The Dynaco Tube Audio Forum

Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Dynaco VTA tube amp kits, all products and all products

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



    Posts : 23
    Join date : 2013-10-16

    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 ?



    Posts : 722
    Join date : 2009-04-30
    Location : East of the sun and west of the moon

    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.



      Current date/time is Fri Oct 21, 2016 4:54 pm