Thursday, October 30, 2014

Saving Money The Old Fashioned Way

Ever since my last Ampeg fiasco I've been looking for an amp-any amp-with a line in line out feature that was cheap. Did I say cheap? Above all cheap.

The Ampeg mess began with a VT22 that was bought on the cheap by a local fellow, I suspect because nobody could repair it down where he got it from. After fielding the numerous curves it threw my way-no filament voltage on the phase inverter, bad tubes, one of which died on the operating table, a number of burned resistors, sick electrolytics etc, and testing every god damned component on the preamp and power supply boards, I was in the 9th inning and wondering how I could declare defeat gracefully.

By the by, there are four different schematics for the VT22, they're all somewhat different so if you are working on one, it is best that you figure out whether you have the right one for your project.

In a last desperate bid I decided I needed to test the preamp and power amp sections separately and I borrowed an amp-a Blackstar head-which had a line in/line out feature. This allows you to take the preamp signal of one amp and run it into the power amp of the other, and vice versa-thus isolating a problem to one section or the other of the corpse on your workbench.

As it happened both sections worked well enough but they were not talking to each other, and the problem that caused all this emotion and wailing was a bad ground on one of the line out jacks.

So much for the Ampeg. It's gone.

Now the quest began for an amp-any amp, but cheap, with line in line out, with no results. On a whim I strolled back to where I keep my junkers and found a Randall RH50 tube head that I'd bought for spare change a few years ago, the kid said the volume was low, and there were the line in line out jacks that I'd wanted. I'd stripped the tubes out of it and had tried with no luck to dump it as a project amp and then forgot I had it.

A set of tubes later, and I had no filament voltage-which was a good thing because it took me right to the filament fuse inside. One fuse and a plateful of junk tubes from my stash of pulls  later I was in business with a functioning piece of test equipment that doesn't sound half bad.

Of course the volume was low. It never worked at all.

Kid, it woulda cost you ten bucks to fix and if you want to buy it back you know where to find me.

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