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The Dynaco Tube Audio Forum

Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Tubes4hifi VTA tube amp and preamp kits and all Dynakitparts.com products


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    Bias KT88 versus 6550 WE

    Skyfrog
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    Skyfrog


    Posts : 6
    Join date : 2013-03-03
    Location : Raleigh, NC
    • Post n°1

    Bias KT88 versus 6550 WE Empty Bias KT88 versus 6550 WE

    Post by Skyfrog Sun Aug 09, 2015 7:37 am

    Hi,
    This question was probably asked before but I cannot find this topic. I obtained some Sovtek 6550WE for my M125. Is there a difference in the bias value? Shall I just replace them and re-bias at 0.60/1.20 like the KT88?
    Thanks bunches.
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    Bob Latino
    Bob Latino
    Bob Latino
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    Join date : 2008-11-26
    Location : Massachusetts
    • Post n°2

    Bias KT88 versus 6550 WE Empty Re: Bias KT88 versus 6550 WE

    Post by Bob Latino Sun Aug 09, 2015 8:28 am

    Hi,

    You would just bias a KT88 and a 6550 in your amp the same ... Just as you said > .60 VDC bias voltage per side for two output tube operation and 1.20 volts per side for four output tube operation. The recommended output tubes to use in an M-125 are 6550, KT88 and KT120. You could also use the newer TungSol KT150 BUT > I don't feel that the extra cost for these (they are about $100 a tube) is worth it ..

    Bob
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    Skyfrog
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    Skyfrog


    Posts : 6
    Join date : 2013-03-03
    Location : Raleigh, NC
    • Post n°3

    Bias KT88 versus 6550 WE Empty Re: Bias KT88 versus 6550 WE

    Post by Skyfrog Sun Aug 09, 2015 9:57 am

    Thanks Bob.
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