High pitched noise when in bypass?!

[A2Music]

My friends,

I have a problem that I'm hoping someone else has experienced. Sometimes when I build a pedal it emits a very high-frequency whining sound only when the pedal is in bypass.

I have fixed this by replacing output jacks before so I thought I had the problem in hand. Tonight I have tried 4 different jacks and can't get rid of the squeal.

Since the problem doesn't exist when the pedal is on I don't blame the layout or the board that I've made. I have made dozens of pedals without this issue.

Any thoughts?

[alex.s]

How is your footswitch wired? Does the effect get grounded when bypassed?

[A2Music]

Thanks for the reply.
I typically wire the switch very simply with the ground to the center pin so the LED will turn on when the effect is engaged. I was just looking at a switch wiring diagram that sends the board's ins and outs to ground when the effect is off. That could be it, huh? I'll try that right away.

Thanks!

[alex.s]

Grounding an effect's input seems to sometimes solve noise issues, so it might be worth trying. Let us know if it helps in your case!

[Geiri]

Use this: http://tagboardeffects.blogspot.com/2012/02/offboard-wiring.html

You won't get any high-pitch noise.

[A2Music]

That was exactly what it needed! I'm so relieved. Thanks for the help. I'm very grateful!

[Geiri]

I always use this wiring method and I like it a lot. I've only once had a high-pitch sound issue before BUT that was the "analog bit crusher" circuit which somehow leaked through the grounding. I blame it on the circuit rather than the switch wiring.