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Ampeg SVP-PRO Probs??

Thumpinthenight

Thumpinthenight

Apr 13, 2004
272
3
69
New York
www.cravetheband.net
#1
My set-up-

Carvin 1500 power amp
Ampeg SVP-PRO
Epifani 3x10

I was using this setup for about 3 years, (all-new stuff).
Last gig, in the middle of a song, the amp stops - just like it was unplugged, then came back after 2-3-secs, then goes out again, comes back....

I checked all my connection cables - ok by tester
" " my sure wireless - ok
Iam suspecting the pre-amp.
Question......Does this sound like one or more of the tubes malfunctioning?? :hmm: Should I take one out at a time and put it on a tester? (I have access to one). Any other ideas????
Thanx in advance
 
#2
That almost sounds like a loose wire somewhere inside, or a bad/cold solder joint. Have you had the cover off & had a look around, checked that all wires are still securely soldered in place? When I say "loose," I mean "not by much." Sometimes you can barely feel the looseness but it's enough to cause cutouts. Sometimes you can see a solder ball rock on a terminal strip as you move the wire.

Note: solder joints can sometimes look fine but be cancerous under the nice shiny surface. They're a PITA. But it's still worth a look. Maybe something will jump out at you.

You could also "refresh" every solder joint you can get an iron onto, but only if you've already got experience with a soldering iron.

I won't say it's not a tube, only that it wouldn't be the first thing I'd suspect.

Plenty of other possibilities, but this is where I'd start.
 
#5
It is more likely a bad solder joint, but don't rule out the tube test first in case one of them is faulty.

I had 1 faulty tube which crackled intermittently at high volume. I replaced the tubes with new JJ 12AX7's due to having noisy groove tubes. To quieten it down I put a nos GE 12AU7 in V4 (no more buzz) :D
 
#6
BFISHER1970 said:
check the solder joints on the power transformer....I have had more than one SVP-Pro with cold solder joints there.....you will most likely find more too
Click to expand...

Agreed - I've had mine serviced twice for this. The first time the tech thought it was only the one solder joint. Several months done the road though another one opened up.

Have your tech resolder all of the transformer solder joints.

I have had two of the SVP-Pros over the years - a black faced one that has an adjustable direct out and the newer one was a gray-faced one that didn't have the adjustable output. The black-faced one (whcih I still have) is the one that gave me these problems.

Dave
 
#7
Vewry first thing to do is isolate. Does the balanced out of the pre die too? Have you tried it with another power amp or the Carvin with another preamp? This will save a lot of time toubleshooting. Many poweramps have overload protection that could do this (not sure about the carvin, though).
 

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