Anyone has a reference system where amplification is SS ?

inna, yes indeed you will have good sound with tube amps but they cannot be left on all the time and thats where I'm coming from.

I do have a solid state Conrad Johnson preamp that does an amazing job with the midrange, especially when it is left on for several days. It makes wonder why I should bother with a tube preamp when it sounds that wonderful. But when I insert the tube preamp it sounds pretty amazing in a different way. From time to time I like to switch up preamps because it keeps things interesting.

@OP "Personally, I will never have a reference system but will always have a good sound with tube equipment and analogue source wherever possible. The core of any music is in the midrange, and if you don't get it right more or less - forget about the rest. Choice of tubes is very important too, the difference can be dramatic, as everyone knows."

That's a rather different argument to the one you started the post with?

“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.