Who makes

Just one last thought. The OP doesn't ask about a speaker's phase angle characteristics. Definitely off topic.

Suffice to say that a speaker with highly negative (i.e., capacitive) phase angle and low impedance characteristics in the power spectrum (say 30 to 400 Hz ??) can really give a tube amp, even a SS amp, a bad day. That in part makes for a tough to drive speaker that calls for a "current" beast like a Bryston or Krell SS amp.

In my case, my tube amp has a large'ish power supply of 1040 joules. I surmise my amp's power supply reserve helps it to muscle its was through some pretty tough negative phase angles in the speaker's bass region.

Bruce

Cdc, I believe that Pass amps are SS amps that use very low, or no, negative feedback. Even still, as a SS amp, I would expect it to be a constant voltage source.

Shakey deal, your last comment is based on a very shaky foundation. LOL :)

I ran a high power/low current Carver m4.0t transfer function amp for years.

It did in fact work best and quite well overall with more "power paradigm" friendly speakers I owned concurrently, specifically Magnepan and Triangle. Though at 360 w/ch it went plenty loud, it left a lot to be desired especially in the bass region with others I also owned concurrently, like OHM, B&W and Dynaudio.

The way to get a conventional solid state amplifier to operate in the Power Paradigm would be to add some current feedback, but not so much that it acts like a 'current source' device.

To my knowledge, no such products exist - for now. If you want to take advantage of Power Paradigm principles, you will, for the time being, have to use a tube amplifier.