[AMPS] Re: Norm's Circuit

[Lamb]

Rich said:

? The equipment used at the transmitting station was never a
consideration.  Measurement of transmitted distortion was the whole
ballgame.

The question is what sort of amplifier was being measured.  Rich probably
did measure distortion but the question is of what.

Norm's amplifier was published on page 157 of the New Sideband Handbook,
published by Cowan Publishing Corp. in 1966 (6th printing) and written by
W6TNS.  The circuit was designed by Norm Roller, W6EDD.  It uses excitation
to provide screen voltage through a clamp tube.  Screen voltage on this
amplifier is  controlled by excitation.  One unique feature of this
particular amplifier is that there is a 2 mfd capacitor between the screen
grid and ground.

A 2 mfd capacitor will prevent the screen voltage from following excitation
variations and necessarily cause the circuit to fail.  It will splatter.  It
is not a G2DAF amplifier and it is contrary to his design.  This particular
amplifier is in fact a cathode driven design.  The design is so poor that I
question Norm's ability to design any linear amplifier.  Interestingly
enough, that particular design might pass a 2 tone test because the
resulting screen voltage would be allowed to be constant in that case.

73,  Colin  K7FM



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