The following is excerpted from an email exchange about the K2-YJ. This particular snippet comments on the merits of current feedback from the output follower triode plate to the previous stage via R4, R5 and R14. Bob and I wondered why Bruce Seddon, who designed the K2-YJ did not simply strap R4-R5 to a portion of  R1, and avoid the large voltage drops on R4 and R5.

-Joe Sousa, Webmaster (added 8-30-8)


Hi,  Joe,

The  K2-YJ  was one of MY  favorite  amplifiers,  TOO,  but  why  the hell  did  he  take  the  positive  feedback  from  the  plate  of the output  stage   ( to sense  the output  current)    and  then  level 

change  to -260  volts?  Why  didn't  he  just  feed it  over  to a tap on the plate  resistor of the  differential  stage?  I  tried  that, and it worked  beautifully.    I modified  my  K2-YJ.  It worked OK  both ways, but  better  with my scheme.  Further,  those  level-changing 

components  could hurt the input  dc  Vos error if they drifted. 

I asked  Bruce  about a  year  ago and  never  got  any reply.  I guess he  was  going  down hill and  could not remember why he  did it.   / Sigh. / rap