Port-O-Phone Model C Carbon Hearing Aid
The Port-O-Phone Model "C" carbon hearing aid was manufactured by the
Port-O-Phone Corp of New York, NY in 1915.
The Model "A" was for mild hearing losses, whereas the Model "C"
(shown here) was for moderate hearing losses. They also had a Model "M"
for severe hearing losses.
The Port-O-Phone Model C measured 3 7/16" x 3 7/16" x 1⅛" (8.7 x 8.7
x 2.9 cm) and weighed 22 oz. (624 g) with everything in the case.
|
 |
Click picture for larger view |
| |
 
|
| |
|
|
Front view of the Port-O-Phone Model "C" carbon hearing aid microphone
case. Note that the sound entered the case via the holes around the
microphone. The center circle is the back of the microphone itself.
|
 |
Click picture for larger view |
| |
|
|
Inside view of the microphone case of the Port-O-Phone Model "C" carbon
hearing aid.
|
 |
Click picture for larger view |
| |
|
|
Close-up view of the microphone of the Port-O-Phone Model "C" carbon
hearing aid microphone case. Notice the unusual arrangement of the
microphone—it is mounted so that its back is to the sound grill. This
way the sound entered the microphone case and had to reflect of the back
of the case and into the holes on the microphone itself. Stephen
Porter, the inventor of the Port-O-Phone had a US patent for a backward
facing microphone that was supposed to increase the sensitivity of the
microphone so it could pick up fainter sounds from a greater distance.
You can read his
patent
application here. The patent (No. 1,171,460) was filed on June 12,
1915 and granted on Feb 15, 1916. |
 |
Click picture for larger view |
| |
|
|
Close-up view of the wiring in the microphone case of the Port-O-Phone
Model "C" carbon hearing aid. As you can see, the design of carbon
hearing aids was very simple.
The 5 wire coils (bottom center) are the resistance windings for the
6 step volume control (shown in picture below). |
 |
Click picture for larger view |
| |
|
|
Top view of the Port-O-Phone Model "C" carbon hearing aid microphone
case showing the 6-step volume control (top right). The angle bracket
in the center was either for hooking the microphone on a button on
your shirt, or for threading a lanyard through so you could wear the
microphone around your neck.
|
 |
Click picture for larger view |
| |
|
|
Right side view of the Port-O-Phone Model "C" carbon hearing
aid case showing the attached label. The label reads "Port-O-Phone",
"[Serial] No. 11561" US Patent No. 1171460", "Model C", "Port-O-Phone
Corp." "Made in U.S.A. New York". |
 |
Click picture for larger view |
| |
|
|
Close-up view of the battery connector of the Port-O-Phone Model "C"
carbon hearing aid and a battery that it fit. The battery connector just
pushed onto the battery pins. One jack was larger than the other so you
couldn't plug it in the wrong way. This hearing aid used a 3 volt
carbon-zinc battery such as this
Gem No. 1A battery. |
 |
Click picture for larger view |
| |
|
|
The Port-O-Phone Model "C" carbon hearing aid connector shown plugged
onto the battery.
|
 |
Click picture for larger view |
| |
|
|
Front view of the earphone of the Port-O-Phone Model "C" carbon hearing
aid. Stamped on the front is "Port-O-Phone" (top) and "Corporation" &
"New York, USA" (bottom). |
 |
Click picture for larger view |
| |
|
|
Side view of the earphone of the Port-O-Phone Model "C" carbon hearing
aid showing the on-off switch. The earphone was 2" (5.1 cm) in
diameter and ¾" (1.9 cm) thick.
|
 |
Click picture for larger view |
| |
|
|
Rear view of the earphone of the Port-O-Phone Model "C" carbon hearing
aid showing the positions for the on-off switch.
|
 |
Click picture for larger view |
| |
|
|
The Port-O-Phone Model "C" carbon hearing aid in its carrying case. Note
the name on the inside flap of the lid.
|
 |
Click picture for larger view |
| |
|
|
Close-up view of the name stamped on the inside of the lid of the
Port-O-Phone Model "C" carbon hearing aid.
|
 |
Click picture for larger view |
| |
|
|
Front view of the Port-O-Phone Model "C" carbon hearing aid in its
carrying case.
|
 |
Click picture for larger view |
| |
|
|
Top outside view of the original Port-O-Phone Model "C" carbon
hearing aid carrying case.
The carrying case measured 9"
long x 5¼" wide x 1½" thick (22.8 x 13.3 x 3.8 cm).
|
 |
Click picture for larger view |
| |
|
(If a larger picture doesn't appear, you may have to
turn your pop-up blocker off)
|
|
|
