Upgrading pre amp advice.

Quite the contrary.  The Upgraded BAT preamp is far from dry.  It is just musical and effortless.  All the instrument just flow with pace, rhythm, texture, timbral accuracy that I just have not found elsewhere.  The Pass Labs XO.2 was very neutral as well but it was a little veiled as if a sheer chiffon curtain was placed in front of it.  The Boulder was slightly on the analytical side and was definitely more towards what you term "Dry". Typically a tube based preamp mated with a Solid state amp gave the most appealingly accurate and musical combination.  The while the solid state preamps I have owned mated very well with the SET amps that I have owned, like the Wavac 833 and NAT Magma New to name 2.  Like I said synergy of the system is important.  At your price point and value for the dollar an VCap ODAM upgraded vk32se or vk51se would definitely be in your wheelhouse.  Remember that the most important person to listen to is "You" and your own ears.  I am just giving you insight into what I have had and what has sounded best to me.  Steve Bednarski of BAT came to visit and spent 5hours listening.  Here are his words:

"your system has the best bass I have heard - and the balance of the sound is way up there as well"

Having owned the Benchmark amp/preamp after reading all the hype about its great measured performance, I immediately found the sound engaging but after an hour fatigue set in.  It was very analytical and lacked the texture a flow that I am now look for. The Benchmark amp sounded better with the stock BAT Vk32se I had as a backup at the time than with the Benchmark preamp in my system.  Just like the Benchmark pre did better with the Stock BAT vk55se monos I had at the time. here is a list of all the amps I have personally owned.  I have also audtioned many many more.  My list of Speakers and preamps is also long just so you get an idea.

My Amps

My Amps

Adcom GFA 555
Adcom GFA 585
Accuphase A50
BAT Vk500
BAT VK6200 pair multichannel (2units) 
BAT VK 600se
BAT VK 600mse pair Mono
BAT VK 655se pair Mono Gen3
BAT Vk 655se Gen2
BAT VK 150se 2 pair Mono
BAT VK 55se mono pair
BAT Rex500 (CURRENT)
Boulder 500ae
Boulder 2060
Bryston 4B 
Bryston 28BSST mono pair
Cary SLM200 pair mono
Cary 805c pair mono
Cary 805ae pair mono
Cary 211m pair mono
Cary 1610 pair mono
Cary 300bse sig pair mono
Classe Ca 101
Classe CA 201
Classe CA 301
Classe CA 401
Classe CAV500 multichannel
Classe Omega Omicron
Classe Omega Reference Stereo 2 pair
Classe Omega Reference Mono's 5 total amps (Orig early manufacture)
Classe Omega Reference Mono pair (CURRENT, last year of manufacture)
Conrad Johnson Premier 8a 2 pair mono
Conrad Johnson Premier 11a pair Stereo
Counterpoint SA220 pair stereo
Counterpoint SA 4 OTL/OCL pair mono
Crown Power Line 2
Crown Studio Reference I 
Crown MacroTech 2400
Crown MacroTech 3600vz
Crown K1 3 Stereo/mono (2 active 1 spare CURRENT HT)
Crown K2 4 stereo/mono (2 units CURRENT)
EAD PM7300 pair multichannel (2 units)
EAD PM1000 multichannel
Emotiva XPA-9 Gen3 (CURRENT HT)
Golden Tube Audio SE40 pair stereo
Golden Tube Audio SE100
Jc Verdier 845 luxe  pair mono
Joule Electra Rites of Passage OTL pair mono
Joule Electra Destiny OTL pair mono  (CURRENT)
Kenwood L-07m pair mono
Krell KMA 100 pair mono
Krell 750mcx pair mono
Krell Chorus 7200 multichannel
Krell Evo600 pair mono
Krell Evolution One pair mono
Lexicon GX7
Melos MAT1000 3 pairs mono
McIntosh mc30
McIntosh mc302
Nakamichi PA7 pair stereo
NAT Audio Magma New pair mono
NAT Audio SE1 pair mono
Pass Labs X600
Pass Labs XA200.5
Pass Labs Aleph (4 in Active Rushmore Speakers)
Phase Linear 1000
Plinius Sa250 mkV
Plinius Sa103
Sunfire Cinema Grand Signature
Carver Silver Seven T
Carver Cube
Threshold T800D pair Stereo
VAC 140 (70/70) pair mono
Viva Verona XL pair mono
Yamaha B1 pair mono
Wavac 833 pair mono
Benchmark AHB2

Amps that I have owned!

I know you currently seek a preamp, I just have not compiled a list yet. I am sure I missed a couple.  Just trying to help with your decision.

Another recommendation for LTA MicroZOTL pre. They have home trial. You can't go wrong with this pre. 

Here is a link for a VK52se with Gen3 boards for $3500 US. You never know what he would take as an offer.The Gen3 board alone is a $1200 ad.  Those are 8 Dueland Caps.  The upgraded the six packs with Oil caps don't know which but you could still do VCap Odams later!  

https://www.usaudiomart.com/details/650276796-bat-vk52se-preamp-upgraded/

I've owned a lot of preamps at a lot of different prices. As my ear has become more fine-tuned, it has exceeded my budget. It sounds like that might be the case with you. I would suggest you look for a solid-built used preamp whose reviews describe what you're looking for. I just traded-om my ARC Ref. 3 which was a wonderful preamp, but I'm getting out of the tube business. I purchased a Pass Labs XP-30. In the reviews I read, the new XP-32 doesn't much improve on the XP-30's sound. But that was way above your budget. Pass Labs have some single box preamps (mine is three boxes, separating power supply and each channel). I'm not sure how much clarity all those boxes buy. Pass does have single-box preamps.

I would look at what Audiogon and other used sites are selling. If you look at a known company like Audio Research, you'll have to read reviews. I bought an ARC LS22 used. It sounded wonderful and seductive at first, but then I began to hear the bloated bass and brittle treble, both of which were hidden by the voluptuous mid-range.

I think you have to do a lot of research fast when you buy used. If there is a deal out there, it will go fast. You might have a few hours to figure out if it's what you want. In my experience a preamp with the attributes you listed does not sell new for $2K.

I have a Don Sachs Model 2 as well and love it. Along those lines you may want to look at his and Lynn Olsen's line Revelation, sold through the Spatial Audio website