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Class A, A/B endangered species?

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Well-known member
Jun 12, 2013
Gazzip said:
...back to the OP:

I would say that A/B might have its days numbered. It was afterall developed to make pure class B work without audible distortion during the push/pull transition, which in turn enabled manufacturers to make products which could get close to pure Class A performance at a fraction of the cost/power consumption. Class D is a (kind of - I await TrevC's input) development of Class A/B which is smaller, cheaper and more efficient, so I believe it will ultimately supersede A/B...

Class A will however always have a place because:

1) It is theoretically the most linear sound possible, which will ALWAYS be sought after by the purist with deep pockets.

2) It is the audiophile snobs weapon of choice. Better or worse is irrelevant. There will always be a demand for it.
My dad's old Alba radiogram had a decidedly non-linear class A single ended valve amplifier. If only he was still alive I could have told him that it was the best possible topology according to a clueless person. Class D uses pulse width modulation that requires filtering and there is no evidence it will supercede class AB in hifi, or is in any way superior apart from a very slight energy efficiency point of view. When you consider that all Class AB amplifiers are class A at low volume there's little point in wasteful class A biasing in a hifi amp.



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