tube amps and electrostatics

I used to own, the Acoustat 3 powered by a Conrad Johnson MV75A-1 -75 watt tube amp, no problems, beautiful sound.
I ran stacked Quad 57's with an AtmaSphere 30 watt stereo amp, beautiful sound ,no problems, also drove the same stacked pair with a 1961 Bell tube integrated(20 watts)great sound no problems.
Used to like my CLS 11Z speakers, but never found a tube amp that drove them as well as my mono Classe DR 6 amps.
Had a pair of Quad 63, that I never tried with a tube amp, but they did like the old Metner mono block power amps.
Now I am back to tubes and stats but it's the Acoustat X with it's own servo OTL tube amps.
Best combination so far of pairing a stat with tubes, but that should be as expected when each is made for the other.

Quad switched from tube amps to the current dumping solid state amps for any number of reasons.
Perhaps because tubes were felt to be obsolete, or because the newer 63 needed- demanded- more stability from an amp, or just because they wanted to, perhaps spurred on by the need to update their line.

I think,there are no rules set in stone,let common sense prevail and don't push either type of amp beyond it's limits.

I am over 50, and I know my ears like most older ears do not even hear much above 12khz or so like they used to when I was a young audio "stud".

So getting flat response that works becomes a lot easier with age. Roll off of highs with ES speakers may in fact be a non-issue for most of us old audio farts. WHose to say a lot of younger ears that listen to the same are sensitive enough for it to matter either.

Mapman, I'm not sure I get the gist of your point in relationship to the chart.

The ear sensitivity chart shows why what measures as flat
response is not heard as flat response normally, It
illustrates why what measures as flat frequency response
may be perceived as bright.

A lot of mass produced SS gear feature things like filters,
loudness controls, and other tonal adjustments that don't
really work that well as a means of addressing this. Tube
amps in some cases may be better suited by their nature to
help compensate for how our ears hear.

Atmasphere always talks about how most amps do not address
how our ears actually work, which is a valid point. He
tends to focus on brightness from odd order harmonics due to
NF in particular, but I guess I'm suggesting there is more
to it perhaps than just that.

Mapman, I would suggest to you that that reflects how the our hearing responds to a flat frequency response. The flat frequency response is a base line. Deviate from the baseline and our hearing would deviate accordingly.