Starting to sound like a cold solder joint. Those jacks (MIDI, audio, etc.) are probably soldered directly onto a circuit board and repeated plugging in/out of the jacks may loosen or even break the connections between the jacks and the board. It is repairable but you better be good with soldering... and you might want to be easier with the thrust of your plug-in from now on, stud!

FWIW, low-volume gigs are what I bought my Motion Sound KP-100s for and I am always pleased by the amount of clean volume I get from it - plus it's a nice, small, one-piece no-problem amp.

[This message has been edited by Esh (edited 11-10-2006).]