I built some three years ago a mono block using soviet 6P45S tubes. These are electrically equivalent to PL519, except the heater voltage/current.
The schematic and one photo attached.
Both transformers are from Italian manufacturer inMadout(.com).
This amplifier gives some 170 W, but the max. power can be increased. Later I made a modification and added a NFET as a screen voltage supply.
With a gas tube only it was a bit too weak for higher power.
Later the max. output power was some 190 W with less than 2 % THD.