new GAN amplifier

You make me laugh Georgehifi. Anyone who knows my posts knows how ridiculous your statement is. Actually you are just like uber and Frank and geoffy. You take things you read, without fully understanding them, then try to apply them to all situations.

You have misapplied EPDR repeatedly in Class-D threads. You wrote those threads, not me. EPDR does not apply to Class-D. People that actually design amplifiers, test them, etc. know this. That is a big statement about your knowledge.

You also believe that AP equipment cannot test Class-D beyond a few watts. That is also not true. That is another statement about your knowledge.

EPRD isn't a term that's used in engineering circles, even if it's a more valid descriptor than than the invented term  "RMS power".

Any amplifier that relies heavily on NFB to present a low output impedance can be brought undone by a nasty capacitive load, and that includes Bruno's hypex modules, particularly when knowing that the output filter is also within the feedback loop. 

When time permits I'll hook up the sig gen and scope and run some tests to see how well the NC500's perform on a typical square wave test Vs a class AB design. 

Sorry, just a correction there @arty_vandelay it’s EPDR (Equivalent Peak Dissipation Resistance.) for those who want to know the complete title.

Here is a snippet from the measuring labs used by HiFi News and Record Review, also used I believe Absolute Sounds use as well. And Stereophile’s John Atkinson also mentions it from time to time when things get into the hairy load area.
https://ibb.co/qxjtkn7

https://www.stereophile.com/content/heavy-load-how-loudspeakers-torture-amplifiers-page-2

Cheers George

Thanks George, my bad - typo.

Typically, in "eng" speak impedance is expressed as a value with a phase angle (polar form) or real + reactive (rectangular form).

EPDR is obviously a means of expressing power dissipated in the amplifier based on instantaneous values of voltage and current at a specified frequency. In other words, a reverse engineered value.