Rectifier Plate Voltage Difference

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Red Planet, Jan 9, 2006.


  1. Red Planet

    Red Planet Member

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    Doing a littlee messing around with my Bias Rite today.

    A while back I had picked up a Sovtek 5Y3 for my SDG Vintage Tweed Proluxe (w/6L6's). The NOS Tung Sol that came with it was acting up a little and I just picked up a cheapo for the moment. The other day I picked up a NOS Sylvania from Jeff Andrews.

    Anyway I had commented to Jeff that the Sovtek Sounded like a Solid State Rectifier to me and now I think I see why. Just in going from the Sovtek to the Sylvania there was a 20 ma drop or so.

    It seems to me the New Production Sovtek is hot as a firecracker and the NOS rectifiers are much more reserved.

    Whats the reason for this? Different design? New Production?

    I had noticed the major difference in going from the Tung Sol to the Sovtek and a very similar difference between it and the Syvania.
     
  2. Red Planet

    Red Planet Member

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    60 Volt drop from what. I'm missin something here. I had a 5Y3 in it and a 5Y3 in it and a 5Y3 in it. Yes I rebiased at every change. Even stuck some 6V6's in it this afternoon.
     
  3. markdurham

    markdurham Member

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    The Sovtek 5Y3 is a russian tube that isn't an exact copy of a NOS 5Y3, and it is much stiffer than a NOS 5Y3. It will give you a higher plate voltage with the same current draw. IMO, it would be a better choice to use with 6L6's, but you may like the extra sag of the NOS 5Y3.
    markd
     
  4. KLB

    KLB Member

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    By the way, once upon a time Sovtek stuffed it's 5Y3 guts inside a tube they labeled as a 5AR4. The plate volts were too low for a 5AR4. I scored a minty JTM-45 Reissue for cheap because the seller didn't realize the problem with this tube and wondered why this particular amp sounded so weak and sagged so much (compared to a real 5AR4.) When I put in a correct 5AR4 and rebiased, the problem was solved.
     
  5. Red Planet

    Red Planet Member

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    Yeah those 5Y3's can make for some serious Sag.
     

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