LSA Voyager GAN Amplifier

Just explaining ASR to folks who don’t understand what it’s all about. There’s been lots of talk here on this thread about ASR before I arrived.

Would there  be harmonic distortion from a 15khz tone that humans could hear or a band limited amp would amplify?

@djones51  No. The reason that tone is used is to look for intermodulations. Those can be quite a bit lower in frequency depending on what other tones are used in the test. How well it does with this test can say a lot about how relaxed/easy going the amp is to listen to since intermodulation distortion is very audible.

The point of the 15khz tone is to see if the amp struggles with those frequencies. As most amps have a much harder time as the frequency climbs above 1khz.

I seriously doubt any class D amp would 'struggle' with a 15KHz tone. If they are at all competent, the amp would just sit there and do it all day. 

I agree with the rest of this quote though- most amps have insufficient feedback owing to insufficient gain bandwidth product to support the feedback at higher frequencies- so the distortion often rises above 1KHz (contributing to harshness and brightness). I think this might be why distortion is often measured at only 100Hz, so as to cover up that issue. I agree that the spec sheets are mostly marketing tools because they almost never tell you any of the more meaningful information, such as you pointed out above ('...THD+N vs power vs frequency over a 20-20k bandwidth'). Such a graph would instantly show who has the gain bandwidth product and who doesn't. Heaven help us if the spec sheets actually showed something useful...

Heaven help us if the spec sheets actually showed something useful...

Hypex and Purifi offer quite a bit of performance data on their amp products, much more than most.