[AMRadio] Ongoing Quest: Legal Limit AM Amp

[Rick Poole]

At 10:09 AM 1/24/2012, WB5OXQ at grandecom.net wrote:

 >>>>>
>I had a 3-500 pair amp and it did not do 375 carrier without the
>plates getting very hot even with lots of air.  My current amp with 4
>572b tubes does better on am but the power supply transformer hums
>pretty loudly on voice peaks but does not seem to overheat.
<<<<<

Good morning, James.

How's that even possible?

572B's are rated at from 120 to 160 watts dissipation each, depending 
on whom you want to believe.  Times 4 = 640 watts absolute maximum 
and in most cases, less than 500.  2x3-500 = nominally 1000 watts 
dissipation.  So how is it possible to drive 4x572B harder than 2x3-500?

Rick WA1RKT