05-10-2021, 03:00 PM
Hi.
The plot deepens with these valves. I used 9v to use as HT. The control grid was easy to find on the ohms range but two wires gave identical readings which initially I thought was odd. I then identified the G2 with 9v. Biasing on what I thought was the G1 gave me current flow, strapping the other wire to the G1 nearly doubled the current so I assume this is a dual control grid valve, I then found the Anode which didn't conduct too well at 9v, removing the G2 stopped anode current, the remaining wire I believe is a screen not a G3 as although a tiny change was noted on anode current its insignificant.
The filament is still visibly growing at 0.92v and 94ma current, raising the filament above 1v the efficiency lowers at the low HT volts of 9v.
I wish someone else had one these to confirm my tests.
The plot deepens with these valves. I used 9v to use as HT. The control grid was easy to find on the ohms range but two wires gave identical readings which initially I thought was odd. I then identified the G2 with 9v. Biasing on what I thought was the G1 gave me current flow, strapping the other wire to the G1 nearly doubled the current so I assume this is a dual control grid valve, I then found the Anode which didn't conduct too well at 9v, removing the G2 stopped anode current, the remaining wire I believe is a screen not a G3 as although a tiny change was noted on anode current its insignificant.
The filament is still visibly growing at 0.92v and 94ma current, raising the filament above 1v the efficiency lowers at the low HT volts of 9v.
I wish someone else had one these to confirm my tests.
