I thank you all for your relies.

Good to know tube/solid-state can be used together. So then since my G-9000 has pre-amp/power amp connected/seperated switching and power amp/pre amp in/0ut jacks.........I could simply hook a tube amp of my choosing to the G-9000's "pre-amp IN/out" jacks, yes?

FWIW....the selector switch has notations for: 1 direct coupled...
2 capacitor coupled...

I've read that old Altec systems and loudspeakers in the 1940's & 1950's ........much older than my 1978 vintage model 19's.......were designed specifically with tube amplification in mind since solid state was still in the future.

Would it be fair to assume then that Altec engineers developing the model 19 system figured most users would power the speakers with modern era (for 1978) solid state amps? Not that it matters, but my G-9000 also happens to be 1978 vintage BTW.

Again, thanks very much guys!

Russ