Ampeg SVT & humidity. Help...

[snowblinder]

Just hoping someone can make some sense of this

Live, I play through an early MTI-era Ampeg SVT. It has been retubed within the last year with a matched sextet of Winged C 6550's. The tube sockets have all been replaced. It was gone completely through, and serviced as needed. It has worked perfectly since it was worked on, until now. About a month and a half ago, my band played a show in one of the hottest, smokiest, most humid rooms I've ever experienced. The SVT ran fine for our set, and I was driving it fairly hard (I usually keep the volume right around 10:00-11:00). However, my rig was also used by many of the bands that followed us. After a few hours of use, it died. When I got it home, I checked the fuse. Replaced the one that had blown, and it worked great. Played shows and practiced numerous times at normal volume for hours on end with no issues.

Then, a few nights ago, we were again playing in a really hot and humid room. I go to turn my amp on and.....nothing. I tried switching outlets, still nothing. Thankfully there was a backup amp available. But I was just wondering, do these amps typically have issues in overly humid conditions? I'd hate to think that I would be forced to play through my backup amp all summer. I know this sounds ridiculous, but I honestly don't know what else could be causing the problem.

The fan on my amp works fine. The front grill is gone, and was replaced with a metal mesh type of grill, supposedly to aid with ventilation. Could having the front so exposed be contributing to humidity getting into my amp and shutting it down?

Anyone else had a similar problem? Suggestions?

Thanks.

[Jerrold Tiers]

When the amp has been ON for a while, humidity should be out of the picture. The hot amp would "bake out" any humidity that "soaked into" the parts or whatever.

if teh amp is stored cold in a humid area, it is perfectly possible for there to be condensation, even water running around over the boards etc. THAT would pose a hazard of "bad malfunctions"....including blowing fuses etc. Bias could be messed up, almost anything might happen.

OK, so teh first case is probably not humidity..... maybe heat, though.

Turning on after it being unused, yes the humidity might have caused condensation and there could be a problem.

I doubt the grille is an issue for humidity, but could it have messed up the airflow? Tube amps are less sensitive to heat, in general, but they are not immune. Bad airflow could get it a lot hotter than expected.

But an open grille would probably improve airflow, so........

[JimmyM]

Jerrold, i was told by the tech who worked on my blue line not to run it without a grille because it bounced the airflow around in there and cooled off the rest of the amp. i thought it sounded a little suspicious and i always wanted an official word from someone at ampeg. any truth to that?