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Fender Deluxe Reverb Squeal Problem

Discussion in 'Amp Central Station' started by omacam, Dec 26, 2011.

  1. omacam

    omacam NEW MEMBER!

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    Hello everyone, I have recently been suffering a problem with my 2008 Fender Deluxe Reverb. I purchased this amp a year and a half ago and have had few problems with it save one- a high pitched squeal which seems to be related with the reverb. Several days after I purchased the amp I was startled when it started squealing randomly and considered sending it back in, but this squealing only persisted for a day and has not been an issue until the past week or so. I narrowed the problem down to the reverb channel, as the squeal is only present if the reverb is turned up on the amp, and turned on via the footswitch. Upon examining the tubes, I saw that neither of the AT7's where lighting up when I turned the amp on. I figured that changing them would solve the problem and did so, but yet the squeal persists. This is my first tube amp and I have little experience in maintenance, would anyone have suggestions as to what the problem is, or how I might fix it? Thanks in advance
     
  2. Vox66

    Vox66 Tele-Meister

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  3. BobbyZ

    BobbyZ Poster Extraordinaire

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    First tube amp then it's time for your first tube amp book.
    Ok normal channel works fine. Then power tubes, PI, V-1 and rectifier must be good.
    That leaves two 12ax7s to cheack out. Pull V-1 and put it in V-2 and V-4. It could be V-5 but thats the vibroto tube so I don't think that's it but if the other two don't do it try that one as well.
    V-1 is the first of the preamp tubes all the way to the right when looking at the back. Swapping around a tube and trying it should find the problem if it's a bad tube.
     
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  5. garytelecastor

    garytelecastor Poster Extraordinaire

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    I would take it in to a tech. If you don't know what you are doing not only can you screw things up royal, you can actually kill yourself. Get a book on tube amps but for this time take it in to a tech.

    Hey Billy, just thought I might mention. I bought a Springer Spaniel off of someone in Park Rapids. Great Dog. He and I hunted and lived together for 13 years.
     
  6. Flewis

    Flewis Tele-Holic

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    my ampeg reverb rocket used to squel like that with the reverb on, i switched to a cooler tube (don't rember what kind I would have to look) and it went away - does it have stock tubes?
     
  7. uriah1

    uriah1 Doctor of Teleocity

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    I always keep 12ax7 and 12at7 spares around for those circustances. To make sure
    it is not power tube or rect, do all the 12a 1st. If ok, then you can narrow it down easier.
     
  8. BobbyZ

    BobbyZ Poster Extraordinaire

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    Hey Billy, just thought I might mention. I bought a Springer Spaniel off of someone in Park Rapids. Great Dog. He and I hunted and lived together for 13 years.[/QUOTE]

    You must know me. Real name is BillyBob. I just do the BobbyZ thing on the web.
    Bet you got the Springer from my cosin Bubba.
     
  9. omacam

    omacam NEW MEMBER!

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    The tubes I switched out were the stock GT-12AT7's, which I replaced with JJ-12AT7's
     
  10. RedRock

    RedRock Tele-Holic

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    There's a good chance the RCA plugs on the back of the the chassis for
    reverb send and reverb return are not making good contact with the small
    RCA jacks. The plugs may be loose; if so, slightly tighten them by pulling them
    out, gently crimping them with pliers, and re-inserting them.

    Sometimes the jacks become corroded. If this is the case, the 2 jacks need
    to be replaced. You can get replacements from www.tubesandmore.com.
    They are about $1.75 each. You can also get replacement RCA plug tips
    there for about $1 each. Removal and replacement in either case would
    require some soldering.
     
  11. Wally

    Wally Telefied

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    omacam, the tube driver for the reverb circuit is V3..teh 12AT7 that is 3rd fromt he right as you look at the back of the amp. turn the amp up, turn the reverb up, and tap on this tube. Do you hear any 'microphonic' noise....a lot of it? IF so, put another 12AT7 in there and see if there is a change. IF htat is not the problem, go to V4. One triode in this 12AX7 is the reverb return tube, and if it is microphonic then it could be your problem. Sub in the tube you can pull form V1 and see if that helps.
    The tip from REdRock about the connections is valid....always check connections.

    Note: those 12AT7's that you thought were not lighting up were in fact functioning....or you would not have heard any production form the amp. V6, the 12AT7 closest to the power tubes, is the phase inverter and if it were bad you wouldn't be getting any sonic production from the amp. AS noted earlier, the 12AT7 in V3 is the reverb driver. IF it were not getting heater voltaeg(lighting up) then you have no reverb production. The 12AT7's light up differently. IN fact, different 12AX7's yield different heater filament glows, too.

    Another possibility on the squeal is a bit more trouble. You say that it squealed a bit when you first got the amp. That indicates that there may be a bad connection somewhere that is making itself evident once again. NOte to self and others: always return amps that have warranties on them at the first sign of trouble. IF this amp is still under warratny, then return it without worrying much about what the issue is....let Fender fix it. IF it is not under warranty fro whatever reason, a tech may be your best friend.
     
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