[Amps] SELL: Ameritron AL1200 Contestor's Amplifier

Tom W8JI w8ji at w8ji.com
Sun Jun 25 00:57:35 EDT 2006


<<Tom -- So why do Eimac's published constant current curves 
on the
tube begin to deviate from a straight line when the anode 
current
exceeds  2.5a peak?>>

Odd-order IM distortion is the result of a transfer function 
problem. We certainly can't tell what it is by looking at 
the curve at one plate current value. Especially if we 
consider how much negative feedback a GG amp has.  The best 
way to determine distortion is to actually measure 
distortion.

> At 1700W and 200 mA Ig, grid dissipation is about 20 
> watts.

<My guess is that it's close to 70v x 0.2a = 14w.>

Eimac's tube calculator software disagrees with that guess 
and predicts 20 watts.

73 Tom 




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