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RE: To the Bored

"You hear it as sounding worse for what ever reason. But I keep saying this. The job of the amplifier is to preserve the signal with the sole exception of gain. Anything else added is distortion and therefore a defect."

The problem is: when one attempts to reduce one form of distortion another "pops up" somewhere else. The relevant question then is: which is more injurious to the music? The original distortion or new artifact introduced by quashing the original distortion? An example of this feedback. Feedback will reduce THD, but it can add new artifacts to the signal. Malcolm Hawksford in his interview with Jan Didden published in AudioXpress had this to say:

"Under large signal conditions, you have transistor slope resistances and slope capacitances which are being modulated by the signal, and that's potentially bad news. Some people call it phase modulation, going back to something Otala brought up many years ago. It's more like a gain-bandwidth modulation, and I prefer to think of it as a time-domain modulation. For instance, in a feedback amplifier, this would slightly modulate the open-loop gain-bandwidth product and you can then calculate what it does to the closed-loop phase shift. It's like a signal-dependent phase shift, which manifests itself as jitter. It is analogous to a signal-dependent jitter, and it basically happens in all analog amplifiers."

Also, THD is a bad yardstick for judging how an amplifier will sound. The harmonic "profile" is in many ways more important. Lynn Olson wrote a good article that is instructive and raises other issues that effect the sound of amplifiers that are not covered by traditional distortion measurements.

The Hawksford interview can be found here: https://linearaudio.nl/my-interviews



"It is better to remain silent and thought a fool, then speak and remove all doubt." A. Lincoln

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