Repair Question - what could this be? | The Canadian Guitar Forum

Repair Question what could this be?

Discussion in 'Amp Building/Technical/Repair' started by guitar69freak, Nov 15, 2019.

  1. guitar69freak

    guitar69freak

    Joined:
    Jul 28, 2019
    Location:
    Ottawa
    i have the first edition Peavey XXX and its not working correctly.

    One day i go to hook up my XXX. i was just the head sitting on the cabinet plugged in to the wall.(Big mistake) I plugged it in to the cabinet as well as my guitar and let the tubes warm up as per usual. once i start to shred my guitar I realize I can't get any sound. i play around with the head and determine there's something wrong with it and hit the power switch. As i switch the power to the off position i hear the guitar fading out. hmmmmmm

    so i do this once again, same thing. does this tell me the output transformer has blown?

    if this is the case, what are some amplifiers that use an OT that is compatible with my first edition Peavey XXX that i can salvage parts from?
     
  2. jb welder

    jb welder

    Joined:
    Sep 13, 2010
    Location:
    Melonville, Canada
    No, that does not tell you the output transformer is blown.
    Could be any one of many much less expensive parts. If you consider all the failures in amplifiers, OT failure is fairly rare.
     
  3. guitar69freak

    guitar69freak

    Joined:
    Jul 28, 2019
    Location:
    Ottawa
    Fairly positive what had happened here was my girlfriend's two year old daughter had switched this on while it was plugged in to nothing but the wall, seeing as it was turned on when i came to hook it up.

    (Never leave your tube head plugged in if it's not connected to a guitar or speaker cab)
     
  4. dtsaudio

    dtsaudio

    Joined:
    Apr 15, 2009
    Location:
    Hamilton, ON
    Not likely an output transformer failure. While it isn't good practice to power up without a load, it still takes quite a bit to blow a transformer.
    First aid, would suggest a bad tube. Start with the 12AX7 tubes.
     
  5. guitar69freak

    guitar69freak

    Joined:
    Jul 28, 2019
    Location:
    Ottawa
    the first thing id done was check the fuse and i know it's not the fuse or else the amplifier wouldn't be turning on.
     
  6. nonreverb

    nonreverb Gold Member

    Joined:
    Sep 19, 2006
    Location:
    Ottawa, ON
    Since you can hear the guitar fading away when you flip the power switch of suggests a relay is also turning off. Did you try playing it on both the clean and dirty channels? My first guess is it's a preamp tube. Just so you know, as long as nothing is plugged into the input of the amp, the output transformer isn't in danger without a load as all that's present is DC on the primary winding......it's when a signal is present that things can get scary.
     

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