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Hearing Aid (Bosch)

Toronto Rehabilitation Institute

This is a hearing aid, composed of a control (amplifier) unit attached by a wire to a small cylindrical earpiece.

The amplifier unit is roughly rectangular with curved corners and encased in silver metal. Attached to one side, there is a metal clip, so the item can be clipped to clothing. At the base of the control unit, there is a deep red plastic section. Attached to the base of this there is a metal cover that is attached by a pin at one end, permitting it to swing open. This reveals a cylindrical opening for a battery with a yellow sticker inside indicating which way around the battery should be inserted, and a small beige plastic section with tiny round holes in it, each of which has a different colour interior and is labelled with a different letter: “T” “V” and “B”.

At the other, slightly narrower, end of the control unit there are a number of protruding switches, dials and sockets, each one in deep red plastic. One, on the side of the unit, is a slide switch which is labelled “M” at one end and “T” at the other. On the corner of the unit, there is a rounded knob, also a slide switch; this is unlabelled. On the other corner of the unit, there is a ridged wheel that protrudes slightly from the instrument. This is numbered in regular intervals from 1 to 5. On the top of the instrument, there is a socket for a flat multi-pinned plug.

Emerging from this narrower end of the unit, there is a length of wire. This consists of two thin wires insulated in white plastic that are coiled together. Attached to the end of this wire, there is a roughly cylindrical attachment consisting of a beige plastic backing, a cylindrical metal section and a small raised cylindrical middle section with a small round hole in the middle of it.

Accession Number:

Alternative Name:

Primary Materials:

Metal: Iron Alloy, Plastic, Metal: Copper Alloy.


On both sides of the control unit, engraved into the metal: “BOSCH”.

Engraved into the metal plate at the base of the amplifier unit: “OMNITRON”

Engraved on the earpiece: “8220”, “253”, “220”

Dimensions (cm):

Height = 1.0, Width = 3.5, Length = 4.5.


A hearing aid amplifies sound for a hearing-impaired person. The control unit provides amplification and power from the unit. The earpiece is intended to be worn in the ear.


This artefact is in good cosmetic condition. There are some minor scratches on the surface of the control unit. The rotating metal plate on the base of the control unit was enamelled; the enamel has been removed at the rotating end of the plate, revealing the brass metal; this is very slightly oxidized.

Associated Instruments:

Manufacturer: Bosch

Date of Manufacture: c. 1960s-1970s


This object was collected in 2018 from the Toronto Rehabilitation Institute along with other objects related to audiology.

Additional Information and References:

Historical Notes:

  • Donated to UTSIC