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I need help biasing Ampeg reverborocket r12r reissue.

Discussion in 'Amp Tech Center' started by buckwalder, Nov 14, 2015.

  1. buckwalder

    buckwalder Tele-Meister

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    This is one of the blue diamond series reissues made between 1996-2006 the first of the series were shipped with el34s the later models had 6l6 power tubes. I have the 6l6 version.

    I have watched youtube videos of how to bias amps and it seems the Fender hotrod series is the closest I can find to this amp. My amp does not have a test point for a multimeter like the fender does.

    From the limited info I can find on the ampeg, I found that the test points are R-30 and R-40 these are two tiny resistors right next to each other.

    Do I test those two resistors one at a time or do I need to get the test probe across the legs of both resistors at the same time?

    This amp does have the tiny blue bias adjustment pot.

    The reason for the question is because I just replaced all tubes in the amp. After turning on the amp with the new tubes I noticed the power tubes had a brighter orange glow ( above and below) the plate than the old tubes. The tubes are Mesa Boogie branded 6l6 STR 440 GRN single getter. The old tubes are J J red label 6l6GC double getter. Thanks ahead
     
  2. ThermionicScott

    ThermionicScott Poster Extraordinaire

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    Sounds like you're just seeing more of the heater glow. That's nothing to be worried about -- it's when the plates themselves are glowing red or orange that you need to be concerned.
     
  3. BobbyZ

    BobbyZ Doctor of Teleocity

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    Yeah heaters glow brighter in some tubes.

    Do you have link for the schmatic ? Tried Google but there's a few to choose from. Including the original which has almost nothing in common with the reissues.
     
  4. buckwalder

    buckwalder Tele-Meister

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    If its just a case of some tubes having a brighter heater glow then, that is a relief. When I put the new tubes is the amp and played it briefly the tone was glorious, the angels sang ect.

    I just want to make sure I'm not running the tubes too hot. Trust me some of the best tones I have ever heard were from amps that where running with red plated tubes. Trouble is, that tone is short lived unless you want to lay out the cash for a Dumble.
     
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