Installation Guide & User Manual PERSONAL PA® Pro Wide–band System 250 Wireless FM Listening System Transmitter Model T4 Receiver Models R7, R7–4 MAN 071 D ® Williams Sound Helping People Hear
PRO WIDE–BAND SYSTEM, MODEL PPA 250 INSTALLATION GUIDE & USER MANUAL Contents Page FAST SET-UP PROCEDURE 4 SYSTEM OVERVIEW 6 CONTROLS AND CONNECTORS 8 DETAILED SET-UP PROCEDURE 4 MOUNTING THE TRANSMITTER INSTALLING THE ANTENNA CHOOSING A CHANNEL CHOOSING AND CONNECTING AN AUDIO SOURCE CHOOSING AN AUDIO SOURCE FOR THE HEARING IMPAIRED CONNECTING THE POWER SUPPLY ADJUSTING THE AUDIO INPUT CONTROL AUDIO PROCESSOR OPTIONS 16 ASSURING EXCELLENT PERFORMANCE 17 RECEIVER USE INSTRUCTIONS 18 BATTER
FAST SETUP PROCEDURE Step 1 Choose a Location for the Transmitter It’s usually most convenient to locate the T4 next to the public address equipment. The location must have the audio feed and 120 VAC power available. Place the transmitter on a level surface where there are no substantial metal or other electrically conductive objects between the antenna and the listening area. After initial adjustments, there should be no need to access the unit.
Step 5 Set the Audio Select DIP Switches Set the Audio Select switch for the type of source you’re using. If you have used the audio cable provided with the PPA 250, there is no need to change the factory set configuration. If you have used a different type of cable, see the T4’s top panel and pages 10 and 13 for the appropriate switch configurations and plug wiring diagrams. See page 15 for Compress vs. Limit adjustments.
SYSTEM OVERVIEW The PPA 250 is a Wide-band FM Listening System which operates in the 72–76 MHz frequency band. Developed for hearing assistance in places of public access, the PPA 250 is designed for those who need help overcoming background noise, reverberation, or distance from the sound source. It includes a complete audio processor optimized for the needs of hearing impaired persons and is easily integrated with your existing sound system.
FIGURE 2: T4 TRANSMITTER CONTROLS & FEATURES Phones Jack Audio Level Indicators 1/4" jack, 220 Ω source impedance. Drives mono or stereo headphone. Monitors exactly what is being transmitted. Four-LED array shows audio level in 6 dB steps. Optimum level is reached when the amber 0 light usually blinks and the red +6 light blinks occasionally.
CONTROLS AND CONNECTORS FRONT PANEL POWER INDICATOR Indicates that the transmitter has power available and that the unit is on. AUDIO ADJUST CONTROL Controls level of audio signal and is connected between the input amplifier and the audio level processing circuit. AUDIO LEVEL INDICATOR A four-LED array shows audio level in 6 dB steps. Indicator is average responding and is calibrated so that optimum level is reached when the amber 0 light usually blinks and the red +6 light blinks occasionally.
INPUT The input can be configured to accept three types of signal sources: Balanced or Unbalanced Microphone, Balanced or Unbalanced Line, and 70 V speaker line. The input is configured to accept various combinations of these inputs by means of the Audio Select switch. (See Figure 3.) PROFESSIONAL MICROPHONE Most dynamic, ribbon, or condenser microphones equipped with a balanced output and a 3-pin XLR connector can be used. Power can be supplied for condenser microphones according to DIN 45596.
unacceptable situation, use a connection scheme like those described in the section Avoiding Ground Loops. Set the Audio Select Switch for Line input when connecting to 2-16 Ω speakers. Set the Audio Select Switch for 70 V when connecting to 25 V or 70 V speaker lines. Speaker lines are most often equalized, making them an inferior signal source. Source signals should not be equalized. TAPE OUTPUT A line level output of the fully processed, “as transmitted” audio is provided through this jack.
DETAILED SETUP PROCEDURE STEP 1: CHOOSE A LOCATION AND INSTALL THE TRANSMITTER It’s usually most convenient to locate the T4 next to the public address equipment because your transmitter location must have the audio feed and 120 VAC power available. FOR SIMPLE INSTALLATIONS Place the transmitter on a level surface where there are no substantial metal or other electrically conductive objects between the antenna and the listening area. After initial adjustments, there will be no need to access the unit.
AVOIDING UNDESIRABLE ANTENNA INSTALLATIONS Transmission (range, directional properties) can be severely impaired by improper installation of the antenna. DO NOT install the antenna within any metal enclosure. DO NOT install the antenna where it is within about 4 feet of any metal object that is more than about 2 feet long.
STEP 4: CHOOSE AND CONNECT AN AUDIO SOURCE Your choice of audio source can greatly affect the usefulness of your hearing assistance system. SIMPLE INSTALLATIONS In simple sound systems, the best audio source is usually a Tape or Auxiliary output jack on the system’s amplifier. Set the Audio Select switch for the type of source you have (See Figure 6.) and plug in a suitable audio cable. If those jacks are already in use, a simple “Y cord” can easily make the connection.
2 TO 16 Ω OR 70 V SPEAKER LINE The T4 input can also be connected directly to 2 to 16 Ω or 70 Volt speaker lines. If you choose to connect to 70 Volt Speaker line, be certain to set the Audio Select switch correctly. Severe damage will occur if you do not. When making such connections, it’s very important to avoid creating ground loops. Pin 1 of the 3-pin connector and the sleeve of the 1/4" jack are connected directly to the chassis.
not helpful to the hearing impaired and can contribute to excessive noise in the receiver outputs. See the section below, Deciding Between Compress Or Limit Settings. If an audio delay is available for use in large auditoriums, it’s usually best to use it.
STEP 5: CONNECT THE POWER SUPPLY The T4 transmitter is powered by a wall mounted transformer supplying 24 VAC. Plug the transformer into a suitable 120 VAC outlet and connect the attached cable to the transmitter. The cable connector has a retaining catch which must be installed toward the top of the transmitter as shown on the T4’s back panel. Though no damage will result, the T4 will not operate if you install the cable upside down. Neither the T4, nor its power supply, are equipped with a power switch.
ASSURING EXCELLENT PERFORMANCE The PPA 250 consists of a transmitter and several receivers used to deliver an audio signal to listeners who are hard of hearing. The audio signal is usually provided by equipment manufactured and installed by others. The PPA 250 provides excellent audio performance under most conditions. However, Williams Sound equipment does not correct faults in incoming audio.
RECEIVER USE INSTRUCTIONS RECEIVER MODEL PPA R7 Receiver Model PPA R7 has a single, wheel-type volume control and an earphone output jack. BATTERY INSTALLATION Open the battery compartment using a coin in the slot in the bottom of the receiver. Press the battery into place, observing proper battery polarity. Incorrect insertion of the battery is difficult, and may cause both mechanical and electrical damage to the receiver not covered by the 5 year warranty.
shorter knob controls the microphone signal level. By adjusting the two volume controls, you can hear a mixture of the transmitted signal and nearby sounds. Note: Some users may not be helped by this system. Severe hearing loss may require using the system with a telecoil coupler (i.e., Neckloop) and personal hearing aid.
BATTERY INFORMATION DISPOSABLE BATTERIES 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 32 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. Battery corrosion is not covered by the Williams Sound five year warranty.
FREQUENCY CHANGE INSTRUCTIONS Normally, the PPA 250’s factory-set channel (usually 72.9 MHz) requires no change. However, if another hearing assistance system or authorized radio service is operating on 72.9 MHz in your area, it may prove necessary to use an alternate channel In this event, the PPA System 250’s operating frequency can easily be changed to an alternate channel to avoid interference. See the following sections for instructions on changing frequencies.
RECEIVER FREQUENCY CHANGE INSTRUCTIONS Tuning for the R7 and R-16 Receivers is determined by a single tuning coil. (See Figure 10.) A plastic tuning wrench (PLT 005) is needed to adjust the receiver tuning coil. FIGURE 10: R7 RECEIVER TUNING Tuning Coil This is a small, square, bright metal can with a screwdriver slot in the top center. Using a plastic tuning tool (PLT 005), rotate the Tuning Coil slowly and gently. Do not press down on the adjustment.
SUGGESTIONS FOR RECEIVER MANAGEMENT Different types of facilities use varying approaches to receiver management and earphone sanitation. Below are some options that customers have used successfully. 1. Regular users purchase or are given their own receiver and take care of their own batteries and earphones. 2. The facility labels a receiver and earphone for each regular user. The facility maintains the units. 3. Ushers issue receivers to people who request them. Earphones are sanitized after use.
TROUBLE SHOOTING GUIDE NO TRANSMITTER OPERATION POWER LIGHT NOT ON Most likely, there is no power. Make sure the power outlet is working and that the PPA 250’s power supply (TFP 016) is connected correctly. AUDIO DIFFICULTIES (AS HEARD IN PHONES JACK ON TRANSMITTER) NO AUDIO HEARD IN PHONES JACK Check to see if there is a signal coming from your audio source. Check and correct your audio source if necessary. Check to see if the Audio Level control has been turned all the way down. If so, adjust it.
NOISE IN AUDIO “GROWS” WHEN PROGRAM IS SILENT The Audio Level control is set too high. You’re probably also seeing the +6 level indicator lighting all the time. To correct, adjust the Audio Level control. It could be that the T4’s Audio Processor is set for Compress when Limit might be more appropriate for the type of program being transmitted. Reset the Audio Select switch for Limit. See page 15.
Check to see if there is a strong interfering signal by listening to the receiver with the transmitter turned off. If an interfering signal is causing overload in the receivers, see the section on insufficient range above. If changing channels does not remedy the problem, use other technology, such as Williams Sound Narrow Band FM or Williams Sound Infrared. USERS MUST TURN RECEIVER VOLUME CONTROLS WAY UP (TO 4 OR 5) TO GET ENOUGH VOLUME Perhaps there is insufficient audio level.
audio equipment may offer application notes for this purpose. Williams Sound offers a document giving suggestions for improving RF immunity in existing audio equipment. (Technical Bulletin: Buzz Or Hum In The Sound System, FRM 531) WARRANTY The Williams Sound T4 Transmitter and R7, R7-4, R7-6, and R16 Receivers are warranted against defects in workmanship and materials for FIVE YEARS.
Pro Wide–band System, Model PPA 250 SPECIFICATIONS PERSONAL PA Transmitter Model T4 Dimensions, Weight: Color: Rack Mount: Power: FCC ID: Operating Freqs: 8.45" (21.5 cm) W x 8.18" (20.8 cm) D x 1.72" (4.4 cm) H, 3lbs. (1.5 kg) Black epoxy paint with white legends One EIA rack space high, 1/2 space wide 1–2 units can be mounted in a single rack space with optional RPK 005 (single) or RPK 006 (double) Rack Mount Kits 21 VAC minimum; 26 VAC maximum, 50 or 60 Hz 4.
