Help Marshall DSL50 noises

Discussion in 'Amps and Cabs' started by seventn, Jul 25, 2006.

  1. seventn

    seventn Member

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    I just got a DSL50 and am quite happy with it but I find that it emits a loud hum. Level frequency hum not buzz. Is that normal?
     
  2. GuitslingerTim

    GuitslingerTim Member

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    Mine had a hum when new. After changing out tubes, speaker cable, speaker wiring, and speakers it went away. Now it's the most quiet tube amp I've heard. :D
     
  3. stump

    stump Member

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    My TSL100 did the same thing. Changed out the preamp and power tubes to fix it. The hum recurred when I moved the amp to my basement and turned out to be the surge protector I was using. Also, don't stand too close to the amp. Try the power outlet first and then tubes. Hope it helps.
     
  4. seventn

    seventn Member

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    Thanks I will try that. I was planning on changing the tubes anyway...will it make a big difference? Planning on getting JJ
     
  5. stump

    stump Member

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    I would start with the preamp tubes. If your amp has the Winged "C" EL34 power tubes they should be fine. Also, you may want to check the bias on the amp and make sure that it is set at between 30 and 45 mV. My bias was 117 on one one side and 105 on the other when I bought it. Being too high or unbalaced could cause hum and/ or noise. If you retube the whole amp I would use JJ KT77s for power, they are an EL34 replacement/equivalent and probably use a JJ803s in V1, ECC81(12AT7) in V2, ECC83s in V3 and V4 if you really want to use JJ's. I'm using an NOS Mullard CV4024(12AT7) in V1, JAN GE 5751 in V2, Tungsram ECC83 in V3 and V4, and JJ KT77s in the power section. I opted for the lower gain tubes in V1 and V2 to tighten up the sound and make the tone a little more "Plexi". Call Mike at KCA and ask him what he recommends or one of the other great tube dealers on this forum.
     
  6. jezzzz2003

    jezzzz2003 Member

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    I believe there is a hum balance next to the bias control on the 2000's, cant remember which is which but it should get rid of that infernal racket.
     
  7. craggan

    craggan Member

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    hum balance control? .. WHERE??

    I have a DSL that Hums too, low level req. Changed all tubes, lowered bias, diff speaker cable, and cab .. nadda.
     
  8. craggan

    craggan Member

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    also .. the hum will just spatter and disapear sometimes ..

    then it comes back.

    Its like a bad tube, but I have retubed the thing 2-3x ..
     
  9. LesPaulMan

    LesPaulMan Member

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    I'll just add that I agree with Stump about playing around with tubes.
    I put a 12AT7 in the last preamp tube socket (phase inverter) of my DSL 50, the sound got much tighter/punchier while also cutting down on some of the hum.
     
  10. myles111

    myles111 Member

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    Check the bias and make sure it is equal for each tube.

    This is a pretty common problem.
     
  11. el34power

    el34power Member

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    I just can't beleive someone has to go threw this with a new amp....of that price:confused: :eek:
     
  12. myles111

    myles111 Member

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    Unfortunately this is a common case today with high production amps.
     

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