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I understand that it is an Accuphase design?
CFP topology gives indeed in general a low phase shift even at highest audible frequency.
CFP is also known to provide good sound stage...

Aside the symmetrical input stage complexity like Halcro design, the VAS and output stage are straight forward and known territory. However, good luck to find these lateral mosfet drivers...😉 R142/143 value seems quite high though...🙄 is X3/X4 transistors the complementary of upper mosfet?
Vbe multiplier seems to have R13 in the emitter (to have a more optimized temperature compensation?) but I have seen that more in the collector side of Q12 in case of vertical mosfet output .
3pf for VAS compensation appears like almost nothing...

Fab
 
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