The Great River PWM-501 is a One-slot, single channel compressor for 500-series format. The Great River PWM-501 uses a unique Pulse Width Modulator as the gain control element, delivering the speed of the FET and VCA compressors with a character of its own. This versatile compressor features a continuous variable ratio control ranging from 1:1 all the way up to 20:1 and attack and release time controls ranging from 0.01 ms to 0.7ms for the former and 0.01 all the way up to 5ms. Versatile, the PWM-501 features a FF/FB control knob offering feedforward or feedback topology as well as a hi-pass filter side-chain EQ to limit unwanted trigger by the low-end such as a kick drum. Two units can be easily be linked for stereo operation. Like all Great River products, the PWM-501 is designed and built in the USA to really high standard. Great River PWM-501 Overview: • Pulse width modulated compressor / limiter • Unique new design from Great River • Output level, threshold, ratio, attack, and release settings • FF/FB control • Stereo linkable with 2 units