RDL / TX-PA40D

RDL's stereo audio power amplifier offers reliability and exceptional versatility.

■Features:
・ Stereo audio power amplifier
・ 20W RMS @ 8Ω - 40W total
・ 15W RMS @ 4Ω - 30W total
・ Left (L) / Right (R) unbalanced RCA jack input
・ Stereo / Mono switching option
・ Studio quality precision compressor / limiter
・ Compressor / limiter controls clipping
・ Compressor maximizes average output
・ Compression possible by adjusting input level
・ Audio compression threshold is displayed by LED
・ Output drives 4Ω or 8Ω speakers
・ High performance Class-D operation
・ Heat resistant and short circuit protected
・TX-PA40D includes North American power cord, TX-PA40DE does not include power cord

■Applications:
The TX-PA40D is suitable for many applications where a high quality, high performance utility amplifier is required to drive a pair of 4 Ω or 8 Ω speakers. It is particularly suited to fixed gain amplification where the gain is controlled by other equipment. Examples include projectors with variable audio outputs used in classrooms, conference rooms, and video conferencing.

The TX-PA40D provides two unbalanced line level inputs on reliable gold plated phono (RCA) jacks. Front panel gain control trimmers allow any gain setting for each channel. Gain ranges cover the range of common balanced and unbalanced audio signal levels. Each output of the TX-PA40D drives a 4 Ω or 8 Ω speaker, or multiple speakers connected to the amplifier at 4 Ω or 8 Ω. Output impedance is selectable via a switch on the front panel of the module.

A front panel switch allows the audio inputs to be summed to mono. In STEREO mode, the TX-PA40D amplifies each left (L) and right (R) audio channel individually. If the speaker positions and stereo amplifiers are not compatible in a particular installation, set the INPUT MODE switch to SUMMED MONO.

The TX-PA40D features a high-fidelity analog compressor/limiter that rivals Class-D amplifiers with traditional digital limiting. The input GAIN setting determines whether to use the limiter alone to prevent clipping, or to use the full compressor/limiter to effectively exceed the average output of a standard 40W amplifier. When the compressor is preventing output clipping, the red LED on the front panel flashes. Signals at normal audio levels maintain audio dynamics and are not affected by the compressor. When the input level is increased to activate the compressor, the LED lights up between full and low. Audio is compressed according to three dynamic times providing aural transparency while maintaining intelligibility, and amplifies audio without clipping for input overloads up to 20 dB. Compression allows the TX-PA40D to produce average audio output levels and intelligibility normally expected from higher rated stereo amplifiers.

The TX-PA40D has a blue POWER LED that illuminates when powered from an external 24Vdc power supply (included). The module is equipped with both thermal and short circuit protection circuits. The highly efficient Class D output stage produces minimal heat at all expected volumes of voice and music. Continuous full power operation with audio tones will not damage the amplifier, but is not recommended.

An ultra-compact, high quality, highly efficient audio power amplifier that offers reliability and exceptional versatility, making the TX-PA40D an ideal choice wherever it is needed. Use the TX-PA40D individually or in combination with other RDL? products as part of a complete audio/video system.

■Specifications:
Inputs (2): Line level (nominal -10 dBV unbalanced), left (L) and right (R)
Input impedance: 10 kΩ unbalanced
Gain adjustments (2): Single turn 1 (per channel)
Minimum input signal level: -18 dBV (compressor threshold crossing)
Maximum input signal level: +15 dBV
Frequency response: 20 Hz to 40 kHz (±1 dB 4 Ω/8 Ω)*
THD+N: Less than 0.1% (1 kHz, 1 W 4/8 Ω); Less than 1% (50 Hz to 20 kHz, 8 Ω)*
*Measured at compressor threshold level equivalent to 12 W RMS (8 Ω) output
Compressor: Threshold 2 dB below rated output, attack and release times automatically adjusted
Crosstalk: More than 60 dB (1 kHz, no compression)
Noise: -75dB or less (20W RMS or less)
Selector (2): Slide switch; output impedance 4Ω/8Ω
Input mode: SUMMED MONO or STEREO
Output: Each channel 20W RMS (8Ω); total 40W
Each channel 15W RMS (4Ω); total 30W
Output circuit: Class-D
Operating environment: 0℃ to maximum 40℃, recommended 20℃
Indicator (2): Red LED: THRESHOLD LED lights up when compressor is operating
Blue LED: POWER ON
Power supply specifications (included): Input; 100V-240Vac, 50-60Hz, 1.5A; IEC C14
Module output: 24Vdc