The imperfect amp: Pass or Ayre?

Specs don’t mean crap, it’s all in what you hear and like.

A lot of audiophiles feel that way. However as I see it specs (and measurements) can often provide a lot of value in two ways:

1) By allowing one to identify and RULE OUT from consideration candidates for purchase that would be poor matches to either the surrounding components or to the user’s requirements. An example of the latter would be how much power is needed to support desired peak volumes. Examples of the former would be incompatibilities due to impedance issues, gain and sensitivity mismatches, and various issues which can result in amplifier/speaker mismatches.

One way in which specs and measurements can sometimes serve that purpose is by providing insight into the priorities of the designer, and in doing so making it possible to identify misplaced priorities. Such as specs that may be TOO good and thus may signify undesirable design tradeoffs. A classic example of the latter would be an amplifier having unusually good Total Harmonic Distortion numbers relative to other comparable kinds of designs, which can signify heavy-handed application of feedback in the design, with the downsides that have been mentioned.

If specs are disregarded and/or are not properly understood the randomness of the process of assembling a satisfactory system, and the likelihood of expensive mistakes, are significantly increased IMO.

2) Specs and measurements are also often useful in troubleshooting problems and diagnosing sonic issues. I couldn’t begin to count the number of times I and many others have referred to John Atkinson’s measurements in Stereophile in addressing such issues in discussions here.

@Nrenter, thank you kindly for the nice words.

Regards,
-- Al

IMO THD measurements are among the most useless of specs, and I would by no means consider amps having relatively high THD numbers, compared to competitive products, to be ones that "from a technical perspective, don’t do very well" (quoting from the OP).

It’s pretty well established that while large amounts of feedback can reduce THD to very small amounts, that usually comes with two significant side-effects:

1) Increased amounts of Transient Intermodulation Distortion, which is not normally measured, and which as far as I am aware does not even have a standardized basis for measurement. That despite the fact that its significance was recognized as far back as the 1970s, when Dr. Matti Otala famously authored several papers on the subject, this being one example:

https://pdfs.semanticscholar.org/b3c0/a892a982ebde91f83f228905dac30186f827.pdf

2) Increases in some higher order odd harmonic distortion components, which occur even though Total Harmonic Distortion is reduced. As Ralph (Atmasphere) has pointed out many times, our hearing mechanisms are extraordinarily sensitive to certain higher order distortion components.

As Gregm aptly quoted above:

If something sounds good & measures well, it is good; if it sounds good and measures bad, you’re measuring the wrong thing!

I believe, btw, that was originally stated ca. 1960 by Daniel von Recklinghausen when he was the chief engineer of the original H. H. Scott company. He later worked for KLH, among other firms, and served for a while as president of the Audio Engineering Society.

Wolf_Garcia, LOL! Thanks for another example of your inimitable humor.

Regards,
-- Al