Hi, I have recently purchased a used Fafner (grey) from around 1997, however I keep getting a very unpleasant sound when I either: a) turn the input gain so that the LED shows when I play hard, b) don't bypass the EQ and have the bass control (or the mids)turned up past 0 and c) when I have the drive on any setting. The sound sounds like a kind of "farting" and at first I thought it was my speakers breaking up, but the sound comes through the DI and line out. I also thought it was that the battery in my bass had gone, but it wasn't. Just for your information my bass has EMGs and a preamp, but when the controls on the preamp are off, the problem persists. I also tried changing the preamp tube and fiddling with the bias settings, but to no avail. Could you throw any light on the situation? Cheers, John.