Help needed ! Traynor YBA 3 custom special

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Scoeb City, Mar 16, 2015.

  1. Scoeb City

    Scoeb City Member

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    Hey Guys on tour right now, and our bassist's Traynor Custom Special YBA-3 is having an issue basically 2 of the EL34 power tubes plates are glowing red like crazy and then the circuit breaker is shutting the amp down. originally it was one tube, and then when we installed new jjel34's two of them are glowing red on the plates.

    what would be causing this? and how could we fix it? we've got access to a soldering gun, a DMM and not much else! hah!

    please help!
     
  2. xtian

    xtian Member

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    You have to turn down the bias adjustment! That's what it's there for, to set the amount of current flowing thru the power tubes at idle. Too much current, and you get redplating.

    There are other reasons an amp might redplate, but we'll talk about that if the bias adjustment doesn't help.
     
  3. Scoeb City

    Scoeb City Member

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    thanks man! but where exactly can i adjust the bias ? looking at the amp i wasn't able to see any kind of adjustment pot?
     
  4. New Old School

    New Old School Member

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    Whoa! Those amps are one of the highest voltage amps out there. 600V!!! I would say you have a burnt resistor or two. Get it to a good tech. There is no bias pot from the factory.
     
  5. donnyjaguar

    donnyjaguar Member

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    Agreed. You can't plug'n'play output tubes on this beast.
     
  6. BassHog

    BassHog Member

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    There are lethal voltages inside that amp, do not go poking around in there unless you know exactly what you are doing. Take the amp to a tech. It either is seriously out of bias or some parts have failed on those 2 tube sockets.
     
  7. Jastacey

    Jastacey Member

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    There is a bias pot on the later YBA-3's ..... if you don't know about this amp, take it to a tech
     

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