Congratulations mapman. It's been said, if it once sounded good it still sounds good. And, with newer electronics...even sweeter.
Back in 1978, I owned DCM Time Window speakers driven by Sansui electronics. That was the best I could afford at the time. Still, I've always wondered how those Time Windows would sound with modern amplification. Maybe awful, but I still wonder. I find that speakers are the one component that keeps giving, so revealing of what they're hooked up to.
I had a similar experience as yours after I got my 300b amps and came up short with a preamp to use, since my previous amp was integrated. With reservations, I pulled out my old Boulder L3AE line stage and put it between my Tron Seven phono stage and my 300b amps. Wow, what a revelation!