What qualities stand out in really good solid state preamps?

Music is thinking rythms dreaming a melody.

Any system well embedded and well chosen , with or without preamplification, will give you that.

The only rules are synergetical choices coupled with acoustics...

Each one of us differ by his needs and by his specific constraining conditions.

Marketers want to convince you that a specific  piece of gear is the solution by itself...It is not even wrong but beside the point ...

Many thought that sound exist or the aspects of sound exist as "neutrality" by itself in an absolute way which is all measurable in some objective way for some or separately all evaluated in some subjective way only . But sound perception is an inseparable objective, subjective and intersubjective and historical conditioned dynamic process.Not a mere state.not an isolated factor.

Then the material conditions as difference between two preamplifier be it two tubes one or two S.S. one will be also part of all the material factors at play...

Sound is like perfume blend , it result from an objective recipe determined by acoustic or chemical  and physical materials parameters and subjective impressions and intersubjective impressions but also statistical studies in acoustics or in perfume industry ...

Sound is as sensual and visceral as odor perception in his intimate revelations(human voice timbre meanings) and as abstract and as concrete as visual conditions in their general and universal display (spatial properties of sound and spatial geometry of sound as in echolocalization ).

«The ears are like two noses who had learned together not only to smell the inside but how to see the outside »-- Groucho Marx studies in kitchen acoustic 🤓

«The nose knows in a primal way what the eyes only believes but which the ears can understand»-- Groucho Marx neurology studies 🤓

«The ears think» -- Groucho Marx studies in the womb 🤓

« Then why did the ears do need so much a mouth? »-- Harpo Marx 🎼

«Because silence is already a music in need of a sound»-- Groucho Marx

«Right the dancing body is not enough I need my harp to think and speak »--Harpo Marx 🎼

Great post!

Especially true if we refer to gear pieces to define and learn about any concept instead of acoustics as a reference, the way we create ourself "neutrality" in a system room teach much more than using a new piece of gear...

Then for reason relating to the characteristics of our system parts /room and specific synergy what we look for will differ for each of us. For example i was looking for a more "organic" synergy , then i pick up tubes preamplification to couple it with my dryer active speakers.... Luckily it was a match in heaven....But the same preamplifier may appear as "trash" for another person needs, and system/room characteristics and level ....There is no rule  in brand name choices preamplification  for a synergy... Electrical specs compatibility but it is not enought to create synergy which ultimately is an acoustic experience...

Growing up where only English is taught/spoken and moving to/working where several languages are taught/spoken (and where English is a second language), it became clear the inevitable pitfall of trying to tie down meanings among people for audio kit adjectives that have been adapted from other senses (at the most proximal) or completely unrelated contexts. This seems a very fast-moving target be it for preamps or something else.

But admittedly, the notion of potentially feeding a SS preamp to a tube power amp had me curious just for how unconventional it is!

Neutrality is an acoustics concept BEFORE being used in gear design...

The sound experience is an acoustics experience first and last....

There is too much variations in price levels and needs and synergetical variations to define a rule valuable for all systems,speaking about preamplifications...

People as usual gave their take on the branded named preamplification of choice... Why not ?

But it will be acoustics knowledge ( not only room acoustic) that will matter as much as gear synergy if you have a budget...