If you look at Stereophile published bench measurements for Class D switching amps (say Bel Canto ref1000m for example) versus traditional class A/B (non switching amps), I think you'll see examples of what Kijanki referred to.
I would expect the switching frequency used/possible given the current state of the technology to be the technical limitation with switching amps. With current technology, effects appear to be measurable within upper limits of human hearing, ie 20Khz.
All amps have limitations. But with non-switching amps, the limitations are due to other design factors. Still, I believe many are capable of measuring flatter to well beyond 20Khz.
Of course what is measured may or may not be an indication of what is actually heard, especially when it relates to the extremes of what humans are able to hear. The upper limits of what humans can hear is probably still the weak point for Class D switching amps. How weak or how much it matters is debatable I suppose, much like what is the effects of CD redbook sampling parameters. Newer CLass D amps using newer technology might push switching frequency up higher than what was possible even just a few years ago. Have not seen measurements on those yet so not sure if the is the case (yet).
I would expect the switching frequency used/possible given the current state of the technology to be the technical limitation with switching amps. With current technology, effects appear to be measurable within upper limits of human hearing, ie 20Khz.
All amps have limitations. But with non-switching amps, the limitations are due to other design factors. Still, I believe many are capable of measuring flatter to well beyond 20Khz.
Of course what is measured may or may not be an indication of what is actually heard, especially when it relates to the extremes of what humans are able to hear. The upper limits of what humans can hear is probably still the weak point for Class D switching amps. How weak or how much it matters is debatable I suppose, much like what is the effects of CD redbook sampling parameters. Newer CLass D amps using newer technology might push switching frequency up higher than what was possible even just a few years ago. Have not seen measurements on those yet so not sure if the is the case (yet).