Originally Posted by edster922
Passive output filters...hm, not sure I even know what that is but your statement seems to imply that there is such a thing as ACTIVE output filters?
In terms of internal parts, what in your opinion would a more audiophile-oriented digital Panny look like? Just curious.
The comparison is between analog amplifers such as class A or B which have no requirement for any output filter (although there is typically some passive components to ensure stability) and class D which has to remove the switching frequency from the output, that being 384KHz or 352.8KHz (44.1K CD) for the XR-55. TI recommends an LC filter at the output, and their data sheets give examples.
Analog amplifiers - no output filter
Class D amplifiers - passive output filter
The thing about the Texas Instrument class D implementation on which the XR-nn series is based is that it is highly integrated and there is only so much you can do external to the chipset. The biggest problem for me is that 100W into 6 ohms is not enough power for my large room. Real improvements will come from newer generations of the chipsets. I linked to an article in Electronic Design in another thread that mentioned some specs for the next generation TI chipsets e.g. 0.004% THD+N full power, a monolithic 240W into 4 ohm design, ... The future looks very good for TI class D.