Phono Stage - The great analog tragedy

While what you wrote, and what I am about to write, has absolutely nothing to do with the "topic", such as it is a topic, I will add that I too have found that upgrading the capacitors used in the RC type RIAA network makes a tremendous difference, BUT one must be certain to use exactly the same values of C as was used by the designer, else the RIAA will be inaccurate. (Even high quality capacitors are only specified to be within a few percent of the marked value; you have to measure each one individually to reproduce the curve.) This really means you need an accurate capacitance meter first to read the values used in the original, and then you need the meter to select from among the replacement capacitors, to find exact values. It's very worthwhile if you have the patience. And of course, PS upgrades almost always help if done right.

(I kind of wonder how you got away with air capacitors since I understand that they can be unstable in value due to humidity, etc.)

In my phonostage are only two small air capacitors 330pf and 110pf are important for RIAA equalization accuracy. All other - interstage, output, cathode filament PS and B+ PS capacitors values are not important in this schematics.

I setted up RIAA air capacitors with capacitor meter. But I don't take into account air humidity. Air capacitor advantage: the dielectric is not sensitive to polarity changes.

Air capacitor advantage: the dielectric is not sensitive to polarity changes.

Neither is mylar, polypropylene, polystyrene or Teflon. 

Or ceramic 

@jasonbourne71 The "reference standard" in High End is the same as it has always been: its resemblance to live music as heard in the concert hall. UNAMPLIFIED. It’s not as though that hasn’t always been the standard for, say, TAS. Can’t speak to Stereophile or the other mags, as they rarely referred to the live experience. 

So, for those of us who play instruments, whichever component renders instruments and vocalists the way they sound in real life is "the best." And that includes dynamics.  Knowing how an instrument sounds (specific brands, too) makes it easier. Unfortunately, many people have never had a music class in their lives, or had to take it in school, so their choices will be based on something other than "live" experiences.

And phonostages are not that hard to identify if someone is familiar with music. The Vendetta, so often referred to in here, had a distinct sound and not for an instant sounded like the phonostage of the Convergent or the Modulus or the Jadis. Their differences were all audible, especially with the Convergent, which had very little sound of its own (except in the midbass).