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

FREESubscriptionto:
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.

 

Hybrid Vacuum Tube/Transistor Hearing Aids

Acousticon Model A-310 Hybrid Hearing Aid

The Acousticon Model A-310 was produced by Dictograph Products Corporation in 1953 and is a sample of the early use of a transistor in a hearing aid.

This second Acousticon vacuum tube-transistor hybrid hearing aid was much smaller than it’s A-300 predecessor. It had a gold anodized aluminum case and weighed only 4 oz. with batteries. The A-310 measured 2½” by 1¾” by ⅞”.

Click picture for larger view

 

Back Next

 

Internal view of the Model A-310 from the front.

Notice the t-coil (coil of wire at the bottom).

 

Click picture for larger view

 
Internal view of the Model A-310 from the rear. This hearing aid used two CK549DX miniature hearing aid vacuum tubes (top center) with a single CK718 transistor (top left) for the output stage.
 

Click picture for larger view

 
This model included a telecoil that was activated by rotating the (blue) receiver plug on the top of the hearing aid. The oval cutout to the left of the blue switch is the microphone opening. For some reason, the microphone was placed here instead of the normal place on the front of the hearing aid.

 

Click picture for larger view

 

Read the manual for the Acousticon Model A-310 hybrid vacuum tube/transistor hearing aid.

 

Click picture for larger view

 

The Acousticon A-310 used a 15 volt 504E "B" battery (bottom) and an 1.4 volt RM-1 mercury "A" battery (top right).

Note: by substituting a transistor for one of the vacuum tubes, filament current drain was reduced by 1/3 resulting in a slightly longer battery life and reduced cost to the user. Hybrid hearing aids were only produced for about a year as fully transistorized hearing aids quickly took over the market.

 

Click picture for larger view

 

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