I have to preface by saying that model 19's are NOT my be all end all loudspeaker of choice.

However, after spending some time listening to my media thru my front end gear on his Firstwatt F5 powered 19's, my love affair with the Thermionic Valve(vacuum tube for the novices) came to an abrupt end, and i don't miss chasing my tail in that arena at all. Nelson Pass has implemented some "magic" in some of his circuit designs.

I love my Crown DC300A behind my A7-500s.
Solid state? Yes.

Class A? No.

Don't get me wrong, DC300 is a "Solid" amp and among vintage class AB amps is pretty good sounding, ultra dependable, and built like military hardware.

But, i think the OP was referring specifically to "Class A" amplification, the 100+ lb space heater kind generally.