As a child Levin experienced the golden age of musical culture that was Berlin in the Weimar Republic, hearing recitals by many of the greatest musicians of that era, including Yehudi Menuhin, Artur Schnabel, Edwin Fischer, Alexander Kipnis, and Erna Berger, and the Calvet Quartet, concerts by the Berlin Philharmonic, and opera productions at the Staatsoper, the Deutsches Oper, and the Kroll Oper, conducted, among others, by Leo Blech and Otto Klemperer.
Opera and lieder recitals were decisive in impressing upon him early on the importance of singing and of the vocal literature for understanding the rhetoric of music and the technical means for its expression on the violin.
Of particular importance were recordings by Yehudi Menuhin, Jascha Heifetz, and Arturo Toscanini, whose rhythmic elan, precision, and unsentimental verve were to remain models of the interpreter's art throughout his professional career.
Through the efforts principally of the violinist Bronislaw Huberman, Palestine — and in particular, Tel Aviv — had become a place of refuge for many of the leading German and Eastern European Jewish musicians of the day.
In Palestine, Levin also reconnected with a childhood friend from Berlin, the pianist and composer Herbert Brün, who had emigrated in 1936 with a scholarship to attend the Jerusalem Conservatory.
In New York, Levin was able to get permission to attend Toscanini's NBC Symphony Orchestra rehearsals, and to get tickets to Toscanini's broadcast concerts; he also made the acquaintance of violin dealer Rembert Wurlitzer, who later played a significant role in providing the LaSalle Quartet with a set of Stradivarius instruments, and then with a set of Amatis.
In September 1948, while still at Juilliard, Levin met the violinist Henry Meyer, who had recently arrived in America from Paris following years of imprisonment in Nazi concentration camps.
Through Herbert Brün, who had come to Tanglewood on scholarship to study composition with Aaron Copland in the summer of 1948, Levin met the pianist Evi Markov, whose family had emigrated to America in November 1940.
In the summer preceding the start of that appointment, they were joined by violist Peter Kamnitzer, whom they had known from Juilliard, and who remained with the quartet until its retirement in 1987.
Its participation in the famous Darmstadt Summer Courses for New Music in the 1950s led to a series of commissions to contemporary composers, most notably György Ligeti and Luigi Nono, and also to many world premieres, including the quartets by Krzysztof Penderecki and Witold Lutosławski.
Levin's philosophy of interpretation can be summarized as a search to know, by a combination of historical research and structural analysis, a composer's exact intentions, and to realize those intentions in the performance of works that have influenced the subsequent course of musical history and that can reveal new aspects for the present when considered from the standpoint of the most advanced contemporary music.