More On Video Tape Editing

It was 1976 that I last setup the timing on an Ampex editor. It was all a matter of timing. Let’s say you wanted to add material to a program. This would be an “assemble” edit. With the machine rolling in playback mode approaching the edit point, the operator would “punch” the machine into record mode about a half second or so prior to the edit point. This just took experience to learn. Now the operator has initiated record mode, but the machine and editor are lining up a series of events to make the edit. When everything lines up, the editor turns on the video and control track erase head. You now have blank tape heading to the rotating video head assembly. The editor is counting time for that newly erased tape to reach the head. When the time is up, the VTR goes into record mode and the edit is made. There is a lot of precision timing going on here, but this is the simple version. These editors did both assemble and insert edits. You used insert to literally insert new material into an existing program. This adds another precision event coming out of record and the end of the edit. With a properly adjusted machine, the edits were absolutely clean.

How did the Ampex store/hold the "splice"? Was it a bunch of memory? Or was it more physical (moving a head in a new direction or pull tape across ANOTHER head somewhere? We get so spoiled by digital electronics there being basically a computer crammed on there. But 60s and 70s might as well use steam punk tech for all I know! :)

One interesting wrinkle not noted here is that when you did a physical edit (splice) to 2-inch VT, it messed up the audio sync for a few frames because the audio and video heads are located some distance apart in the machine. To account for that, you had to dub off the audio around the VT edit point to a separate audio tape recorder before making the VT splice, then dub the audio back to the VT after completing the splice. No wonder so much was recorded “live-to-tape” in those days! This 1960s BBC training film has a lot of details https://youtu.be/PZVaK2TKgFA

Christopher Isert