The 80 watt PA with 4 IRF510's was great, but i blew it up when i increased the supply voltage to 24V. I realized that i need to re-do the layout in a more traditional flat-looking package and watch the drive level because i suspect that i over-drove it when it blew up.
For this reason i fell back to my original plan of using only IRF510 and pushing it as hard as possible. What i have here is my final PA in the 20 M SSB project, it is one IRF510 pushing 18 watts out PEP with a 24 V power supply. It is built into a nice bud box just like all other modules in this radio.
Eventually i will build a 100 watt pa to connect to this, but for now i want to get on the air and see how the IRF510 behaves outputting this much power in class A on 20 M before i tackle the 100 watt amplifier again.