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Possible cause of intermittent volume drop on Peavey XXL?

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  • Possible cause of intermittent volume drop on Peavey XXL?

    I've been using my Carvin V3M more or less exclusively for the past year, and sort of lost track of the fact that the whole reason I bought it was because my Peavey XXL was having issues. The XXL's volume would drop from time to time, usually not enough to be immediately obvious but at least once or twice pretty substantially.

    I bought it used and can personally account for hundreds of hours of use at practice and gigs, so I'm not surprised that it finally needs some work, but I was curious if anyone can point me in the right direction before I take it to a shop where they'll be "unable to replicate the problem" and just spray contact cleaner in it. I haven't had very good results in the past when taking solid state amps in for the repair of intermittent problems.
    sigpic

  • #2
    Just shooting from the hip here, I'd guess an output transistor is flaky or loose solder joint for said transistor. Probably gets flaky after it warms up a bit. Try warming them up one at a time with a heat gun, and see if one drops out with that. Do this while playing through it so you can hear the drop if it happens. I wouldn't go to long with the heat, but those do get pretty hot sometimes when running. Maybe that'll help pinpoint the prob for you or your tech. Intermittents do suck, not much can be done until the issue found.

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    • #3
      I would swap out the V1 pre amp tube with a spare, then do the PI tube the same way and see if it does it again.
      The V1 gets the hardest use so it could be getting ready to give up on you.
      Really? well screw Mark Twain.

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      • #4
        I did a google search on "Peavey xxl head problems," it seems that this is pretty common issue. I couldn't find a universal solution, but few different forum threads were suggesting jumping the FX loop send to the return. Give that a try.

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        • #5
          straycat: It's a solid state, amp, bud!

          etepbbb: Hmmm, interesting idea with the loop, but I run pedals in it. I would think that would act as a jumper. If not, well . . . I have to run the effects.
          sigpic

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          • #6
            First thing I would go after would be a thorough cleaning of all of the jacks and pots.
            EFX loops are famous for dropping signal.
            Deoxit or the correct industrial contact clears (don't use lubricating tuner cleaners and
            I will personally come by and kick your tail if you get a can of WD40 near it...BANNED at the the Cygnus household and shop)!



            Although I don't "advertise" that I do SS repairs that is the first thing, and usually
            gets it.
            After that, open it up (unplugged) and use your nose!
            Along with a VERY close look at the resistors and caps around the output transistors.
            Like a tube amp, those go through the most stress and have the highest potential for issues.

            Also (I wish I had time to do it for you), get any service bulletins you can get your hands on.
            Google!
            Carvin may just send them to you regardless of whether you are the original owner or not.

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            • #7
              Edit...Peavey.
              Sheesh.
              Peavey may email you the TSB's.
              They have been good to me!

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              • #8
                Oh my bad I was thinking XXX I guess.
                Really? well screw Mark Twain.

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                • #9
                  Check anything mechanical first. I had a JCM800 with the same problem and it turned out to be a bad preamp tube socket. I found it by wiggling preamp tubes. Just be sure to use something other than your bare hands to check hot components...trust me.

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