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May 19, 2011

Preserving the Milton Friedman Cassettes

The Economics Cassette Series accounts for the vast majority of the audio recordings in the Milton Friedman papers. This series was a biweekly, subscription-based program that ran from 1968 to 1978. Instructional Dynamics Incorporated (IDI) produced the series, which served as a companion to Friedman's Newsweek columns of the same era. Each program contains an interview with Milton Friedman, recorded either in Chicago, Illinois, or Vermont, during which Professor Friedman comments on the economic issues of the day for approximately half and hour.

Due to their age, these cassettes are severely deteriorated. Specifically, adhesives used during manufacturing have broken down, thus leading to many problems. The first concerns the splice tape that holds the tape to the leader (the nonmagnetic, blank plastic at the beginning/end of each side). Failing adhesive on the sticky side of the splice tape is migrating to the top of the tape, making proper playback difficult. The next problem is the adhesive holding the felt pad on at the bottom of the cassette, which has often dried, loosening the pad (the key to successful playback and reproduction of all audible frequencies) from the cassette mechanism. As we strive to ensure proper preservation through digitization, we must address the aforementioned problems.

Click any image to start the slideshow.

After having been removed from its box, cassette 55 appears normal.

After having been removed from its box, cassette 55 appears normal.

Over the years of storage, the tape pack may have loosened.

Over the years of storage, the tape pack may have loosened. Consequently, the tape is run through its ends between hubs (the wheels) before playback so as to remove any slack and ensure a consistent program during transfer. This is a problem with cassette 55 because the tape, instead of moving all the way through to the end, sticks. Were we to leave the tape like this, the entire program would remain unheard.

The transfer engineer had to manually coax

The transfer engineer had to manually coax the tape to get it to where the leader is visible (see above), requiring a good amount of effort and torque on the inner rings.

A problematic splice point is isolated in a splicing block

A problematic splice point is isolated in a splicing block. As seen through the reflected light, notice how the splice point breaks the natural flow of the tape; the adhesive has failed, and an uneven, blotchy discoloration can be seen throughout. Were one to touch this area, the viscous quality would be obvious. Thus this splice tape must be replaced.

Removing the old splice tape and replacing it means that the tape no longer feel

Removing the old splice tape and replacing it means that the tape no longer feels sticky. Visually, one can now see light reflecting evenly and continuously whereas the old tape broke the natural flow.

With the bad splice point fixed, the full program can now be played all the way

With the bad splice point fixed, the full program can now be played all the way through.

On example two (cassette 59), the felt pad has fallen off its mechanism

On example two (cassette 59), the felt pad has fallen off its mechanism, again the result of failed adhesive. Because it is impossible to reglue the pad to the mechanism, the tape must be rehoused in a new shell before being digitized.

Because the original shell was molded together during manufacturing

Because the original shell was molded together during manufacturing, it had to be broken apart. (This is unnecessary when cassettes are held together by screws.)

The tape in a new shell, including new felt pad and mechanism

The tape in a new shell, including new felt pad and mechanism.

With the tape in the new shell, a new felt pad, and the shell sides screwed toge

With the tape in the new shell, a new felt pad, and the shell sides screwed together, it is now ready for playback. Following transfer, the tape will be returned to the old shell for storage owing to space constraints in the collection boxes and archives’ stacks.