Re; Dynamics, Class D vs tubes…

Another OP question w/o specifics.. my answer is “depends” LO

there are many good and bad tube designs, as well as Ds..

The speakers are rated 89 db at 1 meter and are nominal 4 ohm.  The amps compared were my Conrad-Johnson 27A (class A) and Marantz PM10 (class D).  For the comparison of dynamics I used C-J ART 88 line stage, C-J ART Phono, HW-40 w/SoundSmith Hyperion, Luxman D-10X using a mix of Redbook and SACD.  Dynamics in all cases were determined by the source material.  In other words there was no difference due to which amplifier was in the circuit.  Both amps were played at both moderate (75-80 db peak) and loud (100-105 db peak) volumes.  

Bill Stevenson,  Thank for your experiment and conclusion.  

Many amplifiers, regardless of class, require some increased volume setting to properly drive certain speakers.  It is usually the interaction between an amplifier and the speakers themselves that determine if the “dynamics” at lower volume fulfill your specific desires.  Do not go down the tube vs ss, class AB vs class D thinking there is a simplistic formula that will work for your hypothetical speaker. I wish it was that simple as it would have saved a lot of time and money (but then what would have been the fun in that…)  

I have a bunch of tube amps, I'm a tube amp guy. With my Tekton Perfect Set 2-12s my best demo was with a Rogue Sphinx V3 (class D with tube front end}. It took the class D amp to get the loudspeakers thumping. Big sound, big impact.