Operating Instructions
Manual de instrucciones
MDR-RF940RK
Sony Corporation © 1996 Printed in Japan
• Connecting cord (phono plugs ÷ |
stereo mini jack) |
• The headphones |
Setting up the transmitter
1 Connect the transmitter to audio/ video equipment.
aTo connect to a headphones jack
Transmitter 
•When the AC power adaptor is connected to the transmitter, internal batteries are automatically disconnected.
•Use only the supplied AC power adaptor. Do not use any other AC power adaptor.
Polarity of the plug
•When you connect the connecting cord directly to an earphone jack, the audio signal will not be output through the right channel. In such a case, use the separately sold PC-236HG plug adaptor.
To obtain power from batteries
The transmitter can also be operated by use of four R6 (size AA) batteries.
1 Open the battery compartment lid on the bottom of the transmitter.
2 Insert four R6 (size AA) batteries by matching the + and – on the batteries to the + and – in the battery compartment.
3 Close the battery compartment lid.
Battery life
Battery | Approx. hours |
| |
Sony alkaline battery | 40 |
LR6 (SG) | |
| |
Sony battery R6P (SR) | 20 |
| |
When to replace the batteries
Replace both batteries with new ones when the POWER indicator dims, and a hissing noise increases.
Notes on batteries
To avoid damage to the system caused by battery leakage and corrosion;
–Install the batteries with the correct polarity.
–Do not try to recharge the batteries.
–Remove the batteries if the system is not to be used for a long period of time.
Note
If the transmitter is connected to the headphones jack of the source equipment, set the volume of that equipment as high as possible without distorting the audio signal.
Auto power on/off function
When you remove the headphones, the power turns off automatically. Do not apply pressure to the left ear pad when not using the headphones, otherwise the headphones will be switched on.
/
Mute function
If a hissing noise is heard when the headphones are used outside of the effective range (see the next section), the mute function will be activated and the sound will not be heard from the headphones. To restore the sound, move near toward the transmitter.
After listening to a program
2 Place the new ear pad on the housing and insert the edge of the pad into the groove as illustrated.
Make sure that the entire edge of the ear pad is securely inserted into the groove.
(Additional information
Precautions
• When the headphones are not to be |
used for a long period of time, remove |
the batteries to avoid damage caused |
by battery leakage and subsequent |
corrosion. |
• When the transmitter is not to be used |
| connected audio/video |
| equipment, if the |
| transmitter is connected to |
| the headphones jack. |
| | |
| The mute function is |
| activated. |
| Use the headphones near |
| the transmitter. |
| | |
| Replace both batteries of the |
| headphones. |
| | |
| Replace the batteries in the |
| transmitter if the |
| transmitter is used by |
| battery operation. |
| | |
Distortion | If the transmitter is |
| connectedÊ toÊ theÊ headphones |
| jack, turn down the volume |
| of the connected audio/ |
| video equipment. |
| | |
| Replace both batteries of the |
| headphones. |
| | |
| Replace the batteries in the |
| transmitter if the |
| transmitter is used by |
| battery operation. |
| | |
Loud | Move closer to the |
background | transmitter. As you move |
noise | away from the transmitter, |
| more noise is likely to be |
| heard. |
| | |
| If the transmitter is |
| connected to the |
| headphones jack, turn up |
| the volume of the connected |
English
WARNING
To prevent fire or shock hazard, do not expose the unit to rain or moisture.
To avoid electrical shock, do not open the cabinet. Refer servicing to qualified personnel only.
WARNING
You are cautioned that any changes or modifications not expressly approved in this manual could void your authority to operate this equipment.
Owner’s Record
The model number is located inside the battery compartment of the transmitter and the right inner side of the head band.
The serial number is located inside the battery compartment of the transmitter and inside of the battery compartment of the headphones.
Record these numbers in the spaces provided below. Refer to them whenever you call upon your Sony dealer regarding this product.
Model No. MDR-RF940RK
Transmitter TMR-RF940R
Headphones MDR-RF940R
Serial No.
ÊTransmitter Headphones
Welcome!
Thank you for purchasing the Sony MDR-RF940RK Wireless Stereo Headphone System. Before operating the unit, please read this manual
thoroughly and retain it for future reference.
Some features are:
•Wireless system that allows you to listen to a program free from the restriction of a cord within 130 feet from the transmitter.
•High fidelity sound reproduction
•Compact transmitter which operates on battery power and AC power supplied through the supplied AC power adaptor
•Comfortable Circum-aural headphones
•Automatic ON/OFF function on headphones to preserve battery power
•Mute function to avoid noise when no audio signal is available.
Notes on receiving performance
The system for this equipment utilizes very high frequency signals in the 900 MHz band so the receiving performance may deteriorate due to the surroundings. The following examples illustrate conditions that may reduce the possible receiving range or cause interference with reception.
•Inside a building with walls containing steel beams.
•Area with many steel file cabinets, etc.
•Area with many electrical appliances capable of generating electromagnetic noise.
•Transmitter is placed on a metal instrument.
•Area facing roadways.
•Noise or interfering signals exist in the surroundings due to radio transceivers in trucks, etc.
•Noise or interfering signals exist in the surroundings due to wireless communication systems installed along roadways.
to headphones jack (stereo mini jack)
Discman,
Walkman, TV,
VCR, etc.
bTo connect to LINE OUT or REC OUT jacks
Transmitter 
Connecting cord (supplied)
Left channel | Right |
(white) | channel (red) |
to LINE OUT or
REC OUT
Stereo system,
TV, VCR, etc.
3 Close the battery compartment.
Battery life
Battery | Approx. hours |
| |
Sony alkaline battery | 40 |
LR6 (SG) | |
| |
Sony battery R6P (SR) | 20 |
| |
When to replace the batteries
Replace all the batteries with new ones when the POWER indicator dims, and a hissing noise increases.
Setting up the headphones
1 Open the battery compartment lid on the left inner side of the head band.
In case of battery leakage, wipe off any deposit in the battery compartments before installing new batteries.
(Operating the system
Listening to a program
1 Select the radio frequency with the CHANNEL selector switch.
Select the same channel on the headphones and the transmitter.
CH1 CH2
2 Turn on the audio/video equipment then the transmitter.
POWER 
Take the headphones off before turning off the transmitter. If you turn off the transmitter first, you may hear some noise.
The effective areas of the transmitter
The optimum distance is up to approximately 130 feet (40m) without the system picking up some interference. However, the distance may vary according to the surroundings and environment. If the system picks up some noise while using it within the above mentioned distance, reduce the distance between the transmitter unit and the headphones, or select the other channel.
Notes
•When you use the headphones inside the effective areas of the transmitter, the transmitter can be placed in any direction from the listener.
•Even within the signal reception area, there are some spots (dead point) where the RF signal can not be received. This characteristics is inherent to RF signals, and does not indicate malfunction. By slightly moving the transmitter, location of the dead point can be changed.
for a long period of time, disconnect |
the AC power adaptor from the AC |
outlet holding the plug. Do not pull |
on the cord. |
Also remove the batteries to avoid |
damage caused by battery leakage and |
subsequent corrosion. |
• Do not leave the wireless stereo |
headphone system in a location subject |
to direct sunlight, heat or moisture. |
Notes on headphones
Preventing hearing damage
Avoid using headphones at high volume. Hearing experts advise against continuous, loud and extended play. If you experience a ringing in your ears, reduce the volume or discontinue use.
Caring for others
Keep the volume at a moderate level. This will allow you to hear outside sounds and to be considerate to the people around you.
If you have any questions or problems concerning the system that are not covered in this manual, please consult the nearest Sony dealer.
Be sure to bring the headphones and the transmitter to the Sony dealer when requiring repair work.
audio/video equipment. |
If noise is heard when the |
transmitter is hooked to the |
TV headphones jack, try |
connecting from LINE OUT. |
Replace both batteries of the |
headphones. |
Replace the batteries in the |
transmitter if the |
transmitter is used by |
battery operation. |
Specifications
General
Carrier frequency
| 913.5 – 914.5 MHz |
Channel | Ch1, Ch2 |
Modulation | FM stereo |
Frequency response |
Transmitter | 18 – 22,000 Hz |
|
RF Power | Less than 94 dBµV/m at 3 m |
Power source | DC 4.5 V: supplied AC power |
| adaptor |
| DC 6 V: 4 x R6 (size AA) battery |
Audio input | stereo mini plug |
Dimensions | Approx. 90 mm dia x 35 mm |
| (3 5/8 x 1 7/16 in.) (w/h) |
Mass | Approx. 200 g (7.1 oz.) |
| incl.batteries |
Headphones |
Power source | DC 3 V: 2 x R6 (size AA) battery |
Mass | Approx. 270 g (9.5 oz.) incl. |
| batteries |
Optional accessories
Plug adaptor PC-236HG
(stereo mini jack ÷monaural mini plug)
Design and specifications are subject to change without notice.
(supplied) 
