1. theirflowers21

    theirflowers21 Member

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    May 12, 2006
    My Matchless Clubman amp developed a very irratating buzz over the last few days. It only did this with the chord plugged in, unplugged it was fine. I took the phaser invertor tube out and the buzz stopped, but I replaced it with one that I know to be good and the buzz came back. The other pre amp tubes checked out okay too. I went back to my jcm 900 marshall and it has the exact same problem, buzzing only when something is plugged in. I tried it with a 3 cables, 1 monster, one without a label, and a brand new planet waves cable. Does anyone have an idea of what it is. :( I have had the worst amp luck over the last 3 or 4 months. Thanks for any help you guys can give
     
  2. Riscchip

    Riscchip Member

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    A ground loop maybe? Try moving the power to a different wall socket (in a different room, maybe).
     
  3. donnyjaguar

    donnyjaguar Member

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    If I had to guess, I'd say the amplifier is fine. It sounds like something is getting in through your instrument. I say this because you tried different cords with the the same result. My Strat seems to be sensitive to stray electrical fields in the room such as low-voltage lighting, computer monitors, battery chargers. Basically anything with a switching power supply. There's nothing wrong with my guitar and I've confirmed the ground wire is attached internally, but it could really benefit from some additional shielding. So I should probably ask what you cats use for that. Not sure if foil duct tape is the best answer here, but I don't particularly want to spray nickel paint in the cavity either. I digress, RISCchip may be on the right track too. Case in point, if I drape the power cord in one of my fenders across the reverb tank it definitely picks up some hum.

    Hope this helps!
    DJ
     
  4. theirflowers21

    theirflowers21 Member

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    Thanks for thet info guys. I have had a chance to try the amp in various places today and it still does it. Can a ground loop be the amps problem more than just going to different outlets/buildings? It picks up the noise with all of my guitars and makes the noise even without a guitar plugged in, just the cable in the amp. Wierd. Any other thoughts would be great, I hope its something simple.
     
  5. Riscchip

    Riscchip Member

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    A ground loop doesn't indicate anything wrong with your amp. If you are getting the noise after moving the amp to a different circuit, that's probably not the problem, however (unless you have any effects pedals hooked up that you've been moving along with the amp).

    If it's happening with both amps and all guitars on all sockets, probably not a ground loop, but certainly very strange! I'm sorry but at this point I've probably hit the limits of my usefullness on this problem.
     
  6. donnyjaguar

    donnyjaguar Member

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    I had a look at the schematic. The Clubman uses your typical shorting type phone socket, but doesn't incorporate any more muting functions (like other amp's). Does it buzz equally on both inputs?

    At this point I'm suspicious of:

    R5, R7 & R9
    V2
    J3 & J4
     
  7. ekp

    ekp Member

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    How about the ground at the input jack? You could get all sorts of noise if the ground contacts were not clean. Contact cleaner can be had at Radio Shack, etc.
     
  8. donnyjaguar

    donnyjaguar Member

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    Good point ekp. My gear is nice and clean so I don't often think of this. I've repaired equipment with filthy sockets where someone has spilled liquor into it or jammed a cigarette butt in there etc.
     

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