Im using the quad cortex for our in ears rig and a 6505 for stage volume. I run xlr out to rig from output 1 or 2 and run 1/4 inch out of 3 or 4 to front of amp. This is what happens when we are on stage. sometimes it happens when the midi is connected as well. https://youtube.com/shorts/X_jFJDXQ5fk?si=U-BgIJosC3F_FsXI
Please help
Is that an old QC? The early units apparently connect to ground through the outside of the XLR connector on the cable. You’re using a a cable with a painted connector in the video. The paint will prevent the grounding from happening. That could be the thing that has changed. Just an idea.
Strange that the ground lifts don’t help though. I get a similar hum from the capture out while out1/2 are connected, but that is solved with ground lift on the outputs.