Class A is fun and all but it's needless environmental terrorism especially at speaker level power outputs.
I made a lovely valve headphone amplifier with 0.006% efficiency (1mW audio out, 15 watts of power in). Kinda stupid really.
I'm going to re-use the valves from that amplifier in a Class AB amp for my turntable. The tube in a "starved anode" mode is a low voltage circuit and produces some of the fun distortions at higher volumes. There's no reason why you can't follow that with an accurate AB push-pull or even Class-D (sacrilege!) power amp.