Have you tried using different instrument cables to connect the M9? Are you using any sort of compression on the M9? Are you using high gain settings the amp? Have you tried updating the flash memory on the M9?
Instructions for updating the flash memory on the M9 can be found at the link below:
You will need to adjust the compression settings and EQ on the amp to reduce the amount of hum you are experiencing. I would suggest to lower the threshold on the compressor, and cut some mids and bass and presence.
One more question--i have tried two things
1) Bought a Behringer Hum Destroyer and unless I am using it incorrectly has not solved the problem
2) Tried lowering the threshold on compression as you suggested
Recently played a gig and any time I was not playing my rig was extremely noisy which is tough to control during a song break -- requires lots of fancy footwork lol
Not sure how to solve this but what about a noise gate?
I have this problem too. It has just come on. It was fine on Monday, 4 days ago but now - buzz.
I narrowed it down by simplifying my setup to test.
M9 into clean monitor. That's it. Even without guitar plugged in it buzzed badly.
Interestingly I noticed, if I unplugged the power supply from the M9, and left the M9 connected to the monitor, again with no guitar even connected, there was still some buzz. Then, when I unplugged the power supply completely from the power socket the buzz went away. So, somehow the power supply was effecting the signal even when it was not plugged into the M9 but was plugged into the electricity socket.
Again, this was not the case 4 days ago. Something has changed.
I noticed that the wire has split on the power supply near the power supply unit on the side that goes to the M9. I suspect this may have something to do with the problem but am not sure. It still supplies power, but maybe this split is causing the buzz. Maybe you also have a faulty supply.
I could so with some confirmation on whether this is likely or not. I have not had my M9 long so am surprised that this fault has appeared so quickly. It has been updated to latest firmware and I have tested it with many audio cables that are in good working condition and work fine with other units.