[Amps] Ameritron Amps

[Tom W8JI]

>>>>> 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.

If that is true I wonder why tubes in push-pull amplifiers 
don't blow up, why the output of a PP amp isn't zero, why a 
push-pull self excited oscillator is easily possible to 
build and why it works quite well, and many other things 
like that.

Between the push pull parasitics and the melting of glass in 
the area where there is no dielectric stress that only 
happened in Chinese tubes that would also melt at the same 
spot while only having dc, I'm almost thinking this could 
just be a fixation about parasitics.

73 Tom