Music on Hold Amplifier-1 Watt

Ideal Use Cases

The RDL TX-1W is intended for one defined job: feeding audio into a telephone equipment music-on-hold input. It fits systems whose program source is delivered through a standard unbalanced phono jack and whose telephone interface accepts either a balanced 600 Ω transformer-driver feed or an unbalanced signal. The adjustable output path also covers applications that need anything from line level through a maximum 1-watt unbalanced output.

Its frequency response is tailored to phone systems within the 20 Hz to 20 kHz spectrum. That makes the model aligned with hold-audio integration rather than general-purpose loudspeaker amplification. The ultra-compact format is useful when the music-on-hold interface must be placed alongside telephone equipment without a large amplifier chassis.

Why Choose This Model

The TX-1W brings its key interface options into one unit: adjustable audio level, adjustable gain, a balanced output for transformer inputs, and an adjustable unbalanced output capable of up to 1 watt. Gain spans 10 dB to +25 dB, allowing the connected source and telephone input to be set to an appropriate operating level. The nominal input level is 10 dBV.

RDL also specifies optimized sound quality, low residual noise, and measured distortion figures at both maximum 1-watt output and +4 dBu. These published values give installers concrete references for assessing the unit against the receiving phone system instead of relying only on a general music-on-hold designation.

Installation and Integration

Connect the audio source to the unbalanced input using the standard phono jack. For a transformer input, use the single balanced output rated at 600 Ω. Where the receiving equipment needs an unbalanced feed, use the adjustable unbalanced output, which operates from line level up to 1 watt. Set the adjustable gain and audio level according to the connected equipment.

Power requirements are ground-referenced 24 Vdc at 150 mA. A power supply is not included. The recommended supply is the PS-24AS for the USA or PS-24AX for international use. The ambient operating range is 0°C to 40°C. These requirements should be checked during planning, particularly the ground-referenced supply and input format, because both are explicitly defined for this model.

Performance Highlights

The frequency response is tailored to phone systems within the 20 Hz to 20 kHz spectrum. THD+N is specified at less than 0.5% at 1 kHz with the maximum 1-watt output, and less than 0.2% at 1 kHz and +4 dBu. Residual noise is below -75 dB, referred to 600 Ω at +4 dBu or to 1 watt RMS.

Together, these specifications define performance at both the balanced reference and the higher unbalanced power output. The balanced 600 Ω connection is specifically identified for driving transformer inputs, while the adjustable unbalanced connection supplies the alternate line-level-to-1-watt path.

What Makes It Different

The distinguishing feature is the combination of two output approaches for a single music-on-hold task. The balanced transformer-driver output addresses 600 Ω transformer inputs, while the unbalanced output provides adjustable line level through 1 watt. This gives the installer two documented integration paths without changing the unit’s unbalanced phono-jack input.

RDL describes the unit as ultra compact. Product logistics list a 0.215-pound WEEE weight, a 0.275-pound shipping weight, cardboard-box packaging, and package dimensions of 2 by 2 by 4 inches. Those measurements are package dimensions rather than stated product dimensions.

Final Assessment

The RDL TX-1W is a focused interface for placing an audio feed onto telephone music-on-hold equipment. Its strongest fit is a system that benefits from adjustable gain, a standard unbalanced phono input, and the choice of balanced 600 Ω transformer drive or adjustable unbalanced output up to 1 watt.

Selection should be based on the documented 10 dBV nominal input, required ground-referenced 24 Vdc power, output connection expected by the telephone system, and 0°C to 40°C operating environment. With the appropriate separately obtained PS-24AS or PS-24AX supply, the model provides the specific input, level control, and output formats listed for a compact music-on-hold installation.