Tonebender MKI Questions

[ljudsystem]

... you mean Q2's base right? (the 470k resistor) there's no resistor between -9v and Q1's base on my schematic.

[Electric Warrior]

Yes, sorry about the typo. I'll fix it!

[ljudsystem]

Thanks for the advice. Finding the right amount of leakage is tricky. If the trannys leak to much my pedal starts to snap, crackle and pop.

Spent last night sorting my germaniums after how much they leak.

[Electric Warrior]

Interesting. It wasn't that much of a problem for me.

Have you tried a lower gain transistor for Q2 yet?

[ljudsystem]

No, what hfe would you recomend?

[Electric Warrior]

Maybe try 110 or 100 and see if that improves things.

Edit: oh wait, you already did that. I had been looking at the specs of the transistors you originally used.

[ljudsystem]

Ok, have been experimenting with this circuit for the last couple of days. I've managed to tweek it so there's no gating, just smooth violin like sustain. 

Here are my trannys:

Q1: 64 hfe / 0.015 leakage
Q2: 103 hfe / 0.115 leakage
Q3: 133 hfe / 0.2 leakage

I used the standard resistors and got as close to a smooth decay as i could by changing transistors. then I swapped the 1m resistor and 8k2 resistor (from the base of Q3) for trimmers.

Q1 seems to be hardest to get right. It needs very low leakage or it will start making crackling sounds.
Q2 and Q3 seems to work better with leakage around 0.1 - 0.2. I find it weird for Q2 since that is the only transistor that is biased with a resistor from the power supply...