Solid State or Tube Preamp mated with Tube Monos?

Just wanted your opinions on partnering "tube monoblocks with a solid state preamp" versus "tube monoblocks with a tube preamp." We currently use Wolcott Tube Monoblocks with a beautiful sounding Threshold Stasis R5 preamp; however, I just want to get a sense of the possibilities -- good and bad -- transitioning to a tube preamp mated with the Wolcott monos. Thank you.
since threshold is incredibly neutral, a change might give you a little more warmth, but only a change for the sake of change...if you like the sound save the money.
Thanks for the response Jaybo. The Threshold output impedance is less than 100 ohms; while the Wolcott input impedance is 250,000 ohms. The specs -- given some say that the input impedance on amp should be at least 10X the pre ouput impedance -- seems to mate pretty well. Moreover, the sound of the pieces together seem to approach perfection to a closer degree than other tube and solid state setups we've had. Thanks for your input.
What other preamps have you tried?
Pubul57: Going back nearly quarter of a century, I experienced the following evolution in preamps:

1. Superphon Revelation (S.S.);
2. Counterpoint SA-1000 (Hybrid);
3. Counterpoint SA-5000 (Hybrid);
4. Audible Illusions Modulus 3A (Tube);
5. Threshold Fet 10Hl (which we currently use in 2nd system);
5. Threshold Stasis R5 (in our reference system).

I would say the Thresholds and the Counterpoint were the best of the lot to experience.

I've auditioned in-depth to many preamps in and around New England, some of which were the

1. ASR Emitter w/ Battery Supply/ies;
2. McIntosh;
3. ARC Reference;
3. Krell;
4. Atma-Sphere;
5. Audio Note Kondo;
6. Conrad Johnson;
7. Atma-Sphere;
8. Meridian;
9. Cary;
10. Aesthetix;
11. Sim Audio (?);
12. Ayre (?);
13. Spectral;
14. Linn;
15. Mark Levinson;
16. VTL (?);
17. Sim Audio;
18. Jadis (?);
19. Air Tight (?);
20. Classe;
21. Halcro;
22. Boulder 2010.

There are perhaps some others over the years that I can not vividly recall.

Thanks and happy listening!

? = vaguely recall listening.
Sounds as though you have not only have searched out many options, but are for the most part, are pleased with what you have. But I understand, change for change's sake, although sometimes not listenening for several days is also a nice change and a reminder of how good your sound is when you come back to it.
That being said I'll offer up this because I owned the P220's for a couple of years and loved them. For me they excelled in inner resolution, and because of that I at ist ran my AA Capitole Mk.II cdp direct and than used a
Placette passive which was a nice improvement.
Have you tried or considered a passive?; Music First or Bent Audio or either the passive or active Placette?
Might offer a little bit more of what your system is capable.
Somut, of course I recommend tube preamps over transistor as being more musical :) but whatever you've heard in the past, keep an open mind and for best results audition the preamp at home with your gear rather than anywhere else.

Happy hunting!
Don't mess with success. If you get a chance to put some other top line pre-amps in your system for a few days, do, but only for information. If something blows you away, then buy it, but otherwise just stay informed.

SS vs. tubes makes no sense to me. In their top incarnations either is excellent.

A great SS pre-amp to try is the Jeff Rowland Research Group Capri. Look at Guidocorona's reviews and comments here on A'gon. It unseated his ARC Ref3 and another replaced a Conrad Johnson Premier. In my house, the Continuum integrated unseated my Conrad Johnson CA200. So, you see, despite it's low cost ($2700 without phono-stage and $3055 with) it's in the top echelon.

Thanks for the informative responses gentlemen. It's a privilege to be amongst a community of human beings in touch with not merely cutting-edge audio engineering but more significantly with cutting-edge science.
"Moreover, the sound of the pieces together seem to approach perfection to a closer degree than other tube and solid state setups we've had."

That's what it's all about. Be careful when you are this close. However, if you are thinking of a change, are you wanting a sharper sound or a softer sound?
At this point, I prefer to err on the side of caution and not mess with success, i.e. "Be careful when you are this close."

Like a gentleman advised me about putting on too many layers of spar varnish, "Two or three layers is fine; but, when you start putting on more than that, things are gonna start moving on you (likely for the worse) . . .."