Throwback Thursday to the Oticon Model 550T

On our latest throwback Thursday, we shed some light on the history of the 1946 Oticon Model TA, and the many hurdles William Demant, son of founder Hans Demant, had to overcome to bring the first hearing aid, manufactured in Denmark, to the public market. Over the following years, Oticon made several leaps and bounds in the hearing care industry, leading us to the subject of today’s throwback to 1959: The Oticon Model 550T.

The Model 550T, like the TA before it, came with a number of obstacles and complications for the still young company to overcome. It was Oticon’s first BTE (Behind-The-Ear) hearing aid, and was a relatively new technology at the time. In fact, development of the 550T began just six years after the release of the very first transistor, a piece of electronic equipment that made it possible to manufacture these smaller, more user-friendly BTE hearing aids.

One feature that stands out on the 550T is the small protruding plateau on the side of the hearing aid. This particular feature does not exist in any official documents for the hearing aid until shortly before release in 1959. It is, essentially, the result of a mistake. In the early 1950s, the Danish government wanted to upgrade existing hearing aids in Denmark, and decided to allow hearing aid companies to bid on a contract to develop a new, streamlined hearing aid. Oticon won the bid, and began developing the Model 550T for Danish hearing aid users. The project specification, however, left out one important detail: The new hearing aid had to include a telecoil, a relatively new piece of technology at the time, which acts as a receiver for hearing aids and picks up telemagnetic signals, as seen in, for example, churches. In what can only be described as the 11th hour, engineers got to work on amending the design for the Model 550T. They came up with an ingenious idea; cut part of the hard plastic shell, and smelt it into a slightly curved shape. They then installed the telecoil within the curved part of the shell, and reattached it to the hearing aid alongside a small switch. That small error gave the Oticon Model 550T its iconic design.

You can learn much more about the rich history of audiology and hearing aids in The Eriksholm Collection, where we catalogue more than two centuries of hearing aid history, and interesting pieces of mechanical devices.