[AMRadio] AM Transmitter Advice??


Donald Chester k4kyv at hotmail.com
Sat Feb 18 17:10:28 EST 2006


>From: "Brian Carling" <bcarling at cfl.rr.com>

>Hey - mount those 6AG7s upside down in cooling oil and you
>can run 500 watts to 'em.  I wouldn't try it but I am sure
>SOMEONE has, LOL!

My very first plate-modulated AM rig back in 1959 used a single 6AQ5 to 
drive a pair of 807's as class-B triodes with screen and control grids tied 
together with 20k resistors, and negative feedback round the 6AQ5.  It would 
work for a few minutes, and then distortion would start to creep up.  I 
finally figured out that the 6AQ5 was overheating and the distortion was due 
to thermal runaway.  I turned the driver stage, which was haywired on a 
separate little chassis, upside down and let the 6AQ5 rest in a jar of 
water.  That kept it just cool enough to keep away the distortion.  But I 
would, on the average, overturn the jar of water at least once every time I 
tried to use that lashup.

Don K4KYV


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