Operation Manual

The Autotuning function will automatically tune the reception
frequency to the carrier frequency set on the transmitter. After
a few seconds, you should hear the signal in the headphones
clearly and free of interference.
If your first try fails, set the FREQ selector (9) on the transmit-
ter to a different position and press AUTOTUNING (5)
again.
FREQ (9) lets you select one of three different carrier fre-
quenices.
5. Set the VOLUME control (6) on the headphones to the
desired volume level.
Note: If the transmitter signal is disturbed, e.g., by reflections (multi-
path reception) or shadow effects, the headphones will auto-
matically mute. This function eliminates interference related
noise.
6.6 POWER ON/CHARGE LED Status
If LED is... Transmitter...
…lighting green: …is connected to AC power and audio
source and receives signal. Head-
phones are not on the transmitter, char-
ging function is off.
…lighting orange: …is connected to AC and audio
source and receives signal. Head-
phones are on the transmitter, charging
function is on.
…lighting red: …has detected no signal for several
minutes, headphones are on the trans-
mitter, charging function is on.
…dark: …has detected no signal for several
minutes, headphones are not on the
transmitter, charging function is off, OR
…is not connected to AC power.
7 Important Notes
1. Operating switches on or connecting the transmitter to your
audio source may cause clicks which at high volume settings
may affect your hearing. Therefore, be sure to set the
VOLUME control on the headphones to minimum before
switching between different sources (tuner, turntable, CD play-
er, etc.) or connecting the transmitter.
2. Listening over headphones at high volume levels, particularly
over extended periods of time, may damage your hearing.
3. Your K 920 AFC / K 940 AFC is a radio frequency device
that conforms to the strict European standards. For physical
reasons that have nothing to do with the quality of the pr
oduct,
extremely strong interference sources may affect reception.
In order to maintain interference-free listening
pleasur
e, do not operate your K 920 AFC / K
940 AFC in the close vicinity of radio equipment,
cellular telephones, or directly above TV or com-
puter monitor picture tubes
(see fig. 11). The supplied
connecting cable is long enough to allow the transmitter to be
placed at a safe distance from interference sources.
Inter
fer
ence caused by other users of the 864 MHz LPD
band ar
e beyond AKG’
s control.
8 Specifications
System Performance
Modulation: FM
Carrier frequency band: 864 MHz (LPD band)
Selectable carrier frequencies: FREQ 1: 863.5 MHz
FREQ 2: 864.0 MHz
FREQ 3: 864.5 MHz
T 920 AFC / T 940 AFC Transmitter
Power supply: 9 VDC, 500 mA
Radiation angle:
approx. 360°
Max. radiated power: 10 mW ERP (Equivalent Radiated
Power)
Max. range (free field*): approx. 330 ft. (100 m)
Weight (T 920 AFC): approx. 9.7 oz. (275 g)
(T 940 AFC): approx. 11.1 oz. (315 g)
K 920 AFC Headphones
Distortion: <1%
Type: semi-open dynamic headphones
Weight: approx. 6.3 oz. (180 g)
K 920 AFC Headphones
Power supply: 3 VDC (2 x 1.2 V, 300 mAh AAA
size NiCd rechargeable batteries
supplied)
Battery life: approx. 10 hours
(NiCd rechargeable batteries)
Frequency range: 20 Hz to 22,000 Hz
Max. SPL: ~103 dB SPL
K 940 AFC Headphones
Power supply: 3 VDC (2 x 1.2 V, 600 mAh AAA
size NiMh rechargeable batteries
supplied)
Battery life: approx. 20 hours
(NiMh rechargeable batteries)
Frequency range: 18 Hz to 24,000 Hz
Max. SPL: ~107 dB SPL
Distortion: <1%
Type: semi-open dynamic headphones
Weight: approx. 11.3 oz. (320 g)
* under ideal transmission conditions
8