The other night I was using my AI Focus SA on a medium loud pop gig. I was sharing a power strip with the rest of the band (guitar, keys, DJ, PA). I didn't seem to be getting the volume I usually am able to get from the amp and the amp clipped if I turned it past 3 o'clock. I emailed Rick at AI about this and he said that it was due to low voltage. I haven't had this problem with other amps I've used. Are AI amp paticularly suseptable to voltage problems?