The LTSpice results match my measurements on a similar amplifier, so I am confident that the distortion predicted for the Szekeres circuit is realistic.
So here you go. The not-quite-an-answer to the question probably few people other than myself was interested in: "Is the Szekeres amp (and the derivatives) really hi-fi, or does the source follower just pleasantly warm up the sound by adding plenty of 2nd harmonic distortion?"
It's not an answer, but at least now we have some numbers to argue over. :-D
Edited by rjm003 - 5/3/13 at 1:48am