Hello, this is my first post on talkbass. I have a question about my Peavey Combo 115. I thought maybe someone might be able to help me. The amp sounds really nice. I use passive basses, and I noticed on Saturday night, at the beginning of the second set, the sound seemed to fluctuate up and down momentarily. The master volume was up to ten, gain was at about one and a half, bass volume maxed. I bumped the gain up a little to two, and the problem went away-it never fluctuated after that. A friend who knows more than I do, thinks it may not be broken, because it never fluctuated while playing the set. He suggested lowering the master, and bumping up the gain a bit. He said that this amp might have a sensitive gain; setting it too low could cause this. When I tried his suggestion, it worked perfectly. Could he be right? I hope somebody might have an answer. I don't feel like hauling it back to the store if it's not broken. Thank you all very much, this is a great site. Peace.