The Furman Series II AR-20 is a professional AC power conditioner and voltage regulator designed to protect sensitive electronic equipment from damaging power anomalies such as voltage sags, surges, and brownouts. Operating as an automatic voltage regulator (AVR), it continuously monitors the incoming AC line voltage and actively corrects it to maintain a stable output, typically within a close tolerance of 120V, regardless of fluctuations on the mains supply. This is achieved through a multi-tap transformer and solid-state switching circuitry that automatically selects the appropriate voltage tap to compensate for under-voltage or over-voltage conditions without interrupting power to connected gear. This proactive regulation is crucial for protecting amplifiers, mixing consoles, digital processors, and other audio-visual equipment whose performance and longevity can be severely impacted by unstable power.

In addition to voltage regulation, the AR-20 incorporates a full suite of protective filtering. This includes multi-stage EMI/RFI noise filtration to remove high-frequency interference that can cause hum, noise, and digital glitches in audio and video signals. It also features surge suppression circuitry to clamp transient voltage spikes caused by lightning or inductive load switching. The unit is housed in a standard 1U rack-mount chassis with a series of front-panel illuminated outlets, allowing for convenient power access. A prominent meter or LED array indicates both input and output voltage, providing at-a-glance monitoring of line conditions and the regulator's corrective action.

Designed for reliability in demanding professional environments like recording studios, broadcast facilities, and touring sound racks, the Furman AR-20 ensures that connected equipment receives clean, stable power. This not only safeguards against hardware failure but also contributes to optimal system performance by providing a consistent voltage baseline, which can improve the sound quality of analog audio components and the operational stability of digital systems. For system integrators and engineers who prioritize power integrity as the foundation of a reliable setup, the AR-20 serves as a critical first line of defense in the equipment chain.