Description
The HD-PA35AX is a single-zone, single-input 35 watt power amplifier designed for efficient distributed audio systems. It delivers a constant-voltage output selectable for 25 V, 70 V or 100 V speaker systems and operates on a high-efficiency Class D output stage. The unit includes a worldwide external power supply and a front-panel input gain control for quick setup.
Key features include front-panel bass and treble tone controls, an analog compressor/limiter, and VCA remote output level control compatibility. The analog compressor provides multi-time-constant compression that prevents clipping while preserving dynamics, and a front-panel LED indicates compressor activity. A detachable terminal block provides the amplifier output and remote control connections for integration into larger systems.
Performance specifications include 35 W RMS rated power at less than 1% THD+N, a frequency response of ±3 dB from 50 Hz to 18 kHz, and noise below -75 dB at maximum gain. The compressor threshold is set 2 dB below rated output and the device maintains audio fidelity even when pushed above nominal levels. Total harmonic distortion is specified at under 0.5% at 1 kHz near the compressor threshold.
Connectivity is straightforward with unbalanced summing inputs on RCA jacks and a detachable terminal block for amplifier outputs and remote control connections. The VCA accepts 0 to 10 Vdc or industry-standard 0 to 10 kOhm controls and is compatible with RDL wall controls. A front-panel pushbutton toggles between standby and active modes while a blue power LED indicates supply and operational state.
The HD-PA35AX is suited to small to medium installations requiring an additional zone amplifier such as retail paging, background music zones, or secondary room audio. Its constant-voltage outputs and remote level control make it compatible with distributed speaker systems and centralized mixers. The compressor and Class D topology allow the unit to deliver clear, unclipped average output levels comparable to higher-rated amplifiers.
Installation is simplified by the included 100 to 240 Vac power supply that provides 24 Vdc to the chassis, compact footprint, and detachable terminal connections. Thermal and short-circuit protection are built into the design and the Class D amplifier minimizes heat dissipation under typical voice and music program material. The chassis is engineered and manufactured in the USA and offers reliable build quality for professional AV installations.


