Not many reviews on this unit out there ,so here’s my take. The 770 tube preamp does what all Pre’s should do it neither adds nor subtracts from the musical experience. It presents the music in a pure and uncolored way allowing the artists vison to present itself as recorded. The phono stage is especially magical, dead quiet backgrounds,,natural sounding soundstage, extended frequency response from the very bottom to the highest highs. If the recording is not up to snuff this unit will let you know straightaway, that being said even iffy recordings sound good on this unit. The line stage is equally impressive, I found CD’s that were harsh / brittle & unlistenable now were not only listenable but took on an almost analog quality. Part selection (Vishay, Alps, Sprague ) & build quality should rank this unit up there with the best Pre’s at any price. The 770 uses 6 - 12AX7’s (3 line/3 phono) & 6X4 tube rectification so tubes are plentiful,making this unit a tube rollers delight.