Best Full-Function Preamplifier

Essential, Accuphase, Atmashpere, all good choices, great choices actually. 

I would advise you to look at the Supratek web site. I have what some would consider pretty close to a reference rig and use a Supratek preamp. 

My unit is technically a Chardonnay, having wanted a 6SN7 unit. I did however request  upgrading all the essential parts to max it out. Added about 1K to the stock price. Had it built specifically match a pair of Audiopax M 100s and due to the low 18db gain of the amps, and the high input voltage required  2.5 V, Mick was all to happy to match me up.

Also Mick has a go to repair guy who loves in the states. Believe his name is Slade, could be mistaken.