Hugh Hetherington Hearing Aid Museum
Hugh Hetherington Hearing Aid Museum

The Hearing Aid Museum

Hearing Aids of all types—Ear Trumpets, Carbon Hearing Aids, Vacuum Tube Hearing Aids, Transistor Hearing Aids, Body Hearing Aids, Eyeglass Hearing Aids and much more!

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Click on the "General Information" button (top button above) for an overview and general information on this category of hearing aid.


Hybrid Vacuum Tube/Transistor Hearing Aids

Fortiphone Model 40 Hybrid Hearing Aid

The Fortiphone model 40 hybrid hearing aid appears to be a late comer in hybrid hearing aids. It was manufactured by Fortiphone Ltd. of London. It is not known exactly when it first appeared, but it could have been as late as 1955. It used two vacuum tubes and one transistor. The Fortiphone model 40 used the same case as the Fortiphone model 23 vacuum tube hearing aid.

This hearing aid weighed 4 oz. with batteries, and measured 3⅛" x 1⅞" x ¾".

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The inside of the battery compartment showing the model number.


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The batteries shown installed in the battery compartment. The Fortiphone 40 was powered by a 30 volt "B" battery type 506E (bottom), and a 1.4 volt RM-1 mercury "A" battery (middle right).



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