Large-area; portable FM a ssistive listening system

Ideal Use Cases

The Williams AV PPA VP 37 is designed for large-area assistive listening applications that need a portable FM audio link. The system combines a T27 transmitter with an R37 receiver, allowing microphone or line-level audio to be delivered to the included earbud or neckloop. It is suited to environments requiring 72–76 MHz operation, a supplied personal receiver, and access to 17 selectable channels. With the standard ANT 021 antenna or optional ANT 005 coaxial antenna, the system has a nominal range of up to 1,000 feet, or 305 meters. The AA-powered receiver also supports listening away from fixed power connections.

Why Choose This Model

This value pack provides the primary components needed for a personal FM signal path: the T27 transmitter, R37 receiver, earbud, and neckloop. The transmitter accommodates both microphone and line-level sources, while its 17-channel frequency selector uses external, lockable switches. On the receiver, channels are accessed through a seek button inside the battery compartment. The R37 can also be used with PPA T45, PPA T55, PPA T55C, and PPA T27 transmitters. Its output supports stereo or mono listening accessories through a 3.5 mm phone jack, giving the system flexibility beyond a single fixed output format.

Installation and Integration

The T27 operates from 105–130 VAC at 50–60 Hz and consumes 3.2 watts at 120 VAC. Audio can enter through a 3.5 mm microphone jack that supplies DC power for electret microphones or through an unbalanced, high-impedance RCA line-level input. The nominal microphone input range is 1–10 mV, while the nominal line input range is 0.1–1 Vrms. A screwdriver-adjustable input attenuator provides level control.

Antenna connections support several installation approaches. The transmitter has a thread mount for the standard ANT 021 rubber duckie antenna or ANT 025 telescoping antenna, plus an RF connector for an ANT 024 dipole or ANT 005 coaxial antenna. The R37 receiver uses two AA alkaline or two AA NiMH batteries. Its receiving antenna is integral with the connected earphone or headphone cord. A green LED indicates power and flashes green when the battery is low.

Performance Highlights

The system operates across 17 frequencies from 72.1 to 75.9 MHz. The transmitter uses FM modulation with plus or minus 75 kHz peak deviation, 75 µS pre-emphasis, stability of plus or minus 0.005 percent over 0–50 degrees Celsius, and maximum total harmonic distortion of 1 percent. Its RF field strength does not exceed 80 mV/m at three meters.

The R37 receiver provides a 200 Hz–15 kHz frequency response, minimum signal-to-noise ratio of 65 dB at 100 µV, an AFC range of plus or minus 120 kHz, and a 100 mV input-overload rating. Maximum audio output is 35 mW peak into 16 ohms. The included foam-cushion earbud has a 3.5 mm plug and 32-ohm impedance. Receiver battery life is approximately 50 hours when using two BAT 001 non-rechargeable alkaline batteries. After approximately six minutes without an RF signal, the receiver enters sleep mode.

What Makes It Different

The PPA VP 37 combines large-area transmitter coverage with a compact personal receiver instead of supplying either component separately. Lockable external channel switches on the transmitter help preserve the selected operating frequency, while the receiver’s compartment-mounted seek control keeps channel access contained. The combination of microphone and RCA line inputs supports two common source types, and the included earbud and neckloop provide two listening accessory options. The system carries FCC, Industry Canada, RoHS, and WEEE approvals and is covered by a one-year warranty.

Final Assessment

The PPA VP 37 is a strong match when the installation calls for a 72–76 MHz personal FM system, up to 17 channels, and a nominal range reaching 1,000 feet with the specified antenna options. Its bundled T27 transmitter, R37 receiver, earbud, and neckloop provide a defined starting configuration, while AA battery operation, automatic sleep mode, microphone input, and line-level input address practical portable and installed use requirements.