Furman AR-15 Series II

Voltage sags, brownouts, spikes, and overvoltages — such are the nemesis of every studio’s prized collection of gear. Were you to monitor the power that’s pouring out of your wall outlets, you would discover readings that can vary greatly from facility to facility, depending on factors ranging from service providers to how your studio is wired. If you have not implemented some sort of voltage regulation to control the power feeding your equipment, you are leaving yourself open to a world of hurt.
Publish date:
Updated on

Thankfully, there are devices, such as Furman’s AR-15 Series II AC voltage regulator, to protect our vulnerable gear from power discrepancies. Technology-wise, it uses Linear Filtering Technology that, unlike some more traditional AC conditioners, ensures linear filtering and no leakage to the ground — which means a quieter, more stable signal for your equipment. The Series Multi-Stage Protection + (SMP +) technology is a great asset, as it safely handles damaging transient voltages without sacrificing the entire unit or requiring a trip to the repair shop; another safety feature, Extreme Voltage Shut Down (EVS), shuts off incoming power to the unit in case of accidental connections to 208 or 240VAC. Excellent.

This single space rack-mount unit boasts eight outlets on the back, and one on the front. All are regulated, spike-suppressed, and filtered against RFI. The 10-LED bar graph meter on the front of the unit displays input voltage ranging from 75–150V, and an LED displays “In Regulation Status” showing that the output is within ±5V of 120V. In addition, an indicator LED for “Protection” displays the unit’s working status, while “Extreme Voltage” indicates if the unit is shut down due to protecting against a 145V or higher jolt. To top it off, there is the requisite on/off switch as well as an optional on/off for a gooseneck light, which can be attached to the back via BNC connection.


Nearly slipping all of my discs out of place attempting to lift the AR-15 II out of the box, I got to work. I’ve had a previous power conditioner for quite some time, set in line to protect nearly 30 pieces of outboard gear, but had never given much thought as to what degree it was suiting my needs. But oddly enough, within minutes of installing the AR-15 II, a serious problem cropped up that let it be put to the test. I noticed that, somehow, the air conditioning unit for my machine room was pulling current from the same breaker as the equipment rack — every time the air conditioner would cycle, the Furman would display a huge dip in current. It was so bad that I could clearly hear the AR-15 II sounding off as it compensated for the power drain in order to provide the regulated 120V to the rack.

After hammering out the air conditioning issues, I decided to do a test to see if there was a noticeable difference in the sound quality of equipment protected by the Furman. So, I routed a stereo audio signal through 12 different compressors, EQs, and effects in then rack, then onto two tracks in Pro Tools. After setting all of the processors so that there was a “legible” sound, I tracked 30 seconds of a song with the AR-15 II regulating all of the equipment. Directly thereafter, I bypassed the Furman, plugged the entire rack into the wall, and tracked the same 30-second chunk of music. I heard a fairly notable difference — not huge per se, but a definite difference. During the 30-second sample that was recorded Furman-less, two “clicks and pops” appeared that were absent from the treated tracks, and the low end seemed a bit more apparent too.


After spending tons of money building a studio, it seems truly negligent to forego voltage protection, thus leaving all that great gear in a compromised situation. Within just five minutes of adding the AR-15 II into my rig, I found (and rectified) a potentially serious problem that would have otherwise flown under the radar. Saved hides aside, the unit reduced the noise floor and actually improved my overall sound, which is always a good thing. Basically, if you’ve yet to acquire an AC voltage regulator, there is no time like the present — and the AR-15 II is a great piece to start.

Product type: AC voltage regulator/stabilizer.

Target market: Small to medium size studios that need to protect their gear from electrical problems.

Strengths: Multiple protection technologies. Handles overvoltages elegantly. Improves overall audio quality.

Limitations: Weighs a lot.

Price: $755 list

Contact: www.furmansound.com