The address of the web site with the plots of the Swedish DAF circuit is:
http://home3.swipnet.se/~w-30548/g2daf
Tom said:
"I would think real "experimentation" would be building a clean
amplifier that is properly engineered or even learning how a PA
works, instead of trying to drive a tetrode tube with zero grid bias
and apply screen voltage through a voltage multiplier from the RF
source.
If someone can demonstrate why this is a preferred and reliable
way to produce a clean state-of-the-art SSB amplifier, and
demonstrate why it is good engineering, I'll be all for the DAF."
We can sometimes learn by building and analyzing things that do not work.
Long before we had successful rockets, we had failures. But, by building
failures and analyzing them, we learned how to be successful. I submit that
copying other designs that work is less likely to bring about knowledge of
creative new ideas than working with ideas that do not work. Indeed, most
things that work began life not working.
You may be missing the point. I do not know that anyone has said that the
DAF circuit is preferred or reliable. Certainly not me. My point was that
is unique and may have been condemned because those that duplicated it did
not bother to understand the circuit.
If acceptable distortion is set a -30 db under actual speech conditions, and
the G2DAF circuit does meet those specifications as originally designed I do
not claim that it proves anything.
If the circuit works, it will tell me that at least a few hams who have said
it cannot work should not be trusted on their other proclamations.
If nothing else, we finally have Rich and Tom on the same side of an issue!
That, alone, is progress.
73, Colin K7FM
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