Posted by PakProtector [ 205.188.117.72 ] on January 24, 2006 at 18:03:52:

In Reply to: Re: the Schematic posted by 2wo on January 24, 2006 at 17:36:11:

Nope...remember, this low impedance stuff is at the other end of a high impedance device. The grid resistor, or grid choke. For most power tubes, 100k is good. It is a reasonable compromise between loading and isolating.

For valves like the 1619/1624 or triodes like the 2A3, some makers suggested inductive coupling to ground. Either the secondary of an IT or a grid choke. For a pure resistive element would load the previous stage too much.

Hence Galahad, with its 10k plate load. Even a 2A3( which seems to accept over-spec grid circuit resistance values ), a 60 or 70k might be a better idea...:)
cheers,
Douglas

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