I can play my new DSL40 on the 20w setting on the clean 1st channel for 30-50 mins and the sound will shut off (does the samething on 40w setting). Crunch on 1st channel will be muted and the second channel no problem with sound at all. I've taken it back to the store and of course can't get it to reproduce the problem. I've checked my power connection, no reverse polarity, neutral and ground all fine. I do have 126 volts at the outlet. My power company checked the line coming to the house and had 126v on each leg and no problems with the ground and neutral. The shop that I purchased the amp is running 123v. I cannot find anything on this site to tell me the voltage tolerances of the DSL40. Is this problem an over voltage issue or something else?