Description
Download Manual The HD-PA35U is a compact single-zone audio power amplifier designed to deliver efficient, high-quality audio for paging and background-music applications. It uses a high-efficiency Class D output stage rated at 35 watts and supports either 4 ohm or 8 ohm speaker loads via a rear-panel impedance selector. The unit is engineered to minimize standby power consumption while providing full amplifier functionality when audio is present.
Key features include front-panel input gain and tone controls, a built-in analog compressor/limiter, and a VCA-compatible remote control input for master volume adjustment. The compressor provides automatic protection against clipping while preserving dynamic range for normal program material. The amplifier also includes soft-start protection to prevent turn-on/turn-off transients.
Performance specifications include 35 W RMS output into 4 ohms and 32 W into 8 ohms with <1% THD+N at rated levels and a frequency response of ±1 dB from 50 Hz to 20 kHz. Noise is specified at <-75 dB at maximum gain and THD+N is <0.5% at the compressor threshold. The compressor threshold is set 2 dB below rated output and uses multiple attack/release time constants for transparent control.
Connectivity is straightforward with unbalanced stereo summing inputs on RCA jacks and a detachable terminal block for the amplifier output. Remote VCA control is provided via an RJ45 jack supporting 0 to 10 Vdc control and compatibility with RDL wall controls. The included external 24 Vdc power supply accepts 100 to 240 Vac input and powers the amplifier chassis.
The HD-PA35U is suitable for single-zone installations requiring energy-conscious amplification – examples include small retail background-music zones, staff paging zones, and secondary zones fed from a central mixer. Automatic sleep mode reduces standby consumption to under 1 W while allowing configurable sleep delays from 10 minutes to 2 hours. Sleep mode can also be disabled for continuous operation.
Installation and operation are simplified by front-panel EQ and level controls, rear-panel sleep-delay DIP switches, and clear front-panel indicators for signal, compressor activity, and power state. Thermal and short-circuit protection are built into the amplifier and the compact chassis fits easily into equipment racks or shelf mounts. The HD-PA35U is engineered and manufactured in the USA to meet strict energy efficiency standards.