Dynaco MK III Monobloc

Wasn't the Mk III a 35 watter; sometimes referred to as half an ST70?

They can be wired to run in triode mode, and will do 30W. In pentode mode, they are rated 60W @ <1% THD / 50W @ <.5% THD. You may be thinking of the MK II(actually rated as a 50W amp, but did 35W @ .5% THD.

That's right; thanks. That's how my cousin used them; wired in triode. He drove a pair of Quad 57'S. I still remember that beautiful midrange.