Nasty hum

Hello all,
Problem, any time I happen to turn on my regulated power supply for my FRFR cabs without first turning on my QC, I get a nasty hum from the cabs. I’ve tried to trace the issue but it appears to be only related to the QC… Anyone have an idea what might be causing this issue ?

Please email support@neuraldsp.com for troubleshooting this issue.