F6 Amplifier

So far, the balanced F5 sounds better to my ears.

This is what really matters.

I am looking forward to your impressions.

FWIW,
I grew up listening to all types of guitars and guitar amps. I got really use to the wonderful tone that you get from a personal listening session of a Gretsch and a Silveton with dual 12" alnico drivers. Dad just fired it up a couple of weeks after i went through it and replaced the tubes and some old caps and resitors. He fired it up and played a couple chords and I was just blown away with the sound. Yet to reproduce that sound with a loudspeaker, but then again, it only has to reproduce the sound of one instrument. ZM was joking about tone switch, but that pretty much describes where i came from. Perhaps you could say "colored sound", dunno. Read M2 review at 6 moons and I think you get an idea of what i think is going between F6 and F5. F5t kicks F5 but, IMO. Dunno why:D
 
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You assume the sweet spot is equivalent with lowest distortion.
Not lowest distortion; but device matching; compare SuSy which must have highly matched devices to attain high symmetry. Loop feedback in Mr. Pass's F6 is to lower output Z primarily and secondarily % THD. His F6 is almost perfect before he applies loop feedback. One of his early posts [#14] said:

The transformer secondaries are set up to drive the Fets in a matched fashion, if that is what you're asking.

I understood the wording matched in his statement above to mean got to go the distance and match everything else; otherwise settle for a mishmash of mismatches; and this is not his practice? Besides, the writeup of the old classic in post #38 stressed using matched bjt output devices.
 
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