On a serious note: could be that your AC is polluted, and if the fridge turns on, it can cause noise in your amps. Same goes for lighting. On the other hand, there might be something wrong in your preamp, so listen if it occurs when the preamp is on/off. Also listen if it occurs with both mono amps. If it's just one, that one should also be checked.
Help my speakers are farting,,,,
I have a pair of mono tube amps hooked up to my speakers, and according to my girlfriend they are making farting noises, which I have to concur with, I do have a cheater plug installed, which took care of the hum, so I haven`t a clue as to why the noises, This is something that just started, there been no changes to my system, please help,