Noise/hum but only live at gigs.

    I get noise, hum ground. But Only at gigs. It only goes away If I lower the volume on the volume/expression pedal(dvp3)) not from guitars. It’s very inconvenient to have to be next to the volume pedal when the song ends. It only makes noise live, not at home, and not at rehearsal we’re we use the same exact setup as live. We use our whole wireless IEM system and my guitars are wireless nothing is different but being at a venue. We are not playing bars we play nice theaters/venues. We don’t always use the same FOH sound. Most venues have their own, but still get the hum. Just this past Saturday we were up in New Hampshire at a venue only 2.5 years old and I still got that same hum. I hit all the ground buttons on the Kemper, didn’t do anything and tested the quad box where I plugged in my rack everything was fine and ground was good. I can’t recreate this anywhere, and at the venue there really isn’t time to do a lot of trouble shooting. Setup-soundcheck-silence-Show-load out. Any ideas what this could be and why only at venues. Oh rack gets plugged into Furman m8lx power conditioner. Thanks.

    The fact that the guitar volume doesn’t kill it but the expression pedal does, definitely suggest a ground loop issue somewhere in the chain. Alternatively it could be an open jack socket somewhere. Do you have outputs from your Kemper rigged to a patchbay or anything? Another cause could be a bad cable between the Kemper and the FOH or a bad speaker cable if your are using a powered These kinds of problems can be an absolute nightmare to trace but usually it’s something really simple that just didn’t seem obvious at the time. It you plug straight into your KPA with nothing else connected to it (ie no Wireless, no IEM, no connection to FOH) and just monitor on headhones via the KPA front headphone out, is it still there? This would rule out the KPA being faulty. Next add back connections one at a time starting by replacing the guitar cable with the wireless. If that is still Ok on headphones the the problem is between the KPA and the rest of your system. Once you find it you will be better placed to decide how to deal with it.