My old Welbourne Laurels produced ~8W stock. Cy Brenneman added a fixed bias and some other little mods and he tells me he cut the distortion in half while raising the output to 11W. I run these with Western Electric 300Bs.
They make plenty of power for my speakers which put out ~110db 1w/1m. The Cogent field coil drivers are pretty much unobtanium now though. The set up is not complete yet: custom mounting racks are in progress and there is some minor tweaking to the network still.
System overview:
Rendering of the racks in progress:
Racks welded up:
Pink noise at the listening position, no smoothing:
The wooden area around and behind the mains are the visible portions of the built in 30Hz bass horns that run on different amps with a passive line level 2nd order 65Hz low pass. Here is one of the mouths as the loft was nearing completion:
