I'm about to just sell everything and start over. Just started having major hum issues...... thought it was amp issue, old thread here: http://www.talkbass.com/forum/showthread.php?t=532927&highlight= Took basses and rig to tech, definetly fixed one basses' issue (just the input jack), that one's down to only buzzing when I'm 2 feet from my amp and facing it (passive bass), that I can deal with. Now, the other bass is an active Ibanez Soundgear 5 string. The rig is an Ampeg B2R head, into an Ampeg 410 cabinet. I used to run through a power conditioner but after taking everything apart to track down noise I've not put the head back in the rack and am noticing how much easier it is to lug..... When I took the bass to the tech, he re did the input jack, redid the shielding in the control cavity, checked the battery connector in case it had some wires broken. It didn't make a peep at practice that night.......whoooooooo happy me right? Three days later I take it and my practice amp (crate BT15) over to my guitarists house for practice. Up to this point, NO bass ever made a wrong noise through the little guy. I plug in and OW. Noise back! *sigh* I'm very frustrated. One thing the tech had suggested is that if what he did didn't fix the issue, it might be a bad pot. So, last night I dragged out every combo of speaker and amp and bass I had. I even plugged the bass directly into the subwoofers. So, the noise sounds like 60 cycle hum. The bass is properly grounded now so that's not the issue. When running through my head into a subwoofer (Yorkville model) you don't hear the sound, which just means that the frequency is higher than the sub can replicate right? I also plugged my practice amp direct into a bigger speaker so I could hear more and the sound was there, so its not the head apparently. The Ibanez has a volume knob, pickup selector knob, and a stacked treble/bass knob.Towards the end of this frustrating (and messy) hunt, I found out that if I turned both of the stacked knobs completly left (i.e. cut), the sound was gone. When boosting the bass only, there is a low grade hum that sounds like it wants to turn into feed back and changes pitch. When boosting the treble only, the horrible noise appears but at a lower level. When boosting both, I thought I'd kill my speakers-noise back! I always run with the treble at detent (sp?) and the bass boost almost all the way, up till now I'd never turned them off . So, does this sound like the tech's fear that the stacked knob has a bad pot? Fear because *of course* that's the expensive knob to replace. I can use the bass if they're all the way off but it sounds meh. Heck the passive sounds better. I'm really frustrated...... all I want is to plug in and play!