This is legendary British tube hifi stalwart Audio Note's M2 Line Special Edition preamp, based on the 6SN7 tube and with all-tube PSU. Phenomenal sound quality and that Audio Note "rightness", this is a great way to bring some tube sweetness and tonal richness into a system - and works great with solid state power amps (I used mine with ATC Active monitors to great effect).
This unit (serial number M2-547) is an older model, approximately 13 years old, but was serviced by Audio Note in 2014 (invoice available upon request) and is in perfect working order - and sounds fantastic! It was a UK model bought second-hand in the UK, but I had it converted by Audio Note to US voltage prior to moving here in 2014, hence the service.
The 6SN7 valve is a NOS Tung-Sol (Arcturus badge) I procured worth almost $200 last year, though you can purchase stock replacements from Audio Note for not a lot (believe they use Sovtek?). I feel the Tung-Sol improved things all-round over stock.
There is some fading of the gold color on the control knobs, especially the volume (due to wear). Should be possible to order replacements from Audio Note for reasonable money (they're not the types to gouge you on incidentals).
This was by far the best preamp I'd heard in my system after many years of searching - head and shoulders better than a lot of well-regarded models, including from Manley, Bel Canto, ATC, Krell, etc etc. Indeed, it set me on the path towards my current all-Audio Note system! I'm only selling because I've simplified my pre/power/phono setup by moving to an Oto Phono integrated. :)
Pick-up much preferred from NYC area (I'm in Park Slope, Brooklyn) though I might be able to arrange some form of insured delivery at buyer's expense.