Williams Sound PPA 300 Troubleshooting guide

Installation
Guide &
User
Manual
PERSONAL PA Deluxe System 300
Wireless FM Listening System
Transmitter Model T20
Williams Sound ®
Receiver Models R7, R7–4
Helping People Hear

PERSONAL PA Deluxe System 300
Installation Guide & User Manual
Contents Page
Overview 4
Set-Up and Operation
T20 Transmitter
Antenna Connection
Power Connection
Audio Connection
Using a Microphone
Audio Processor Options
4
R7 / R7-4 Receivers
Using R7, R7–4 Receivers
Additional Receiver Instructions
Controls and Features 5
Battery Information 10
Suggestions For Receiver Management 11
Using a Remote Antenna 11
Troubleshooting Guide 12
Radio Interference / Tuning Instructions 14
Warranty 14
System Specifications 15
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3

Overview Set-Up & Operation
Thank you for purchasing the Personal PA Deluxe
System 300 from Williams Sound Corporation. T20 Transmitter
Step 1: Install the antenna.
The PPA 300 is a Wide-band FM Listening System
which operates in the 72–76 MHz frequency band.
Designed for hearing assistance in places of public
access, the PPA 300 is for those who need help
overcoming background noise, reverberation, or
distance from the sound source. It’s easily integrated
with your existing sound system or can be used with
a microphone as a stand-alone system.
Your PPA 300 has two principal parts: the T20
Transmitter and the R7 or R7-4 Receivers. Much like
a miniature radio station, the transmitter and
microphone pick up the sounds you want to hear and
broadcast them over an FM radio signal. The
receivers pick up the broadcast up to 500 feet away.
To avoid difficulties, read through this manual as
you begin to use the system. Then save it for
questions that arise as you continue to use your PPA
system.
If you have any problems with this Williams Sound
product, don’t hesitate to call us toll-free at
1-800-843-3544.
The “rubber duck” whip antenna fits into
the hole on top of the transmitter and
threads onto a mounting stud inside.
Guide the antenna onto the stud and turn it
clockwise to tighten. Do not use excessive
force to tighten the antenna. It only needs
to be finger-tight.
If the optional remote antenna (ANT 005)
is more appropriate, contact your dealer or
Williams Sound Corp. The remote antenna
installation is detailed on page 11.
Step 2: Connect the Transmitter to Power.
The T20 is supplied with a wall
transformer power supply (TFP 016). Plug
the power cord into the “Power” connector
on the rear panel of the T20. Then plug the
transformer into a 120 V, 60 Hz wall
outlet. The indicator light on the front
panel of the T20 should glow when the
power is connected.
There is no ON/OFF switch. Due to low
energy consumption, the T20 is
designed to run continuously.
Sound System Amplifier
Loudspeakers
Microphones
Line-Level Output
R7 / R7-4 Receivers
w/Earphones
Line-Level Input
T20 Transmitter
Tape Out/Phones
Audio Level
HiOk
Power
FM Auditory AssistanceTransmitter
Adjust
Williams Sound
+-
WB NBOn
Transmit Status
Figure 1: Overall System Diagram
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4

Figure 2: T20 Transmitter Controls & Features
Audio Indicators: Tape Out/Phones:
Amber LED "Ok" for nominal input signal level 1/4” jack, 600 mV, 100 Ωsource impedance. Also drives
Red LED "Hi" for excessive input signal level mono or stereo headphone. Monitors exactly what is being
Tape Out/Phones
Audio Level
HiOk
Power
FM Auditory AssistanceTransmitter
Adjust
Williams Sound
+-
WB NBOn
Transmit Status
transmitted.
Power Indicator:
Green LED RF Indicators: Green LED "On" indicates transmitter RF is on
Amber LED "WB" indicates wide–band channel is selected
Amber LED "NB" indicates narrow–band channel is selected
Audio Level Control:
Rotary pot, screwdriver adjust,
used with audio indicator lights
Balanced Audio Input
Line
Mic 70V
FM Auditory AssistanceTransmitter
Select
Unbalanced
Audio Inputs
20 Hz
175 Hz
725 Hz
Hi-Pass Filter
Antenna
Power: 24 VAC, 60 Hz, 10VA
RF Power
75 Ohm
Made in USA Williams Sound Corp.
Channel
COM IN 1 IN 2 IN 3
-12dB Max-6dB
1st
Digit
2nd
Digit
Use with TFP 016
Power Supply
Audio Inputs:
All inputs are actively mixed into a single
signal, allowing use of mono, stereo,
3 channel or 4 channel audio sources
Balanced Audio Input:
Combination 3-pin female
XLR/1/4" stereo jack, accepts
balanced or unbalanced microphone
and line level inputs, 25 V or 70 V
audio input
Input Selector Switch:
3-position slide-type, selects: mic/line/70 V
on combination XLR/Phone audio input
jack
Unbal. Audio Inputs:
Four screw terminals, three unbalanced
line-level inputs,
one ground, actively mixed
High-Pass Filter Switch:
3-position slide-type,
20 Hz, 175 Hz, or 725 Hz,
6 dB / octave roll-off
RF Output Switch:
3-position slide-type,
Full power, -6 dB, -12 dB
Remote Antenna Output:
F-type connector for 75 ΩCoaxial
Antenna (ANT 005) uses RG-59 cable.
Power
Connection:
3-pin, Molex
connector for TFP
016 power supply
Channel Selector:
2 rotary switches set the operating
frequency
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5

The wall transformer can be plugged into
a switched outlet that turns on when the
other sound equipment is turned on. If
turning the T20 on creates a hum or buzz
in the sound system, see the
Troubleshooting Guide on page 12.
Step 3: Make audio connections.
Step 3a: (If you will be using the T20 with an
existing sound system)
Refer to the Overall System Diagram, on
page 4. The T20 has been designed to
accept virtually any type of audio input,
with up to four different input signals
actively mixed together. The best sources
for audio signal from sound system are as
follows:
1st Choice: TAPE OUT or LINE OUT
2nd Choice: BOOSTER or BRIDGING
3rd Choice: Speaker Terminal, or
Speaker Transformer tap
Input connection options for the T20
transmitter are as follows:
Balanced Audio Input Concentric Jack:
1. Accepts balanced and unbalanced
XLR or TRS 1/4" Mic-Level or
Line-Level Inputs
2. Accepts balanced and unbalanced
Mic-Level or Line-Level Inputs
3. Accepts balanced and unbalanced
Speaker-Level Inputs
(25V, 70V speaker line)
See Figure 4 for connection details.
Use the audio cable and adaptor supplied
to connect the T20 “Audio In” jack to an
appropriate audio output jack on the sound
system mixer or amplifier. (See Figure 3.)
If your amplifier or mixer does not have
RCA-type connectors, you can obtain
adaptors from your Authorized Williams
Sound Dealer or a local radio parts store.
If the TAPE OUT jack is already in use, a
Y-Cord can be used to connect the T20
and a second device to the same jack.
Unbalanced Audio Input Terminals:
Accepts one to three unbalanced line-level
signals, which are actively mixed. The
three inputs share a common ground
connection.
Step 3b: (If you will be using the T20 with a
microphone as a stand-alone system)
Any professional low-impedance
microphone may be used with the T20.
Plug the microphone into the concentric
jack (“Balanced Audio Input”) on the rear
panel of the T20. The T20 supplies
positive DC voltage to power condenser
microphones per DIN45596. (Standard
dynamic microphones may also be used.)
Make sure the input selector switch is in
the MIC position. Talking into the
microphone should cause the audio
indicator light to flash on the front panel.
If you use both the Microphone input and
the Audio Input on the T20, the signals
will be mixed.
Step 4: Set the Input Selector Switch.
If you are using the combination
XLR/phone plug input jack, make sure the
selector switch is set in the proper position
as shown in Figure 4.
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6
RCA to 1/4" Adapter
To T20 Concentric Jack
RCA to RCA Cable
From Sound System Line Output
Figure 3: Using The Audio Cable Supplied With The System

Dynamic Low
Impedance Mic
Simplex Powered
Condenser Mic
2 1
3
2 1
3
Male XLR Connector
To T20 Input LINE
MIC 70 V
Unbalanced
Dynamic Mic
Battery Powered
Condenser Mic
1/4in. 2-Conductor
Phone plug to T20 Input
LINE
MIC 70 V
Balanced Line 2 1
3
Male XLR Connector
To T20 Input LINE
MIC 70 V
Shield Grounded As Required
Shield Grounded As Required
Shield Grounded To Amplifier
Shield Grounded To Amplifier
4, 8, 0r 16 Ohm
Speaker Line
2 1
3
Male XLR Connector
To T20 Input LINE
MIC 70 V
25 or 70 Volt
Speaker Line
2 1
3
Male XLR Connector
To T20 Input LINE
MIC 70 V
Balanced
Line
LINE
MIC 70 V
LINE
MIC 70 V
1/4in. 2-Conductor
Phone plug to T20 Input
1/4in. 2-Conductor
Phone plug to T20 Input
Unbalanced
Line
Figure 4: Audio Connection Wiring Detail
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7

0
–10
0
Hard Limiter (Always Functional)
Compress
–10
–20
–20
–30
–30
–40
–40
+10
+10 +20
Hard Limit
Noise Reduction
Soft Limit
Audio "OK" Light ON Audio "High" Light ON
RELATIVE INPUT LEVEL
RELATIVE OUTPUT LEVEL
Figure 5: T20 Audio Processor Performance
Step 5: Set the Hi-Pass Filter Switch.
The High-Pass Filter switch is used to
reduce low frequencies. It is normally
used in the middle (175 Hz) position to
provide high frequency emphasis that
improves speech understanding for hard of
hearing listeners. If the program content is
primarily musical, it can be used in the left
(20 Hz) position. The right position
(725 Hz) may be used for further low
frequency reduction, or it may be used to
reduce low frequency system noise due to
pick up of ventilation system noise, etc.
Step 6: Set the RF Power Switch.
In some situations, the radio signal
produced by the transmitter can enter
other types of equipment and create a hum
or buzzing sound in the sound system.
This is due to poor RF protection in the
other equipment, NOT a problem with the
transmitter.
The normal switch position is MAX power
(right).
If you encounter a hum or buzz in the
sound system when the T20 is turned on,
move the switch to the -6 dB (middle
position). If the buzz diminishes, but
persists, move the switch to the -12 dB
(left) position. If this does not solve the
problem, refer to the Troubleshooting
Guide on page 12.
However, if the amount of buzz does not
change when the RF power switch is
moved from MAX to -12 dB, the buzz is
not related to RF interference from the
T20.
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8

The system range is decreased when
power is reduced, but usually still covers
the entire seating area.
Step 7: Use a receiver to test the system and set
the input level control.
Audio Processor Options
The audio processor in the T20 is capable of four
modes of operation. The effects of these modes are
charted in figure 5.
Compressor Mode
Compressor mode is used for hearing assistance to
limit the dynamic range of the audio signals.
Hearing impaired people generally have a reduced
tolerance for wide dynamic range. The T20 is
shipped in Compressor Mode.
Noise Reduction Mode
The T20 can also be configured for for 2:1
compression. This is for use only with a receiver that
has a 2:1 expansion circuit for noise reduction.
Noise reduction is typically used in narrow-band
operation for high quality audio.
Soft Limit Mode
The T20 can also operate in a soft limit mode, which
allows full dynamic range of audio signals. This
mode may be preferred for musical programs, but
may provide too much dynamic range for hearing
impaired listeners.
Hard Limit Mode
Hard Limit Mode is useful if the T20 has been
installed with external signal processing.
For assistance in selecting an alternate audio
processing mode, contact Williams Sound technical
assistance at 1-800-328-6190.
Receiver Instructions:
Receiver Models R7, R7-4, R7-6, R16
Receiver Model PPA R7 has a single, wheel-type
volume control and an earphone output jack.
Step 1: To install the batteries, open the battery
compartment using a coin in the slot in the
bottom of the receiver. Press the batteries
into place, observing proper battery
polarity.
Step 2: Plug the earphone or headphone into the
earphone jack.
Step 3: Turn the receiver on by rotating the
volume control in the direction of the
arrow on top of the case. Turning the
knob in the direction of the arrow will
increase the volume. Turning the knob
against the arrow will decrease the
volume. To avoid draining the battery,
make sure the receiver is turned off when
not in use.
Step 4: If you are using the T20 with an existing
sound system, make sure the sound system
is turned on. Have someone speak into a
microphone while you listen with the
receiver and earphone. You should be able
to hear their voice through the receiver.
If you are using the T20 with a
microphone, have someone speak into the
microphone while you listen with the
receiver and earphone. You should be able
to hear their voice through the receiver.
Step 5: The T20 Transmitter has a screwdriver-
adjusted input level control located on the
front panel to compensate for different
input signal levels. Adjust the control so
the “OK” audio light flashes with the
signal. It’s alright if the “HI” light comes
on occasionally. Reduce the signal level by
turning the control counter-clockwise if
the “HI” light is on all the time.
If the “OK” light does not come on at all,
turn the T20 input level control clockwise
to increase the signal. If the input level
control is fully clockwise and the “OK”
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9

light still does not come on, you will need
to increase the signal level at its source
(mixer or P.A. amplifier).
Note: The earphone cord is the receiving
antenna. Do not bunch up the cord, wrap it
around the receiver, or place the receiver
in a shirt pocket. The cord should hang as
straight as possible.
Additional Receiver Instructions
PPA R7-4, PPA R7-6:
The R7-4 and R7-6 receivers feature a channel
selector knob on top of the receiver. Turn the
selector knob until you hear the desired program.
Model R16:
The R16 Receiver features a microphone input and
dual volume controls. The taller knob turns the
receiver on and off and controls the FM signal level.
The shorter knob controls the microphone signal
level. By adjusting the two volume controls, you can
hear a mixture of the FM signal and nearby sounds
picked up by the microphone. For more
information, see the instructions included with the
R16.
Battery Information
In normal use, a heavy-duty 9 Volt battery such as
the Eveready 216 will last about 10 hours. Alkaline
batteries such as the Eveready 522 will provide
about 17 hours of use. If the sound becomes weak or
distorted, replace the battery. The indicator light
may still be on, even with a battery that is weak.
Do not leave dead batteries in the receivers.
Rechargeable Batteries
The receivers can also use a rechargeable battery. We
recommend only 7-cell, 8.4 Volt types
(BAT 003). (Most batteries available through
department and radio stores are 6-cell, 7.2 Volt
types. They will not perform satisfactorily with
Williams Sound receivers and may be damaged by
the Williams Sound BAT 005 Charger) A fully-
charged battery (BAT 003) will provide about 5
hours of use per charge. The battery may be
recharged without removing it from the receiver.
The BAT 005 Single Charger has a cord that plugs
into the receiver “EAR” jack to charge the battery.
The CHG 1269A Multiple Charger can charge 12
receivers simultaneously through the receiver “EAR”
jacks.
Receivers can be left charging continuously when
not in use. The receiver should always be turned
OFF while charging. It takes about 14 hours to fully
charge the battery.
!! WARNING !!
DO NOT ATTEMPT TO RECHARGE
DISPOSABLE BATTERIES!
The batteries may heat up and burst, causing
possible injury and damage to the equipment..
Avoid shorting the plus and minus battery
terminals together with metal objects. Battery
damage and burns can result!
Use only Williams Sound Supplied chargers and
batteries!
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10

Suggestions For
Receiver Management
Different types of facilities will use different
approaches for receiver management and earphone
sanitation. Below are some options that customers
have used successfully.
1. Regular users purchase their own receiver
and take care of their own batteries and
earphone.
2. Some facilities label the receiver and
earphone with the names of regular users so
each person uses the same receiver and
earphone.
3. Ushers issue receivers to people who request
them. Earphones are sanitized after use.
Foam ear cushions can be replaced or
washed with a mild detergent, rinsed
thoroughly and air-dried. The EAR 022
Surround Earphone can be sanitized with an
alcohol pad.
4. The receivers can be stored in a multiple
compartment storage case with a credit card
or driver's license left as collateral for the
receiver.
5. Regular users purchase their own earphone
or headphone and bring them to use with
receivers at the facility.
Using A Remote Antenna
The optional ANT 005 Coaxial Antenna is intended
for use with rack-mounted transmitters or in
installation areas where a remote antenna is needed
for maximum operating distance.
Per FCC Rules, only antennas supplied by Williams
Sound may be used with this transmitter.
Do not cut or alter the antenna cable before
reading the instructions below!
The ANT 005 Coaxial Antenna is a length of coaxial
cable with an "F" connector on one end and an
80 in. antenna built onto the other end. The last
80 inches of the antenna make up the active element,
which is covered by nylon braid. The active
element should never be altered. The remainder of
the antenna cable is RG-59 coax feedline. The
feedline can be shortened if you have the tools to
install a new F-connector. If you need a longer
feedline, extension cables are available from
Williams Sound in 50 foot lengths (WCA 008 50).
Never splice coax cables together. Always use
proper connectors.
Installing The Remote Antenna
Step 1: Remove the “rubber duckie” antenna from
the T20’s top panel by turning it
COUNTER-CLOCKWISE.
Step 2: The ANT 005 Coaxial Antenna connects
to the “Antenna” connector on the rear
panel of the T20 Transmitter. To use this
antenna connector, remove the shrinkwrap
with a sharp knife.
Step 3: Use a pliers to remove the cap on the
connector. Be sure to turn COUNTER-
CLOCKWISE to remove the cap.
Step 4: Attach the cable, making sure the center
wire on the cable enters the hole in the
center of the receptacle. The connectors
screw together and need only be “finger-
tight.”
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11

Remote Antenna Location Guidelines
For maximum signal strength, it is best to select an
antenna location somewhere within the listening
area. The preferred location is towards the front of
the listening area and above the seats. The active
element (nylon braid covered portion) should be kept
straight, not coiled, and must be vertical.
Radio signals will generally pass through non-metal
structures. The antenna can be mounted on a wall, in
a corner, or behind a wooden beam. It may also be
hung vertically from the ceiling, with a small weight
attached to the end to make it hang freely. If you
need to run the feedline through a wall, a 1/2 inch
hole is necessary to pass the connector through.
Avoid placing the antenna within four feet of steel
beams or near structural steel elements. Metal
studs, ductwork, and foil-backed insulation can
absorb radio energy, greatly reducing the range
of the system. DO NOT put the active element
(last 80 inches) inside a metal conduit. The
feedline is categorized as Class II wiring. Thus, it
may be (but is not required to be) routed through
metal conduit, but NOT with microphone cables
or AC power wiring.
Nylon clamps and screws are provided to attach the
Coax Antenna to a wall. Locate the clamps every
3– 4 feet. DO NOT bend the cable sharply at any
point. Allow at least a 3" radius for turns. DO NOT
staple the cable in place. Use the cable clamps
provided or hang the antenna from the excess nylon
braid at the end of the antenna element.
Troubleshooting Guide
For most efficient troubleshooting, use high quality
headphones to monitor what is being transmitted.
Plug them into the “Tape Out/Phones” jack on the
T20.
Transmitter “Power” light not on.
1. Make sure the wall transformer is plugged into
the transmitter.
2. Make sure the electrical outlet is on.
No sound through receivers.
1. If some of the receivers work, but others don't,
check for bad batteries or earphones on the
receivers that aren’t working. Check to see that
the receiver frequency matches the transmitter
frequency. The frequency sticker is on the
bottom of the transmitter and inside the back
cover of the receiver. If they do not match, see
the Tuning Instructions on page 14.
2. If none of the receivers work, check to see if the
power is connected to the transmitter and the
“Power” light is on. Check to see if the
transmitter and receivers are set on the same
frequency. Look at the two channel switches on
the T20’s rear panel, checking the settings
against the chart on top of the T20.
4. Check to see if the Transmitter is connected
properly to the sound system. See page 6.
5. Turn the screwdriver-adjust input level control
located on the T20 front panel clockwise to
increase the input signal strength until the audio
indicator light flashes.
6. If you are not using an input signal from a sound
system, make sure the microphone is plugged
into the “Mic” jack on the rear of the T20
transmitter and the input selector switch is in the
MIC (left) position.
7. Make sure the antenna is installed and connected
properly. See pages 4 or 11.
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12

Sound is of normal volume. “HI” audio light not
continuously on, but sound is distorted.
1. The source audio might be distorted.
2. Input select switch might be in wrong position.
Try other positions.
Too much noise when talking stops. Normal
sound compressed excessively. Red “HI” light lit
too frequently.
1. Turn audio adjust counter-clockwise. Red “HI”
light should blink only occasionally. Audio
“OK” light should be on when there is normal
audio present.
2. Consider changing the audio processor option.
The T20 is shipped in Compress Mode. See
page 9 for details.
Sound through the receivers is weak and noisy.
1. Turn the screwdriver-adjust input level control
located on the T20 front panel clockwise to
increase the input signal strength until the audio
indicator light flashes. The audio fed into the
T20 may be noisy or weak. Use a headphone in
the “Phones” jack on the front of the T20 to
listen to the input signal. If it is weak and noisy
from the phones jack, turn up the appropriate
mixer control or try a different audio source.
2. Increase the input signal level from the sound
system by turning up a mixer control.
3. Make sure a valid wide-band channel is selected
and make sure the transmitter and receivers are
tuned to the same channel.
Scratchy noise when receiver volume control is
adjusted.
1. Open the back of the receiver case by opening
the battery compartment. Keep lifting on the
battery door and the back of the receiver case
will open like a book.
2. Remove the screw from the center of the volume
control and remove the knob.
3. Lift the clear plastic cover on the control and
spray GC SPRA-KLEEN, LPS Contact Cleaner,
or equivalent into the control. Replace the knob
and rotate the control several times.
4. Replace the screw and close the case.
Buzzing or humming noise in sound system.
1. There is nothing wrong with the T20 transmitter.
One or more pieces of equipment in the sound
system are being disturbed by RF (Radio
Frequency) signals produced by the T20. The
most likely suspects are your amplifier, mixer, or
tape deck. The RF gets into the other equipment
primarily through the power cord, speaker wires,
or unshielded inputs, all of which can act as
antennas.
Try moving the “RF Power” switch to the -6 dB
or -12 dB position. This will reduce the system
range somewhat.
2. If remedy one does not solve the problem, we
recommend using the optional Coax Antenna
(ANT 005), which should be located 15–20 feet
away from the other sound equipment. You may
add additional RG-59 feedline as needed.
3. If changing to the Coax Antenna doesn’t help,
it’s time to dig deeper into the problem. This
involves a slight modification to the equipment
causing the problem. Unless you have the
necessary technical skills, this is best left to a
qualified electronics repair technician. Call your
Authorized Dealer or Williams Sound
Corporation for more information. Ask for the
Buzz Paper.
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13

Figure 6: T20 Channel Selection
Radio Interference /
Tuning Instructions
The PPA 300is usually not disturbed by other radio
services. However, there are no clear or exclusive
channels for ANY radio service. One of the unique
features of the PPA System 300 is that the operating
frequency can easily be changed to an alternate
channel in the field to avoid interference.
The T20 Transmitter provides 10 wide-band and
10 narrow-band standard frequencies for hearing
assistance use.
Transmitter Frequency Change
Procedure:
Set the two rotary “Channel” selector switches to
match the desired channel listed on the the chart on
top of the transmitter. (See Figure 6.)
One of the 10 standard wide-band channels must be
selected for use with R7 or R7-4 Receivers. The
narrow-band channels are available for use with
Williams Sound’s line of narrow-band receivers,
including the R19, and R19-4.
Wide-Band Channels
1st Digit 2nd Digit Freq (MHz) CH
00 NA NA
0 1 72.100 A
0 2 72.300 B
0 3 72.500 C
0 4 72.700 D
0 5 72.900 E
0 6 75.500 F
0 7 75.700 G
0 8 75.900 H
0 9 74.700 I
1 0 75.300 J
Narrow-Band Channels
1st Digit 2nd Digit Freq (MHz) CH
1 1 72.025 11
1 2 72.075 12
1 3 72.100 13
1 4 72.125 14
1 5 72.175 15
1 6 72.225 16
1 7 72.275 17
1 8 72.300 18
1 9 72.325 19
2 0 72.375 20
2 1 72.425 21
2 2 72.475 22
2 3 72.500 23
2 4 72.525 24
2 5 72.575 25
2 6 72.625 26
2 7 72.675 27
2 8 72.700 28
2 9 72.725 29
3 0 72.775 30
3 1 72.825 31
3 2 72.875 32
3 3 72.900 33
3 4 72.925 34
3 5 72.975 35
3 6 74.625 36
3 7 74.675 37
3 8 74.700 38
3 9 74.725 39
4 0 74.775 40
4 1 75.225 41
4 2 75.275 42
4 3 75.300 43
4 4 75.325 44
4 5 75.375 45
4 6 75.425 46
4 7 75.475 47
4 8 75.500 48
4 9 75.525 49
5 0 75.575 50
5 1 75.625 51
5 2 75.675 52
5 3 75.700 53
5 4 75.725 54
5 5 75.775 55
5 6 75.825 56
5 7 75.875 57
5 8 75.900 58
5 9 75.925 59
6 0 75.975 60
61 - 99 NA NA
Note: NA = Not Available
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14

Receiver Frequency Change
Instructions
Tuning for the R7, R7-4, and R-16 Receivers is
determined by a single tuning coil, and is stabilized
by phase-locked-loop circuitry. A plastic tuning
wrench (PLT 005) is needed to adjust the receiver
tuning coil.
Step 1: Use the transmitter as a tuning signal
source. Have someone speak into the
microphone so you have something to
listen to.
Step 2: Disconnect the antenna from the
transmitter. The receiver must be tuned
under weak signal conditions.
Step 3: Open the back of the receiver to expose
the circuit board. Open the receiver battery
flap first. The receiver back snaps open
like a book.
Step 4: Locate the tuning coil. (See Figure 7.) Use
the headphone supplied with the receiver
to listen for the transmitter signal while
you slowly and gently rotate the tuning
slug inside the tuning coil with the tuning
wrench. Adjust the tuning coil slowly and
carefully. Do not press down on the tuning
slug. Adjust for maximum signal.
Step 5: Re-tune all the receivers and mark the new
frequency inside the case for future
reference.
Warranty
The Williams Sound T20 Transmitter and R7, R7-4,
R7-6, and R16 Receivers are warranted against
defects in workmanship and materials for FIVE
YEARS. Microphones, earphones, cables, carry
cases, rechargeable batteries and chargers are
warranted against defects in workmanship and
materials for NINETY DAYS. This warranty does
not extend to intentional or accidental physical
damage. This warranty applies only to products
returned to Williams Sound for service. To return a
product for service, call 1-800-843-3544 and request
a Return Authorization (RA) number.
Tuning Coil
Figure 7: R7 Receiver Tuning
Williams Sound ®
Helping People Hear
15

PERSONAL PA SYSTEM 300 SPECIFICATIONS
PERSONAL PA Transmitter Model T20
Dimensions, Weight: 8.45" (21.5 cm) W x 8.18" (20.8 cm) D x
1.72" (4.4 cm) H, 3 lbs. (1.5 kg)
Color: Black epoxy paint with white legends
Rack Mount: One IEC rack space high, one or two
units can be mounted in a single rack
space with optional RPK 005 (single) or
RPK 006 (double) Rack Mount Kits
Power: External power supply(TFP 016), 24 VAC,
50 or 60 Hz, 10 VA, 230 mA max. current
drain
FCC ID: CNMT20
Operating Freqs: 72–76 MHz, 10 wide–band and
10 narrow–band channels,
Stability: ±.005% stability, 0-50˚C
Deviation: ± 75 kHz max. for wide–band channels,
±5kHz max for narrow–band channels
Pre-Emphasis: Wide-band: 75 µsec, narrow–band: 300
µsec
RF Field Strength: 8000 µV/m at 30 m max., 20 mW typical
Nominal Range: 300-500 ft. (90-150 m)
AGC Options: (1)Standard variable slope
compressor/limiter (2)Noise Reduction
(3)Soft Limit (4)Hard Limit
Frequency Response: WB: 30 Hz – 15 kHz ±3 dB, .25% Max. THD
NB: 30 Hz – 5 kHz ±3 dB, .25% Max. THD
Signal to Noise Ratio: 60 dB with R7 Receiver
Front Panel:
Power Indicator: Green LED
RF Indicators: Green LED "On" indicates
transmitter RF is on
Amber LED "WB" indicates
wide–band channel selected
Amber LED "NB" indicates
narrow–band channel selected
Audio Indicators: Amber LED "Ok" for nominal input
signal level
Red LED "Hi" for excessive input signal
level
Audio Level Control: Rotary pot, screwdriver adjust, used with
audio indicator lights
PERSONAL PA Receiver, Model PPA R7
Dimensions & Weight: 3-5/8" L x 2-3/8" W x 7/8" H
(92.1 mm x 60.3 mm x 22.2 mm)
3.2 oz (90 g) with battery
Color: Gray
Battery Type: 9 Volt, Eveready 522 Alkaline
or BAT 003 Ni-Cad
Battery Drain: 14 mA, nominal
Battery Life: 32 hours with Eveready 522,
6 hours/charge with BAT 003
FCC ID: CNM R7Y
Operating Freq.: Pre-Tuned, Adjustable, 72 MHz - 76 MHz *
Intermediate Freq.: 70 kHz
FM Deviation: 30 kHz
De-Emphasis: 75 uS
AFC Range: ± 300 kHz
Tape Output: 1/4” jack, 600 mV, 100Ωsource
impedance, also drives mono or stereo
headphone
Rear Panel:
Audio Inputs: All inputs are actively mixed into a single
signal, allowing use of mono, stereo, 3
channel, or 4 channel audio sources
Balanced Audio Input: Combination 3-pin female XLR/1/4”
stereo jack, accepts balanced or
unbalanced microphone and line level
inputs, 25 V or
70 V audio input
Mic Input Levels: Lo-Z, 100 µV min. to 50 mV max. 1 mV
nominal, 3 kΩinput impedance. Supplies
simplex power 20 V (DIN45596) for
condenser mics
Line Input Levels: 21 mV min. to 10 V max., 212 mV
nominal, 100 KΩinput impedance
70 Volt Input Levels: 216 mV min. to 100 V max., 2.16 V
nominal, 100 KΩinput impedance
Unbal. Audio Inputs: Four screw terminals, three unbalanced
line-level inputs, one ground, actively
mixed
Input Selector Switch: 3-position slide-type , selects: mic/line/70
V on combination XLR/Phone audio
input jack
High-Pass Filter Switch: 3-position slide-type, 20 Hz, 175 Hz, or 725
Hz, 6 dB/octave roll-off
RF Output Switch: 3-position slide-type, Full power,
-6 dB, -12 dB
Antenna Outputs: Thread Mount for "rubber duckie" flexible
whip antenna, optional hard-wired 75 Ω
Coaxial Antenna (ANT 005) uses RG-59
cable, 400 ft. (140 m) max. cable length
Power Connections: 3-pin Molex connector
Channel Selector: 2 rotary switches set the operating
frequency
Sensitivity: 2 µV at 12 dB Sinad with squelch
defeated
Squelch: Squelches at 10 µV for minimum
50 dB S/N ratio
Input Overload: 20 mV
Frequency Response: 100 – 10 kHz, ± 3 dB
Signal-to-Noise Ratio: 50 dB at 10 µV
Receive Antenna: Integral with earphone/headphone
cord
Audio Output: 250 mW, max. at 16 Ohms
Output Connector: 3.5 mm mini phone jack, also serves as a
charging jack for rechargeable battery
Earphone: Earbud-type with foam cushion,
3.5 mm plug, 32 Ω
Williams Sound Corp.
10399 West 70th St., Eden Prairie, MN 55344-3459
U.S.A. 800-328-6190 / 952-943-2252 / FAX: [phone]
www.williamssound.com
© 2001, Williams Sound Corp. MAN 050B