new GAN amplifier

purify look good but keep in mind those IMD measurements conducted at relatively low power and with a LPF in line.

Not just low power Arty, but "very low" power, as the testing equipment used, the Audio Precision in line external Class-D switching noise filter has a LP slope of 52db per octave, and any more than a few watts through it would burn it out a flash.
Would be very nice if you could listen to normal power music through this AP filter, as then everyone would love Class-D (even me), virtually no switching noise or phase shift in the audio band, no heat, light weight, low power and cheap, what could be better

Cheers George

I see you are parroting what someone told you about using the AP to measure a Class D amp. Funny I have tested Class D at 100’s of watts on our AP. Can’t imagine how I did that ....

I’m talking about the Audio Precision’s auxiliary AUX-Filter which goes between the Class-D and the AP Analyser, it’s a 52db per octave passive low-pass filter and can only take low power, it eliminates the Class-D’s switching noise for testing purposes only can’t be used for real music levels, even Stereophile state they can only put low power wave forms through it with it in use.

I said it years ago if you have a look in their comments, when Stereophile first started using this AP AUX switching noise filter, I complained they weren’t showing us anymore what is representative of what comes out of the speaker terminal of Class-D with this AP filter in between the Class-D’s output and the AP Distortion Analyser, especially the screen shots of the 10khz square waves.

As you can see years back Stereophile used to show with (top) and without the AP low pass filter, and it’s always used at very low power.
Today they never show the square wave "without" the filter in line (bottom), which is not representative what’s coming out of the speaker terminals.
https://ibb.co/MnK3mcm

I am going to guess I have far more experience with AP equipment and getting the most out of it than the average Stereophile writer who is a casual user. Hint that filter is optional dependent on external circuitry and amplifier performance.