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Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com

'78 Deluxe Reverb Strange Problem

Discussion in 'Glowing Bottle Tube Amp Forum' started by StoogeSurfer, Sep 9, 2017.

  1. StoogeSurfer

    StoogeSurfer Tele-Afflicted

    Jan 26, 2011
    USA
    The reverb is cutting out when I lean the amp back on an angle. I have definitely isolated the problem to the tank itself, because it doesn't happen when the amp is angled but the tank is out of the amp and level on the floor. Having opened the tank and visually inspected it I can see nothing that would be causing this problem, no shorts are visible. Ideas?

    Image1504969395.699440.jpg
     

  2. StoogeSurfer

    StoogeSurfer Tele-Afflicted

    Jan 26, 2011
    USA
    Might have found the problem. I noticed that when I removed the bottom cardboard "floor" of the tank, the problem went away. And I see visible marks where at least one spring has been rubbing against the cardboard.
     

  3. StoogeSurfer

    StoogeSurfer Tele-Afflicted

    Jan 26, 2011
    USA
    So maybe that wasn't the problem. The reverb still cuts out when I first angle the amp backward. But I discover that if I kick it the amp couple times while it's angled back, the reverb comes back to life. It is as if I have to loosen up the springs. Weird.
     

  4. Ringo

    Ringo Poster Extraordinaire

    Mar 16, 2003
    Memphis TN
    Do you have another reverb tank to try with the amp? to make sure it is the tank that is the problem?
    Did you look closely at the tiny wires from the phono jack to the reverb tank transducers? I've had a few of them where the wire was broken where it was clamped down inside the tank, I was able to fix them by very carefully resoldering the wire and I just moved it out from under the metal tab that clamped it in place.
     
    robrob likes this.

  5. Silverface

    Silverface Poster Extraordinaire Ad Free Member

    Age:
    65
    Mar 2, 2003
    Lawndale CA
    Bad tank. I've had similar problems that I isolated to one of the transformers. Just replace it - they're about $20.
     
    StoogeSurfer likes this.

  6. StoogeSurfer

    StoogeSurfer Tele-Afflicted

    Jan 26, 2011
    USA
    I did look and don't see any issues there. Tapping the amp seems to work every time though. Also if I don't tilt it back as far. So that's my fix for now. Genius, isn't it?
     

  7. ecosse

    ecosse Tele-Meister

    329
    Jul 24, 2011
    Nova Scotia, Canada
    RCA connection for Reverb send/recovery? Pull the cables and reinsert them a few times. A light squirt of contact cleaner on them wouldn't hurt either.
     

  8. codamedia

    codamedia Friend of Leo's

    Apr 4, 2009
    Western Canada
    Clean the RCA connectors (tank and amp) and touch up the solder joints within the tank.
    It also doesn't hurt to try a different set of RCA cables... just to eliminate those as the culprit.
     

  9. StoogeSurfer

    StoogeSurfer Tele-Afflicted

    Jan 26, 2011
    USA
    That may be what I do, thanks. I was eyeing those little transformers wondering whether they might be doing their own thing. The tank also always makes this weird kind of mild reverb crashing sound all on its own while the amp warms, happens up every time, usually after about a minute.
     

  10. Silverface

    Silverface Poster Extraordinaire Ad Free Member

    Age:
    65
    Mar 2, 2003
    Lawndale CA
    That means the springs, output transformer in the tank and recovery stage (the 12AX7 and associated circuitry) are working and the problem is at the input - probably one of the two small wires leading to that transformer or inside the transformer itself.

    It's a very common cause of reverb problems and does indicate tank replacement if the input cable/connection to tank all check out.
     
    StoogeSurfer and viccortes285 like this.

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