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I started into high end audio when I was a working scientist. I quickly learned to just check the top few variables and then ignore the specs for choosing components.. They can tell you a bit about the component... like the power... but there are so many not measured that you just can’t really assess the sound and compatibility with them. Even as someone that loves data, charts, and relationships... I don’t look at them. To me, a waste of my time. Some people really like them... but at best they can only be the very faintest of indicator.
You have to listen to them yourself and read professional reviews of the same units. This way you calibrate yourself to the generally accepted characteristics in sound and terminology, learn what the unit sounds like to you, and also realize what sound characteristics you like and want.
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All reviews are of systems. So within all reviews are information about the system and its components. Usually a reviewer reviewing a preamp will use several amps to check for compatibility... and document the differences. There are lots of high level generalities... but they are just that... generalities and any unit can be vary different. Over many years and decades if you work hard and are good with unstructured problems you will develop the ability to read reviews and know “house sounds” well enough to put together the system you want.
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This is a great challenge and pleasure to some, something one can be fascinated for a lifetime and reap great rewards. Or it can be incredibly frustrating if you are not good at it. If you are the latter, then you either throw up your hands and say it’s all bs or you go to showrooms, listen to systems and have someone piece together something you like. I have an incredible system that brings incredible enjoyment to me that I have built over fifty years. My best friend has a $30K system that sounds absolutely terrible.. he was a scientist as well he would read reviews and choose award winning components and when he put them together the sounded absolutely terrible. His system has sat there untouched for ten years.