From: apogosso@tpg.com.au   
      
   ."John L Stewart"  wrote   
      
   > In a previous post John Byrnes asked why I used a resister rather than   
   > an MJE340 for the long tail in a phase splitter. The short answer is   
   > that it works & very well at that.   
   >   
   > The question has gotta be, 'why does it work so well'? For success the   
   > circuit surrounding the splitter stage needs to satisfy the relation,   
   > Rk(mu + 1) >> rp + Rl.   
      
   I would rewrite the relationship as (also ignoring "+1" after "mu"):   
      
   Rk >> (1 / Gm) + (Rl / mu)   
      
   It is more convenient as in most cases you start from Gm anyway. Also, for a   
   pentode you simply ignore the second term of the right side of the formula,   
   not bothering calculating the exact mu and Rp of the pentode, which are   
   difficult to derive from the curves. Also for a pentode Gm shall be   
   Gmplate+Gmg2, but again it is insignificant given that Rk shall be "much   
   greater".   
      
   > Some folks still like the self-inverting output stage. It is useful as a   
   > musical instrument accessory for the even order harmonics (2nd, 4th,   
   > .Etc) it generates. See one at this link-   
   >   
   > http://ax84.com/media/ax84_m276.gif   
   >   
      
   Why do you think it generates even harmonics, as usually a push-pull circuit   
   tends to cancel the even harmonics out?   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)