Revision of Very Best Amplifier ... 2015

[oks]

The MPSA42 and MPSA92 are not suitable for two pairs of MOSFETs and a 100mA quiescent current each. The transistors will overheat if the rail voltage and quiescent current are not drastically reduced. There are other Goldmund-based circuits, such as the GM 29 or Telos 300. These use one MPSA per MOSFET.

 

[oks]

I'm afraid if you want to use the board from post 1, you'll need more powerful drivers with heatsinks. For example, 2sa1358 and 2sc3421. MPSA and others in TO-92 won't work, in my opinion.