Blackface Vibrolux reverb - reverb stopped working

Discussion in 'Amps and Cabs' started by lavinci, May 6, 2016.

  1. lavinci

    lavinci Member

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    The reverb on my BFVR just stopped working and I need some advice:

    BACKGROUND:
    I noticed about a month ago it was not as drippy as it used to be when I had it cranked to ten.
    I usually have it set on 3 to 4 normally, but then I found I had to set it at 5-6 to get the same reverb effect.
    WELL yesterday, I turned the amp on and I have NO reverb coming from the amp at all

    but the Vibrato still works, but no reverb....

    okay walk me through this...
    Where do I start on trying to fix the problem....
    NOTE: I'm not a tech, but want to try to as much as I can myself.
     
  2. Blues Power

    Blues Power Member

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    im no tech either but I think V4 and V5 power the reverb. you can do a google search on it. if not those two than maybe 3 and 4
    I think 2 new tubes and youll be good again
     
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  3. remocity

    remocity Supporting Member

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    V3 and V4
    12at7 in V3 and 12ax7 in V4
     
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  4. pbmw

    pbmw Member

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    Same thoughts. It's the tubes.
     
  5. swiveltung

    swiveltung Member

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    Tubes first.
    Clean tank cable ends at the amp next.
     
  6. Muzzy

    Muzzy Supporting Member

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    I'd start with tubes too.
     
  7. dewey decibel

    dewey decibel Supporting Member

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    Looking at your amp from the rear, take the reverb driver tube (V3, 3rd from the left) out, and replace is with V1(all the way to the left). If you get reverb, that was your problem. If not, replace V3 with the original tube, and try the tube from V1 in the reverb recovery spot (V4, 4th from the left). If you get reverb sound, that was your problem.

    Swap these tubes with the amp on standby (or better yet, off), and be careful if the amp has been on as they can get HOT...
     
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  8. soldersucker

    soldersucker Member

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    Tubes
    Cables
    Pan.
    Good luck.
     
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  9. tele_player

    tele_player Member

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    You mean 'from the right', unless you also mean 'with chassis upside down'.
     
  10. Bluesful

    Bluesful Supporting Member

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    This is what I was thinking. I've had issues with the original RCAs in my '67 Vibrolux. I really should just put in some new RCAs and store the originals.

    So OP, yeah it's probably a tube issue but don't discount the RCAs.
     
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  11. dewey decibel

    dewey decibel Supporting Member

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    :jo

    Sorry....
     
  12. lavinci

    lavinci Member

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    @dewey decibel found the culprit..., V4 (12AT7) was not doing its job.
    ....
    I swapped V1 into V4 and the reverb came back... with a tad more noise. I speculate because the 12AX7 has more gain the the 12 AT7.

    so where is the best place to buy a replacement tube, or set....
    or as @Bluesful said, maybe I should pull all the tubes and replace the whole set....
     
  13. MasterEvan07

    MasterEvan07 Supporting Member

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    :eek:
    My '70 Super had the reverb die and I just haven't gotten around to looking into it and my brain didn't even consider tubes first...what a rookie mistake on my part! This thread just helped me focus and remember sometimes there are much simpler solutions than anticipated - excellent...
     
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  14. dewey decibel

    dewey decibel Supporting Member

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    Awesome, easy fix! As far as replacing them all IDK, vintage tubes can last quite awhile, but of course it never hurts to have spares. As far as who to buy from, there is a sticky at the top of this forum you should check out.
     
  15. lavinci

    lavinci Member

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    Can I just buy one tube, or do they need to be matched?
    V4
    sorry this is my first rodeo, replacing tubes in my amp.
     
  16. remocity

    remocity Supporting Member

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    Are you sure V4 had a 12at7 in there?
    I think you may be a little confused about which is V1.
    Looking at the back of the amp, V1 is to the far right.
    The reverb send tube is V3 which should be a 12at7.
    V4 is the reverb recovery and also has another function which we don't need to get into for this particular problem.
    V4 should be a 12ax7.
    You can and should buy individual tubes.
    NO reason to replace all the preamp tubes!
    There is a sticky at the top of the amp and cabs section that will give you a list of all the tube vendors.
    Hope this helps.
     
  17. dewey decibel

    dewey decibel Supporting Member

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    No, preamp tubes (except for some special situations) don't need to be matched. You can pretty much plug in and play with all preamp tubes. The power section is where you'd want to worry about matching, biasing, etc.

    Also, if the amp hasn't ever been re-capped or checked out by a tech in general you may want to consider having that done.
     
  18. lavinci

    lavinci Member

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    yes, I was mistaken....
    The tube I took out of V4 is labelled 7025.
    ....so should I replace it with a 12AX7
     
  19. remocity

    remocity Supporting Member

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  20. Elantric

    Elantric Silver Supporting Member

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    I bet you have a broken transducer that used to hold the spring inside the Reverb pan / tank.

    This occurs from age and transport - inspect the Reverb tank, If Springs are loose and not connected to the transducers, order a new Reverb tank


    https://www.tubesandmore.com/products/P-RMOD-4AB3C1B
     

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