My amp is an Ampeg BA-210SP (not the V2). I purchased it used. It has a bad hissing problem. It hisses even when the bass isn't plugged in. The volume and treble controls increase the volume of the hiss. I took it in to the shop but it didn't hiss there. It also makes crackling sounds sometimes, mainly when I play hard, even if the volume is all the way down to 1.