Ampeg SVT VR Hum problem

Discussion in 'Amps and Cabs [BG]' started by snaverb, Aug 20, 2009.


  1. snaverb

    snaverb

    Feb 19, 2007
    Atlanta, Ga
    I have an 07 Ampeg SVT VR, and it worked perfectly until about 5 days ago. As soon as i turn the amp on, I let the tubes warm up in standby for about a minute or two, and as soon as I switch the amp off standby, I get a pretty loud and annoying hum.

    I also have a SVT CL, So I swapped the power tubes, then I swapped out each pre-amp tube, still hums the same.

    Its not my bass, or my instrument cables, the hum happens when my bass isnt even plugged into the amp. Swapped my speakon speaker cable out, that didnt work.

    Im not sure what else to try. I really hate to have to put it in the shop, anyone got any ideas, suggestions ? Maybe someone has had the same problem and can tell me whats causing the hum.

    Thanks
     
  2. WOOFMAN

    WOOFMAN

    Mar 12, 2003
    USA, PNW
    Look for loose or frayed wires. That would be my next step.
     
  3. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    Might be a disconnected wire somewhere. But I think a trip to the shop is in order. Beats throwing money at it and not getting it fixed, plus you can die if you don't know what you're doing.
     
  4. brothernewt

    brothernewt Some people call me the stormtrooper of love...

    Apr 13, 2004
    Happyrock, OR
    Check your polarity switch and try it on a different outlet. Also check that the impedance switch is correct for the cab you're using... after that, shop time.
     
  5. snaverb

    snaverb

    Feb 19, 2007
    Atlanta, Ga
    Thanks everyone... I tried a different outlet, and messed with the polarity switch, still nothing but loud annoying hum. Im gonna look into the pre-amp stage for any loose wires, ect, if I cant find anything there, Im gonna have to take it to the shop, but I hate to part with it, I've only had it about 2 weeks, it was shipped from California to Atlanta, it arrived in perfect condition, props to UPS, but maybe something got jarred in shipping or something..... but then again, it has worked perfect up until a few days ago sigh
     
  6. Tim1

    Tim1

    Sep 9, 2005
    New Zealand
    Sorry to hear about the hum issue, great amp. You have pretty well checked the obvious, as advised. If I were you I would take it to a tech and have it all checked out while he is at it, since you appear to have purchased it second hand. However, I believe that there is a 5 year warranty over there so you might want to see if it is transferable. Also it has been stated on this forum that Ampeg is reinstating its service centres....
     
  7. BassmanPaul

    BassmanPaul Inactive

    Sounds to me like you have a bad output tube. Don't use the amp again until you take it to a tech. You could cause more damage.

    Paul
     
  8. username1

    username1

    Dec 28, 2005
    alberta canada
    try balancing the bias controls better to each other. They can still be in the green but alot of hum can be eliminated by adjusting them in relation to each other, try to keep them both in the green though. I have reduced alot of hum in my svt classic so it is dead silent by playing with them.
     
  9. MingusBass

    MingusBass Commercial User

    Sep 27, 2004
    Fort Wayne,Indiana
    FYI-The Ampeg warranty is not transferable. Just one of the risks of buying second hand.

    Take it to the shop and be done with it. You've already waited longer than I would have.
     
  10. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    Really?

    It used to be...... all you needed was the receipt or other proof of original purchase date.... Even if you were owner #6. Loud evidently dropped that like a hot potato.
     
  11. MingusBass

    MingusBass Commercial User

    Sep 27, 2004
    Fort Wayne,Indiana
  12. BassmanPaul

    BassmanPaul Inactive

    Sad!!!!

    Me
     
  13. Nighttrain1127

    Nighttrain1127 Supporting Member

    Nov 27, 2004
    Near Worcester MA
    Isn't there a hum balance pot on the back of that SVT?
     
  14. BluesyCat

    BluesyCat I'm irresistible. Gold Supporting Member

    Jul 28, 2006
    Southern California
    Staff: Bass Gear Magazine
    solution could be here:
    http://www.talkbass.com/forum/showthread.php?t=434417

    AND
    on the Ampeg.com FAQS page: #17....
    Q17) I did not receive a warranty card when I bought my amp. What do I do?
    Not to worry! As of January 1, 1996 your sales receipt is your proof of warranty. The warranty is transferable by simply passing the original sales receipt or a copy to the next owner.

    So it looks like they contradict themselves. I wonder which it is. The product tags that were attached to the head ALSO state it IS transferable.
     
  15. username1

    username1

    Dec 28, 2005
    alberta canada


    There is a hum balance control on the back of an old V4b but not on the new classic but you can balance the bias controls together anyways.
     
  16. snaverb

    snaverb

    Feb 19, 2007
    Atlanta, Ga
    UPDATE:

    I tried everything I knew, and ended up putting it into the shop. I dropped it off on Thursday. I didnt even bother with the transferable warranty. I took it to a place that I trust, and was referred to by SVT owners. I already miss the VR badly... even when it wasnt turned on, it just looked so awesome sitting there. Guess I'll be using my backup until I get it back.
     
  17. BluesyCat

    BluesyCat I'm irresistible. Gold Supporting Member

    Jul 28, 2006
    Southern California
    Staff: Bass Gear Magazine
    When you spoke to Ampeg, did they confirm that the warranty is transferrable?
     
  18. snaverb

    snaverb

    Feb 19, 2007
    Atlanta, Ga
    I didnt mention it to them at all. They just gave me the info to the place they use in my area, and said if its a warranty issue, then to bring my receipt, and something else. But I had never heard of that place, I took it to a trusted and well known tube guy here in Atlanta who has fixed many SVTS - He actually had an early 70's SVT he was about to work on while I dropped my VR off, very cool
     
  19. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    The SVT balance does NOT do the same thing as the bias controls.

    It is NOT a bias balance, it is a gain balance in the phase splitter. As such it does cancel some hum, but the main function is to balance the two halves of the circuit for gain.

    And yes, there IS a balance control in the VR.
     
  20. BluesyCat

    BluesyCat I'm irresistible. Gold Supporting Member

    Jul 28, 2006
    Southern California
    Staff: Bass Gear Magazine
    Did your well-trusted tube guy figure out the hum in the VR?
     
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    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
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