Originally Posted by jondog
I've had mine for awhile and I like it, but recently the tube has started acting up. It adds crackles and static that goes away when I switch the tube out. I've swapped two different tubes, a GT 12AT7 and a vintage Sherwood 12AZ7 with similar results. Any ideas? The amp still sounds great most of the time and I don't really need to engage the tube . . .
I've been reading that folk's with this amp have been disconnecting the ribbon connector, and spraying the contact's with a good contact cleaner...from the Carvin site;
"Back in May (? I think) I picked up a used BX500 from someone at the TalkBass forums. It seemed like just what I needed for a portable rig for a jazz camp. I found the power more than adequate and the tone controls extremely flexible. I had no trouble getting a range of tones I liked.
It had a minor problem with the tube channel, but worked fine with the tube bypassed. I used it that way for several months.
Then it started going silent intermittently. The problem got worse until it left me silent at a band rehearsal.
BUT... I am not afraid to tinker with gear I own out of warranty. I pulled the lid off and reseated all of the ribbon connectors that I could reach. That fixed the problem for the rest of the rehearsal.
Yesterday I had some time to take the BX500 apart and hit every ribbon connector and the tube socket with my favorite contact cleaner (Caig DeoxIT D5). Whaddya know, even the tube is now working correctly!
So, if you're having problems with your BX500 going silent on you, and you're comfortable poking at its innards, unplug it from AC power and give it the full "deep tissue massage" treatment with some good contact cleaner, and it'll probably work just like new again.
I hope someone finds this helpful."