Ampeg SVP 1500 problem

[martinace]

Hey guys, I was wondering if anybody knew anything about this power amp. Or amps in general, I know next to nothing about them. I just got it a little while ago off craigslist and it worked great the first couple weeks. Then I turned it on at a show I was playing, and a small puff of smoke accompanied by a spark came out of the front. It made it through the show fine, then a week later the same thing happened, except now the red signal light is coming on and it is clipping my sound. Still plays, but only at very low volumes. How can I fix this?? Thanks for reading, I know it was a bit of typing for a message board haha.

[Jerrold Tiers]

That's the same as an Audio Centron MP1200 PA amp. Ampeg borrowed it as a bass poweramp. Roughly the same power as an SVT-4PRO, but not as "heavy-duty" as the 4-PRO. It was a "lighter duty" PA amp, mostly on account of the heatsinking.

As far as knowing anything about the amp, I designed the PA version, so.......

A spark and puff of smoke is bad..... I suspect that at least one of the mosfets may have croaked, that can happen without totally taking out the amp, if the gate and source resistors open. Might be something else, too.

The good news is that enough of the protection circuit is working that it has apparently not done a severe meltdown. If the protection is operating, it automatically turns down the input level as well as limiting output. it will (if working) tolerate a short circuit all day.

However, yours is damaged, needs a tech, and you may not like the bill. But do not turn it on again, and maybe you can get by without as big a bill as if the thing were thoroughly blown.

[martinace]

Sorry for the late response, thanks a lot for the info. I'm going to take it in, fingers crossed it is not too bad!