Strange pedal problem

[kerrynet32]

Hmm, never seen a problem like this before so I am very confused. Heres the background/problem:

This is a pedal I am building thats an high octave pedal. It has a gain control, and also a clean blend control. Then it has a switch to turn off the octave so its only a gain boost. The octave section is the tranformer/diode part of the octavia, and the octave switch is connecting/disconnecting one of the diodes from the transformer.

So the problem is the following. When the pedal is set to octave mode and the gain control is over half, then is bypassed (True Bypass) there is a buzz for a few seconds after bypass is hit. This also happens if it is bypassed and the gain control is turned down then back up. Seems wierd because its wired as True Bypass, so there shouldnt be this problem. The problem doesnt happen when the pedal is set on boost mode.

I suspect that it could be something like a electrolyte capacitor that is getting very charged, and then isnt being discharged fast enough, therefore draining through ground (which is connected to the jacks) and making sound until it is discharged.

Anyone have any other ideas?

Thanks, Kerry

[what_wires]

Do you have a schematic?

[kerrynet32]

I would prefer to not post it, but I can email it to you if you let me know your email address or email me.

Thanks
Kerry

[Chappy]

Kerry

I'll give it a try if you send it to me. You are probably correct about the cap.
Check out Robert Keens site. I remember something about this being an issue in his "Millenium Bypass" circuit. i think he fixed it with a bleeder resistor.

Chappy

[kerrynet32]

Chappy, thanks. It looks the like the article right under RG Keens "the Rat Bypass" explains something like my problem. http://www.geofex.com/Article_Folders/M ... millen.htm

It looks like a good option to try would be for me to put a 10M resistor connecting to the circuit out, to +9v.