The FP-PA18H is a high efficiency 18 W power amplifier with a line input, 8 ohm output and audio compressor capable of operation in a high ambient temperature environment. The thermal characteristics of the module case and construction throughout using high temperature components permit operation over a range of 0 to 70 degrees C. The FP-PA18H is ideally suited to outdoor applications, signage and other installations where ambient temperatures may become elevated due to limited convection.(Note: The power supply must be mounted in a location with a maximum ambient temperature of 40 degrees C. The FP-PA18H module is available separately for installation with a high temperature power supply or in systems with distributed 24 Vdc power. Contact RDL technical support for more details.)The FP-PA18H features a balanced line level input that may be connected unbalanced. A gain control located next to the terminal block is designed to be adjusted manually or with a trimming screwdriver. The gain range will accommodate standard unbalanced levels as well as professional balanced levels. The output drives one 8 ohm speaker or multiple speakers connected to present an 8 ohm load to the amplifier.The FP-PA18H includes an analog compressor/limiter for fidelity audibly superior to conventional class D amplifiers with digital limiting. The input GAIN setting determines whether the limiter alone is used for clipping suppression, or if the full compressor/limiter will be used to substantially increase the average output power beyond that of a standard 18 W amplifier. A red COMPRESSION LED flashes when the limiter is preventing output clipping. Normal audio level signals remain unaffected by the compressor thereby preserving audio dynamics. If the input level is increased so that the compressor is active, the LED remains dimly lit between peak flashes. The audio is compressed according to three dynamic time constants providing aural transparency while maintaining clean, unclipped amplified audio for input overloads of up to 20 dB. The FP-PA18H, with compression, is capable of producing average audio output levels and clarity normally expected from amplifiers with a much higher output power rating.Main Features:18 Watts RMS into 8 Operation in Elevated Ambient Temperatures to 70CInput / Output Detachable Terminal Block ConnectionsLine Level Balanced or Unbalanced InputCompressor/Limiter Controls ClippingLED to Indicate Audio Compression ThresholdCompressor Produces Maximized Average Output PowerAudio Quality Superior to Standard AmplifiersUltracompact All Metal ConstructionHigh Efficiency Class D OperationThermal and ShortCircuit ProtectionSpecifications:Input: Line level (+4 dBu nominal balanced; 10 dBV nominal unbalanced)Input Impedance: 10 k balanced bridging; 5 k unbalancedGain Adjustment: Single turn audio taperMinimum Input Levels:Balanced: 18 dBu (to cross compressor threshold)Unbalanced: 20 dBV (to cross compressor threshold)Maximum Input Levels:Balanced: +23 dBuUnbalanced: +21 dBVFrequency Response: 20 Hz to 20 kHz (+/ 1 dB)*THD+N: < 0.5% (20 Hz to 20 kHz)*Compressor: Threshold 3 dB below rated output, automatically adjusting attack and release timesCMRR: > 45 dB (50 Hz to 3 kHz)Noise: < 72 dB (below 18 W RMS, +4 dBu input)Output Power: 18 W RMS into 8 Output Circuit: Class DOutput Signal Detector Threshold: 30 mW @ 20 Hz; 20 mW @ 30 Hz; 10 mW @ 50 Hz; 5 mW @ 65 Hz through 20 kHzOutput Signal Detector Output: Open collector, 5 mAAmbient Operating Environment: 0 C to 70 C MaximumIndicators (3):Red LED: COMP LED indicates compressor activityGreen LED: OUTPUT ACTIVE (controlled by output signal detector)Blue LED: POWER on24 Vdc power supply current: 80 mA (idle), 975 mA (max.), Ground referencedPower Supply (included): 100 to 240 Vac, 50-60 Hz, 1A max.; 24 Vdc output to moduleDimensions: Height: 1.15 in.(2.92 cm); Width: 3.25 in.(8.26 cm); Length: 3 in.(7.62 cm) *measured at compressor threshold level equaling 12 W RMS output powerPackage Type: Cardboard BoxPackage Dimensions: 4.375 x 7 x 2.25 in.Shipping Weight: 1.03 lbs.WEEE weight: 0.755 lbs.Tariff code: 8543.70.9910