Preamp under $2,000 used

4hannons, Thanks for response, yes I do have a hard time turning off, some things sound amazing, its broadening my listening scope of music. Cables are pretty good, Kimber speaker cables and Audioquest Columbia RCA. Yes you are correct you can also rethink or read reviews on different components and cabling and wonder, I think some things may be irrelevant once you get to a certain level of good components/ cables just a matter of opinion.

Thanks to all for feedback, Conrad Johnson sounds like a great option and a few others. I was really hoping for more feedback on Levinson since my amp is Levinson and Ayre or Parasound- solid state type preamp. Although this has perked my interest on some tubes suggestions. 
Oh and if anyone has not tried Tidal HiDef it's pretty amazing. 
Thanks! 

Initm, I’ve never owned Conrad Johnson, but heard it recently at a dealer...very rich and full sounding, but a bit too soft, I like a punchier sound with dynamics and detail. Music should be fun to listen! I currently own tube and ss pre’s. I don’t notice ss is any quieter than tube, if that’s a concern. Getting advice here on Agon is great, but only takes you so far, at some point you just have to jump in the pool. Please keep us posted on your interesting journey. 

Audible Illusions M3A.

There's a Pass Labs x2.5 that I'd think would be a significant improvement in your system and is under $1500.  I'd put this in the "you just can't go wrong with this" category given your price range and goals. 

However, since you're also open to ideas on the tube front, for $2k (or maybe less with a metal case) you can have Don Sachs build you one of his SP14 preamps.  If you call him and discuss your setup and needs he'll probably give you some good thoughts, and as a big bonus I believe you have a short trial period so little risk involved.  This is what I'd do as this could potentially get you to the "truly special" product category, so I'd encourage you to at least give Don a call (no association BTW).  Hey, it's free.  Anyway, best of luck in your quest. 

As always, with questions like this you get as many recommendations  as the number of folks responding and mostly personal favorites. I don't think you'll hear first hand experience from someone who has tried different preamps with those particular amps but I can fairly confidently tell you if you mostly listen to jazz, blues, or music with female/male vocals, you'll be impressed if you put a good quality tube preamp in front of the ML amplifiers, or any high quality SS amplifier. This is of course if you're not looking for an absolute neutral sound which most tube preamps will to deliver. If musical "truth" is important to you, a high quality SS preamp is probably a better option. Just my 2 cents.