Gidon Kremer - Lockenhaus 1983 (4-LP box set)
Back story: Recorded at an early version of the chamber-music fest Kremer cofounded in Austria, this set is from the long-defunct German label Orfeo, which shut down abruptly (in 1986, I think) and kinda turned into Teldec when Orfeo's label-head was on the run from the German authorities. (Somethin' about defrauding investors.) The LPs took advantage of "direct metal mastering" (DMM), which may be why even a semi-audiophile like me can tell they sound great. I scored a sealed box for 15 chips on eBay.
Composers: Brahms, Webern, Boccherini, Mozart, Schubert, Kuhlau, Bruch, Chopin, Faure, Bartok, Ives, Messiaen, Schnittke, Shostakovich, Milhaud, Asriel, Joplin