Amp Fluff

We’ll have a full report on the April edition of SoundClub soon but, first, a few pics and a story about a very old amplifier.

Yes, it’s the Peavey 8.5C which once ran the bass bins in the club PA but more recently has been providing the low end on the monitors. There had been reports of the drum fill cutting out on loud events, and this seemed to be becoming more frequent. Intermittent faults are tricky to diagnose and we kind of left the problem for a while, waiting for the cause to become clearer… until the thing shut down five minutes into a sound check, then came back on again, then went off again… and we had a SoundClub coming up anyhow so we finally took the thing out of the amp rack, popped the lid and had a look.

We’ll let you know if this fixes the problem. Looking forwards to another 20+ years out of the old clunker.

The back of the amp. Looks like there might a dust-related thermal overload issue.

View of the heatsink and fan assembly, prior to loosening up the dust with an old paintbrush and sucking it up with a vacuum cleaner.
View of the heatsink and fan assembly, prior to loosening up the dust with an old paintbrush and sucking it up with a vacuum cleaner.

We took the fan out first...

Close-up on those power transistors wearing their furry coats

Close-up on those power transistors wearing their furry coats

Sucking out the muck with a vacuum cleaner
Sucking out the muck with a vacuum cleaner