Ampeg
SVT's could be the greatest bass amp of all-time. Ampeg SVT-CL's could
also be the most difficult and dangerous amp to service of all-time.
It's been well documented online, notably in this four page, 28 picture
epic by:
Bustedgear.com
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| SVT-VR (Vintage Reissue) |
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| SVT-CL (Classic Reissue) |
Here's a message I sent to famous touring band:
"It had at
least six different problems, notably some bad power tubes, screen grid
resistors and cathode power resistors. There's no telling what took
what down, it's the chicken or the egg really. I'm sure it got worse
and worse, eventually the amp was working against itself.
I
know I ramble on about these. They're a great bass amp. The best.
But the way they're constructed is almost impossible to safely work on.
You have to dismantle and un-pancake pc boards to work on or replace
components, removing the power tubes and all attaching sockets. Once
you get a feel for the damage you have to reassemble to test, repeat
disassemble to repair, etc. ad nauseam. Flipping around an 85 lb. amp
is not easy, nor safe when there's close to 700 volts DC. If anything
touches any metal it's fireworks...sometimes the nuts pop off
the chassis just when you've put it back together, you have to pull it
apart to retrieve and start over...it's challenging.
Some
guys prop it up with wood to test it, some stand it upright, it's just
crazy. So basically I got
the new tubes in, it was still in fault mode. There were some burnt
components on the power tube board I replaced, still not right. On the
board (under the power tube board) there were some off voltages,
isolated
and replaced key resistors. Things are lining up now. I've had it
on, on the bench, and it's been in the green for the last 2 hours. Btw
L., it's been on the bench since Tuesday when we hoisted it up
there, I have not been able to move it nor complete any other jobs
since."
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| SVT CL PC Board 1 |
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| SVT CL PC Board 3 (Board 2 Underneath) |
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| SVT VR all on one board |
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