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
thanks,
Eddie
2 posters
Can 6GH8 plug n Play on VTA ST-120 ?
EddieGnz1- Posts : 23
Join date : 2013-10-16
GP49- Posts : 792
Join date : 2009-04-30
Location : East of the sun and west of the moon
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:
12AU7:
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:
12AU7: