Anyone has a reference system where amplification is SS ?

“Reference system” will only exist the day there is a system that can not be changed improved upon. State of the art playback is subject to personal preferences. If one seeks accuracy then solid state gives us state of the art in accuracy. If one seeks euphonic colorations then one can use tube gear or better yet tube simulation DSP. With tube simulation DSP one can have the bed of both worlds with an unprecedented level of control. 

phd, I don't think tube equipment should be left on all the time to sound best and I didn't read anyone say it here. I do remember someone said some years ago that a particular Lamm preamp had to be left on for a few days to sound its best.

Switching preamps is fun indeed, as is tube rolling.

And that's another advantage of tube electronics. Can you do transistor rolling ?

Can you do transistor rolling ?

@inna

some solid state allows for adjustment of negative feedback. the darts have zero negative feedback, and that matters a lot in it’s musical flow and lack of grain and lack of solid state dryness.

tube rolling has an upside, and also a degree of confusion as to what is correct, and the uneasy feeling never knowing when something is going to blow.....and not knowing if something is going 'off'. tubes are always changing to some degree.

“nd that's another advantage of tube electronics. Can you do transistor rolling ?”

No. but with tube simulation DSP you can do a lot more than just tube rolling