Would like to upgrade amplifier and would appreciate suggestions.

Thank you for all the replies and sorry for the late response, as I work long days out of town and now have an opportunity to answer.

First off, as I said in my original post, next year I plan on getting new speakers and yes, more efficient speakers.

I have now decided to hold off on the amplifier until I decide on a speaker, but I will more than likely be getting something in the 150 to 200 watt range as regardless of efficiency, speakers still need enough power for dynamics, and to run the lower frequencies/larger drivers with authority...especially those Moabs that millercarbon has.

I still would like to upgrade my Zesto Leto 1.5 preamp for now, as I just upgraded my Zesto Andros 1.2 to the Andros Deluxe 2 phonostage.
The next step up if I stayed with Zesto would be their flagship 'Leto Ultra 2'  but there are so few reviews out on it and @ $11,000.00 I am hesitant to buy it blindly.

I am interested in suggestions on what the best all around, best sound and reliability, tube preamp for around $10K new or used and if I decide on a different brand, I can just sell my current preamp.

Again, thank you for the previous replies.

You are not "doomed" and "limited" to expensive SS amplification that would drive your speakers wonderfully. That was the case as little as 5 years ago, as class A and A/B and tube amps were definitively superior to class D. No longer. In fact, class D is surpassing the others. 

Please read my review of the Legacy Audio i.V4 Ultra Amplifier. IGNORE ignorant people who would rant against its being class D. They have no clue about current developments.  

Has anyone told you that if you switch speakers, you will lose much of the aspects of sound quality that you may adore with your current speakers? The presentation will be fundamentally different. You are not assured to enjoy it more, or even as much. Imo, if you love your current speaker's sound, I would advise looking for an amp suitable, not taking a flier on a different speaker. Only if you are fundamentally dissatisfied would I recommend swapping speakers, or if you have an itch to go an entirely different direction. It's wide open, for sure. But, you will not be keeping the characteristics you currently have if you swap speakers. Be forewarned. You switch genres, and it's a different playing field, for better or worse! 

It is entirely possible to obtain better/preferable sound quality by keeping those speakers and moving to an amp such as I have suggested above. NO ONE can tell you that swapping to a higher efficiency speaker with lower power would be preferable. It is entirely possible that you could switch to a different, purportedly better, speaker and end up less satisfied! Be careful not to simply leap at suggestions that make it appear there is only one way to obtain superior sound. 

I have built hundreds of systems, using speakers of all sorts, and I assure you that in terms of satisfaction/preference, higher efficiency speakers do NOT always win. They often are quite difficult to set up optimally, and can be a PITA to tame. How the system is setup and the skill of the system builder is critical in which is preferred. There are many higher efficiency speakers with inherent limitations and idiosyncrasies that must be accepted, and they do NOT assure satisfaction. You will have no inherent advantage switching to that genre of speaker and amp. 

As can be seen, there are hard core fans of all sorts of speakers, amps, systems, etc. You pick your authority, you get your results.  

VTL 450 MKII used should fit you budget.

Speaker efficiency has nothing to do with the quality of sound. If you think getting a high efficient speaker is the answer you will probably end up disappointed. Those 170 watt QS amps are most likely better than some of those other amps you are looking at!

@yogiboy

Agreed... high efficient speakers usually have their own sonic peculiarities.. and..there are some that are good.

I bought my GMA speakers new 20 years ago... they have low hours, look new, but they are aged and I do want to get a new pair of speakers... and I would like to go up in efficiency.
One of the reasons for keeping my amps, is I may find after updating the speakers that they are just fine with a more efficient speaker.
Would like to get 93-96 db speaker.