Gemini GPA-4000 600W Stereo Power Amplifier Amp Bi-polar output stage technology for the finest sound quality and reliability- High output power to drive professional loudspeakers without clipping- Comprehensive protection circuitry withprotect LED indicator * 1/4TRS & XLR balanced/unbalanced inputs- SpeakonTM & 1/4 speaker outputs-Three modes of operation - stereo,parallel mono, and mono bridge- Ground lift switch- Decibel (dB) level meter with clip LEDs Selectable voltage for worldwide operation- Dual aluminum extrusion heat sinkdesign with directly mounted outputtransistors for no-fault operation- Air guide with front-to-rear airflow andcooling fan for thermal stabilityand reliability Compact 2U well balanced enclosure- Steel reinforced chassis- Frequency Response of 30Hz - 50 kHz- Signal to Noise Ratio of 100 dB belowrated power at 8 ohms