I am looking at the PP version of the single valve spud amp. Perhaps with a small 10k a-a. Or perhaps teh Z565's I have on my shelf. Do the valve stage as a common cathode diff amp with a CCS as the cathode load. 25:1 turns ratio if I run from the 16R tap( and a 10k A-a ). I figure I'll need soome fraction of a volt, perhaps a whole volt RMS output. More like a half I suspect...

So, a pair of 12A4, the 12B4 with mu=20 and I'll have less than unity gain to the output. the active linestage will be able to feed it noooo problem. It will be absolutely class A, and might even work with 12B4's. Either will plug right in, the CCS will set the op point.

Seems like nothing I have seen to date anyway...
regards,
Douglas