Nikolai Myaskovsky (pedagogue, friend of Prokofiev, composer) (1881-1950) (
www.myaskovsky.ru) wrote thirteen string quartets between 1911(?) and 1949, changing in style and difficulty.
A complete cycle was available on Soviet Melodiya LPs, was mastered on Russian Disc CDs that were available a few years ago but aren't now, and the first release of another outing of that cycle (played by the Leningrad Taneyev Quartet) is soon to be available on the Northern Flowers label.
(A page written by me is linked to on the Myaskovsky.ru page and I'm certainly a fan of the composer's music, the first and last of the quartets, both in the key of A minor, from 1930 and 1949, are among my favorites of his works in fact... the first three quartets are on this first disc.)
(Quartets 3, 4 and 10 are revisions of works from 1911 or so- and sound like it...- hence "from 1911 to 1949" even though his "first" quartet is from 1930 :) )