 He taught there until 1926, when his solo career became all-absorbing, but resumed teaching there in 1931 until his departure from Germany in 1944.At the same time he gave concerts throughout Germany and, increasingly, in various parts of Europe, and had a busy broadcasting career.In 1927, he performed the Bach Double Violin Concerto in D minor with Alma Moodie (a student of Carl Flesch) and the Berlin Philharmonic (BPO)

In 1935 he formed a celebrated trio with the pianist Edwin Fischer and the cellist Enrico Mainardi, with whom he remained active until 1948.