Description
The D-HA1A is a compact Format-A stereo headphone amplifier designed to receive stereo audio and 24 Vdc power over a single twisted pair cable. It converts Format-A signal pairs into a 3.5 mm mini-jack headphone output and offers a user volume control on the front panel. The unit is optimized for low-noise listening environments and discreet bedside or in-room installations.
Key features include a single-turn user volume control, a standard 3.5 mm mini-jack output, and dual RJ45 Format-A jacks for input and loop-through. The audio input circuits provide high common mode rejection to minimize hum and interference in long twisted pair runs. There are no illuminated indicators to avoid distractions in dark locations such as hotel rooms.
Audio performance supports 25 mW per channel into 100 ohms with frequency response from 10 Hz to 40 kHz at ±1 dB. Distortion is specified at less than 0.01% THD+N at 1 kHz and 10 mW, and noise is below -90 dB at maximum gain. Crosstalk is better than -85 dB at 1 kHz and better than -70 dB across 20 Hz to 20 kHz.
Connectivity is via RDL Format-A over standard twisted pair cabling using RJ45 connectors. The unit uses Format-A pairs B and C for left and right audio and accepts 24 Vdc power supplied by the Format-A sender. One RJ45 jack may be used as input while the second provides loop-thru to additional receivers or modules.
The D-HA1A is a practical solution for guest room and hospitality audio where compact size and low visual impact are required. Typical applications include bedside listening, restroom audio stations, and other in-room audio endpoints requiring simple user control. The module delivers reliable headphone-level output without adding noise or interference to the signal chain.
Installation is straightforward using standard twisted pair cable and a Format-A sender for centralized audio distribution and power. The Decora style steel front panel and rear enclosure provide a clean appearance and secure mounting in a wall or cabinet. An automatic reset fuse protects the unit and connected Format-A power source while maintaining easy serviceability.