Quiet amps (those with a very low noise floor) reign supreme with high efficiency horn speakers. Just because an amp is
horn quiet doesn’t mean it’s a good listen. Unless there is an opportunity to A-B a particular amplifier one might assume a quiet amp,
most any Class D, is truly a good sounding amp. I owned Hypex nc400 monoblocks and Benchmark ABH2 at the same time. Both
being dead silent. There was no question (through my ears) the Benchmark was a much cleaner sounding amp, I believe the audiophile term is transparent. If you want a quiet, “transparent “ amp think Benchmark. Granted they are several times the price of many of
the above mentioned brands but hey, we’re talkin’ quiet amps, not amps based on price.
I also have several tube amps that are silent through big ol’ horns.