Have a look at the last layout for the JC-120, it shows the layout of the same PCB I think.
The JC-120 appears to be 2 lots of JC-60 amps in one box.
This is the closest I have on that amp.
The JC-120 appears to be 2 lots of JC-60 amps in one box.
This is the closest I have on that amp.