The FP-PA18 is a high efficiency 18 W power amplifier with a line input, 8 ohm output, integral audio compressor and an automatic sleep mode. The FP-PA18 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-PA18 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-PA18, 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 Automatic Energy-Saving Sleep ModeSelectable Sleep Delay: Off, 5, 15, 25 MinutesInput / 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 AmplifiersUltra-compact All Metal ConstructionHigh-Efficiency Class D OperationThermal and Short-Circuit ProtectionSpecificationsInput: 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 timesNoise: < -72 dB (below 18 W RMS, +4 dBu input)CMRR: > 45 dB (50 Hz to 3 kHz)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 kHz Output Signal Detector Output: Open collector, 5 mASleep Mode Power Consumption: < 1 W (amplifier and included power supply)Sleep Mode Delay: 5, 15 or 25 minutes (selectable)Sleep Mode Disable: SelectableActive Mode Delay: < 150 mS after input audio detectedAudio Detector Threshold: -50 dBu balanced, -52 dBV unbalancedAmbient Operating Environment: 0 C to 50 C MaximumIndicators (3):Red LED: COMP LED indicates compressor activityGreen LED: OUTPUT ACTIVE (controlled by output signal detector)Blue LED: POWER on; Dim: Sleep mode active; Bright: Amplifier active24 Vdc power supply current: 16 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: 1.025 lbs.WEEE weight: 0.755 lbs.Tariff code: 8543.70.9910