EDIT: I put a bypass capacitor across the battery. The set was a little unstable with my bench power supply. It was better with a battery. The capacitor settled it down with the bench supply. It could be the supply reacting to load? It is voltage and current protected?
When I get back to work on the 40/80 this may be my AF amp. I put a small telephone receiver (145 ohm speaker) on it and it was load enough for easy chair listening.
EDIT: This amp will work with a single rechargeable cell. (1.2Volts)