Noise problem

Discussion in 'The Workbench' started by Jeru78, Jan 14, 2020.

  1. Jeru78

    Jeru78 New Member

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    Hi

    I'm playing a Marshall JCM 800 Lead Series Model 2210.
    It has been making this enoying noise for a while.

    It occurs (only) when I open the master volume button.
    No guitar plugged in.

    Can anyone tell what's causing this noise en how to get rid of it?

    I tried using different speaker cabinets, changing cables, different wall outlets, ... and the problem remains.

    Thanks!
     

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  2. ricksdisconnected

    ricksdisconnected Well-Known Member

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  3. marshalltsl

    marshalltsl Well-Known Member

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    :welcome: to the Forum.

    Best of luck fixing your amp. I'm sure some amplifier technician MF members will help you.
     
  4. tce63

    tce63 Well-Known Member Premium Member

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    :welcome: to the forum, a great place
     
  5. BanditPanda

    BanditPanda Well-Known Member

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    Let me first say that I am by no stretch of the imagination an amp tech and never will be. Anything I say here has been learned from this site and in fact I don't know how well I've learned it !!! lol
    In any event some questions:
    Do you have experience changing tubes? This an important question in order to avoid killing yourself.:wow:
    Do you have a spare, in good order pre amp tube available for testing purposes? More than likely a 12AX7.
    I'll stop here awaiting reinforcements and your answers.
    BP
    p.s. and :welcome:
     
    neikeel likes this.
  6. ampmadscientist

    ampmadscientist Well-Known Member

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    Start the reactor... Free Mars!
    Plug a guitar cable between send and return then re-test.
    Plug a footswitch into the FS jack, and retest. Operate the footswitch did the probem go away?
     
  7. Jeru78

    Jeru78 New Member

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    Hi, just tried it. The noise problem remains.
     
    tce63 likes this.
  8. Jeru78

    Jeru78 New Member

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    Hi, I never changed a tube. But I guess I will manage watching some Youtube examples ... (hope I don't die ... haha ) ... I think I know someone who has some spare parts (tubes), who's coming over next week. I'll let you know what he brought before starting experimenting.
    Thankx!
     
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  9. BanditPanda

    BanditPanda Well-Known Member

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    Good show. Just remember the " death" part is factual as there are enough stored volts in there to do that.
    BP
     
    tce63 likes this.
  10. ampmadscientist

    ampmadscientist Well-Known Member

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    Start the reactor... Free Mars!
    Yes it can be a noisy preamp tube.
     
    instinctfx likes this.
  11. neikeel

    neikeel Well-Known Member

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    Sounds like a dodgy preamp tube to me as suggested above (ECC83/12AX7 or 7025). Suggest you buy a new one from a reputable source and replace each one in turn with the new one until the problem goes.
    You do not have to remove the amp from the chassis, just the back panel. You should turn the amp off between each change (I confess I tend to just use standby when rolling but if you are new to this turn it off each time.
    Please report back when you have done this.
     
  12. Seanxk

    Seanxk Active Member

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    I've just fixed the very same noise problem today, it was the stand by switch on an 800.
    Power off and disconnected from wall, conservatively spray deoxit cleaner in the tiny holes at the back of the switch ( power switch too while you're there ), toggle a few times and try.
     
    tce63, neikeel and marshalltsl like this.
  13. Jeru78

    Jeru78 New Member

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    Thanks for the advice so far guys !! ... I got a shoe box full of old (but never used) Fender and Ruby Tubes (they were in my dad's house ...) Also including two Fender 7025-12AX7A. Will these do the job? (I must admit I'm a bit scared now hearing about the danger for stored volt)
    I already removed the electronic panel from the head.
     
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  14. ampmadscientist

    ampmadscientist Well-Known Member

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    Start the reactor... Free Mars!
    Don't be afraid.
    [​IMG]
    If you die, you will be immortalized in the Marshall Amp Forum Hall of Fame :hbang:, recognized for extraordinary bravery in the face of Amplifier noise.
    Good luck.
     
    BanditPanda likes this.
  15. Jeru78

    Jeru78 New Member

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    Thanks for the advice so far guys !! ... I got a shoe box full of old (but never used) Fender and Ruby Tubes (they were in my dad's house ...) Also including two Fender 7025-12AX7A. Will these do the job? (I must admit I'm a bit scared now hearing about the danger for stored volt)
    I already removed the electronic panel from the head. Can I use the Fender 7025-12AX7A to test? So I have to make sure I dont touch the Capacitors? How long do they stay charged?
     
  16. Jeru78

    Jeru78 New Member

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    Thanks for the advice so far guys !! ... I got a shoe box full of old (but never used) Fender and Ruby Tubes (they were in my dad's house ...) Also including two Fender 7025-12AX7A. Will these do the job? (I must admit I'm a bit scared now hearing about the danger for stored volt)
    I already removed the electronic panel from the head. Can I use the Fender 7025-12AX7A to test? So I have to make sure I dont touch the Capacitors? How long do they stay charged?
     
  17. neikeel

    neikeel Well-Known Member

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    If you only remove the back panel to tube juggle there is nothing to shock you.
    yes, assuming your 7025 is good then swap away.
     
    Peter McAteer likes this.
  18. Jeru78

    Jeru78 New Member

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    It was indeed a broken tube.
    Thanks!
     

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