Why do some amps make a loud pop noise on standby and others don't ?

Discussion in 'Marshall Amps' started by Kelia, Feb 21, 2020.

  1. Kelia

    Kelia Well-Known Member

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    Hi guys ,........I was wondering why my 2205 when I flick it on standby
    makes a loud pop noise and my Vintage Modern and 2555SL are dead quiet ?
    Can old electrolytic capacitors be the cause ?

    Tx
     
  2. MarshallDog

    MarshallDog Well-Known Member Premium Member

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    Thats a good question. I have always wondered that myself.

    I have a Fender 68 Custom Deluxe reissue and with the stock tubes it made a pop. With EH tubes in it no pop...not sure why.
     
    Last edited: Feb 21, 2020
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  3. lespaul339

    lespaul339 Well-Known Member

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    My old 2203 I used to have made that noise, but my JTM 45 does not.
     
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  4. scozz

    scozz Well-Known Member

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    I don't know why either,...both my Marshall avt combo and my Dsl1hr pop, but not my SC20. I had a 1980 Fender 30 all tube 1-12 combo that popped when switching channels with the footswitch!

    [​IMG]
     
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  5. South Park

    South Park Well-Known Member

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    It is a voltage spike going to ground you can hear in the speaker. Some stand buy switch’s are not soft start and some are not .
     
  6. ricksdisconnected

    ricksdisconnected Well-Known Member

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    :wow: :wtf:
     
  7. South Park

    South Park Well-Known Member

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    What you are hearing in a tube amp is power going to ground . Any spikes ripples box cars you will hear in the speakers .
     
  8. MickeyJ

    MickeyJ Well-Known Member

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  9. Kelia

    Kelia Well-Known Member

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    Happy I'm not the only one !.....very annoying and don't like the sound it sends to my old Pre Rola's,
    and even if they weren't Pre Rola's ,.......I wouldn't want to damage a nice quad of good speakers .
     
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  10. Matt_Krush

    Matt_Krush Well-Known Member

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    The silencing at the switches is typically a 1M resistor shunting the impulse to ground.

    Like some pedals are quiet when you pull the cord out and some are not.
    The quiet ones have the 1M from signal to ground shunt.
     
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  11. ampmadscientist

    ampmadscientist Well-Known Member

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    Tube amps are not really all tubes in this modern day. There is op amps for reverb and effects loops, etc....
    When the power is turned off the capacitors can discharge, and there is DC at the outputs of the SS components. This is what is making the POP sounds.

    In some amps, there is mute circuits to prevent the popping.
    In other amps there is no mute circuits.

    The best strategy is to turn your master volumes to 0, before you shut the power off. This usually stops the pops from happening.
     
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  12. Kelia

    Kelia Well-Known Member

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    Thanks for your input !.
    Would @MickeyJ solution above cure the problem or because of the SS op gyzmo's ,....it won't ?
     
  13. ampmadscientist

    ampmadscientist Well-Known Member

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    The cap across the switch might help the pop from the switch itself.
    But other pops from SS stuff might still happen...
    See?
    When you turn the standby on/off, the op amps are still on.
     
    Last edited: Feb 21, 2020
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  14. Kelia

    Kelia Well-Known Member

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    Thank you !
     
  15. MickeyJ

    MickeyJ Well-Known Member

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    I think it would cure your problem.
     
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  16. SkyMonkey

    SkyMonkey Well-Known Member

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    Probably not much help to you, but my VS65R makes a fair old crack if I just switch it off.
    It has a switching input jack, so I briefly unplug the input lead as I turn it off.
    Silent.

    My DSL40CR is fairly well behaved in comparison if I just switch the red off.
    No switching jack, but no pop if I switch to standby first.
     
    Last edited: Feb 22, 2020
  17. EADGBE

    EADGBE Well-Known Member

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    My 2203X did that when I turned it off. I took it to a tech and they replaced a bad electrolytic capacitor and installed a new standby switch. It no longer pops now.
     

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