517
Item nr.
| Production | Switzerland, 1954. |
|---|---|
| Tubes | 2x DF64, DL68. |
| Cabinet | Metal. Size 6x9.5x2cm. |
| Power | Batt 1.5 and 22.5V (Eveready 412). |
The hearing aid was produced in Switserland. Production was probably around 1954, give or take one year, though I didn't find a direct reference for this. RadioMuseum.org claims that the DF64 was intoduced around 1953, and by 1955 most hearing aids were at least partially transistorized. The company Phonak still exists and produces hearing aids, now with transistors and ICs. This unit was sold and maintained in Brussels. 
My request for information was routed to the 
Dutch Phonak office ("Because You are best serviced by our representative in your own country"), but because this branch only exists since 1999, they couldn't give any information.
Inside the battery lid one finds a little sticker with instructions on how to place the batteries. Like in the earliest home tube radios, the heater battery is called A and the plate battery is B.
| Obtained | 6/2020 from Antoine; sn=31664. |
|---|---|
| Condition | 9. |
| Disposed | Sold 3/2024. |
The unit was donated to me, together with a storage case and (dead) battery. To see the inside, four small bolts must be removed, two near the battery lid and two near the earphone jack. 
Everything inside is of course very tiny. Above the output tube (the larger one) is the output transformer.