With both balanced and single-ended outputs, an almost limitless number of configurations to suit just about any cartridge needs, and an improved input stage for less noise, the Pass Labs XP-17 Phono Preamplifier packs a tremendous offering of features and performance in its $4,300 price tag.
Pass Labs is highly renown for their audio components, some of which are pure Class A. Besides preamplifiers and power amplifiers, they also produce phono preamplifiers (also called phono stages), having begun with the Aleph Ono in 1997. The XP-25 is their latest version, which was designed by Pass Labs engineer Wayne Colburn.
With vinyl experiencing such an incredible comeback over the past few years, so have phono preamplifiers, a.k.a., phono stages. They are required because the output of a phono cartridge is so low - on the order of 0.3 mV to 5 mV - that the inputs of preamplifiers that don't have phono stages can't amplify the signal enough for the power amplifier down stream.
conrad-johnson (lower case c and j) was formed in the mid-seventies, shortly after I became seriously interested in audio gear. I'm sure the two events were entirely unrelated. Their first product, a preamplifier, was immediately recognized as "state of the art," and so their storied history began. I encourage you to visit their website for more details. There, they provide a long list of products that have been reviewed as "Best of Class", and even "Best in the World."