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    Can 6GH8 plug n Play on VTA ST-120 ?

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    EddieGnz1

    Posts : 23
    Join date : 2013-10-16

     Can  6GH8  plug n Play on VTA ST-120 ? Empty Can 6GH8 plug n Play on VTA ST-120 ?

    Post by EddieGnz1 on Tue May 27, 2014 5:22 pm

    I found a way to buy a 6GH8 that someone was using on their ST-70. Will it work as the center tube on the ST-120 driver board ?

    thanks,
    Eddie
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    GP49

    Posts : 791
    Join date : 2009-04-30
    Location : East of the sun and west of the moon

     Can  6GH8  plug n Play on VTA ST-120 ? Empty Re: Can 6GH8 plug n Play on VTA ST-120 ?

    Post by GP49 on Tue May 27, 2014 6:33 pm

    No, you can not do that.  

    Not only do the pinouts differ; the tubes are of two different types.  

    The center tube of the ST-120 is a twin triode, nominally a 12AU7.  The 6GH8A is a pentode-triode.

    "Someone" was probably using the 6GH8 to replace the 7199 pentode-triode in a STOCK Dynaco Stereo 70 (a wiring change is required, the 7199 has yet another different pinout) but that amp has a totally different driver/inverter circuit from that in the ST-120.

    6GH8:

     Can  6GH8  plug n Play on VTA ST-120 ? 9ae

    12AU7:

     Can  6GH8  plug n Play on VTA ST-120 ? 9a

      Current date/time is Fri Sep 20, 2019 12:19 pm