DAT: The Marvel That Became a Preservation Challenge

DAT—more precisely, R-DAT—has been with us since 1987. I remember when Sony introduced it. It seemed like a marvel of engineering: extremely thin tape, a head drum rotating at 2,000 RPM, and two hours of digital audio inside a cassette small enough to fit in the palm of your hand.

Articles at the time loved comparing the tiny recorded tracks with the width of a human hair. When I first saw and heard DAT as a teenager, I understood the fascination. It was digital, quiet and remarkably compact. At home, I was still recording on reel-to-reel tape, so the contrast was dramatic. I remember watching the hubs turn slowly inside the shell and thinking, “That is a lot of information on very little tape.”

Five years later, I was working as a recording engineer. Analog tape machines were still in the studios, but DAT was the latest rage. The Sony PCM-2500, Panasonic SV-3700 and Tascam DA-30 were among the machines everyone wanted.

Personally, I was disappointed by the sound. I did not know whether the difference was inherent in digital recording or resulted from the design of the particular deck. All I knew was that the output did not match the input—it sounded different.

When clients wanted both a ¼-inch tape master and a DAT master, I mixed as I normally did, monitoring the console output. For DAT-only masters, however, I changed the monitoring path. Instead of listening to the console output, I monitored the output of the DAT deck. This allowed me to hear—and compensate for—the coloration introduced by the DAT recording while I was mixing.

Everyone Had a Favorite Tape

Studios also had strong preferences about DAT tape. Some used Maxell and others Sony, but Ampex was the king of the hill. I suspect that part of its popularity came from the wide choice of tape lengths, which allowed studios to charge clients different amounts according to the length of the session.

My personal favorite was HHB. In hindsight, my clients and I were fortunate. I do not know who manufactured HHB’s tape, but more than 30 years later, those cassettes generally play more reliably than almost any other DAT tapes that come through my door.

A few manufacturers tried to extend the format. Pioneer produced a 96 kHz machine that still recorded at 16 bits, while Tascam offered a 24-bit machine that remained at 48 kHz. Neither variation became widely adopted. I am fortunate to have a very low-hour Tascam DA-45HR in my collection, so I can still accommodate the 24-bit format.

Digital Does Not Mean Permanent

Today, apart from enthusiasts who still enjoy recording on DAT, it is primarily a legacy format—and one with plenty of problems.

DAT depends on a complicated mechanical system. The tape is narrow and thin, the recorded tracks are microscopic, and successful playback requires the tape to pass the rotating heads at precisely the correct angle and tension. Small tracking differences, contamination, tape deformation or deterioration can result in clicks, dropouts, bursts of noise, muting or complete loss of playback.

Compatibility between machines is important. A cassette that produces serious errors on one DAT deck may play considerably better on another. Recordings made on a machine that was slightly out of alignment can be especially troublesome decades later.

The fact that audio comes through a digital connection does not necessarily mean the transfer is perfect. DAT machines use error correction and concealment to hide information they cannot read properly. A recording may appear to be playing while the machine is compensating for errors—or replacing parts of the signal it cannot recover.

When Straight Playback Is Not Enough

When clients send me DAT cassettes, I normally begin by attempting a straightforward transfer. The exceptions are Ampex, BASF and Sony consumer tapes. These are known troublemakers and are never played before baking; they go directly into the dehydrator.

Other cassettes may also require additional work if straightforward playback is unsuccessful. This can include cleaning, careful mechanical attention, transfer into another shell, testing on several machines or adjustment of the playback system before a clean transfer can be made.

This is also why repeatedly trying a problem DAT in an unknown machine is not a good idea. If the tape is damaged or the transport is malfunctioning, each unsuccessful attempt may make the situation worse.

I have often been asked to work on recordings that another facility could not transfer successfully. Failure on the first machine does not always mean the recording is lost. The correct deck, careful diagnosis and a controlled playback procedure can sometimes recover material that initially appeared unreadable.

DAT was an extraordinary achievement. But like so many recording formats, it has reached the stage where access depends on the cassette itself and on the availability of working machines, replacement parts and people who understand them.

If a DAT contains an irreplaceable master, performance, interview or family recording, now is the time to transfer it—not after the remaining machines have disappeared.

Do you have a DAT that will not play, or a previous transfer containing clicks, dropouts or missing audio? Contact me to discuss a specialist evaluation.