Help with BBE BMAX-T

[Countrysinger]

Whenever I use my Bmax-t it makes the horns in my cabinets produce sounds like glass breaking. They chatter. I've even turned then all the way down and it still happens. I thought I had tossed the horn in my Mark Bass cab, so I took it in and had it all checked out. I put this pre-amp away for a while and decided to check it out again yesterday during practice. It was doing it again. Could it be the tube has gone microphonic? I've never had that happen before, so I don't know for sure.

[Arjank]

I never heard "glass shatter" with my Bmax-T, but what I did have sometimes (only live) is "spikes".
I did remove the tube and rubbed the pins with sandpaper so they make good contact with the socket and problem disappeared.
In your case I would say try a different tube. Maybe you should go for a NOS Philips 5751 these sound very nice and clear.

[Countrysinger]

I've even turned off the bright switch, maximizer and comp. Then dialed the mids and highs to zero and the problem is persists.

[ptidwell]

Try changing the tube. I had a similar problem, but not exact, the tube change fixed it. BTW it was the stock GT12AX7C that was causing the problem.