From: phil_a@tpg.com.au   
      
   "Alex Pogossov"   
      
   >   
   > In any case, an abrupt interruption of the plate current will cause a   
   > voltage spike on the OPT primary. The stored magnetisation energy of   
   > Lp*(Ia^2)/2 will have to be dissipated. Lp can be quite high in a decent   
   > amp. If a load is connected, then the energy will be dissipated in the   
   > load giving you a loud crack in the speaker. A residual smaller energy   
   > stored in the leakage inductance Ls*(Ia^2)/2 will most likely be safely   
   > dissipated in a snubber of say 2200pF+5K usually connected in parallel to   
   > the OPT primary.   
   >   
   > But what is the load is not connected? Then the huge magnetisation energy   
      
      
   ** Why huge ???   
      
   If Lp is say 100H and  Ia = 0.1A  then how many Joules is that ?   
      
      
      
      
   ....  Phil   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)