Radio Design Labs STPA18 Power Amp

Radio Design Labs STPA18
Power Amp

View all Radio Design Labs products

Radio Design Labs STPA18

The ST-PA18 features a balanced line level input that may be connected unbalanced. The gain control range will accommodate standard unbalanced levels as well as professional balanced levels. The module bridges the input signal. LOOP OUT terminals permit a balanced input to be fed to additional amplifier modules making the ST-PA18 an ideal component in distributed audio system design.

The LOOP OUT may also be used to feed a subwoofer amplifier (see RDL ST-CX2S Subwoofer Filter). The ST-PA18 output will drive an 8 ohm speaker or multiple speakers connected to present an 8 ohm load to the amplifier and it is capable of driving 4 O loads. A red COMP LED is provided to indicate the threshold of the integral compressor. Audio levels that could cause the amplified output to clip are compressed according to two dynamic time constants. Normal audio level signals remain unaffected by the compressor thereby preserving audio dynamics and preventing the compressor from increasing feedback potential when the amplifier is used for paging.

The compressor is designed to remain aurally transparent while maintaining clean, unclipped amplified audio for input overloads of up to 20 dB. The ST-PA18 produces average audio levels and audio clarity normally expected of amplifiers delivering much higher output power. The ST-PA18 operates from an external 24 VDC 1A power supply, sold separately. A POWER LED illuminates when the module is powered. The module provides thermal and output short-circuit protection.

18 Watts RMS Audio Power Amplifier
Output for 8 ohm Speaker
Maximized Audio Level at Full Power Output
Superior Audio Quality at High Output Levels
Line Level Balanced or Unbalanced Input
LOOP OUT to Feed Additional Amplifiers
Integral Audio Compressor to Control Clipping
High Overall Audio Operating Level
LED to Indicate Audio Compression

Specifications:

Input: Line level (+4 dBu bal; -10 dBV unbal)
Input Impedance: 20 kohm balanced bridging; 10 kohm unbal
Gain Adjustment: Single turn
Minimum Input Levels: -16 dBu* balanced; -18 dBV*unbalanced
Maximum Input Levels: +25 dBu balanced; +22 dBVunbalanced
Frequency Response: 20 Hz to 20 kHz (+/- 2 dB)*
THD+N: < 1%*

*measured at compressor threshold level equaling 12 W RMS output power

Noise: < -75 dB (below 18 W RMS)
Compressor: Threshold 3 dB below rated output,automatic adjusting attack and release
CMRR: > 45 dB (50 Hz to 120 Hz)
Output Power: 18 W RMS into 8 O
Output Circuit: Class D
Ambient Operating Environment: 0° C to 30° C Max; 20° C Recommended

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