Tube Watts vs. Solid State Watts - Any credence?

To be more specific, my tube amp has a 1040 joule power supply. In my "un-technical" way, I interpret that as "head room" because my amp presumably can handle short term power demands that exceed its rated power output of 150 wpc, subject to FR, speaker impedance and tap output impedance. Am I mixing and matching terms and concepts here??

Yes.

Its important to understand that the concept of 'dynamic headroom' and the resulting spec was entirely 100% marketing on the part of the manufacturers of inexpensive amps and recievers during the 1970s.

A worse amplifier has higher dynamic range? Worse how?

I did explain that in my prior post, here it is again: the amp has a small power supply that will not allow it to operate at full power continuously. On top of that, it would probably overheat if it did due to poor heatsinks. Further, it is biased class AB and likely exiting the A region with less than 1/2 watt output. These properties will allow the amp to put out brief spikes of power that otherwise its design does not allow in a steady state condition. The higher the headroom number (in db) the cheaper the amp.

Class D FWIW is not an exception to this rule of thumb- the best class D amps will make about the same power whether continuously or not.

"And also that amplifiers from different manufacturers using the same class D module will often have considerably different max power specs. "

I know that often different manufacturers interested in optimizing performance use customized power supply circuits to that end. Bel Canto with their M series amps is an example. Accountings I have read support the notion that the power supply used makes a big difference in class D amp performance as well, but given the nature of Class D switching technology, these can be much smaller and lighter than what is required to power comparable Class A or A/B.

I have also read of some high end Class D amp vendors using more traditional larger and heavier power supplies with their Class D amps to help assure the nth degree of performance I would assume.

Have a nice Day, Andrew.

Gee, in all this time on this thread no one has bothered to mention the most distinguishing feature of tube amps vs solid state amps. That is the lack of the irritating harmonics present in solid state amps. Not to mention the more natural and realistic presentation. So, in that sense tube Watts are actually even better than solid state Watts than if we only consider dynamic headroom.

Well, I learned something new about dynamic headroom and why it often is not a good thing when advertised even though it sounds like it is. These guys are trickier than big tobacco even!!!