Induction loop amplifier with network control and Dante digital

The Williams AV Digi-Loop DL207 NET D is a medium-area, dual-channel induction-loop amplifier with Dante digital audio and Ethernet-based control. It extends program audio to listeners using T-coil-equipped devices, with conference rooms identified as a representative application. Two loop outputs, broad input compatibility, onboard processing, calibration tools, and fault monitoring make it a purpose-built center for professionally designed hearing-loop systems.

Ideal Use Cases

This model is suited to conference rooms and other medium-area spaces that require hearing support for people using T-coil devices. With both outputs driven, its specified coverage reaches 30,000 square feet for perimeter loops with a 3:1 aspect ratio or 18,000 square feet for perimeter loops with a 1:1 aspect ratio. A high-level input accepts 25 V, 70 V, or 100 V feeds from distributed audio and paging systems, while balanced or unbalanced microphone and line connections accommodate conventional AV sources.

Why Choose This Model

The DL207 supplies two loop outputs rated at 9.5 Arms per output, allowing it to serve dual-loop installations from a single 1 RU chassis. Its XLR mic/line input can be configured for microphone, -10 dBV, +4 dBu, or +8 dBu signals and includes a 24 V phantom supply. A separate terminal-block line input supports -10 dBV, -4 dBu, +4 dBu, and +8 dBu sources. Dante digital audio capability adds another integration option for compatible systems.

Signal management extends beyond basic amplification. Available adjustments include input mixing, parametric equalization, compression, metal-loss compensation, high-pass and low-pass filters, automatic gain control, audio delay, and output levels. Priority-input selection has an adjustable threshold, helping the amplifier accommodate installations where one source must take precedence.

Installation and Integration

The rackmount enclosure measures 19 inches wide by 1.75 inches high by 10 inches deep, with a 17-inch-wide chassis, and weighs 9.2 pounds. Its internal universal power supply accepts 100-240 VAC at 50/60 Hz and uses an IEC 320-C14 inlet. Variable-speed, temperature-controlled fan cooling supports operation within the specified 0-35°C temperature range and 0-90% relative humidity.

An RJ-45 Ethernet connection provides function control and calibration through the DigiLoop PC App, which requires Windows 7 or higher. Firmware updates are performed through the standard-B USB connection. The front-panel backlit blue LCD and control button/dial provide local menu access. When a hearing-loop system is correctly designed, installed, and commissioned, the product is designed to meet IEC 60118-4, with test specifications provided to IEC 62489-1.

Performance Highlights

The amplifier has a specified frequency response of 45 Hz to 9.0 kHz within ±2 dB, referenced at 1 kHz. Rated loop distortion is less than 1% at the rated output current with a 1 kHz sine wave. Each output provides 16.1 Vrms continuous loop-drive voltage and supports a DC loop-resistance range from 0.5 to 3.0 ohms. The specified rated load is 0.5 ohm DC with 135 µH inductance.

Audio delay is adjustable from 0 to 165 milliseconds. Built-in calibration resources include a test-tone generator with pink noise plus loop-current adjustment and matching. A front-mounted 1/4-inch stereo headphone jack can monitor a menu-selected input or output. The loop-fault relay supplies normally closed, normally open, and common contacts rated at 2.0 A at 30 VDC.

What Makes It Different

The DL207 brings Dante digital audio, Ethernet application control, conventional analog inputs, and distributed-speaker-level compatibility into one dual-channel hearing-loop amplifier. Configuration save and load functions simplify repeatable setup, while the loop-test function assists commissioning. Open-circuit, short-circuit, and thermal protection address operating faults, and the dedicated fault relay enables external status integration. The combination of two rated outputs and internal calibration tools is especially relevant where matched dual-loop performance is required.

Final Assessment

For a medium-area hearing-loop installation, the DL207 NET D offers clearly documented output capability, flexible source integration, detailed signal processing, and both local and network-based setup. Its strongest application is a professionally designed dual-loop system that needs Dante support, connection to existing AV or paging infrastructure, and calibration and monitoring features in a compact 1 RU rackmount format.