Noise bleed through true bypass

[Dave]

Hey all,
So I'm now at the point where I'm happy with the circuit of my harmonic percolator prototype but I've run into a little problem that I'd like to cure if possible. The pedal has an oscillation mode which is basically a footswitchable ground lift which lifts ONLY the board's ground connection. What I have found is that if I leave oscillation mode on and bypass the circuit there is still a very faint whine in the background. I have tried two different bypassing schemes:
http://www.dirtbox.net/diy/wiring-a-3pdt-for-true-bypass/
and
http://tagboardeffects.blogspot.fr/2012/02/offboard-wiring.html
and both still suffer from the problem. So my question is, A is it possible to stop this problem or should I just put up with it and B, if I can stop it, how?
Thanks for any help and suggestions.
Dave

[Madferret]

If the circuit is bleeding through using true bypass maybe something is wrong with the switch? Using true bypass should mean that the board doesn't come into contact with the guitar signal at all so it'd have to be leaking in somewhere in the switch? Maybe I'm wrong, so sorry if I'm on the track but it could be worth trying a different switch.

[Vince]

The other day I made a Silicon Fuzz Face with the exact same issues. A very faint whine when in bypass. The whine stopped when I touched both BC108 transistors as if it were a ground issue. After prodding, poking and reflowing solder I gave up and just made another board which worked perfectly. I have no idea what the cause was so I just put it down to a poor joint on the board or just one of those freaks of nature.

I realise it doesn't help you much just maybe reflow the solder?

[vick]

I have had that happen before when the output wire to the circuit was laying right against the wwire that ran to the tip of the output jack.  The noise seemed to be bleeding through the insulation and was being picked up even in bypass.  Re routing the wires a bit solved the problem.

[Beaker]

+1 on Vick's suggestion.

I've built  a Harmonic Perculator without problems, but it is a massively loud pedal, so will amplify any unwanted noise along with the signal.

I too have come across a problem like this when building a Fuzz Factory. I had it in and out of the enclosure half a dozen times - worked perfectly out of the box, whined when put back in.

Just like Vick's description above, re-routing a couple of wires sorted it out.

[Dave]

Thanks for the suggestions chaps, I'll give that a go.
Thanks
Dave