Channel Selector Grounding Question

[zpyder]

I'm new here and I've started to fall in love... creating my own pedals will be much easier with a support group rather than without.

I recently put together a very simple device which switches channels for me.  It gives me two sends and two returns so I can switch between two banks of effects.  It consists of a DPDT and some wires in a metal box, like this:


           __FX LOOP 1__
           |                   |
SND 1   -----|    |------   RTN 1

IN ----------|     |--------- OUT

SND 2   -----|    |------   RTN 2
           |___________|
              FX LOOP 2

where the DPDT is in the middle - hope that makes some sense...

anyways, my box is metal and my jacks all have metal housing, so everything is grounded together.  Will this cause a problem?  I noticed some humming at my old practice space, but now that we've moved to a new one I don't have any problems ... sounds like a grounding issue to me but I know very little.  I don't trust the thing to go on random stages, so I leave it at home, but I REALLY want to make it reliable!  It'll upgrade my rock...

I guess I should go out and buy a 3PDT and add an LED to it also, that'd be helpful.

Any other suggestions?

thanks!
zpyder

[GibsonGM]

I don't think the ground was the issue, Z...maybe shielding is more responsible?  Something in your jam space might have been radiating energy and getting in your pedal.  A nearby light dimmer, etc.

One thing, tho...if the 2 FX loops have different ground potentials (like, one actually has a little DC voltage on it), that would cause issues.   But if it's quiet in another location, I really think it's shielding.  Are you just using different pedals in each loop?  If the hum comes back, take them out 1 by 1, sub in others, etc., and you may find an offender.

[zpyder]

GibsonGM, thanks for your reply...

I'm pretty new at this so please bear with me.  Shielding shounds like a reasonable cause, but what would I do to properly shield?  I'm using an electrical box (one that would go in a wall and contain a light switch or power outlets) for my case - solid metal, cheap aluminum alloy I imagine, and thick... How do you shield your boxes?

Yes, the basic reason why this thing wants to be in my rig is that I come from the oldschool where we overdrive the amp to get distortion.  I accomplish this by cranking my amp into overdrive and using a passive volume pedal so if I want clean tones I turn it down (lower volume gives extra dynamic as well).  anyways, I want to use this thing to switch between my Driven Loop and my Clean loop, cause I'll use some reverb on the clean, etc... you get the idea.  I can effectively switch 3 pedals on and 2 off at once which is very hard with only two feet.

soooo.... I appreciate your response, one more question.  isn't there always DC voltage running along the signal path?  I imagine low, but I don't understand why this would be wrong.

thanks!
zpyder