QD Audio "V Series Power Amplifiers" deliver from 500 Watts to 6800 Watts of power in two to three rack spaces. High current transistors combined with low noise input amplifiers enable the V series to deliver exceptional power. Built around robust and advanced toroidal transformers, they deliver clean power on demand. The advanced protection circuitry guards against short circuit and open circuit, and also protects against ultrasonic and RF interference. A high current power supply increases reliability and performance. Other features include center-dented gain controls, input peak limiter, and fast recovery to ensure low distortion. The variable speed Fans effectively cool the amp and protect against overheating. Input is through XLR connectors for output. The V Series Power Amplifiers have sub woofer outputs with a selectable low pass filter at variable frequency upto 200Hz. Dynatech V Series Power Amplifiers are specially designed for professionals who value high power, audio clarity, reliability and lasting performance.