Cole's primary instrument, the 1739 'Sleeping Beauty' by Domenico Montagnana, was a gift to him which had been purchased for $17,000 in 1952. It was with this instrument that the Curtis String Quartet's best known recordings for Westminster Records were made, among them Dvořák's American Quartet and Smetana's Quartet in E Minor From My Life; Mendelssohn quartets, opp. 12 and 44, no. 1; Schumann quartets, op. 41, nos. 1 and 3; Debussy and Ravel quartets; the Franck Piano Quintet; and two works of Ernő Dohnányi, the Quartet in Db-Major, and the Piano Quintet No. 2. In the two works with piano, the Curtis String Quartet was joined by their longtime friend and collaborator, the pianist Vladimir Sokoloff.