Help with dying amp

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Grandnoise, Jan 20, 2008.


  1. Grandnoise

    Grandnoise Member

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    So I have a (possibly) 1972 Carlsbro 60PAR, and I am having a few volume issues, when I turn it on there is barely any volume and what you can hear is very distorted, The controls all work correctly from what I can tell seeing as they are almost inaudible.

    I recently rewired the cab and sorted it all out to make sure it wasn't the problem (as it had happened before with one of my other heads and the cab) and I have checked the Ohms match.

    I am not very Tech savvy but if anyone can identify the problem from description that would be great. and BTW all the tubes light up as if they are working although one of my EL34 power tubes has gone very silver on the side, whereas the other looks clean and fine.
     
  2. pfrischmann

    pfrischmann Member

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    I'm not sure in your case but the few times I've heard a serious drop in volume and a distorted and more so a fizzy sound, it's turned out to be a blown OPT.
     
  3. Grandnoise

    Grandnoise Member

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    to replace that, its gonna cost a bit isn't it?
     
  4. pfrischmann

    pfrischmann Member

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    If that's the problem, It could be something simpler like a bad solder joint or a fried cap. I'd guess a replacement transformer, if you can get one would be like $75-$120. plus labor, if your not going to do it yourself.

    If your a DIY'er, Geral Weber has a pretty cool troubleshooting approach using a 100 watt lighbulb in series with the amplifier. Using this simple tool and his approach can help figure out which part of the amp is misbehaving. It's probably not the most scientific approach but I've used it several times with good results.

    FWIW,
    DIYing this probably won't save you a lot of money and will take more time than taking it to a tech. You'll probably learn a lot and have some fun if you are so inclined.

    FWIW and IMHO.
     
  5. PRNDL

    PRNDL Member

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    >> I recently rewired the cab and sorted it all out to make sure it wasn't the problem
    >> (as it had happened before with one of my other heads and the cab)

    Bingo!

    Amp gremlins are notoriously sneaky and their handywork is usually hidden from first, second and third view.

    Start by measuring and posting all the voltages and comparing with known values.
     
  6. Grandnoise

    Grandnoise Member

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    Well I think I'll take it to a tech as I can do basic soldering but once it goes further than basic soldering I am lost. thanks for the help guys just one last question now, anyone know an amp tech in Leeds UK
     

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