06-21-2011, 06:31 PM
The original tube was likely a 6H6G type, sometimes also called shouldered tubes, but I suspect that they are somewhat harder to find then a 6H6 GT. The 6H6 is a dual diode with no grid cap lead to deal with, and uses a normal Philco tube shield, so you can stick whatever glass tube you like in it's place, a metal tube just looks wrong in there. If it used a Goat type form fitting shied you would want to find a 6H6 G with an ST style glass.
Regards
Arran
Regards
Arran