So I was just playing for about 2 hours, stopped for about 20 minutes to write out a tab, then plugged in my guitar and turned the amp on with it on standby and i heard this clicking sound. It almost sounded like the fan was hitting something. So I tried turning the fan off and it keeps making the noise, so it's not the fan. I then tried turning it off of standby to fully on and the clicking came through the speakers. If you are looking at the back of the head, the noise is coming out of the area on the right side. It doesn't seem like it's the tubes... The head is only about 10 months old, purchased new. I have a call into Mesa to ask them about it, not sure what's going on. Any ideas?