[nevermind]

С запасом по фазе ещё повожусь.
А ток Q15, Q16 = ~ 6,5mA в покое. Думаете, маловато?
P.S. ну нравятся мне симметричные схемы :)
Кроме того,
"There are difficulties in relying on one's own or on other listeners' ears for quality assessments in audio circuitry. However, it is possible to form opinions on the nature of circuit structures which lead to favourable audience responses, and of these the most readily defined is that of symmetry in the circuit architecture.
Of course, one must accept that true symmetry, as between NPN and PNP devices, or between those of N-channel or P-channel construction, is not really practicable, simply because of mobility of electrons and holes is so dissimilar. Nevertheless, at low frequencies, some measure of mirror-image symmetry is feasible, and this seems sometimes to be preferred by listeners when two otherwise similar circuit structures are compared.
In contemplating this observation, it is tempting to rationalize this preference as a consequence of the sensitivity of the ear to any slew-rate limiting effects, since it can be argued that in a truly symmetrical structure the inevitable stray load capacitances will be driven in both polarity directions and will, in consequence, have betters slewing characteristics than a single-ended driver system"
(с) J.L. Linsley Hood - Electronics & Wireless world, January 1985, pages 31-34.

Вот хочется самому послушать.