NOS 6SN7GTB RCA VT-231 tubes made in the U.S in 70s. Clear glass, black ribbed plates, red printing, side ring getter
Closely matched pairs and quads
The same ribbed plates like 56′ 6SN7
Also the same mica spacers, the only difference is base and getter type and position
Click to see All 6SN7 6SN7GT 12SN7 12SN7GT in stock