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DSL40c making static popping noises

Discussion in 'Marshall Amps' started by Kadin wallner, May 11, 2021.

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  1. Kadin wallner

    Kadin wallner New Member

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    It randomly started while I was playing and I shut it off for a few days. I just turned it back on to see if it stopped but it’s still there and while I was listening for the popping noises it made a SUPER loud noise that hurt my ears and it didn’t stop until I turned it off. I actually caught video of it

    https://youtube.com/shorts/5MYaY_iYZRk?feature=share
     
    Last edited: May 11, 2021
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  2. solarburnDSL50

    solarburnDSL50 Well-Known Member Platinum Supporting Member

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    I always trouble shoot tubes. Which is normal maintenance.

    They can hum, scream or give static sounds.
     
  3. Jethro Rocker

    Jethro Rocker Well-Known Member Silver Supporting Member

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    Yep agreed. Start with power tubes and see.
     
  4. Kadin wallner

    Kadin wallner New Member

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    Do I replace them?
     
  5. solarburnDSL50

    solarburnDSL50 Well-Known Member Platinum Supporting Member

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    Always good to have an extra set of known good tubes since you have a tube amp.

    While amp is on tap power tube lightly with a pencil or like. If they make noise it's them. Same with preamp tubes. I can usually tap right at the base of each tube on the chassis and figure out which tube it is. I tap my finger on the chassis near each tube. It's called being microphonic.
     
  6. Yamariv

    Yamariv Well-Known Member

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    OP, if you're replacing your power tubes you'll have to bias them. From the sounds of your post you probably don't know how to do that and probably shouldn't be working in a live amp as it can kill you. You can start by getting a couple good new 12AX7 preamp tubes and rolling them in each preamp position to start. If that doesn't solve the problem move to the power tubes.

    A sneaky way to get around having to bias your power tubes is to order the same output reading that will be written on the side of the tubes if they are a matched pair ie: 39,26,32 etc..If you order the identical reading tubes you should be pretty close to the right bias as before and can at least swap the EL34's for a good pair to see if that fixes it. Like others have said above, you should have several good known tubes on hand as spares if you own a tube amp.
     
  7. Jethro Rocker

    Jethro Rocker Well-Known Member Silver Supporting Member

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    Ypu can also pop in 2 new power tubes and see, even if bias is off some. Just enough to hear if it fixes. While it could be preamp tubes, Power tubes have a way lower lifespan than preamps that's why I suggested trying them first.
     
  8. solarburnDSL50

    solarburnDSL50 Well-Known Member Platinum Supporting Member

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    Finger tap to the chassis reveals most tube microphonics. Right next to the tubes. Quick and easy.

    If it is power tubes he'll have to bias them which I know you know.
     
  9. solarburnDSL50

    solarburnDSL50 Well-Known Member Platinum Supporting Member

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    You could spray the pins with dexoit too prior to changing them. In and out a few times of the tube socket.

    Check some YT vids about this stuff.
     
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  10. Mitchell Pearrow

    Mitchell Pearrow Well-Known Member VIP Member

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    Looks as if you already know the answer, and @solarburnDSL50 method is very reliable, @Jethro Rocker I have done just as you have pointed out on power tubes before as well ..
    Good luck with getting your amp back to healthy.
     
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  11. Kadin wallner

    Kadin wallner New Member

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    Okay thank you guys I’ll get new tubes and see what happens and I’ll follow your directions so I don’t kill my self trying to fix my amp lol
     
  12. KraftyBob

    KraftyBob Well-Known Member Gold Supporting Member

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    **Deleted my post as it pertained to the 40CR and realize you have the 40C**
     
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  13. Yamariv

    Yamariv Well-Known Member

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    Keep us posted!
     
  14. Kadin wallner

    Kadin wallner New Member

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    I looked in the back of the amp and I was tapping the tubes with a wooden chop stick to see if the amp would make the terrible noise again. I couldn’t replicate it but i noticed one of the tubes is glowing blue in some spots. Could that be the issue?
     
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  15. solarburnDSL50

    solarburnDSL50 Well-Known Member Platinum Supporting Member

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    It's got gas.

    It was a power tube. It maybe operating at less than.
     
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  16. solarburnDSL50

    solarburnDSL50 Well-Known Member Platinum Supporting Member

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    Make sure the tube is seated right. Secure in the tube socket. Tap on the chassis right at the bass of each tube. Can you hear your tap? You have a microphonic tube.
     
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  17. solarburnDSL50

    solarburnDSL50 Well-Known Member Platinum Supporting Member

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    You got new tubes coming. This will help trouble shooting. Jus don't get your hopes up. New tubes out of the box can be buggered. We'll figure it out. Plenty of techs here know their shit. I know basics.
     
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  18. Kadin wallner

    Kadin wallner New Member

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    On my tubes it says EL34 VLVE 00101 18/15 on both tubes which numbers are the output reading
     
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  19. Jethro Rocker

    Jethro Rocker Well-Known Member Silver Supporting Member

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    Yeah I have done that before. Never had power tubes go micro but I have had static amd such. Changed em out, done.
     
  20. Jethro Rocker

    Jethro Rocker Well-Known Member Silver Supporting Member

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    None of them. It might not have that written on them. But at least changjng them can determjne if they are the prpblem even before biasing.
     

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