Peavey 6505+ Hum Problem! ARGHHH!

Hey Guys,

Not sure if anyone is still watching this thread or not, but I need to get some clarification over the resolution. I'm currently experiencing the same issue that everyone else has mentioned in forums regarding the Peavey 6505+ Effects Loop Hum.

I've done a ton of testing and can say the following:
  • When the effects loop is not connected (via any cables), the Hum is not there
  • When the effects loop is connected (via any cables), and switched off - the Hum is there
  • When the effects loop is connected (via any cables), and switched on - the Hum is there
  • When the effects loop is connected (via any cables), and I am using my standard lead channel (front of amp) - the Hum is there
  • When the effects loop is connected (via any cables), and I plug my guitar (alone) into the amp, the Hum is there.
  • When a Noise Canceller is added to the effects loop - the HUM IS GONE! However, it remains in the standard Lead Channel (front of amp)
  • When the effects loop is connected (via any cables), and no cable is plugged into the front of the amp, the Hum is Gone.
Firstly, yes - I am using a noise cancellation device in my standard lead channel (front of amp) - ISP Decimator G String II. I've removed the ISP Decimator and replaced it with an Boss NS-2 and the issue is still there.

My setup is as follows - Guitar>Wireless System/Tuner>ISP Decimator II G String>Maxon 808 (in the ISP loop)>into the front of the amp. In my effects loop I have Send>MXR Amp+>Maxon Delay>Return. Some people are stating that it is not enough noise to cause any issues on stage, I can say that this is not the case.

The thing that is making me lose my mind is the test where I took the Hum out of the Effects Loop by adding a Noise Canceller, but it remained in the standard lead channel (front of amp). This means to me that the Effects Loop signal is somehow bleeding over to the standard Lead Channel even if it is not turned on (but still connected).

Seriously! Somebody give me an answer that can assist. And please don't say add batteries, because I've removed the pedals from the front of amp and it still causes the issue....
 
Not trying to dig up old shit... but for science...

Stick balanced cables in your entire setup - That solved the problem for me. From your Guitar to amp, Head to Cab & FX Loop (including the small 6" patch cables from pedal to pedal. You might need to solder these up yourself if you can't find balanced patch cables.

For me at least 90% of the ground loop disappeared after switching to fully balanced