ลองดูคับ จาก
http://www.leonaudio.gr/4x50sch.htm Q12 should be mounted on the heatsink with Q9 and Q11.
R22,R23 are 2Watt Resistors.
For R11,R12 I used two 0.33 Ohm-2W resistors to get one 0.165 Ohm-4Watt.
I adjusted R16 so that the voltage drop on R12+R11 is 43mV with no speaker connected (and the box closed it is important).
I replaced the MJ15003/4 output transistors with toshiba 2sc5200/2sa1943.
Use BC639/640 or 2SC2240/2SA970 instead of MPSA06/56, I used these are only for the simulation.
Last modification I added a transistor between input stage and voltage gain stage Q13 (See Douglas Self site for theory).
