I am building one of those Chinese aplifiers, but in mine I replaced the IRF530s by an MRF9120 (already had it). It does work, but:
- the input power has to be below 5W (or even less), so an attenuator might be needed
- the amplifier has no output filter whatsoever; I bought another Chinese LPF board for it
- it doesn't put out 100W, unless with 16-20V. The best I got is 45W, which was good enough for me.
Note that you will also have to derive a T/R signal from the uBitx, either from the PTT key itself or, as I am planning, from the TX power line.
73 de PU1OWL Rafael