[Amps] SB220 Improvements

[Vic Rosenthal]

2 wrote:

> **  An early 2, 3-500Z circuit from Eimac's Bill Orr used chokes/caps on
> the grids.  Heath, Drake and Kenwood copied the idea.  However, I have
> yet to read an account of Bill Orr's reasoning behind the idea. 

Didn't the 30L1 do this as well?  Maybe they all copied Collins.  As I
understand it, the caps are series resonant with the grid lead inductance at
some frequency, and -- at least at that frequency -- move the grid potential
closer to ground, improving stability (again, only at one frequency).  The
chokes are there to provide a DC path, of course.

73
Vic K2VCO