Master tape can be made from any digital or analog audio format.
Duplication is done on professional machines made by danish company called Lyrec.
The copying process is done with DIGI BIN MASTER or LOOP BIN MASTER.
Duplication is done with Dolby HX PRO.
Sources for master tape could be digital files (WAV, MP3, MD, DAT) or analog formats (MC, R2R, LP).
Digital files are preferred in WAV (PCM, 44,1kHz / 48kHz, 16bit).