Personal PA® FM Base Station Transmitter

Product Highlights

  • Made in the USA
  • Meets ADAAG Guidelines
  • Accommodates any number of listeners


The cutting-edge PPA T45 transmitter offers multiple digital audio input options, and an OLED high-resolution screen with easy-to-manage menu navigation.  Features 3 powerful microprocessors and the same high-quality audio and RF performance you’ve come to expect from Williams Sound.  It’s technology that takes the guesswork out of complex audio installation.  Simply select among voice, music, or hearing assistance in the application preset menu, and this transmitter quickly configures itself.  With a range of up to 1000 feet, the PPA T45 is ideal for large venues where superior coverage is essential.


System Includes

(1) PPA T45 transmitter
(1) ANT 025 antenna
(1) TFP 048 power supply
(1) WLC 004 Main Power Cord (U.S.)
(1) WCA 013 RCA Audio Cable, 3ft.
*All items can be purchased separately
Ppa t45 front and rear nb


  • Multiple Digital Audio Inputs (AES, SPDIF) provide direct connection to digital signal sources
  • OLED high-resolution screen with simplified menu navigation, offers comprehensive and convenient access to full system functions
  • DSP Audio Processing
  • Sleek and stylish new design
  • Simple set-up and operation
  • 1000’ operating range
  • OLED display, push-button menus
  • Microprocessor controlled
  • Adjustable RF power output
  • Combo XLR, ¼" TRS inputs
  • Lifetime PLUS Limited Warranty (90 days on accessories)


PPA T45 Architectural and Engineering Specifications


There shall be two models of the transmitter - one with Ethernet control capability and one without.  The transmitter shall be a microprocessor-based unit.  It may be configured through the on-screen menu.  The model with Ethernet control will also be configurable over an Ethernet (10 base T) network accessible through common web based browsers.  It shall have a transmitting range of up to 1000 feet.  It shall have 17 wideband channels operating on 72.1–75.9 MHz.  It shall be supplied with a top mount 39" whip antenna and external power supply.

Front Panel:
The transmitter shall have an OLED screen displaying current settings and menu functions.  Channel/frequency selection, audio input source, audio presets (Hearing Assist, Music, Voice and Custom), audio input level, high and low pass filter, compressor gain and RF output power shall be configurable via the menu or web browser.  There shall be a 10 segment LED indicating audio input level and an RF “on air" LED.  A ¼" stereo headphone jack allows monitoring of the transmitted audio.

Rear Panel:
The transmitter shall be powered by an external 24VAC power supply.  It shall have a 75Ω F-connector on the rear for remote antenna applications and an RCA line level output.  It shall have analog ¼"/XLR combo microphone or line level input jack, XLR AES3 and S/PDIF RCA digital input jacks.  The model with ethernet control shall have an RJ-45 Ethernet jack.

The transmitter shall be compatible with all Williams Sound FM wideband 72-76 MHz receivers and have a lifetime limited warranty.

The transmitter without network control shall be the Williams Sound model number PPA T45.

The transmitter with network control shall be the Williams Sound model number PPA T45NET.



8.45" W x 8.25" D x 1.72"H (21.5 cm x 21 cm x 4.4 cm)


Transmitter: 3.0 lbs (1.36 kg)

Shipping Weight: 4.50 lbs (2.04 kg)  (Transmitter, Power Supply, Antenna and packaging)


Black/Silver with black legends on the front, white legends on the back

Rack Mount:

Standard 19" Rack, 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

Power Supply:


Desktop Style Transformer (TFP 048).

Input: 100-240 VAC, 50/60 Hz.  IEC Line Cord.

Output: 24 VDC, 750 mA, 18W.  2.5mm ID center positive barrel connector.   

Approvals:  UL, CUL, Energy Star V, CSA listed.

Power ON Indicator

Push On/Push Off latching power button, backlit Green indicates Power ON, backlight off indicates power OFF.

Temperature Range:

Operating: +32° F to +104° F (0° C to 40° C)

Storage: -4° F to +158° F (-20° C to 70° C)

Menu Settings:

Audio Presets (Music, Voice, Hearing Assist, Custom), Frequency/Channel selection, Frequency/Channel mode, Audio Input Source (Microphone, Line, Phantom, Digital AES/EB, Digital S/PDIF), High Pass Filter, Low Pass Filter, Compression, RF Output Power, Screen Saver Delay, Test Tone (400 Hz), Headphone Volume, Headphone Source

RF Section

Operating Frequencies:

72.1-75.9 MHz , 17 wideband channels (selectable)

Frequency Accuracy:

± 2 ppm stability, 0-50˚ C


± 75 kHz maximum.


75 µsec.

RF Field Strength:

Does not exceed 80 mV/m at 3 m

Compatible Antennas:

ANT 005, ANT 021, ANT 024, ANT 025, ANT 028, ANT 029, ANT 034.

Transmission Range:

Up to 1000 ft (304 m) with ANT 005 coaxial antenna mounted on rear chassis connector.

RF Timer:

Menu selectable - 30 Min, 4 Hours, or Always On.  Timer starts when no audio is present.

RF Power:

Menu selectable - High, Medium, Low, OFF.

RF Outputs:

(1x) #10-32 stud connector in center of unit (pcb mounted)

(1x) F-connector on rear chassis

RF Transmit Indicator:

1 Green LED, indicates RF “ON"

Audio Section

Audio Processor Functions:

DSP.  Compression: 1:1, 1.5:1 or 2:1. High Pass and Low Pass Filter Frequency control.

Frequency Response:

31 – 16000 Hz, ±3 dB (“Music" Audio Preset)

Signal-to-Noise Ratio:

≥74 dB Transmitted RF

Total Harmonic Distortion:

Less than 0.25% @ 1 kHz (RF output)

Common Mode Rejection:

>57 dB @ 1 kHz, Mic or Line

Audio Inputs:

(1x) Combination 3-pin XLR, 1/4" TRS jack for Mic or Line Level Analog Audio.  Balanced or Unbalanced Line Level, or Microphone with Selectable Phantom Power.

(1x) XLR for Digital Audio, AES3/EBU, supported sample rates 44.1 kHz and 48 kHz.

(1x) RCA for Digital Audio, S/PDIF, supported sample rates 44.1 kHz and 48 kHz.

Audio Input Gain Adjust:

In menu, adjustable to 0 to -50 dB, in 1dB steps

Phantom Power:

14.4 VDC applied through 2.2 kΩ resistors to analog combo jack: Pin 2 and Pin 3 on XLR jack, or tip and ring on 1/4" TRS jack

Audio Level Indicators:

10-LED array that reads -18 to +9 dB at 3 dB intervals. 7 Green, 2 Amber, and 1 red LED.  Green LEDS indicate normal operating audio level peaks, Amber LEDS indicate close to overload peaks, Red LED indicates overload peaks.


Input Levels (Bal or Unbal):

(at Audio Input Gain = 0dB)

Nominal (1st Amber LED)

Overload Warning

(Displayed on Screen)

Absolute Maximum Ratings*


-55 dBV (1.7 mV RMS)

-15 dBV (180 mV RMS)

+20dBV (10.0 V RMS)


-25 dBV (55 mV RMS)

+16 dBV (6.3 V RMS)

+20 dBV (10.0 V RMS)


Headphone Output:

1/4" TRS stereo jack, mono signal, 15.7 mW, maximum in 33 Ω (level adjustable in menu 0 to -40 dB in 2 dB steps)

Line Output:

RCA jack (black), -10 dBV (.32 VRMS).  Output impedance 100 Ω.


RJ-45 on back of unit (PPA T45NET only)


FCC, RoHS2, WEEE, Industry Canada


Lifetime PLUS Limited Warranty (90 Days on most accessories)

Accessories for Personal PA FM Base Station Transmitter [PPA T45]

ANT 005 Remote Coaxial Antenna

ANT 021 Rubber Duckie Antenna

ANT 024 Dipole wall-mount antenna

ANT 025 39" Telescoping Antenna

ANT 028 39" Telescoping Antenna with Swivel Connector

ANT 029 Remote Antenna Kit

ANT 034 Remote Antenna

MIC 094 Unidirectional headband microphone-XLR

RPK 005 Single rack mount kit

RPK 006 Dual rack mount kit

TFP 048 Power supply for PPA T45, PPA T45NET

WLC 004 AC main power cord (U.S.)


Download/View Name Type Language
PPA T45 Specifications Specifications English
PPA T45 Sell Sheet - Portuguese Sell Sheets Portuguese
FM Brochure - Low Res Brochures English
FM Brochure - High Res Brochures English
PPA T45 Sell Sheet Sell Sheets English
PPA T45 User Manual - English Manuals English
72 MHz FM Antennas Application Guides English
PPA T45 User Manual - Portuguese Manuals Portuguese
FM Frequency/Channel Chart Technical Bulletins English
PPA T45 User Manual - Spanish Manuals Español


Name Description Duration
Williams Sound - PPA T45NET Introduction

An introduction to the PPA T45NET. The world's first network controlled assistive listening transmitter.