Just recently picked up my dream amp, a 1999 ampeg svtcl in great condition with appears to be new ruby tubes. It sounds as nasty as I expected (good) but has started making this ripping/distorted sound when I play on the low G, and has started doing it on any low notes. I'm playing it through an 8x10, I've tried both inputs and even taking the head off the cabinet to no avail. I run the bass at 9 oclock, mid at 2 and treble at 3. It will make a white noise surging sound when I take it off standby for about 2 seconds but clears up, and even that only happens half the time. I'm going to see a tech in about 2 weeks about it, any ideas otherwise? Got it from GC, still.within the 30 days.