Re: Cathode Bias PushPull

"Eeysore"
>
> I've seen it in a VOX AC30 for example. FOUR EL84s sharing a single Rk.
I
> modified it to use 2 resistors.


** What I do is double the value of Rk to 100ohms,  add  3 x 5W 4.7 volt 
zeners in series  ALL  in parallel with Rk  to limit the cathode bias 
voltage to about 14 volts.

Cools the poor,  over-heated EL84s off and increases power out by moving
the 
stage further into class AB.

Works a treat.




....  Phil