The last picture is the older project (developed for last two or three yeares). It is module amplifier (i-AMP), separate output stage and a few input stages (similar like slewmaster project at diyaudio.com).
I have made 4 or more output stages, with bipolar transitors (2,3,4 pairs) and one double bootstrapped mosfet output stage for subwoofer (whrere drivers voltage is bootstrapped from negative and positive rail, so the output is swinging nearly rail to rail, the Vgs voltage is not wasted anymore).
This is the example of THD and IMD plots for IPS board with ECC88 tube + BJT output stage (you will never find a combo like this
).
OPS wit 4 pairs
OPS with 3 pairs
Cliffjumper IPS board at work
But the main question is why ?
That is why
Before I had to build a prototype every time I have made something new, now I will have to change only 7cm x 7cm driver board.
The same I have made with SMPS, that is why I have started i-SMPS project, You are building main board which can take a universal driver boards made whatever you want. No need to solder whole SMPS again. Work is 10000% faster going this way.
So now I have i-AMP and i-SMPS projects, both are interesting but second one is more dangerous
.
Regards