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!

Home Enter the Museum About Us Contact Us

FREE Subscription to:
Hearing Loss Help
The premier e-zine for people with hearing loss

Your email address
will never be
rented, traded or sold!

Your First Name:
Your E-mail:
Search this site:

 Results per
 page

 all words
 any words


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

 

Eyeglass Style Transistor Hearing Aids: 1954-1990

Otarion L10 "Listener"

The Otarion Model L10 "Listener" eyeglass hearing aid was manufactured by Otarion Electronics, Inc. of Chicago, IL.

The Otarion Model L10 was introduced on December 9, 1954 and went on sale in January 1955. It was probably the first commercially-made all-transistor eyeglass hearing aid in the world.

(Note: Akumed MBH of Germany had come out with a 2 vacuum tube & 1 transistor eyeglass hearing aid in 1954 (patented in 1952). This was likely the first commercially-made eyeglass hearing aid in the world. Another unique feature of this hearing aid was that the arms could not fold.)
 

Click picture for larger view

 

Next

 
Front view of the Otarion Model L10 "Listener" eyeglass hearing aid. Early models of eyeglass hearing aids had thick frames and very thick arms—they looked very "heavy" by today's standards.

This hearing aid weighed 2.1 oz. (58 g) without the battery.

 

Click picture for larger view

 
Rear view of the Otarion Model L10 "Listener" eyeglass hearing aid.

It used discrete components, and as such, needed both sides of the eyeglass frames to house all the electronics—hence its "fat" arms.

Furthermore, since the electronics filled both arms, only one ear could be aided. In the model shown at the right, it provided amplification for the left ear.

Note the ear mold attached to the left arm.

 In addition, since the microphone and receiver were on opposite sides of the eyeglasses, this effectively made this aid function as a CROS, (Contralateral Routing of Sound) hearing aid. The hearing aid picked up the sound from one side of your head and you heard it in the opposite (contralateral) ear.

Click picture for larger view

 
Front view of the folded Otarion Model L10 "Listener" eyeglass hearing aid. This hearing aid had maroon-colored plastic frames.

 



Click picture for larger view

 
View of the rear half of the right arm of the Otarion Model L10 "Listener" eyeglass hearing aid showing the volume control knob (left). It was situated ahead of the ear. The microphone port is the "hole" on the right.

 

Click picture for larger view

 
View of the inside of the right arm of the Otarion Model L10 "Listener" eyeglass hearing aid showing the serial number (21201) stamped near the front (left).

 

 

Click picture for larger view

 
View of the front inside of the left arm of the Otarion Model L10 "Listener" eyeglass hearing aid showing the manufacturer's name (Otarion), the model (Listener) and location of manufacture (Dobbs Ferry, NY).

 

 

Click picture for larger view

 
View of the rear inside part of the left arm of the Otarion Model L10 "Listener" eyeglass hearing aid showing the battery door (center) and the ear mold (bottom).

 

 

Click picture for larger view

 
Close-up view of the inside of the left arm of the Otarion Model L10 "Listener" eyeglass hearing aid showing the battery door removed (top) revealing the battery compartment.

The battery door just slid up in two tiny grooves.

 

Click picture for larger view

 
Close-up view of the inside of the left arm of the Otarion Model L10 "Listener" eyeglass hearing aid showing the battery door removed (top) revealing the battery in the battery compartment.

The Otarion L10 "Listener" used a No. 625 battery.

 

Click picture for larger view

 

Close-up view of the inside of the left arm of the Otarion Model L10 "Listener" eyeglass hearing aid showing the battery door half shut.

 

 

Click picture for larger view

 
View of the underside of the top of the eyeglass frames of the Otarion Model L10 "Listener" eyeglass hearing aid with the glass removed showing the hidden wires in the top of the groove.

This was needed since both arms housed the electronics. As a result, there needed to be a way of connecting both sides with wires. The way they did it was to run 2 wires along both arms to pins at the front and run hidden wires across the top of the eyeglass frames (as shown).

Click picture for larger view

 
Outside view of the hinge of the Otarion Model L10 "Listener" eyeglass hearing aid.

In order not to have wires visible at the corner hinges, Otarion came up with an ingenious method for connecting the wires in the arms and the eyeglass frame together.

 Note the two pins sticking off the end of the arm. These pins automatically made contact with the "plates" (right) when the arms were opened up so you could put the eyeglasses on and broke contact  (shown) when the arms were folded. In this way the electrical signals were transferred from one side to the other. (Both arms had the same arrangement.)

Click picture for larger view

 
Another close-up view of the hinge area of the Otarion Model L10 "Listener" eyeglass hearing aid showing the two pins and plates.

You had to keep the ends of the pins and the "plates" clean or they would soon corrode and the hearing aid would cease working, or cease working properly.

Note: there was no on-off switch on the volume control or elsewhere as none was needed. Simply folding the eyeglass arms broke the contacts at the hinges and prevented any current from flowing.

Click picture for larger view

 
 

At the right is an advertising invitation for the Otarion Model L10 "Listener" eyeglass hearing aid dated April 1955.

Here is a copy of the slick 4-page brochure for the Otarion Model L10 "Listener" eyeglass hearing aid to entice people to purchase it. Notice the stress on invisibility—just as is done today.

 

 

 


 

Click picture for larger view

 
 

The Otarion Model L10 "Listener" eyeglass hearing aid in its original case.

 

 


 

Click picture for larger view

 

 

The original case of the Otarion Model L10 "Listener" eyeglass hearing aid.

 

 

 

 


 

Click picture for larger view

 

(If a larger picture doesn't appear, you may have to turn your pop-up blocker off)