]

Thank you very much for the reply.

I did read the article but I'm not that experienced, also my english is not so good

I thought it was as simple as soldering wires to the expression jack with a resistor to compensate the 20k ohm from the pedal

[Nocentelli]

I thought it was as simple as soldering wires to the expression jack with a resistor to compensate the 20k ohm from the pedal

You need a variable resistance that goes 0-100k if you want the same range as the pot.

You could add a resistor of 82k in line with the expression pot, but then you'd only get 82k -> 102k, so only a small change from nearly-maximum to maximum delay time.