Dob brings up a very important point, class D amplification has undergone an incredible evolution during the last 10 years. Recent offerings of most class D manufacturers are significantly more musically satisfying than what was available just a few years ago.
Not only designers are evolving their creations to optimize synergy with various proprietary and off-the-shelf power conversion modules, but users are progressively learning how best to integrate these emerging amplifiers into their systems.
I am starting to suspect for example, that some solid core ICs may not be appropriate with certain class D amps, and may generate audible intermodulation in complex treble passages, together with a certain unspecific thuddiness in the bass region. I will need to investigate further, but early results may suggest a possible correlation.
Besides W4S and Spectron, other non uber-expensive class D brands/series to consider are at least the current Bel canto Ref 500M and Ref 1000M monoblocks, H2O, and the Rowland 102, 201, and 501 offerings. The Rowland amps just mentioned yield their best only when fed DC through an external Rowland PC-1 power rectifier. For more elastic budgets, Chapter Audio, Rowland, Spectron, and even Levinson offer higher end class D products, ranging from $20K to over $40K.
In general, most class D amps exhibit transparency, excellent dynamics, and very good bass control on speakers with wabbly impedance. But, designers being totally human (just like audiophiles are), they make engineering and sonic decisions based on budget and personal musical preference. Therefore, class D amps sound as different as there are models on the market. . . In the end, it is worth while attempting to listen to a few different class D amps before dropping some final $$$$s.
Saluti, Guido
