[Amps] IMD

[Joe Subich, W4TV]

Karl,

> If you look at the AL-1200 specs they claim 1200W with 3 
> tubes so no matter how anyone wants to spin it Im not doing 
> anything different at 750W with two.

The AL-1200 uses a 3CX1200A7 - not 572Bs.  The only Ameritron 
amplifier using 572Bs is the AL-572 and it specifications are 
for 1300 W output with FOUR tubes.  That's 325 watts per tube 
vs. 375 watts per tube that you claim and a gain of 12.3 dB vs.
11.7 for your "hottest" unit.  

Your gain is lower by more than .5 dB and the tubes are being 
pushed harder indicating the probability of increased IMD and 
poorer linearity.  

73, 

   ... Joe, W4TV