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Ampeg SVP-PRO Probs??

Discussion in 'Amps and Cabs [BG]' started by Thumpinthenight, Sep 29, 2008.


  1. Thumpinthenight

    Thumpinthenight

    Apr 13, 2004
    New York
    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?? :meh: 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. craig.p

    craig.p

    Sep 28, 2008
    New Hampshire
    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.
     
  3. detracti

    detracti

    May 5, 2006
    Seattle
    The behavior makes it sound like a circuit breaker kicking off and then resetting itself.
     
  4. BFISHER1970

    BFISHER1970 Supporting Member

    Dec 14, 2005
    Pensacola, Florida
    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
     
  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. Delta T

    Delta T

    Oct 3, 2008
    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. lug

    lug

    Feb 11, 2005
    League City, Tx
    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).
     
  8. I have heard of buildup inside those power amps. Shine a flash light in there and see if the inside of the Carvin is dirty. If it is, clean her out with some compressed air.
     

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