Entry level tube amps?

I think any great tube amp will give you more life and texture in the midrange, that's what tubes are known for!

The best tube amps I've ever heard were from BAT and Music Reference. While you're looking to "get into" tubes, for your budget you might be able to buy a used one that will satisfy you for a good while. You might buy your first and last tube amp at once.

What is the rest of your system consist of? What are you currently using as a pre? If you are all SS, you will get more tube bang for your buck adding a tube preamp first, and then going to a tub amp.

I have CJ 16LS v2 for pre. I've always used SS power amps. I've used Theta, Proceed, Mark Levinson, and currently First Watt amp. All the gears in my system are listed in the link that says "System" next to my user id.

I like the sound of my system. The sound can be characterised as dynamic, clear, detailed, well extended to both freq extremes. The midrange is smooth, realistic, and life like. I really like the realistic harmonics of the piano, thanks to the amp from Nelson Pass.

The one thing I miss from the sound is the texture in the midrange. As I have expressed in the original post, I would like to hear more resin in the bow of cello, and reed of the sax. I'm not sure if that's all possible with the change in the power amp alone. That's why I am calling it as a trial.

That's a pretty nice system you have there. I was going to suggest that you look at new speakers, but...

I am of the opinion that source components (and speakers) make the largest change in overall sound quality, and that the improvements diminish as you get to the middle (power amp). Have you tried other CD players or transposts/DACs? I have tried a couple of universal disc players (admittedly not the Linn) and have not been satisfied. Just my $.02 worth.

The RM-9 is a very good amp, but if you don't need that much power the Music Reference RM-10 at a very solid 35 watts could be a better choice.