PPA 458

Personal PA® FM Assistive Listening System

Product Highlights

  • Microprocessor controlled
  • PPA T45 professional transmitter
  • Up to 1000’ operating range
  • Transmitter is FCC Part 15 compliant
  • Made in the USA


The Personal PA® 458 features the cutting-edge PPA T45 transmitter, with multiple digital audio input options and an OLED display with easy-to-manage menu navigation. Features three powerful microprocessors and the same high-quality audio and RF performance you’ve come to expect from Williams Sound. With an operating range of up to 1000 feet, the PPA 458 is ideal for large venues where superior coverage is essential. This complete turnkey solution includes four PPA R38N receivers, each featuring an OLED display and on-screen channel selection with easy access to 17 pre-set, wideband frequencies (72-76 MHz). The system is expandable, accommodating any number of listeners. This system complies with 2010 ADA guidelines for hearing assistance and is covered by Lifetime PLUS Limited Warranty.

Replaced by FM 458.

NOTE: Approved by the FCC for operation in U.S. markets. The system cannot be used in all countries. Check with your government radio regulations for 72-76 MHz operation.


System Includes

(1) PPA T45 Transmitter
(4) PPA R38N Receivers
(2) NKL 001 Neckloops
(4) EAR 022 Surround Earphone
(1) ANT 025 Whip Antenna
(1) TFP 048 Power Supply
(1) WLC 004 Main Power Cord (U.S.)
(1) WCA 013 RCA Audio Cable, 3ft.
(1) IDP 008 ADA Wall Plaque
(4) BAT 001-2 AA Alkaline Batteries
Additional 17-channel receivers (PPA R38) may be purchased for multi-channel applications.
All items can be purchased separately.
Ppa 458 ada nb


  • PPA T45 professional transmitter
  • Up to 1000’ operating range
  • Transmitter is FCC Part 15 compliant
  • OLED display, push-button menus
  • Microprocessor controlled
  • Accommodates any number of listeners
  • Adjustable power output
  • Combo XLR, ¼" TRS inputs
  • Meets ADAAG guidelines
  • Lifetime PLUS Limited Warranty. 90 days on accessories.
  • Made in the USA


ANT 025

Used with

PPA T45, PPA T45NET, PPA T27 Transmitters

Connector type

Screw to PCB

Cable type


Nominal Impedance




BAT 001-2

Alkaline, 1.2 Volt

EAR 022


Around-ear speaker


3.5mm mono



Driver Size

23 mm

Nominal Impedance


Freq. Response

20 - 20kHz



Max Power Input

30 mW


118 dB @ 1kHz

IDP 008

10-3/8" (L) x 6-¼" (W) x 1/8" (H)

PPA R38N Architectural and Engineering Specifications

The receiver shall be encased in black, PC/ABS impact-resistant plastic with a hinged battery door. The receiver shall be a body-pack style and include a detachable belt-clip for hands-free operation. The receiver shall have a 3.5mm stereo jack to accommodate stereo or mono low impedance earphones, headphones and neckloops. The receiver shall have a power button that is backlit indicating power is on. The receiver shall receive 17 preset wideband channels between 72-76MHz. Channel selection shall be made in the menu. The receiver shall have channel-lock capability.

The receiver shall have a slide switch inside the battery compartment to select disposable Alkaline or NiMH rechargeable battery operation. It shall have charger contacts on the bottom of the receiver for use with Williams Sound drop-in chargers CHG 3512 and CHG 3502. The recevier shall operate up to 50 hours with two disposable AA Alkaline batteries (BAT 001-2) and up to 32 hours with two AA NiMH rechargeable batteries (BAT 026-2).

The receiver shall provide a maximum output of 35mW at 16Ω with an earbud type earphone. The systems audio frequency response shall be 200Hz to 15kHz ± 3dB and the signal to noise ratio shall be 65dB min. The receiver sensitivity shall be 2µV or better at 12dB Sinad with squelch defeated. The receiver shall accept up to ±75kHz FM deviation and have a 75 µS de-emphasis time constant.

The receiver shall have FCC, Industry Canada approvals and be compliant with RoHS and WEEE regulations. The receiver shall be covered by a Lifetime PLUS Limited Warranty, 90 Days on most accessories.

This receiver model shall be the Williams Sound model PPA R38N.



  4.1" x 2.85" x 1.38" (104 x 72 x 35mm)


  4.6oz (130g) with batteries. 2.6oz (73g) without batteries


  Black/Silver.  Black ABS Plastic case with Aluminum faceplate.

Battery Type: 

  (2) AA Alkaline or (2) AA NiMH Rechargeable


Battery Life: 

  (2) AA non-rechargeable alkaline batteries (BAT 001-2), approx. 50 hrs.

  (2) AA rechargeable NiMH batteries (BAT 026-2), 1500mAh, approx. 32 hrs.

Current Consumption: 

  52mA nominal

Operating Temp. Range: 

  32° – 122°F  (0° to 50°C)


  17 Wideband, accessed via menu

Operating Frequencies: 

  72.1, 72.2, 72.3, 72.4, 72.5, 72.6, 72.7, 72.8, 72.9, 74.7, 75.3, 75.4, 75.5, 75.6, 75.7, 75.8, 75.9 MHz*

FM Deviation: 

  75 kHz


  75 µS

Display Screen: 

  1" OLED

Power Indication: 

  Power button, backlit green.

  Good battery strength - glows solid.  Low battery - flashes.


  2 µV at 12 dB Sinad with squelch defeated

Input Overload: 

  100 mV

Frequency Response: 

  200 Hz – 15 kHz, ±3dB


  FM, +/- 75 kHz peak deviation

Signal-to-Noise Ratio: 

  Minimum 65 dB @ 1.0V

Receive Antenna: 

  Integral with earphone/headphone cord

Audio Output: 

  35 mW max at 16 Ω

Headphone Connector: 

  3.5 mm stereo jack, mono output for stereo or mono earphones/headphones

Supplied Earphone: 

  Stereo,earbud-type with foam cushion, 3.5 mm plug, 32 Ω

Power Save Mode: 

  Enters sleep mode after approximately 3 minutes of no RF signal


  FCC, Industry Canada, RoHS, WEEE


  Lifetime PLUS Limited Warranty, 90 Days on most accessories.

PPA T45 Architectural and Engineering Specifications


There shall be three models of the transmitter - an FM transmitter only, one with network control and one with network control and a Dante input. 

The transmitter shall be a microprocessor-based unit.  It may be configured through the on-screen menu. 

The model with network control will be configurable over an ethernet (10 base T) network accessible through common web based browsers.

The model with Dante input will also be configurable over an ethernet (10 base T) network accessible through Dante Controller. 

The transmitter 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 front OLED menu or web browser.  

There shall be a 10 segment LED bar graph indicating audio input level and an RF “on air” LED.  A 1/4” stereo headphone jack will allow monitoring of the transmitted audio.


Rear Panel:
The PPA T45 shall be powered by an external 24VDC 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 1/4”/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.

All transmitter models shall comply to FCC Part 15.


The FM transmitter shall be the Williams Sound model number PPA T45.

The FM transmitter with network control shall be the Williams Sound model number PPA T45 NET.

The FM transmitter with network control and Dante input shall be the Williams Sound model number PPA T45 NET D.




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, fading from bright to dark indicates Sleep Mode*

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, Ethernet/Network Settings (PPA T45 NET and PPA T45 NET D).


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, or ANT 025

Transmission Range

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

*RF Time-out (Sleep Mode)

Menu selectable - 30 Min, 4 Hours, or Always On; timer starts when audio is below the -21dB VU level and no buttons are pressed

RF Power

Menu selectable - Full, 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 Air”


Audio Processor Functions

DSP based;  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 and PPA T45 NET D) supports CAT5e cable lengths up to 328 feet (100 meters); 10/100 Base-T IEEE 802.3 compliant, unique MAC address.  Cat5e sheilded cable must be used to meet FCC requirements.**


RJ-45 on back of unit (PPA T45 NET D only) supports CAT5e cable lengths up to 328 feet (100 meters); 10/100 Base-T IEEE 802.3 compliant, unique MAC address.  Cat5e sheilded cable must be used to meet FCC requirements.**


FCC including Part 15**, RoHS2, WEEE, Industry Canada


Lifetime PLUS Limited Warranty (90 Days on most accessories)


*Stresses above these ratings may cause permanent damage.  Exposure for extended periods may degrade reliability.

**Effective July 11, 2016, the FCC has mandated tighter emissions limits on auditory assistance transmitters (72-76 MHz) manufactured or imported after this date to help avoid interference with and/or degradation of other airborne signals (All products manufactured prior to July 11, 2016, are compliant).  Williams Sound FM transmitters – PPA T46, PPA T27 and PPA T45 (all models) – all have received a Grant of Certification from the FCC and are fully compliant/approved under this new mandate.



TFP 048

Input: 100-240 VAC, 50/60 Hz, 0.5 A

Output: 24 VDC, 0.75 A

0.3 lbs

WCA 013


Single RCA - RCA audio cable

Used with

PPA T27, PPA T45, PPA T45NET audio input cable

Connector type


Cable type





3 ft

Other Models

PPA 458 PRO Personal PA® FM Listening System
PPA 458 NET Personal PA® FM Listening System
PPA 458 NET PRO Personal PA® FM Listening System

Accessories for Large Area FM Listening System [PPA 458]

All Williams Sound headphones and earphones are compatible with this product.

ANT 005 Remote Coaxial Antenna

ANT 025 39" Telescoping Antenna

BAT 001-2 Two AA alkaline batteries

CHG 3512 Body-pack charger, 12 bay

EAR 013 Single mono earbud

EAR 022 Surround Earphone

RPK 005 Single rack mount kit

RPK 006 Dual rack mount kit

WCA 013 RCA to RCA audio cable (3 ft)


PPA 458 All Versions - Specifications Specifications English
FM Frequency/Channel Chart Technical Bulletins English
PPA R38 Quick Setup Guide Manuals English
PPA R38 User Manual Manuals English
PPA T45/NET/D User Manual - English Manuals English
72 MHz Antenna Selection Guide Application Guides English
PPA T45 User Manual - Portuguese Manuals Portuguese
PPA T45/NET/D Specifications Specifications English
PPA T45 User Manual - Spanish Manuals Español
PPA R38 Specifications Specifications English


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