The A 1 is a hearing amplifier for people who wish to improve their hearing
only in case of need.
Switching on and off, adjusting the volume
The device is turned on and off and the volume adjusted by turning the knurled
knob on the top (see illustration
on last page).
The A 1 is equipped with an automatic gain control
If the wearer speaks or there is a loud noise, at the very same moment the
volume is sharply reduced. Unpleasantly loud sound peaks are thus prevented,
and the wearer’s own speech retains its natural sound. The automatic gain
control is set in the factory to provide optimum comfort.
Adjusting the frequency response
Using the adhesive strips provided, the small holes in the receivers transducers
can be closed. The frequency response changes depending on how many holes
are covered in this way (see illustration
on last page). If all holes are left open
all sounds are balanced, to a considerable extent. If all holes are closed,
primarily speech is transmitted.
Power supply
The A1 has an economical and environmentally-friendly power supply in the
form of the BA 90 storage-battery module. Charging the battery provides
approx. 10 hours of operation at medium volume. Longer operation is possible
when a second battery module (accessories) is used. One of these at a time can
be charged in the L 90 charger. Overcharging is impossible, so the battery
module may remain plugged in over a longer period.
Technical data
Frequency range
100 - 12,000 Hz
Transducer principle
Dynamic
Microphone
Elektret microphone, mono
Acoustic amplification
approx. 30 dB
Characteristic sound pressure level
124 dB at 1 kHz
Operating time
approx. 10 hrs.
Weight
45 g
Scope of delivery (except for
1 A 1 hearing amplifier
supplementary package No. 03713):
1 plug-in charger L 90-220 or L 90-120
1 storage battery BA 90
4 adhesive strips
Subject to modifications
