Format-A Stereo Headphone Amplifier

The RDL TP-HA1A is an ultra-compact stereo headphone amplifier designed for RDL twisted-pair Format-A systems. It receives the Format-A input and operating power through an RJ45 connection, then provides a user-adjustable stereo headphone output on a standard mini-jack. Rated output is 25 mW per channel into 100 ohms. A second RJ45 serves as a Format-A loop-through, allowing the signal path to continue to additional modules. Its all-metal construction, flat-surface mounting capability, and automatically resetting fuse make the unit a focused solution for adding a controllable headphone listening point to an existing Format-A installation.

Ideal Use Cases

The TP-HA1A is intended for installations that need a local stereo headphone feed from an RDL TP Format-A sender. It is especially relevant when the audio carried on Format-A signal pairs B and C must be available at a compact, surface-mounted listening position. Because the module includes a loop-through RJ45, it also suits systems where another Format-A module must remain connected downstream. The standard mini-jack output accommodates standard headphones, while the onboard level control lets the listener set the headphone level directly at the module.

Why Choose This Model

This model combines audio output, level adjustment, power reception, and signal loop-through in one small metal enclosure. Power is supplied by the connected Format-A sender over RJ45, and the specified requirement is 24 Vdc at 30 mA. That arrangement keeps the signal and power connections within the Format-A cabling scheme. The 3.9 x 2.57 x 1.13-inch chassis is compact enough for placement on a flat surface where access to the headphone jack and level control is needed. An automatically resetting fuse provides integrated circuit protection.

Installation and Integration

Connect the input RJ45 to an RDL Format-A sender using twisted-pair cable. The TP-HA1A uses Format-A signal pairs B and C. If the installation continues to another module, use the RJ45 Format-A output as the loop-through connection. The sender supplies power through RJ45; the product data specifies 24 Vdc at 30 mA and identifies the PS-24AS for USA applications and PS-24AX for international applications as recommended power supplies. Mount the enclosure to any flat surface, connect standard headphones to the mini-jack, and use the user level control to set the listening level. The module measures 3.9 inches long, 2.57 inches wide, and 1.13 inches high.

Performance Highlights

Audio performance is defined by a 10 Hz to 40 kHz frequency response, rated within ±1 dB into 100 ohms. Stereo output is 25 mW per channel into the same load. THD+N is specified below 0.01% at 1 kHz and 10 mW, while noise is below -90 dB at maximum gain. Crosstalk is below -85 dB at 1 kHz and below -70 dB from 20 Hz to 20 kHz. These published figures provide concrete bandwidth, distortion, noise, and channel-separation values for evaluating the amplifier within a Format-A headphone distribution path.

What Makes It Different

The TP-HA1A is specifically built around RDL TP Format-A. Its RJ45 input carries the Format-A source and sender-provided power, while the RJ45 loop-through supplies a connection for additional modules. The device concentrates its user-facing functions at the listening endpoint through a standard mini-jack and local level control. The combination of a 25 mW-per-channel stereo output, use of signal pairs B and C, ultra-compact metal construction, flat-surface mounting, and automatically resetting fuse distinguishes it as a purpose-built Format-A accessory.

Final Assessment

The RDL TP-HA1A is a precise match for a Format-A system that requires a compact, controllable stereo headphone output. It delivers documented audio performance, receives both signal and power over RJ45, and supports additional module connections through its loop-through output. For installations using an RDL Format-A sender, its defined signal-pair usage, 30 mA power requirement, metal enclosure, standard headphone connection, and local level control provide clearly specified integration options.