Most Bizarre Live Sound Issue EVER. In Need Of Help!

The Problem: Signal (or ground?) Noise/Buzz/Hum

Original Signal Chain: G&L L2000 -> Boss TU-3 Tuner -> Markbass Mini Boost -> HBE Hematoma -> TC Electronics Spark Booster -> EHX Big Muff -> EHX Pulsar Tremolo -> IMP DI (all powered with Hardwire V10 Isolated Power Supply) (using short patch cables - can't remember the brand, but let's assume they are mid-grade cables)

With this set-up, I had some VERY bad buzzing, but only at church - not when I plug into my amp at home. When touching the knobs/switches on my bass, the noise almost completely goes away. When touching the control cavity cover on the back (even with my leg, through my jeans) the buzzing gets far worse. Originally I assumed this was some sort of ground loop so...

Step 1: Flip Ground/Lift switch on DI. This had little to no effect.
Step 2: Bypass effects pedals, going straight into the DI. Again, little to no change. I even tried disconnecting the power supply, and still nothing.
Step 3: Change battery/play in passive. Playing passive helped - but there was definitely still some funky buzz going on.
Step 4: Try another bass. I went with a passive and an active - both had the same results as the G&L.
Step 5: Remove control cavity cover. A couple of times this nearly eliminated the problem.

HERE'S WHERE THINGS GET INTERESTING!!!

Step 6: Have someone else hold/play the bass.

Believe it or not, that fixed it. Completely. Intrigued, I tried figuring out what was different about me that was causing this issue. This leads us to...

Step 7: Stop using on stage Aviom (in ear monitor). This, also fixed the issue. I had my friend try using the Aviom and playing the bass, and the buzz came back.
Step 8: Use wireless IEM (Sennheiser, off stage). Again, this fixed the problem.
Step 9: Plug my power supply into another outlet. This fixed the issue, but there is a disclaimer - I had to be plugged into an outlet 50 feet from the stage, in the congregation. When bypassing the pedals, this did not help at all - it only helped when using the pedals.

So... it seems to me that we have way too much plugged into one circuit, and somehow, being connected to a wired Aviom (who's power is also plugged in on stage) is causing a massive buzzing sound. Here come my questions.

1. Have any of you ever experienced something like this?
2. Is my touching the controls a way of "regrounding" the bass, if you will? Why does this cause the buzz to go away?
3. Why is this only happening to me? It doesn't happen to our acoustic guitarist, keyboardist, or electric guitarist.
4. What is the actual problem? We have a lot plugged into a bunch of different outlets, all on stage. No one knows how many circuits, or what size circuits we have on stage.
5. How would you fix this? Buy any gear? Pedal/power conditioner/wireless rig/etc? Do we need to bring out an electrician or something?

Thanks in advance everybody!!

 

Thanks for the replies.

At one point, I had thought it was a ground loop, but it confused me that the culprit seemed to be the Aviom. Thank you for clarifying!

And I'm plugged into an outlet all by myself, no powerstrip involved. And like I mentioned - the problem even occurs when I'm bypassing my pedals completely, and the DI is passive.

Any thoughts on why the ground switch doesn't eliminate my problem? My apologies if that's a dumb question.

 

Thank you - that makes a lot of sense!

So sorry to hear I'm not the only one... I'll let you know what I discover.

Will do - thank you!

It is not doing the same thing. That's what I had thought too... it's possible that this is the case with all of my basses, but I find that a bit hard to believe - and I'm having this issue with all of them...

 

Hey guys - quick update.

We’re having someone come and check out the electrical system later this month, but I’ve found a solution that works for me. I picked up the Line 6 G70 Wireless System, and that killed the ground loop. So far I’m happy with it, as it has replaced my tuner, my ABY, and has a gain adjustment with saveable presets, so changing basses during the set is much easier for my sound engineer.

Thank you all for the input - hopefully we can get the wiring and circuits in that building figured out so no one else deals with the same issue.

 

Rounds and flats.