The 7130 compressor/limiter shall have an output capacity of +18 dBm from 20 Hz-20 kHz, ±1 dB and total harmonic distortion shall be less than 0.25% to +18 dBm, 20 Hz-20 kHz in either the compression or limiting mode with up to 30 dB of gain reduction. The unit shall accept high impedance, unbalanced microphones. The microphone preamplifier circuitry shall employ field effect transistors for low noise. The compressor shall be capable of any combination of line-line, mic-mic, or line-mic operation. Balanced inputs shall be possible by using optional input transformers. Outputs shall be transformer isolated or direct for connection to a balanced or unbalanced 600 ft line. The compressor/limiter shall be equipped with a selector switch to place the unit in one of three modes of operation: OUT, COMPRESS, or LIMIT. The normal threshold of compression shall be 0 dBm output. An input level control shall vary the gain when the selector switch is in the OUT mode. It shall also determine the relative threshold when the unit is in the COMPRESS or LIMIT mode. Two switches shall be provided for the selection of three release times and three attack times. The unit shall be equipped with a meter, governed by a function selector switch, which indicates amount of compression or output level in dB. When indicating output level, three ranges shall be selectable so that 0 VU on the meter corresponds to an output level of 0 dBm, +4 dBm, or +8 dBm, unbalanced, and +2 dBm, +6 dBm, or +10 dBm balanced output. The unit shall operate on 120/240 V AC, 50/60 Hz.