Strange Switching Signal Bleed

[LyleCaldwell]

I'm stumped.  I've got a fairly complex but logical switching system wired up, and I am getting signal bleed between the A and B signals.  The circuit seems logical, and works as expected except for the bleed.  It's totally passive, and I'm using high quality switches (all ON-ON).  When I test with my meter, the inputs and outputs of A and B show infinite potential, which I expect.  But if I play a guitar through A, I hear it coming out very faintly in B (and vice versa).  All my solder joints are good, there are no touching joints or wires, and none of the wire have faults in the insulation.

I've never had this problem before, even with other complex switching schemes.

Here's a diagram of the wiring (warning - large image) :  http://psionicmedia.net/lyle/music/switches.jpg

Am I missing something obvious?  Thanks in advance.

[R.G.]

It's likely that you're getting capacitive crosstalk, especially if you neatly dressed all those wires to lie very close and parallel to one another.

The answer is simple - use shielded wire. RG174 is the defacto standard for inside effects wiring. It's about 0.1" thick coaxial cable. Rewire
at least A or B  (or both!) with RG174 coax and ground the shield. You should have no further crosstalk. For each shield run, ground only one
end of the shield.

[LyleCaldwell]

R.G.,

Thanks.  I am already using shielded wire as much as possible, telescoped as you describe.

Anyway, I found the problem and fixed it.  Had a very slight ground loop with the ground wire routing - no hum, but some crosstalk.

I had the ground wire tied from the input jack ground (stereo jack) to the output jack grounds and then to the loop grounds, using the "ground is ground" theory (which I have always found suspect, but had never found an actual issue with when wiring guitars, basses, and simple effects).  I disconnected the existing ground wires and re-routed them so the input ground went to the loop grounds and then separately to the two output jack grounds.  Problem solved.

Grounding is such a mysterious thing, no matter how much I read and what experience I get - there's always a new twist.  According to my meter, there's no difference between how I originally had it and how I have it now.  But the crosstalk is gone now.