[5] Her grandfather, Mark Pester, was a well-known Bessarabian violinist (a classmate of Jascha Heifetz, Mischa Elman and Efrem Zimbalist at the St. Petersburg Conservatory) and conductor.
[4] Since 1977, he has conducted master classes at various festivals and teaching programs throughout the United States, Eastern and Western Europe, Korea, Japan and Australia.
In 1983, a concert by Zeltser in Bologna, Italy, attracted an audience of over 50,000, which has been claimed to be an all-time record for paid public attendance for classical music.
[citation needed] Zeltser has performed nearly 20 times with the Berlin Philharmonic under von Karajan.
[11][12] Zeltser and his wife have created a commercial website through which they aim to make available every piece of classical music ever written.