I presume Q202 is passing a bit of current in order to require heatsinking but why?
Simon,
Q202 acts as a temperature sensor for stabilising the bias.
I guess Q205/6 just switch it off.
Not sure why I posted this Hans will tell you. Probably because I've used this as a 1W PA in my Softrocks for a good few years..
73 Alan G4ZFQ
