How do I choose a phono preamp?

Technics turntables are the most simple and solid turntables. Very well made with a removable headshell that makes trying other cartridges a breeze. PS Audio Stellar Phono is fantastic. The used market should have one for $1500ish. Many great cartridges. Ortofon is solid. $5000 should get you started very nicely.

I gather from lewms comments that your speakers are excellent.

How to pick a cartridge: 

https://www.leson.org/choose-phono-cartridge/

Aside from the tonal characteristics people try to write about

I advise paying attention to 

1. IMAGING. Both WIDE channel separation (high 20’s, even low 30’s), and TIGHT channel balance (1.0 db, even 0.5db) are needed to properly present the Phantom Imaging the engineers put in the grooves.

2. TRACKING FORCE. the published imaging specs were achieved at heavier or lighter tracking force? Lighter is preferred due to:

a. stylus life, lighter will last longer

b. lp groove wear. successfully tracking lighter will be less wear.

c. anti-skate. amount of force required is related to tracking force

3. STYLUS PROFILE, see link above

4. CANTILEVER MATERIAL, see link above

With a 15K budget, I would allocate about 10-11K for table & cart, 3-5K for phono stage, 1K for cleaning records. With 10-11K for a TT (with ~8/3K split between table and cart), there are lots of options. I would figure out what kind of preferences you have:

- look: traditional DJ (Technics), something with wood (LP12-ish), more of a skeleton design Rega/VPI?

- Are you into 78s? Yes/No

- Do you want option for second tone arm, say for mono cart?

- Do you want anything automatic? Say arm return at end of record? Or fully manual?

- Any preference for direct drive (Technics) vs. belt (pretty much everything else)?

Once you have answered those questions, it will narrow down the field substantially, make it more approachable. 

The PAVCR manual method for cleaning an LP will get a Cleaning finish that can only be described a purified for much much less than $1K.

Neil does supply a per LP costing that I can't recollect, but it is ball park $00.02c per LP.

I use this cleaning method today above all options available to me. 

I expect that you will enjoy the vinyl with the Martin Logans.  Not much bass extension but listening to strings on them goes to a level hard to replicate with other types of speakers.

One of my three systems uses the CLS and I gravitate to it when I want ti listen to strings!