The EAR-Yoshino 868 is a no-frills version of the $13,500 EAR 912 (no meters and faceplate handles, fewer controls), a pre-amp Art Dudley gave a rave review to awhile back. The 868 is an over-looked bargain, selling for around $3000 used, $3500-4000 used from dealers. I would much rather have one in my system than a comparably priced ARC, for instance.
EAR’s designer Tim de Paravicini has a vast, deep knowledge of electronics and circuit design, amongst the best in the world of still-living masters. Though EAR is a low-profile company in the U.S., it and Tim are very well known in the UK. He designed and built the electronics in Roger Waters’ recording studio, as well as those in the state-of-the-art tube tape recorder of Kav Alexander of Water Lily Records. Kav’s work on the Meeting By A River album (with the great Ry Cooder) won him a Grammy for best engineering.
Paravicini is rather opinionated about hi-fi, having little use for boutique parts and audiophile tweaks. Perhaps that’s why he is not more popular amongst fickle, trendy, High End consumers (present company excluded, of course ;-). He rarely modifies existing products, working on their design until he considers them "finished", not a work-in-progress. He therefore does not benefit from a steady stream of reviews of frequent "new" model introductions---in reality updates of models whose sales have begun to decline.
If you like the sound of your 509 (what’s not to like?!), there is every reason to expect you will like the 868. Available with or without a phono stage, it has excellent hook-up provisions: A balanced/XLR input, five unbalanced/RCA inputs, two balanced/XLR and two unbalanced/RCA outputs, and a pair of tape ins and outs. If you have patience, and can wait for a couple of months to maybe a year for one to come up used, be ready to jump on it---they go fast. The one on Audiogon last week went in just hours.