name of the game was to create SIT amp for Greedy Boyz Hordes ......
naah, I don't care for Hordes, I have all the fun
logical thing would be to put emulated SIT in same position as in DEFiSIT/SissySIT, which is positive rail; from some reasons I tried in simulations to put it down (lower rail), then realized that that approach is resulting in difficulties - choice of small P channel mosfets for Source follower/level shifter, having low threshold Ugs is much smaller than counterparts in N polarity
however, me being stubborn as I am, stayed with P channel .......
SF Ugs is important, beacuse it is additive to feed point of Schaded mosfet, which in this case we have as -3V8 (ref to output) , then Ugs of TP2640, so resulting biasing voltage at TP2640 gate is around -5V4, ref to output
in same time , Ugs of upper mosfet is +4V42, which means that resistances from rails to adjacent gates are still pretty symmetrical
one of interesting things - of all lately seen amps, only this one is having same current distribution of output parts as real DEFiSIT is having - up to clipping point of more active part, parts are working in antiphase , fighting each other..... and only at and after clipping, lesser acting part ( one with lesser xconductance) is helping other one
see attached - graph from sim, but confirmed in vivo....... though, easier to post this than capturing scope screen ..... counting on fact that I have a scope from Lee De Forest time, but before triode invention
sim shown from output sine of around 20Vpp @ 8R load
biggest sine - upper mosfet current
smaller sine - current through load
smallest sine - Schaded mosfet current