Buzz only when Vol pot turned down

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Sean, Feb 7, 2012.

  1. Sean

    Sean Supporting Member

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    At a gig the other night I had a buzz coming from the amp only when the volume pot (on the guitar) was turned down. If I turned the pot up at all, the noise went away. I assumed the volume pot was bad, but I can't get it to happen again at home with the same rig. I also plugged the guitar into another amp and there is no problem.

    Am I correct in assuming that there was something in the electric line (refridgerator compressor, flourencent ballast, etc) that was causing this or is there something I am missing?
     
  2. midnightlaundry

    midnightlaundry Member

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  3. Calaban

    Calaban Member

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    I have the same problem with my 335 and my Pro Reverb (or any amp) but only when using my MJM London Fuzz (germanium).

    I'd love to hear some opinions on this.
     
  4. Ronsonic

    Ronsonic Member

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    First suspect would be the guitar wiring. This is not an uncommon symptom when something is connected backward.
     
  5. Sean

    Sean Supporting Member

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    The guitar is wired correctly- The amp is a Vibroverb- I gig this set up constantly. Never had the issue before.
    I figured it was a tube and swapped out V2 (because I use the reverb channel) for a known good 12ax7. No dice, same thing. I figured the volume pot was worn away down at the end, but when I got home, there was no noise to be had from either the guitar or amp.
    I did have a fuzz pedal in the chain, but the noise came whether or not any pedals were on. Turning on gain based pedals did not make the problem worse. Turning off everything did not make it any better. I didn't have time to futz with anything any further than that. The amp worked fine otherwise and I was more than able to get thru the night.

    The first thing I always do when trying to fix any issue like this is to replicate it, and I can't in this case.
    I'm gonna call it a 'gremlin' for now and chalk it up to something else on the same line that was giving me a problem. Who the hell knows what else was included on the smae circuit. There was also a flat screen TV not far away from me. If anyone else has a suggestion or the same experience, chime in please.
     
  6. Sean

    Sean Supporting Member

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    I should also add that this guitar has (and has had without issue for a long time) a Suhr BPSSC. Not that I think that would affect anything, but who knows.
     
  7. guitarcapo

    guitarcapo Senior Member

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    Ever have an amp that hums when there's no guitar plugged in...but when you plug a guitar in the hum goes away? That's always fun.
     
  8. donnyjaguar

    donnyjaguar Member

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    Sean, there's nothing wrong with the guitar. Its EMI at the gig, probably from lights.
     
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  9. CharAznable

    CharAznable Member

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    I get that but only with fuzz
     
  10. donnyjaguar

    donnyjaguar Member

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    The noise is being induced onto the shield of the instrument cable. When the volume is turned up the inductance of the pickup coil filters out the noise. When the volume is turned down its directly connected to the centre conductor and you hear noise. This is exaggerated by any high-gain pedal.
     
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  11. TANFK

    TANFK Member

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    Just wanted to thank you for these posts... I was having the EXACT same issue and it was exacerbated by a gain pedal... LOL
     

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