Who makes

Bifwynne, thanks. I was just going by what I was reading atmasphere.
I think Al hit on one company, Pass Labs, that made the solid state amp act like a current driven amp. And The Carver amp that Bob mentioned looks interesting too.

12-02-13: Bifwynne
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.

That is another good point. Is the current output more important than the voltage as that is what gives the speaker its dynamic range? What is voltage good for? It seems like a cheap way make the amp appear to be powerful when reading the specs.
Thanks all. I will have to give this some thought. Previously, I had the simplified idea that if a speaker is over 8 ohm, and especially 16 ohm like those back in the 60's, you need tubes because you just won't get any power out of a reasonable sized ss amp.

The Zamp puts out 12 amperes at 45 watts. It still seems to me that current capacity, along with slew rate, would increase dynamic headroom before clipping. Because 12 amps x 120 volts = 1,440 watts, not 45 watts.
Atmasphere makes a convincing argument for tubes and I can see how his amps could better a ss amp in the right setup. What I don't get is do you want the power of a tube amp at the impedance peak to lower the FR or the reduced power of a ss amp to control resonances? Is this where the whole voltage / power paradigm relates to which is better for which speaker? Because for the rest of the frequency range, this would not matter. Other than nominal speaker impedance.
Is it easier to make a ss amp that can drive a 2 ohm load than a tube amp?
A vented speaker benefits from the control of a ss amp? Would a sealed box benefit from the deeper extension of a tube amp as there is no impedance peak from a vented port? Just that of the driver itself.

So if we have a one ohm load, to do 45 watts the current will be the square root of 45, or 6.07 amps.

Thanks Atmasphere. I think you are talking about speaker impedance and how it requires a certain amount of power to drive it? But what about musical dynamic peaks? That's what I'm, mistakenly(?) trying to get at. If you play a song at 90 dB with 110dB musical peaks like rim shots, don't you need the current to give that dynamic range for the 10 milliseconds?

the power supply of the amplifier is shorted out for 10 milliseconds. FWIW, we make tube amps with greater amounts of current by *that* measure...

So tube amps have more current on tap than ss?