The above amp loses power after 5 to 10 minutes of play and I get reverb even with the control in the off position. This is with the volume and master at half and on clean. In overdrive it does the same though I ocassionally get chorus or a sort of hammered repeat, It has been checked by engineers at Marshall who found no fault in any mode although I have heard from a reliable source that there have been these sort of problems before and the suggestion was to do with the switches. As i had to send this back via the dealer more than 200 miles away and back to marshall, I wouldn`t want to do it again with the same result even though it`s under warrasnty.