I was experiencing some microphonic feedback at my gig on Saturday so I took the KPA into my local store and did some A/B testing with a stock Toaster head. On some of my profiles I experienced a sound comparable to a mobile phone left on an amp when the signal had decayed and the strings were muted by a palm over the pickup area. This did not occur on the toaster so I swapped the mains cables and tried again, the sound was still there. I then tried some different profiles on my Powered rack and this noise only manifested itself on some of them. I have a Suhr Standard Pro with a cordial cable and on the test profiles the noise gate was up at 3.
Any thoughts?