10W Class AB with parallel transistors - Qualified Success

I began some detailed measurements. In particular, I was interested at where the onset of distortion began. 

I started collecting data to build a chart on output power v input power. When I started measuring at higher output levels I found the buffer amplifier was in fact distorting above 1W of input power. Not surprising given it was designed to deliver 1W but something I hadn't considered till now.

But this means the first transistor I started measuring is probably not going to be the best transistor given the gain is lower than I wanted.

 

 

I call this a qualified success because I have a very robust and stable amplifier that delivers 10W, albeit distorted, and a maximum observed output of 14W with US$0.50 worth of transistors is outstanding.
At 5W it probably ticks all the boxes.

When time permits I'll test the second board I already have populated with a different transistor.

73's