Correct, the 600-R is not an integrated amp, sorry, my bad.
Many integrated amps have pre amp outputs (line level) to connect to power amps - not sure if yours does but would be surprised if it does not.
If it does you could connect your current integrated pre amp outputs to a separate power amp (solid state, hybrid, or tube). That is what I did when I purchased my AVA hybrid Fet Valve power amp - connected my existing pre amp outputs to it.
Some people prefer solid state pre amps with hybrid or tube power amps. There is no "best" or right way as far as that goes - that is up to your brain/ears. Assuming the gear matches up properly (input/output impedances).
Last I knew AVA would allow a trial period so you could try it out to see if you like it. You would be responsible for the cost of return shipping only if you disliked the sound.
I "progressed" from my hybrid integrated; to using it as a pre amp with AVA Fet Valve hybrid amp; to replacing the integrated with an all-tube pre amp; and finally replacing the Fet Valve power amp with an all-tube power amp. Each step along the way I discovered I wanted more and more of what proper tubes can do for the sound. So much that I ended up with all tube gear.
However you go, good luck in your pursuit of audio perfection!
