If anybody has the balls to do it, an 833-A SET with its grid driven by a tube headphone amp with a transformer output about 600 Ohms and the 1000 Volt B+ to the 833A's through Hammond 1642SE transformer will give you more than enough power. It is not too difficult to build and I will email schematics of how I perfected this. The Hammond transformers are good for 300 ma before the cores saturate and the 833A run at zero grid bias draws about 115 ma. I use this and it is more than enough for my speakers rated at about 85 db.
But if you want more, a GM-100 triode run at 4000 to 5000 volts can give you more if you don't mind the finned anode cap offering instant death to anyone who touches it. It was designed in Bulgaria (the same country which sells glow-in-the-dark cloth from which you can sew together a suit to wear when walking from outside sunlight into a dark movie theater to watch a movie about radiation disasters) by some knuckleheads who wanted to call the 833A a wimpy choice of vacuum tube.
But if you want more, a GM-100 triode run at 4000 to 5000 volts can give you more if you don't mind the finned anode cap offering instant death to anyone who touches it. It was designed in Bulgaria (the same country which sells glow-in-the-dark cloth from which you can sew together a suit to wear when walking from outside sunlight into a dark movie theater to watch a movie about radiation disasters) by some knuckleheads who wanted to call the 833A a wimpy choice of vacuum tube.