Hey everybody! I've been a member on here for a while but this is my 1st post. I don't know a lot about amps but have learned quite a bit just by reading the threads on here. My old Super Lead amp seemed to start humming a little louder than usual about 4 months ago, about the same time I got my brand new Vox AC30 C2. Maybe it was jealous? :Ohno: It shouldn't be because I still love it. Anyway, the hum was there whether I had my guitar plugged in or not. I decide to change out a couple of preamp tubes to see if that helped. The v3 tube was changed out about 1 1/2 years ago so I didn't see the need in replacing it. I also tried cleaning the sockets on all 3 of the preamp tubes by spraying DeoxIT D5 on the pins of the tubes and inserting them and then pulling them back out several times. I hope DeoxIT was ok to use. After cleaning the sockets and installing the new preamp tubes, the hum was still there and now I'm getting a crackling kind of sound but not all the time. Just when I play certain chords like an open A or if I hit a B bar chord on the 7th fret, it's really bad. Also, it seems to be ok when I'm using the lead pickup on my Strat. It's mainly when I'm using the rhythm pickup (the more warmer, bass sound) that I get the crackling sound and when I make that B bar chord on the 7th fret, it's really bad. Sometimes when I make that chord, I get a really loud noise, like a low pitched vibrating type of sound. I will have the power tubes replaced if that's what's causing the problem but I'd rather not do that right now if that's not going to solve this problem. If anyone has any ideas on what's causing this, I would greatly appreciate your input. Thanks!