This is the definitive seminar on chanting Hare Krsna, given by Ravindra Svarupa
February 2001, Mayapur
The 6 classes are listed here in the correct order (sometimes  when finding these classes online they're not in correct order)

Ravindra Svarupa - japa seminar (Mayapur 2001)

Issues Of Reform In ISKCON Since 1977 Seminars by HG Ravindra Svarupa Prabhu

Ravindra Svarupa Pr Seminar -  Issues Of Reform In ISKCON Since 1977 Part - 02 - 1997 Radhadesh

Ravindra Svarupa - japa seminar (Mayapur 2001)

Amrita Bhaktas