Television & Radio Listening Aid D.A.1

This Television & Radio Listening Aid was the principal exhibit at October Earls Court National Radio Show by  Masteradio Ltd. & described as;

Television and Radio listening aid, a device consisting of a control unit with volume and tone controls and incorporating a lightweight headphone.

This unit may be connected to any radio or television receiver and enables a deaf person to listen in, using the normal volume required for the household from the loudspeaker.

It has been tested by the National Institute for the Deaf and other authorities and found satisfactory.
Practical Wireless Oct 1952, Page 464

In questo link sono elencati 89 modelli, di cui 53 con immagini e 55 con schemi.
Elenco delle radio e altri apparecchi della Masteradio, London