Whilst looking for an alternative to the 6C8-G, I looked into the history of the this tube and the 6N7 which has similar characteristics.
Comparing the two:-
6C8-G 6N7
Vp 250V 250V
-Vg 4.5V 5V
Ip 3.2mA 6mA
mu 36 35
rp 22.5k 11.3k
gm 1.6 3.1
fA 0.3A 0.8A
The 6N7 came first in 1936, mainly for making the most of battery output stages (before universal mains power)
The 6C8-G was introduced by Ken Rad in Jan 1937, it must have very similar geometry because the mu is practically identical.
The main difference is that the cathode heating is much less, which results in half the gm and double the rp.
This got me thinking that it might be possible to modify the characteristics of a 6N7 by inserting a resistance in the heater supply of the 6N7?
best
DaveP
Comparing the two:-
6C8-G 6N7
Vp 250V 250V
-Vg 4.5V 5V
Ip 3.2mA 6mA
mu 36 35
rp 22.5k 11.3k
gm 1.6 3.1
fA 0.3A 0.8A
The 6N7 came first in 1936, mainly for making the most of battery output stages (before universal mains power)
The 6C8-G was introduced by Ken Rad in Jan 1937, it must have very similar geometry because the mu is practically identical.
The main difference is that the cathode heating is much less, which results in half the gm and double the rp.
This got me thinking that it might be possible to modify the characteristics of a 6N7 by inserting a resistance in the heater supply of the 6N7?
best
DaveP
