Hbarrel, your very reasonable question is made complex by the experience many of us have had that none of the specifications are meaningful and consistent indicators of what an amp will actually sound like in real world listening experiences. The power output is useful ballpark information once you know the sensitivity of the speakers you plan to drive, and some specifications may tell you about a likely incompatibility (e.g., impedance at input and output). But in my experience, little to nothing in the way of specifications is a reliable indicator of what the unit will actually sound like.
For example, while it is certainly true that lower distortion is usually better than higher, an amp that has materially lower distortion achieved through the liberal application of negative feedback will most likely sound inferior to an amp with higher measured distortion but more judicious (or zero) use of negative feedback. It is also certainly true that higher slew rate capability (or "rise time", etc) can be a positive factor in achieving greater resolution and clarity, but high slew rate coupled with ringing and overshoot will sound terrible.
Over the years, I've given up looking at any specifications as indicators of good sound. If I need some indicator of what may be worthwhile auditioning, I instead consider build quality, robustness of power supply, parts quality and manufacturer's track record/reputation. Ultimately, I only care how the unit actually sounds when I listen to it and I refuse to even think about specifications as a substitute indicator of sound quality.
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For example, while it is certainly true that lower distortion is usually better than higher, an amp that has materially lower distortion achieved through the liberal application of negative feedback will most likely sound inferior to an amp with higher measured distortion but more judicious (or zero) use of negative feedback. It is also certainly true that higher slew rate capability (or "rise time", etc) can be a positive factor in achieving greater resolution and clarity, but high slew rate coupled with ringing and overshoot will sound terrible.
Over the years, I've given up looking at any specifications as indicators of good sound. If I need some indicator of what may be worthwhile auditioning, I instead consider build quality, robustness of power supply, parts quality and manufacturer's track record/reputation. Ultimately, I only care how the unit actually sounds when I listen to it and I refuse to even think about specifications as a substitute indicator of sound quality.
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