Telex Stereo Receiver SR 400 User Manual

Telex  
Operating Instructions  
ST300  
Transmitter  
SR-400  
17 Channel Receiver  
SR-50  
Single Channel Receiver  
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INTRODUCTION  
WHAT IS THE TELEX SOUND  
ENHANCEMENT SYSTEM?  
WHAT FREQUENCY BAND DOES THE  
TELEX SYSTEM OPERATE IN?  
The Telex Systems feature a synthesized transmitter  
and single channel or synthesized receivers operat-  
ing in the VHF Band between 72-76 MHz. See Ta-  
ble 1 for standard frequencies available.  
Transmitter: The transmitter generates and ampli-  
fies a RF (Radio Frequency) carrier signal, modu-  
lates this carrier with the microphone signal, and  
radiates the modulated RF carrier.  
Each transmitter channel can be utilized by any  
number of receivers in any given area. Up to eight  
simultaneous systems can be used, and with proper  
placement of adjacent channels, up to ten systems  
can be used.  
Receiver: The FM VHF receiver is tuned to the fre-  
quency of the transmitter. The receiver picks up the  
radiated RF signal from the transmitter through the  
antenna and converts the RF signal into audio volt-  
ages for use with an earphone, headphone, button  
receiver, neckloop, etc. The receiver frequency must  
be matched to the transmitter frequency.  
ANT.  
ANT.  
RF CARRIER  
SIGNAL  
SOUND  
SOURCE  
FM  
EARPHONE  
RECEIVER  
TRANSMITTER  
Figure 1  
Block Diagram of Typical Sound Enhancement System  
-1-  
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OFTEN ASKED QUESTIONS  
Question: Can more than one system be used si-  
multaneously?  
Whenever the system is in use, the transmitter  
should be left on to prevent the receiver from pick-  
ing up outside interference.  
Answer: Yes but never on the same frequency.  
You will need to have different frequencies for ev-  
ery receiver/transmitter combination. All transmit-  
ters are factory set for specific frequencies.  
AVAILABLE FREQUENCIES  
CHANNEL  
FREQ. in MHz  
A
B
C
D
E
F
72.100  
72.200  
72.300  
72.400  
72.500  
72.600  
72.700  
72.800  
72.900  
75.500  
75.600  
75.700  
75.800  
75.900  
74.700  
75.300  
75.400  
Question: Is the system more sensitive in any one  
particular direction?  
Answer: No, the transmitter’s antenna radiates  
equally in all directions, but the signal is attenuated  
by your body, walls or other surrounding objects.  
The receiving antenna is essentially sensitive in all  
directions as well.  
G
H
I
J
K
L
M
N
O
P
Question: Can the receiver receive other transmis-  
sions when the transmitter is turned off?  
Answer: Yes it can. Telex systems operate in the  
VHF Band between 72-76 MHz. However, it is not  
susceptible to radio wave skip, CB’ers or standard  
FM radio transmissions.  
Q
The frequency your system operates on is computer  
selected for least interference, but there is no such  
thing as a 100% clear channel all the time, any-  
where in the U.S.A., forever!  
Table 1  
Frequencies Available  
If the system is going to be used in a permanent  
fixed location, it should operate interference free un-  
til such a time or date when someone else begins  
using the same frequency.  
If the system is going to be moving among various  
locations, you may run into occasional frequency  
conflicts.  
-2-  
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TECHNICAL INFORMATION  
SR-50 RECEIVER  
GENERAL DESCRIPTION SR-50  
The Telex SR-50 Receiver is a component of a sys-  
tem which operates on 17 factory preset channels in  
the 72 to 76 MHz frequency band. The receivers are  
designed to be used with Telex ST-300 and PST-170  
transmitters, but they can be used with other brands  
of transmitters in the 72 to 76 MHz band provided  
the frequencies match.  
The receiver is turned off when the control is in the  
extreme counterclockwise position, when viewed  
from the rear and the volume is loudest when the  
control is in the extreme clockwise position.  
Headphone Jack: The receiver jack accepts a  
0.140-inch (3.5 mm) diameter miniature phone plug.  
A variety of accessory units can be plugged into the  
jack for reception of the desired channels being  
transmitted.  
OPERATING FEATURES  
Volume OFF/ON Control: The thumbwheel con-  
trol serves as both an off/on switch and as a volume  
control.  
Belt Clip: The belt clip supplied is detachable by  
spreading the wire apart at the tops and removing  
one side of the clip form the case and then the other.  
HEADPHONE JACK  
R
Telex  
A
CHANNEL  
VOLUME OFF/ON CONTROL  
BELT CLIP  
BATTERY  
ORIENTATION  
BATTERY COMPARTMENT COVER  
Figure 2  
Operating Features SR-50  
-3-  
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SPECIFICATIONS  
SR-50 Single Channel Receiver  
Temperature Range .....................................................................................................0 to +50 degrees C  
Supply Voltage ...............................................................................................2-3 Volts, (2) AA Batteries  
Battery Life ..............................................................................................................20-30 Hrs - Alkaline  
8-10 Hrs - Nicad  
Sensitivity (12 dB SINAD @ 25 kHz deviation) ...................................0.5µ V typical/1µ V maximum  
Distortion...............................................................................................................................less than 2%  
Frequency Response - 100 Hz-10 kHz .............................................................Less than 3 dB Variation  
Audio Output @ 10% Distortion  
Battery Input  
Voltage  
2.0V  
3.0V  
15 mW  
10 mW  
80 mW  
50 mW  
8 ohm  
32 ohm  
Controls and Connections ................................................................................Volume OFF/ON Switch,  
Audio Output Jack  
SR-400 SYNTHESIZED  
RECEIVER  
General Description SR-400  
The Telex SR-400 Receiver is a component of a  
system which operates on seventeen user selectable  
channels in the 72 to 76 MHz frequency band. The  
receivers are designed to be used with the Telex  
ST-300 and PST-170 Transmitters.  
Treble Control: A push button treble control is pro-  
vided to enhance higher frequency audio when the  
button is engaged, indicated by  
.
Headphone Jack: The receiver jack accepts a  
0.140-inch (3.5 mm) diameter miniature plug. A va-  
riety of accessory units can be plugged into this jack  
for listening.  
Operating Features  
Volume OFF/ON Control: This thumbwheel con-  
trol serves as both an off/on switch and as a volume  
control. The receiver is turned off when the control  
is in the extreme counter-clockwise position, when  
viewed from the rear, and the volume is loudest  
when the control is in the extreme clockwise posi-  
tion.  
Belt Clip: The belt clip supplied is detachable by  
spreading the wire apart at the tops and removing  
one side of the clip form the case and then the other.  
NOTE: A headphone or other device must be  
plugged in the headphone jack in order to turn on  
the SR-400. This is to prevent draining the batteries  
if the switch is accidently left on.  
-4-  
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SET  
SWITCH  
BUTTON  
BELT CLIP  
TREBLE CONTROL  
HEADPHONE JACK  
Telex  
SET  
SR-400  
P/N:71166000  
FCC ID: B5DE405  
S/N:00001  
E.D.R.  
BATTERY  
COMPARTMENT  
VOLUME OFF/ON CONTROL  
Figure 3  
Operating Features SR-400  
SPECIFICATIONS  
SR-400 17 Channel Synthesized Receiver  
Temperature Range .....................................................................................................0 to +50 degrees C  
Supply Voltage ...............................................................................................2-3 Volts, (2) AA Batteries  
Battery Life ..............................................................................................................16-20 Hrs - Alkaline  
12-16 Hrs - Nickel Metal Hydride  
8-10 Hrs - Nickel-cadmium  
Frequency Response....................................................................................................100-10 kHz ±3 dB  
Sensitivity (12 dB SINAD @ 74 MHz)...................................................................................1µ V max.  
Distortion...............................................................................................................................less than 2%  
Audio Output @ 10% Distortion  
Battery Input  
Voltage  
8 ohm  
15 mW  
80 mW  
32 ohm  
10 mW  
50 mW  
2.0 V  
3.0 V  
Controls and Connections.................................................................................Volume OFF/ON Switch;  
Treble Control Switch; Channel Selection Switch  
Audio Output Jack  
-5-  
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ST-300 SYNTHESIZED  
TRANSMITTER  
General Description  
The Telex ST-300 is a base station transmitter which  
operates in the 72-76 MHz band and accepts a wide  
range of audio input levels.  
Operating Features  
ST-300 Front Panel  
1. Power Button  
2. Headphone volume adjustment  
3. Headphone Monitoring Jack  
4. SET Button  
5. Back Lit LCD Display  
6. UP and DOWN Adjustment Buttons  
ST-300 Rear Panel  
1. XLR Input Connector: Accepts bal-  
anced dynamic microphone, 600  
ohm line or 70 Volt line inputs  
2. Unbalanced Audio ¼" Input Con-  
nector.  
3. Antenna Jack: Accepts telescoping  
antenna (supplied) and optional  
HGA-1  
4. Power Input Jack: Accepts any  
source of 12-15 VAC/DC 700 mA  
minimum.  
Figure 4  
Operating Features ST-300  
Front and Rear Panel  
-6-  
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9
1
5
RF POWER: HIGH  
8
CHANNEL  
UNBALANCED  
888dB  
+3 +6  
-10  
0
-5  
AUDIO LEVEL  
6
7
BALANCED  
AUDIO LEVEL 888dB  
2
AUDIO LEVEL  
MIC 600W 70V  
88.8  
EDR  
MHz  
FREQ.  
8
4
3
1. Channel Indicator  
2. Audio Input Meter  
3. Frequency Indicator  
6. Unbalanced Audio Level  
7. Balanced Audio Level  
8. Balanced Input Selection  
9. Lock Out Indicator  
4. Enhanced Dynamic Range Model Indicator  
5. RF Transmit Power (High when lit, Norm when not)  
Figure 5  
LCD Display Functions  
ST-300 Specifications  
Audio Input: ..........................................................................................................Balanced Female XLR  
Mic Selected.........................................................2K ohm input impedance/0.5 mV-70 mV input range  
600W Selected ....................................................300K ohm input impedance/70 mV-7 Volt input range  
70 Volt Line Selected................................................150K ohm input impedance 7 V-70 V input range  
Unbalanced Audio Input ..................................10K W input impedance/10 mV-1.0 VRMS input range  
RF Power Switch ..........................80,000 µV/m at 3m in “Hi”, approx. 25,000 µV/m at 3m in “Low”  
AGC Range ......................................................................................................................................30 dB  
Signal-to-noise Ratio:  
Normal..........................................................................................................................................58 dB  
EDR Enabled................................................................................................................................77 dB  
Pre-Emphasis....................................................................................................................................115mS  
Maximum Deviation.....................................................................................................................±25 kHz  
Frequency Control Crystal.........................................................................................+/-.005% tolerance  
Available Frequencies................................................................................................See Table 1, page 2  
Max. Transmitter Output Power ......................................................................................80 mV/m at 3m  
Power Requirements ................................................................................12-15V, AC or DC @ 300 mA  
Dimensions...................................................................................................7 ½"W x 1 3/4"H x 6 7/8"D  
FCC ID......................................................................................................................................B5DM508  
-7-  
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EQUIPMENT SET-UP  
ST-300 Synthesized Transmitter  
Antenna  
12-15V  
AC/DC  
-
+
UNPACKING: Unpack your sound enhancement  
system. If there are any damages or shortages, refer  
to the "Warranty Service Information."  
ST-300 TRANSMITTER LOCATION: Select a  
suitable location for the ST-300 Transmitter. Try to  
keep a clear, unobstructed path between the trans-  
mitter and receiver and allow plenty of free space  
around the transmitter antenna.  
Figure 7  
Connecting Power  
SYSTEM SET UP SESSION  
ANTENNA CONNECTIONS: Connect the tele-  
All of the channel and input selection functions are  
accessed from the front panel. Press SET button  
once to begin a Setup Session. Whenever a function  
is flashing, the UP and DOWN buttons can be used  
to adjust it. Once set, the next function will start to  
flash. To access a specific function, press set until  
the function is flashing, the features are accessed in  
the following order:  
scoping antenna to the rear panel ANTENNA jack.  
For best results, the antenna should be vertically  
aligned. Tighten the knurled ring to hold the antenna  
in place, and extend the antenna to full length.  
Channel  
RF Power  
Unbalanced Input Level  
Balanced Input Option  
Balanced Input Level  
ANTENNA  
CHANNEL SELECTION: Turn the ST-300 on by  
touching the POWER button. (The ST-300 is de-  
signed to return to "on" if power is disconnected  
while the unit is on. This is so the unit can be  
switched on and off with a power strip or rack  
power).  
REAR PANEL  
Figure 6  
Antenna Connection  
The LCD display will light up and show the Chan-  
nel, Audio Meter, Frequency (and E.D.R. if it has  
been enabled). Press the SET button once and Chan-  
nel letter will flash. Use the UP and DOWN Arrow  
buttons to select the desired channel A-Q. Press  
SET when the desired channel is displayed and the  
channel is set. The channel letter will stop flashing  
and the RF Power indicator will flash.  
POWER CONNECTION: Plug the AC power  
adapter into an electrical outlet. Plug the other end  
of the cord into the power input jack on the rear  
panel of the ST-300.  
-8-  
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RF POWER SELECTION: While the RF Power  
indicator is flashing, press the UP ARROW for  
HIGH and DOWN for NORM (the RF Power line  
will not be displayed). NORM power should be  
used for small to medium sized venues and when-  
ever multiple systems are being used. Press SET  
when the power is set and the Unbalanced Input  
level will flash.  
Enhanced Dynamic Range (E.D.R.) Operation  
The Telex ST-300 Transmitter is equipped with  
E.D.R., Enhanced Dynamic Range (companded) au-  
dio. This mode greatly improves the Audio Signal to  
Noise Ratio when used with the Telex Model  
SR-400 receiver. The E.D.R. mode must be selected  
on both the transmitter and receiver to be effective.  
1. To engage the E.D.R. function, turn the ST-300  
off with the power switch.  
UNBALANCED INPUT LEVEL  
ADJUSTMENT: If the unbalanced audio input will  
not be used, with the Unbalanced Input Level flash-  
ing use the UP button to set the level to OFF and  
press set to go to Balance Input Selection.  
2. Press and hold the SET button while you turn the  
ST-300 back on. The E.D.R. symbol will be dis-  
played in the lower right corner to indicate the  
mode is active.  
If the Unbalanced input will be used, connect the in-  
put now and apply audio content. With the audio  
content playing and Unbalanced Input level flash-  
ing, watch the audio meter. The peak signal should  
not go above the 0 dB segment, use the UP and  
DOWN buttons to adjust the input level so that the  
loudest input lights up the 0 dB segment. When the  
level is set, press the SET button and one of the  
Balanced Input Options will flash (default is 70V).  
3. Repeat the procedure to disable the E.D.R function.  
Change Lock Out  
The ST-300 SET button can be locked to prevent  
E.D.R. activation, and unintended channel changes.  
1. To engage the Lock Out Feature, press the UP  
and DOWN buttons at the same time and hold  
them down for 10 seconds.  
2. The padlock symbol will appear and the set but-  
ton is disabled.  
BALANCED INPUT SELECTION: If the bal-  
anced audio input will not be used, with one of the  
Balance Input Options flashing press SET so the  
Balanced Input Level is flashing. Use the UP and  
DOWN buttons to set the level to OFF and press  
SET to end the setup session.  
3. To unlock the system, press the Up and DOWN  
buttons and hold them for 10 seconds or until the  
padlock symbol disappears.  
AUDIO MONITOR: Turn the Monitor (volume)  
control all the way down (counterclockwise). After  
the audio input levels have been adjusted, Stereo  
headphones with a ¼ in. plug can be plugged into  
the Monitor jack. If you wish to monitor the audio  
program material, turn up the monitor (volume) con-  
trol to the desired level. The monitor control does  
not affect the transmitted audio level.  
If the Balanced input will be used, with one of the  
options flashing use the UP and DOWN buttons to  
select the correct input. With the correct input dis-  
played, press SET and the Balanced Input Level in-  
dicator will flash.  
CAUTION: Permanent damage can result if 70V  
line is used with the Input Selection improperly set.  
BALANCED INPUT LEVEL ADJUSTMENT:  
Make sure the Balanced Input Selection is set cor-  
rectly, then connect the input and apply audio con-  
tent. With the audio content playing and Balanced  
Input level flashing, watch the audio meter. The  
peak signal should not go above the 0 dB segment,  
use the UP and DOWN buttons to adjust the input  
level so that the loudest input lights up the 0 dB  
segment. When the level is set, press the SET button  
and the Setup Session will end.  
-9-  
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Problem  
Solution  
Transmission sounds compressed on SR-50 or  
SR-400  
E.D.R. function may be engaged on the ST-300.  
See setting E.D.R. function on page 9. The  
E.D.R. feature can only be used with the  
SR-400 and must be active on both transmitter  
and receiver to be effective.  
SET button does not work, cannot change  
channel  
Lock Out is engaged, press and hold UP and  
DOWN buttons until the padlock symbol disap-  
pears.  
MULTIPLE SYSTEM INSTALLATIONS: As  
with any radio device, interference can occur at any  
time. The frequencies offered are shared with other  
legitimate users. The severity of interference varies  
with the distance to the interfering station. Multiple  
systems further complicate installations. The follow-  
ing steps are suggested in order to achieve best re-  
sults in your installation.  
2. Set your transmitter(s) to channels with no or  
minimum interference. Each transmitter must be  
set to a separate frequency. For best results when  
using multiple transmitters, each transmitter  
should be installed separately as far as possible  
from the others.  
3. Turn on the transmitter(s) with an active audio  
input. Test walk a receiver through the expected  
listening area to verify coverage. The system  
should now be ready for use.  
1. In order to determine whether your selected fre-  
quencies have minimum interference, Telex rec-  
ommends that you first temporarily install the  
receivers in your proposed setting and monitor  
the channel for interference. To do this (with  
fresh batteries installed) turn on your receiver,  
but DO NOT turn on any other receiver or trans-  
mitter at this time. If audible interference is pres-  
ent, this may indicate another user on the  
channel. Monitoring should be repeated for each  
channel that you propose to use. DO NOT use  
channels that have interference.  
-10-  
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EQUIPMENT OPERATION  
SR-50 SYNTHESIZED  
SR-400 SYNTHESIZED  
RECEIVER  
RECEIVER  
Operation of the SR-50 Receiver  
Operation of the SR-400 Receiver  
Try to keep a clear, unobstructed path between the  
transmitter and receiver antennas for clear reception.  
Try to keep a clear, unobstructed path between the  
transmitter and receiver antennas for a clear trans-  
mission.  
Plug in a unit such as an earphone, headphone but-  
ton receiver, induction coil neckloop, or audio-input  
hearing aid into the headphone jack. (The cord acts  
as a receiving antenna.)  
2
1
Rotate the VOLUME OFF/ON control slowly in the  
clockwise direction while monitoring the volume  
level.  
3
E.D.R.  
When satisfied with the volume level, place the Re-  
ceiver in a pocket or clip it to your belt for conve-  
nience.  
4
Figure 8  
SR-400 Display  
Always return the VOLUME OFF/ON control to the  
OFF position when the receiver is not in use to pre-  
serve battery life and prevent battery leakage.  
1. Channel Display A through Q and low battery indi-  
cator  
2. Lock Indicator (see Change Lock Out)  
3. High Frequency Emphasis Indicator (on when  
symbol is showing)  
4. Enhanced Dynamic Range Indicator.  
Channel Selection  
1. Turn the receiver on and plug a listening device  
into the headphone jack. A channel letter will  
show in the display.  
2. Press the set button once and the Channel indica-  
tor will flash.  
3. Press the  
button and the Channel will cycle  
up, match the channel to the transmitter being  
used (ST-200, ST-300, PST-16, or PST-170).  
4. Press SET, the channel indicator will stop flash-  
ing and the channel is set.  
-11-  
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Enhanced Dynamic Range (E.D.R.) Operation  
Change Lock Out  
The SR-400 SET button can be locked to prevent  
E.D.R. activation, and unintended channel changes.  
The High Frequency Emphasis button will remain  
active at all times for the convenience of the user.  
The Telex ST-300 and PST-170 Transmitters are  
equipped with E.D.R., Enhanced Dynamic Range  
(companded) audio. This mode greatly improves the  
Audio Signal to Noise Ratio when used with the  
Telex Model SR-400 receiver. The E.D.R. mode  
must be selected on both the transmitter and re-  
ceiver to be effective.  
1. To engage the Lock Out Feature, press the SET  
and buttons at the same time and hold them  
down for 10 seconds.  
1. To engage the E.D.R function turn the SR-400  
off with the volume control thumb wheel.  
2. The padlock symbol will appear and the set but-  
ton is disabled.  
2. Press and hold the SET button while you turn the  
SR-400 back on. The E.D.R. symbol will be dis-  
played in the lower right corner to indicate the  
mode is active.  
3. To unlock the system, press the SET and but-  
tons and hold them for 10 seconds or until the  
padlock symbol disappears.  
Low Battery Indication  
3. Repeat the procedure to disable the E.D.R. func-  
tion.  
1. When there is approximately 10% of the battery  
life left, a battery symbol will flash alternately  
with the channel letter in the LCD display.  
2. When there is only 5% battery life left, the bat-  
tery symbol will constantly flash in the display.  
E.D.R.  
Low Battery Display  
-12-  
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BATTERY REPLACEMENT  
The SR-50 and SR-400 Receivers use two (2) AA  
For additional information refer to the “Battery In-  
batteries. When the batteries are low the sound will  
be distorted. Replace weak batteries with two fresh  
AA batteries, and position them in the battery com-  
partment as illustrated in Figure 9.  
formation” Section.  
NOTE: If the unit is to be stored for any length of  
time make sure you remove the batteries from the  
unit.  
BELT CLIP  
BATTERY  
ORIENTATION  
BATTERY COMPARTMENT COVER  
Figure 9  
Battery Installation - SR-50 and SR-400  
-13-  
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BATTERY INFORMATION  
General  
Alkaline Batteries  
Improper battery selection, use, installation and care  
are the cause of numerous wireless system failures.  
Alkaline batteries such as Mallory’s DURACELL®  
or Eveready’s ENERGIZER® provide the most reli-  
able operation in wireless transmitters and receivers.  
The use of low cost carbon-zinc batteries is NOT  
RECOMMENDED.  
*ENERGIZER® is a registered trademark of Union  
Carbide Corporation.  
*DURACELL® is a registered trademark of  
Duracell Inc.  
ANTENNA INFORMATION  
Antenna Alignment  
Antenna Placement  
Proper antenna placement probably has the most ef-  
fect on your TELEX Wireless System’s overall per-  
formance. Following the suggestions that follow  
should result in “dropout free” performance.  
Figure 10  
Antenna Alignment  
Good and Bad  
Figure 11  
Distance Between Transmitter and Receiver  
-14-  
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-----Keep the distance between the transmitter and  
the receiver(s) as short as possible. The greater the  
distance the weaker the signal.  
DO NOT - Mount the transmitter on, or next to,  
metal such as beams, walls with metal studs, etc.  
This will “detune” the transmitter antenna which  
can result in loss of signal at the receiver.  
Make sure the “signal path” between the transmitter  
and receiver(s) is unobstructed. You should always  
be able to visually locate the antenna of the trans-  
mitter at all times.  
LOCATION  
IS OK  
Telex  
power  
Monitor  
ST-300  
set  
LOCATION  
IS BAD  
Telex  
Monitor  
power  
set  
ST-300  
SIGNAL REACHES ANTENNA AT FULL STRENGTH WITH NO OB-  
STRUCTIONS.  
Figure 14  
Transmitter Antenna Placement  
Figure 12  
Keeping Site Clear to Antenna  
Attempting to operate the sound enhancement sys-  
tem through or around walls, ceilings, metal objects,  
etc., will reduce system range and performance.  
SIGNAL REFLECTION OFF A METAL OBSTRUCTION CAUSES  
REDUCED SIGNAL AND “MULTIPATH”  
Figure 13  
Operating Through Obstruction  
-15-  
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TROUBLESHOOTING  
Reread the sections of this manual to make sure you  
have completed system set-up properly.  
If you are unable to solve the problem, contact the  
dealer from whom you purchased the system for as-  
sistance.  
PROBLEM  
SOLUTION  
DISTORTION -System's audio quality seems  
distorted at medium to high input levels  
Reduce audio gain on transmitter by adjusting  
the gain controls.  
HISS - System seems to produce a "hiss" which  
is undesirable.  
Check the gain settings on the transmitter and  
the volume control on the receiver. They may  
be too low.  
Make sure the antenna is connected and fully  
extended. Follow the location suggestions on  
page 15. Change the location of the transmitter  
antenna or avoid the bad area with the receivers.  
DROPOUTS - When moving around the area  
in which you will be using the system there  
seem to be locations where the signal  
"swooshes" or completely disappears.  
INTERFERENCE - System picks up signals  
other than the ST-300 Transmitter.  
Make sure the Telex ST-300 is turned on - this  
will usually eliminate the interference signal.  
If problem persist with the transmitter "ON", try  
changing to another channel.  
REDUCED DISTANCE - System doesn't oper-  
ate as far as it once did. System doesn't' operate  
as well as you think it should.  
Receiver Battery is possibly in need of replace-  
ment. Transmitter antenna possible located in-  
correctly. Receiver not tuned properly.  
BATTERIES DON'T LAST  
If using "throw away" batteries make sure they  
are alkaline. If using nickel-cadmium or nickel  
metal hydride batteries make sure they were  
fully charged when yo are using them and fully  
drained when you are done before recharging  
them.  
HUM - Audio System emits hum or buzz thru  
speakers and sound enhancement receiver.  
Locate Transmitter away from the audio equip-  
ment.  
-16-  
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CUSTOMER SERVICE INFORMATION  
If your receiver or transmitter should need servicing under the warranty, please contact:  
Customer Service Department  
TELEX COMMUNICATIONS, INC.  
8601 East Cornhusker Highway,  
P.O. Box 5579,  
Lincoln, Nebraska 68505-5579 U.S.A.  
Phone: (402) 467-5321 or 465-7021  
All claims of defect or shortage should be sent to the above address. When returning items for  
service, you must provide date and proof of purchase, such as a copy of the sales receipt, to es-  
tablish warranty. A letter should be included outlining all symptoms and claimed defects. Infor-  
mation on how the equipment was installed and used is very helpful. Please include your phone  
number and return address in case our service technicians need to contact you.  
Units that have been modified cannot be accepted for repair.  
Include all information requested by the Service Department. Then pack the unit as follows:  
Check the unit to see that all parts and screws are in place. Then wrap it in heavy paper or put  
it in a plastic bag. If the original carton is not available, place the unit in a strong cart on that is  
at least six inches bigger in all three dimensions than the unit. Fill the carton equally around the  
unit with resilient packing material (shredded paper, foam, etc.). Seal it with gummed pap er  
tape, tie it with a strong cord, and ship it by prepaid express, United Parcel Service or insured  
parcel post to the Telex Service Department.  
It is very important that the shipment be well-packed and fully insured. Damage claims must be  
settled between you and the carrier and this can delay repair and return of the unit to you.  
Telex reserves the right to make changes in design and improvement on its product without as-  
suming any obligation to install the same on any of its products previously manufactured. Fur-  
ther Telex reserves the right to ship new and/or improved products which are similar to the  
form, fit and function of products originally ordered.  
-17-  
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FCC INFORMATION  
The Telex SR-50 Receiver, and SR-400 Receiver are authorized under part 15 of the FCC Regula-  
tions. Changes or modifications to this equipment could void the user’s authority to opera te the  
equipment.  
The Telex Model ST-300 Transmitter is authorized under Federal Communications Commission and  
Industry Canada Rules. Licensing of the Transmitter, if required, is the users responsibility and  
licensability depends upon the users classification, and frequency selected.  
CAUTION: Changes or modifications made by the user could void the user's authority to operate the  
equipment.  
Operation is subject to the following two conditions: (1) This device may not cause interference, and  
(2) This device must accept any interference, including interference that may cause undesired opera-  
tion of the device.  
ACCESSORIES and PARTS  
Rack Mounting Kit  
RM-S for mounting one ST-300.............................................................................................71081-001  
RM-D for mounting two ST-300’s .........................................................................................71081-002  
Earphone (for SR-400 and SR-50)  
(single) ...................................................................................................................................59840-005  
Earphone (for SR-400 and SR-50)  
(dual).......................................................................................................................................59840-001  
Collapsible Lightweight Headphone  
(for SR-400 and SR-50)  
(dual))......................................................................................................................................59840-007  
NL-4S  
Induction Coil Neckloop..........................................................................................................71120001  
Antenna, Telescoping  
for ST-300.................................................................................................................................877960-1  
Belt Clip  
for SR-50 and SR-400 .................................................................................................................358815  
Power Supply  
for ST-300 ....................................................................................................................................730139  
-18-  
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TELEX COMMUNICATIONS, INC. 12000 Portland Ave. South, Burnsville, MN 55337,U.S.A.  
PN 804018 Rev. D  
SEPT 2005  
Made in U.S.A.  
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