What would cause noise to come through the speakers while the amp is on standby?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by JTM fan, Feb 24, 2009.

  1. JTM fan

    JTM fan Member

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    When I power up my amp, while it's on standby.....I can hear random crackly noises....almost like a bad preamp tube?

    What could this be?
     
  2. WaltC

    WaltC Member

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    What kind of amp?? Different amps have different methods of "standby" and not all remove *all* B+ from all the tubes. How loud is the noise? Is it coming through the speaker(s) or from the amp/cab/chassis?
     
  3. slider313

    slider313 Silver Supporting Member

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    It could be a bad power tube.
     
  4. JTM fan

    JTM fan Member

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    It's a dual channel, (4) EL34 type amp.......
    The noise isn't very loud at all, I would say just under speaking volume......and yes it is a sounding through the speakers.
    It doesn't start right away when I fire up the amp......but more like it's been warming up for 20 seconds.
    It sounds like a bad tube to me, but I always thought you wouldn't be able to hear it until you took it off of standby. So it's a crackly buzz type sound.
     
  5. capnjuan

    capnjuan Member

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    Hi JTM fan; how long has it been since the power tube sockets and pins were cleaned? Sometimes can get a little corrosion at the points of contact. CJ
     
  6. JTM fan

    JTM fan Member

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    Not sure, I just got the amp a month or two ago.....I'll have to clean them tonight to see if that makes a difference! Thanks for the idea.
     
  7. FrankieSixxxgun

    FrankieSixxxgun Member

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    Try a new set of power tubes. Maybe some filament current is leaking through. Filaments are always hot even if the amp is on standby.
     
  8. amp-head

    amp-head Member

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    Aside from tubes it could be an intermittent problem with either the input jack(s) or the speaker jack. Do you have any odd symptoms at all when you are playing through the amp?
     
  9. Rosewood

    Rosewood Member

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    Standby switch is upside down.:)
     

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