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Ampeg SVT-3 Pro issue.

Discussion in 'Amps [BG]' started by gravyhighway, Jan 15, 2013.


  1. gravyhighway

    gravyhighway

    Joined:
    Feb 23, 2010
    Last week my head stopped producing sound so I ran through every troubleshooting option I.could imagine. So I call Ampeg and they suggest that's it's my preamp tubes. I replaced them today and still nothing. I mean it hisses when I raise the volume on the head but still no sound besides that. Anyone know what else it could be?
     
  2. jeffbrown

    jeffbrown

    Joined:
    Jun 13, 2007
    Location:
    New Hampshire, USA
    Hook it up to a cab, plug in a bass and try to play a few notes. :bag: If still nothing happens, perhaps a trip to the shop is in order. :(

    Good luck.
     
  3. Low Sound Love

    Low Sound Love

    Joined:
    Mar 25, 2010
    Location:
    Ghent, Belgium
    You could try to plug another preamp into the power amp section of the 3-Pro. That way you can determine if the problem is in the preamp or the power amp.
     
  4. gravyhighway

    gravyhighway

    Joined:
    Feb 23, 2010
    Well thanks. I fortunately still have a warranty on it so. If I can't figure it out I that baby as backup.
     
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  6. B-string

    B-string Gold Supporting Member

    Joined:
    Nov 21, 2008
    Location:
    Lake Havasu City, Az USA
    You didn't engage the mute button by accident did you?
     
  7. anderbass

    anderbass

    Joined:
    Dec 20, 2005
    Location:
    Phoenix. Az.
    Gravy,
    A super easy test you could try yourself is simply patching a guitar cord between your fx-loop/(send-receive) jacks. Then let us know If this made the amp play fine again or not.
     
  8. gravyhighway

    gravyhighway

    Joined:
    Feb 23, 2010
    Well the mute button is off and I'm not really sure what you mean by patching a cable. Do you mean simply plugging in a cable through the in and out?
     
  9. gravyhighway

    gravyhighway

    Joined:
    Feb 23, 2010
    I plugged in a cable from the in & out of the effects loop and while still on mute I unplugged them and there was a bit of loud pop.
     
  10. B-string

    B-string Gold Supporting Member

    Joined:
    Nov 21, 2008
    Location:
    Lake Havasu City, Az USA
    Yes, one end of a instrument cable to effects send, other end of same cable to effects return.
     
  11. B-string

    B-string Gold Supporting Member

    Joined:
    Nov 21, 2008
    Location:
    Lake Havasu City, Az USA
    Did you try the cable with the mute off? That was the whole point.
    The pop you heard could mean the power amp is still good. If the amp will not play with the loop cable in the effects loop, turn the master down and plug your bass into the effects return. Turn up the master and see if you get sound. If you do the preamp has the trouble and the power amp is okay.
     
  12. gravyhighway

    gravyhighway

    Joined:
    Feb 23, 2010
    OK well I got sound through the return. Is it possible I may have put a tube in wrong or maybe not all the way when I replaced them.
     
  13. JimmyM

    JimmyM Supporting Member

    Joined:
    Apr 11, 2005
    Location:
    Apopka, FL
    Disclosures:
    Endorsing: Ampeg Amps
    Maybe. It's also possible your effects loop is corroded...clean it with contact cleaner.
     
  14. B-string

    B-string Gold Supporting Member

    Joined:
    Nov 21, 2008
    Location:
    Lake Havasu City, Az USA
    Did you get sound with the loop cable or just direct bass to effects return?
     
  15. B-string

    B-string Gold Supporting Member

    Joined:
    Nov 21, 2008
    Location:
    Lake Havasu City, Az USA
    It is possible to bend tube pins and not have them install properly. IF you bent pins use a retracted ball point pen barrel to CAREFULLY bend the pins back straight.
     
  16. gravyhighway

    gravyhighway

    Joined:
    Feb 23, 2010
    Ok I double checked all my tubes and everything is in there fine. I took to a friend and he said the tubes are all good but still no sound. What else could it possibly be?
     
  17. B-string

    B-string Gold Supporting Member

    Joined:
    Nov 21, 2008
    Location:
    Lake Havasu City, Az USA
    Have you plugged your bass straight into the effects return to see if you get sound? If you do the power amp is okay, if you don't (and your bass works in a different amp ie the cable and bass are okay) then the power amp has a fault you need an experienced tech to repair. I am assuming the speaker cable and speaker cab are okay as you heard a pop through them before.
     
  18. gravyhighway

    gravyhighway

    Joined:
    Feb 23, 2010
    Yeah I get a signal through the effects loop. All my cables and bass work perfectly fine. New preamp tubes and driver tubes.installed properly.
     
  19. B-string

    B-string Gold Supporting Member

    Joined:
    Nov 21, 2008
    Location:
    Lake Havasu City, Az USA
    What exactly do you mean by "through the effects loop"? Do you mean by plugging into the effects return or using a cable to loop from effects send to effects return and bass plugged into the normal input?
    This point is very important.
     
  20. gravyhighway

    gravyhighway

    Joined:
    Feb 23, 2010
    Yes I ran my bass through the effects return.
     
  21. B-string

    B-string Gold Supporting Member

    Joined:
    Nov 21, 2008
    Location:
    Lake Havasu City, Az USA
    Okay the more expensive and harder part to repair is okay then (the power amp). From there it could be a bad solder joint in the preamp or a faulty mute circuit (I don't have the schematics). A tech will need to pull the preamp to test and inspect if you are not under warranty. You have done all you can for now. Sorry.
     

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