@cfarrow @decooney, I agree with your recommendation. I use a pair of JL Audio subs with my 45, 2a3 and 300b amps in the past and didn’t miss a beat. I typically favor sealed enclosures and felt the JL’s had the speed and bass tightness to open up the soundstage and give me all the lower bass I needed.
What I like most about quality subs paired with a nice tube amp setup paired with reasonably matched main speakers - I don’t find myself hunting different audio tracks. Sealed or ported, or plug the ports when needed. Look at the high-end audio shows and what they use too.
My tube monblocks are 100wpc or 120wpc depending on which output tubes are used, and produce plenty of power, and yet if we want low end reinforcement at low volume levels, nice and accurate little sub(s) can sure make the entire tube amp or SS experience even better.
I turn my dual subs off once in a while to hear the mains, and sure its good, yet end up turning them back on eventually. :)