Disintegrating Audio Tapeon January 24, 2012 at 11:49 pm
I had a job recently restoring some old Sydney radio recordings from someone who had a lot of quarter-inch reel to reel tapes – but instead of them being in half-track stereo (where the deck records across the entire width of the tape at once), these were quarter-track.
Being Ampex 407 where that, 456, 407 and 457 are the primary offenders of binder breakdown, where Ampex stopped using whale oil to make the tape binder due to whaling being banned in the 70′s and using a synthetic replacement, its this replacement that has affected over 1 million reels of tape, and engineers are finding old master tapes are not playing back without a fight. Over time, this binder breaks down and creates a mess all over the tape transport, taling the recorded material with it.
The cure is to bake the affected tapes (yes, like you would with a cake) in a convection oven for a few hours at no more than 50 to 60 degrees celsius. Because those binders act as moisture absorbers the idea is to drive the moisture out of the tape long enough to let you get a good transfer to another format. Playing these tapes without baking will cause a squealing sound from the tape which is a cue to stop playback immediately and preventing any damage to them.
Unfortunately, some of the stuff I’m currently dealing with is in such a state, that the oxide is literally peeling away from the tape surface as its being played – caused by someone before me playing the tapes without giving them the bake treatment first. Baking tape is by no means a permanent fix – the tape reverts back to its horrible state within a week or so.
I encountered one such tape just today – check out the pile of torn off oxide at the bottom of the tape deck!
Remaster guys, I beg you – please don’t play affected tapes without baking them first. You’ll risk permanent damage to the tape and if its a master, you’ve had it.