Best Options For A Tubed Preamp - $2500 Or Less, Preferably Used To Maximize Value

+1@ghdprentice

+1 for the Audible Illusions, Modulus 3A. I see a couple over on the "other site" for $2K +/- a few bucks. Buy from a reputable dealer. GL

If you want certain sound qualities it's important to pay attention to what the tubes in the unit are. I tried a few 12au7 based preamps and was never satisfied noatter how much rolling I did. When I switched over to a don sachs model 2 that used 6sn7s a light went off. A little bit of warmth but nothing syrupy. Just a very natural sound with great detail. I loved the sachs which was based on the tubes 4 HiFi preamp which is a kit but the guy will build it for you with upgrades available such as better capacitors and such. What I ended up with was a ModWright LS100.tjey can be had used for less than 2500 and my goodness. It's a wonderful sounding preamp. 

Used Modwright LS100 . Right in your range, excellent pre. Great company

The ProJect Pre Box RS2 Digital is a balanced preamp with a selectable tube output (or solid-state if not selected) with multiple selectable filters, a headphone amp, and dual DAC (ESS Sabre Pro 9038). It has a small form factor. New it is a little more than your spending target, used, a little less.

The Schiit Freya+ is a balanced preamp with selectable tube section (giving 12dB gain) that uses 6SN7 and other octal tubes or available solid-state LISST octal modules in its tube section, It has also a buffered solid-state output section and a passive no-gain section. Its form factor is table-top, due to the tubes extending partially out of the metal housing. Price new about $900, used less, excluding LISST or tubes, which are additional.