K 940 AFC - Earphones AKG - Free user manual and instructions

USER MANUAL K 940 AFC AKG

Dear customer: Thank you for purchasing an AKG product. The K 920 AFC / K 940 AFC wireless headphone system is based on advanced UHF transmission technology. In order to make optimum use of the benefits of your K 920 AFC / K 940 AFC, please take a few minutes to read the instructions below carefully before operating the equipment. Please keep the manual for future reference. 2 Description The K 920 AFC / K 940 AFC headphone system

• uses state-of-the-art UHF radio transmission technology;

• features an ”Autotuning” function that automatically tunes the headphones to the transmitter frequency for optimum reception;

• connects to any audio, video, TV set, PC, or notebook com- puter with a headphones, line, or recording output;

• provides perfect sound reproduction, full mobility, and signal transmission through walls and ceilings over a distance of up to 330 feet (100 m) under ideal transmision conditions (free field). To share your listening enjoyment with other persons, you can operate your transmitter with several headphones simultaneously. K 920 AFC / K 940 AFC headphones are available separately. 3 Precautions

1. Operate the headphones with two AAA size

1.2 V rechargeable (supplied) or 1.5 V dry

2. Never try to charge dry batteries using the

transmitter’s charging feature.

3. Before charging the headphones batteries,

always make sure that the batteries in the head- phones are rechargeable types.

4. Dispose of spent dry or rechargeable batteries conforming to

local waste disposal rules. Never throw batteries into fire.

5. Operate the transmitter with the supplied 9 VDC, 500 mA AC

adapter only. Check that the AC voltage stated on the AC adapter is the same as that available in your country. Using the transmitter with a different AC adapter voids the warranty.

6. Always switch the headphones OFF after use.

7. Never try to open the headphone or transmitter case. Refer

servicing to qualified service personnel only.

8. Never place the equipment near heat sources such as

radiators or electric heaters or expose it to direct sunlight, excessive dust, humidity, rain, temperatures below freezing, or impacts.

9. Never use alcohol, petroleum-based cleaners, or paint

thinners to clean the headphones or transmitter

10. If you do not use your headphones system for an extended

period of time (e.g., when traveling), disconnect the AC adapter fr om the AC outlet.

Also refer to section 7 Important Notes. 4 Unpacking and Optional Accessories

Your headphones system package contains the following components: K 920 AFC, or K 940 headphones T 920 AFC, or T 940 AFC transmitter Connecting cable with stereo mini jack plug and L/R RCA plugs for connecting the transmitter to your audio source Stereo mini jack to 1/4” adapter jack AC adapter for powering the transmitter (9 V DC, 500 mA) Two 1.2 V AAA size recharge-able bat- teries: NiMh, 600 mAh (K 940 AFC) or NiCd, 300 mAh (K 920 AFC) for powering the headphones (inside the headphones) If anything is missing, contact your AKG dealer immediately.

4.2 Optional Accessories

1. POWER switch: switches power to the headphones On

2. Status LED: illuminates green to indicate power to the head-

phones is ON, and r ed to indicates the batteries inside the headphones ar e being charged. 3a Charging contacts 3b Charging jack for optional external charger

9. FREQ: frequency selector

10. Charging contacts

11. POWER ON/CHARGE: tri-color LED indicating charging

and operating modes 6 Operating Notes

6.1 Connecting the Transmitter to AC Power

1. Connect the cable on the supplied AC adapter to the DC 9 V

jack (8) on the transmitter rear panel as shown in fig. 3.

Check that the AC voltage stated on the AC adapter is the same as that available in your country. If it is, connect the AC adapter to a convenient AC outlet (see fig. 4). The transmitter will automatically be ready to operate. Note that the transmitter will switch on as soon as it de- tects an audio signal at the AUDIO IN jacks or the jack.

6.2 Connecting the Transmitter to Your Audio

Source You may connect the transmitter to a headphones output (mini jack or 1/4” jack), LINE, or REC outputs.

6.2.1 Connecting to a Headphones Output

1. Before connecting the transmitter to your audio source,

switch the audio source OFF.

2. Referring to fig. 5, plug the red RCA connector (right

channel) on the supplied connecting cable into the red AUDIO IN R socket (7) and the white RCA connector (left channel) into the white AUDIO IN L socket (7) on the trans- mitter rear panel.

3. Connect the stereo mini jack plug on the connecting cable

to the headphones output of your audio source (fig. 6/7).

4. If the headphones output on your equipment is a 1/4”

jack, plug the supplied mini jack to 1/4” adapter jack onto the connecting cable. Connect the adapter jack to the headphones output.

6.2.2 Connecting to a LINE or REC Output

1. Before connecting the transmitter to your audio source,

switch the audio source OFF.

2. Referring to fig. 6/7, plug the red RCA connector (right

channel) on the supplied connecting cable into the red LINE OUT R or REC OUT R socket and the white RCA connector (left channel) into the white LINE OUT L or REC OUT L socket on your audio source.

3. Connect the stereo mini jack plug on the connecting

cable to the jack (7) on the transmitter r ear panel (see fig. 8).

ging the Batteries in the Headphones In order to ensure the longest possible service life for the re- chargeable batteries, we deliver them uncharged, inside the headphones. Ther efor e, you will need to char ge the supplied batteries before first operating your headphones system. Befor e char ging, pull the pr otective foil away fr om the earphone in a straight movement.

WARNING: If you operate the headphones on dry

batteries (see section 6.4), never try to charge the batteries using the transmitter’s charging feature. This would cause serious damage to your headphone system. Dispose of spent batteries conforming to local waste disposal rules.

1. Referring to fig. 12, place the headphones on the trans-

mitter such that the charging contacts (3) on the bottom of the left-hand earphone will rest on the charging contacts (10) on the transmitter. The POWER ON/CHARGE LED (11) on the transmitter will light red to indicate that the batteries in the headphones are being charged. If signal is present at the transmitter audio input, the POWER ON/CHARGE-LED (11) will light orange. If the POWER ON/CHARGE LED (11) fails to illuminate, ro- tate the headphones to the point that the charging contacts (3) will rest on the charging contacts (10) on the transmitter. The batteries will be fully charged after approximately 7 hours. (The POWER ON/CHARGE LED (11) will continue lighting red.). You may leave the headphones on the trans- mitter for as long as you like without risking to overcharge the batteries. Important: In order to maintain full battery capacity for as long as possible, discharge the batteries completely about once a month: Switch the headphones on and leave them outside the transmitter until the status LED (2) extinguishes. Recharge the batteries as described above.

6.3.1 Optional External Charger

Alternatively, you use can the optional external charger to charge the batteries as shown in fig. 12. The batteries will be fully charg- ed within approximately 7 hours.

1. Plug the charger cable into the charging jack (3b) on the

2. Plug the charger into a convenient power outlet.

The status LED (2) on the headphones will illuminate red to indicate that the batteries are being charged. Note: You can use the K 920 AFC headphones even while char- ging batteries.

6.4 Replacing Batteries

The capacity of any rechargeable battery will decrease over time. If you feel that you need to recharge the supplied batteries more often than would be convenient, you may consider replacing the batteries with new AAA size 1.2 V rechargeable or 1.5 V alka- line dry batteries.

1. Remove the ear pad from the left-hand earphone as shown in

2. Remove the old batteries.

3. Referring to fig. 10, insert the new batteries into the battery

compartment (4). Make sure to align the batteries with the polarity marks inside the battery compartment.

Replace the ear pad on the earphone and r otate the ear pad CW to the point that the ear pad will click into place.

6.5 Setting Up the System

1. Remove the headphones from the transmitter.

2. Switch ON the audio source to which the transmitter is

connected. If audio signal is present at the transmitter input, the POWER ON/CHARGE LED (11) on the transmitter will light gr een. Note: If no signal ar rives at the transmitter input for appr ox. 3 minutes, the transmitter will automatically switch off and the POWER ON/CHARGE LED (11 will extinguish.

3. Set the FREQ selector (9) on the transmitter to its

ENGLISHThe 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 89 Troubleshooting

ENGLISH Symptom No sound. POWER ON/ CHARGE LED does not light. Mono sound on headphones. Loud noise. Distorted sound. Remedy

1. Connect AC adapter to transmitter and/or

2. Connect transmitter to audio source.

3. Switch audio source on to feed signal to

Set audio source volume to desired level.

5. Charge batteries.

6. Switch headphones on.

7. Set VOLUME control to desired level.

1. Connect transmitter to AC power.

2. Check orientation of batteries in battery

3. Place headphones on transmitter correctly.

1. Switch audio source to stereo mode.

2. Check cable connection between transmitter and

use FREQ selector to select different carrier frequency and press AUTOTUNING on headphones.

4. Charge batteries.

2. Use FREQ selector on transmitter to select

different carrier frequency and press AUTOTUNING switch on headphones.

3. Charge batteries.

1. AC adapter is not connected to transmitter

2. Transmitter is not connected to audio source.

3. Connected audio source is switched off.

Volume control on audio source is at zero.

5. Batteries are low.

6. Headphones are switched off.

7. VOLUME control on headphones is at zero.

1. Transmitter is not connected to AC power.

2. Batteries are not correctly aligned with polarity

3. Headphones are incorrectly positioned on

1. Connected audio source operates in mono

2. Transmitter is not correctly connected to audio

1. Transmitter and receiving frequencies are not

2. Audio level at transmitter input is too low.

3. Input signal is noisy.

4. Batteries are dead.

5. Transmitter position.

1. Audio level at transmitter input is too high.

2. Transmitter and headphones carrier frequencies

3. Batteries are dead.1 Introduction

audio/video, tv, PC o notebook.

audio/video, tv, PC o notebook.

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