My 15w Acoustic practice amp stopped working awhile back. I found a good deal on a Rumble to replace it but I could not let it go. I talked to my amp tech when I was in on another matter and he gave me a couple of things to look at that typically fail on those amps since since the repair cost would be several times the value of the amp at a minimum.. So $12 in parts from Mouser later and a schematic from Acoustic later I am going to take a run at repairing it. Nothing to lose at this point