Description
Download Manual The HD-PA35UA is a single-input, high-efficiency audio power amplifier designed for constant-voltage distribution systems. It delivers 35 W RMS into 25 V / 70 V / 100 V outputs and uses a Class D output stage to minimize heat and maximize efficiency. The amplifier supports single-zone use and can extend zones from other RDL HD-series mixers.
Key features include front-panel input gain, bass and treble tone controls, and a VCA-compatible remote level control via rear-panel RJ45. The unit implements an analog compressor/limiter that prevents clipping while preserving dynamics for normal program material. It also provides selectable sleep mode behavior to conserve power when no audio is present.
Performance highlights include a frequency response of ±3 dB from 50 Hz to 13 kHz, THD+N below 0.5% at the compressor threshold, and a noise floor better than <-75 dB at maximum gain. The compressor offers automatic attack and release with three dynamic time constants and a threshold positioned to increase average usable output. The amplifier meets Energy Star audio efficiency criteria and consumes less than 1 W in sleep mode.
Connectivity comprises unbalanced stereo summing RCA inputs, a detachable terminal block for constant-voltage speaker outputs, and an RJ45 port for VCA remote volume control compatible with 0 to 10 Vdc control or standard RDL wall controls. Rear-panel DIP switches select the sleep-mode delay from 10 minutes to 2 hours or disable sleep mode for continuous operation. A front-panel pushbutton toggles standby/active states and three front LEDs indicate signal, compressor activity and power state.
Typical applications include retail background music and paging, meeting rooms needing an additional zone amplifier, and retrofit installations requiring efficient constant-voltage distribution. The analog compressor enables sustained average levels comparable to higher-rated amplifiers while preventing speaker clipping during peaks. The compact footprint allows placement in equipment racks, behind displays, or in shallow enclosures where space is limited.
Installation is straightforward with a single audio input and detachable output block for fast speaker wiring. The amplifier provides thermal and short-circuit protection plus soft-start switching to eliminate turn-on thumps and pops. Built and tested in the USA to strict energy conservation standards, the HD-PA35UA offers long-term reliability and predictable behavior in mixed-voice and music environments.