Value of a preamp?

Vintage Preamps are loaded with Features that Integrated Amps typically omit:

Balance; Two MM Phono Inputs; Tape Loop; Mode Switch; Filters including Fletcher Munson 'Loudness' for Low Volume Listening; Match Gain for 3 inputs (volume stays the same as you change Inputs)

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A good tubed preamp will greatly enhance your sound period.

A good tubed preamp will greatly enhance your sound period.
 

I disagree, as there are satisfying SS preamps also such as Dartzeel, Audionet, Griffon Commander…  it depends on the execution and of course user preference 

Most important component in the chain...

I agree with most above. And yes, there are very good solid state preamps.