1959HW problems

Discussion in 'Marshall Amps' started by farshad salamat, Apr 6, 2020.

  1. farshad salamat

    farshad salamat New Member

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    my amps has gone from a very loud amp into a very quiet one and the sound that's coming from the amp is distorted.

    so I'm looking to the wise people of the forums for advice and help
     
  2. South Park

    South Park Well-Known Member

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    Did you check the tubes
     
  3. ampmadscientist

    ampmadscientist Well-Known Member

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    Because the speaker is bad?
    Because the HT fuse is blown?
     
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  4. EADGBE

    EADGBE Well-Known Member

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    Yes check the tubes.
     
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  5. Matthews Guitars

    Matthews Guitars Well-Known Member

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    You should have a full set of good spare tubes. If not, WHY NOT? If you do, swap them all in and see how it goes.
     
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  6. El Gringo

    El Gringo Well-Known Member

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    I am not well versed in all aspects of the tubes , I do know it is easy to swap the pre amp tubes no problem . When it comes to power tubes that's where the bias issue comes into play and that is a foreign land for me ? Please enlighten me ?
     
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  7. neikeel

    neikeel Well-Known Member

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    Always try tubes first, pre then output, but (as mentioned) you will need to check/adjust the bias for the output tubes to work properly and safely.
    There are things to check first. For example the speaker jacks and connections, speaker cab, input jacks are clean and making good contact, similarly the output selector switch (flick it back and forth a few times).
    Then take a brand new ECC83/12AX7 or 7025 and replace each preamp tube one at a time and retest. If that does not do the trick you are going to have to go to a tech to test the output tubes (and from your description worryingly) the output transformer.
    Gives us some more info and we can help.
     
  8. Bull Rock

    Bull Rock Well-Known Member

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    Any Sound coming from speaker... Prob just a tube issue. My CR40 worked great for two weeks... Then was super quiet... Like barely audible at full blast. Put a known good 12ax7 in each slot until BAM, back to life. Probably tubes bro.
     
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  9. Bull Rock

    Bull Rock Well-Known Member

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  10. farshad salamat

    farshad salamat New Member

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    So i had a set of pre amp tubes and switched them out and nothing changed. I then did what you told checked the rest and it was all working properly, now i don't have a set of power tubes at hand. I'm waiting for those to arrive and swap them, I have had the amp for 9 years and never changed the tubes so i have never biased an amp
     
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  11. Chris-in-LA

    Chris-in-LA Well-Known Member

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    Just swap in the new power tubes and see if it works, the bias can be adjusted later. Btw, do you use an attenuator? They can go bad, try running straight into the speakers to rule out a bad attenuator.
     
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  12. Bull Rock

    Bull Rock Well-Known Member

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    Not sure what exact amp you have, but someone here or Google it may have instructions to bias your amp make and model. Just be aware there is some potential serious risk involved with the process. Don't just monkey around haphazardly in there. If you are unsure please take it to a tech.
     
    Last edited: Apr 7, 2020
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  13. Bull Rock

    Bull Rock Well-Known Member

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    Safest direct problem checker.
     
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  14. Chris-in-LA

    Chris-in-LA Well-Known Member

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    Right straight into the amp with a good cable too. Eliminate everything else and work back from there.
     
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  15. Bull Rock

    Bull Rock Well-Known Member

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    Yah!
     
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  16. farshad salamat

    farshad salamat New Member

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    Update: i just swapped out all the pre-amp tubes and power tubes. It sounded normal for like 4 seconds and then back to low volume and crossover distortion
     
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  17. Bull Rock

    Bull Rock Well-Known Member

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    I'm afraid I cannot help you man, sounds like a power issue.... but someone else will probably be along with the knowledge you need. Lots of techy guys in here. Sorry bro. Message ampmadscientist from the above post. That's a good start.
     
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  18. ampmadscientist

    ampmadscientist Well-Known Member

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    Step One
    Test Speakers
    This problem may not be an amp problem, it may be a speaker issue.

    Are you able to test the speakers?
    Do you have a 9 volt battery?

    Plug a cable into the speaker cabinet.
    Always use a real speaker cable, not a guitar lead.
    Touch the 9 volt battery to the free and of the speaker cable.
    There should be a loud POP when you touch the battery to the cable plug.

    If the sound is weak, instead of a loud POP, there could be a speaker problem.
    Touch the battery over and over to make sure that the speaker makes a loud POP every time.

     
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  19. Chris-in-LA

    Chris-in-LA Well-Known Member

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    Check your attenuator.
     
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  20. farshad salamat

    farshad salamat New Member

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