Having an issue with my HT Club 40 (purchased 2015). I am experiencing loud feedback (that increases with increased volume) on both channels when i run my guitar directly into the front of the amp, both with a pedal chain or not. However, when using the effects loop (with guitar also plugged into front of amp) everything works perfectly. I had my power tubes changed 1 month ago, no trouble there. And after the noise began I had the preamp tubes changed to Tungsols, they sound amazing, but didn't solve the problem. Anyone have an insight into what could be going on? Thanks!