Class D AMPLIFICATION: Saviour or what?

Is Class D amplification the silver bullet for the next generation?

We asked Paul McGowan of PS Audio. Here's what he says:

One of the notions alive and well with many in the high-end community is the idea that a class D power amplifier will cause listener fatigue over time; and that same notion seems to apply to many digital audio products as well.

In my experience these biases are all based in fact, at least at one time in their evolution, but tend to become part of our culture and then rarely ever go away.  This is a problem for many of us in the industry because we have to battle those biases on a daily basis.  I am sure you’re familiar with many of the biases I am referring to.

Silver wire sounds bright.  Tubes are wooly and soft in the bass.  CD’s sound bright.  Solid state is cold and overly analytical.  Ported woofers make “farting” sounds.  Sealed box woofers can’t go as low as ported ones.  Tubes are always warmer.  DSD recordings always sound better than standard CD’s.  Gross generalizations that have all been true at one time or another – yet they stick with us and become part of our “facts” that we cling to and never question – even if they are no longer true.

As I mentioned a few days ago, there’s no question that early CD’s sounded bad – but that doesn’t mean modern CD’s have to carry that stigma forever.  It’s also true that early solid state equipment sounded overly analytical and sterile, yet today we can make a solid state design sound overly lush or, for that matter, any way we wish.  And the early class D power amplifiers did fatigue the listener but so much progress has been made that it’s time to pull ourselves out of biases of the past and try and update our thoughts.

Tomorrow I will begin to explain why older class D amplifier designs sounded the way they did, how those generalizations came into being, and why some designs still deserve the unenviable reputation of being hard and bright.

We will then explore what’s being done today and what the current state of the art is.

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