This documentary is a dual portrait: a tribute to a friend named Rej, and a deep look at Bertha, an AMPEX MM-1000 — one of the legendary 16-track analog tape recorders that defined the sound of late-1960s and 1970s recorded music. Introduced in 1967, the MM-1000 was the first practical 16-track machine and was used by studios like Record Plant and Wally Heider's to track everyone from Hendrix to Sly Stone.

What makes this worth watching is the intersection of people and machine. These tape recorders are massive, temperamental beasts — refrigerator-sized transports with precision-aligned heads, capstan motors, and tube or discrete-transistor electronics that need constant maintenance. Keeping one alive in 2026 at a working studio (Earth Works Amsterdam) is a small act of preservation, and the documentary captures both the technical craft of running analog gear and the human relationships that form around it.

Carlos Mats brings a filmmaker's eye rather than a gear-nerd's checklist, so expect cinematography and atmosphere alongside the engineering. For anyone curious about analog audio, studio history, or what it actually takes to keep half-century-old electromechanical equipment running, this is a rare and specific story from a tiny channel.