scanfield

I normally only change volume slightly depending on the guitar I play, but I've heard it at different volumes.

Hi everyone, Over the past couple of weeks my Line 6 Spider IV 30 has started whistling in high-gain situations. I've tried this with several different guitars and have the same results, so I don't think it's a pickup-related problem. Interestingly, I haven't noticeably changed anything recently - the amp is in the same location in the same room I've had it for the past 2 years, I sit in the same location to play, I have a programmed high-gain setting which I use, same cord. Nothing jumping out as obvious that might be new and causing interference. Any suggestions on how I might troubleshoot this? Thanks. Steve