Yeah, I know they're cheap but I can't afford to replace it right now … Here's what's going on—I have two of these amps, one of which my nephew gave me because it has a loud hum on all but two of the amp models. Last night I heard that my good one had developed a scratchy noise like a blown speaker cone that becomes apparent as a held chord dies away. It also seemed to have started happening on the second amp … I tried different guitars and different chords to no effect. I tried switching the connections, i.e., Amp 1 to Speaker 2, then Amp 2 to Speaker 1—same sound on both ways. Messing around with it, I then discovered that the problem appears to vanish if I run the amps in Preset mode instead of Manual—this would seem to indicate that the speakers are okay as are the 12AX7's that control the modeling. If this is the case, could both of these amps have developed a problem with the power amp chip? I've recently been running them together with an AB/Y pedal, but I don't see how that could create a problem, or am I missing something?