Way back in 1997 when I restarted PS Audio, it was to address a problem that had really bothered me for quite some time. Being robbed of harmonic richness—the overtones of music you didn't know were missing until they were returned.
In those early days the thieves were passive power conditioners that bleached music into a pale shadow of its former self in a most insidious way. If you weren't paying attention, you'd never know they were missing. Kind of like a pickpocket lifting your wallet—you happily go about your business until it comes time to pay the bill.
Class D amplifier output stages are generally not much different. On first listen some manage to sound surprisingly good for short periods of time, but compared directly with a full bodied amplifier, like the BHK, even the best among them are exposed as threadbare.
Over the years we too have been lulled into their promise, only to be left wanting that which is missing and forever lost.
Take the top ten contenders of class D platforms and perform blind listening tests on them. It won't take long before you've thrown 3/4 of the lot out as screechy and confused by complex musical passages. The balance have mitigated some of those problems and are candidates for further work, though none remind us too much of music over long term listening on a highly resolving system.
It turns out there are a few tricks to be applied to this small handful of contenders that turns them from sonic ruffians into at least tamed neutrality (though their new persona is about as exciting as that of a bank teller).
Having a neutral platform as a starting point for a design isn't a half bad place to be.
More tomorrow.
