[Amps] Ameritron Amps

[Steve Thompson]

R L Measures wrote:

>>
>> I can see an oscillation causing very high dissipation,
> 
> 
> Push-pull parasitics, yes, push-push parasitics no.  To explain:   With 
> a push-pull parasite, the VHF energy from one tube alternately  pushes 
> energy into the other tube,and vice-versa, so both tubes have  high 
> dissipation until the operator stops transmitting.  However,  since 
> there is a load on each half-cycle, there is no wild and crazy  arcing, 
> and grid-I is not excessive. If you want to see a push-pull  parasitic, 
> short out both parasitic suppressors in a SB-220,  transmit, and with a 
> litle bit of luck you will see both anodes turn  bright red,  The 
> frequency is c. 50MHz.  .
>  However, Push-push parasitics tend to run amuck because they are  not 
> loaded.
Sounds very complicated. A bit of reactance in the load line is all 
that's needed to get dissipation up. Given that the circuit has to come 
up with 360deg of phase shift somewhere in order to oscillate, it would 
hardly be surprising if the load line was reactive.

Steve