Installation guide

Williams Sound
®
Helping People Hear
6
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. The PPA 250 can
also be used with a microphone as a stand-alone system.
Your PPA 250 has two principal parts: the T4 Transmitter and the R7 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.
Listeners may sit anywhere and can make the audio signal as loud as they wish without
causing PA system feedback or disturbing others.
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.
Sound System Amplifier
Loudspeakers
Microphones
Line-Level
Output
R7 / R7-4 Receivers
w/Earphones
Line-Level
Input
T4 Transmitter
Phones
PPA T4 Professional FM Auditory Assistance Transmitter
Williams Sound
Power -12dB -6dB 0dB +6dB
Audio Level
Lo
Increase
Decrease
Too Hi
Audio Adjust
RF Carrier
Ok
Ok
Frequency Synthesized, Channel-Selectable
FIGURE 1: OVERALL SYSTEM DIAGRAM