Tube Watts vs. Solid State Watts - Any credence?

"The amp can put out a considerably greater amount of power for relatively brief periods of time than it is rated to deliver continuously, or the amp can **not** sustain power outputs that are close to its maximum instantaneous capability for longer than relatively brief periods of time."

Al, what's the difference other than worded?

Is there an amp not capable of putting out more power cleanly for a shorter period of time? Soft clipping amps which tend to lessen the need considerably and enable fewer watts to "go further" perhaps?

In any case, one wants to avoid the extra distortion that most amps will produce when pushed hard by not having to run them too hard. I think that's a good rule to follow in all cases.

A worse amplifier has higher dynamic range? Worse how? Because it clips easier? And therefore has more gross distortion at volume? Because it has less dynamic range? Worse it has an order of magnitude higher THD than the "better" amp? I see where this is going. :-)

You educated guys now totally confused the hell out of me.
So what should I want? Class A 500 wt/ch tube amp?

One strike against Class A tube amps in particular is their very high cost, has anyone actually checked out what a good 100 Watt Class A tube amp goes for? Hel-loo! One assumes you're NOT referring to milli watt SET headphone amps, not that there's anything wrong with them as all.

Mapman, my point is that without further information one doesn't know whether to view a "good" dynamic headroom spec as the glass being half full or being half empty, so to speak.

And my perception over the years and decades is that a "good" dynamic headroom spec often (although not always) correlates with lesser quality (and less expensive) designs.

Is there an amp not capable of putting out more power cleanly for a shorter period of time?

Most well designed class A amps would be good examples, as Ralph indicated. In fact with a class A amp, as I understand it, the more power is continuously delivered to the load, the less power the amp will dissipate internally, and therefore the cooler it will run internally. Which suggests the possibility that in some cases a class A amp might even be able to deliver slightly more power continuously than briefly.

Re your last paragraph, I would certainly concur.

Best regards,
-- Al