AC Line Voltage Regulator
power conditioner
AR-15 Voltage Regulator / power conditioner
Congratulations on your purchase of a
to 15 A
Furman AR-15 AC Line Voltage Regula-
Safety Information
tor / Power Conditioner. The AR-Series
To obtain best results from your Furman AR-15
please be sure to read this manual carefully.
regulators are designed specifically for
any audio, video, or computer rackmount
system requiring clean, filtered, and regulated AC power for optimum operation.
AR-15 Features
• Provides nine regulated, conditioned AC
outlets—eight on the rear panel and one on
the front
• Series Multi-Stage Protection Plus
(SMP+) with extreme voltage shutdown
• LiFT (Linear Filtering Technology) with
zero ground contamination
• Eight rear panel outlets and one front
panel outlet
• BNC connector on the rear panel allows
you to attach any standard (12VAC 0.5
amp) gooseneck lamp to illuminate the
rear of your rack
• Extreme Voltage Shutdown indicator LED
• Output In Regulation indicator
• Ten-LED bargraph input voltmeter
• Fast-acting user-accessible circuit breaker
protects against overload or shorts
• Very low stray magnetic field leakage
• Input capacity is 15 A; output capacity is 12
WARNING: To reduce the risk of electrical
shock, do not expose this equipment to rain or
moisture. Dangerous high voltages are present
inside the enclosure. Do not remove the covers. There are no user serviceable parts inside.
Refer servicing to qualified personnel only.
The lightning flash with arrowhead symbol,
within an equilateral triangle, is intended to alert
the user to the presence of uninsulated dangerous voltage within the product’s enclosure that
may be of sufficient magnitude to constitute a
risk of electric shock.
Important Safety
Please Read Prior to Installation
1.Please read and observe all of the safety and
operating instructions before the AR-15 is
operated. Retain these instructions for future
2.The AR-15 should not be used near water
— for example, near a bathtub,
kitchen sink, in a wet basement,
near a swimming pool, etc.
3.Do not place the AR-15 near
heat sources such as radiators,
heat registers, stoves, or other appliances
that produce heat.
4.Route the power cord and other cables so
that they are not likely to be walked on,
tripped over, or stressed. Pay particular attention to condition of cords and cables at
plugs, and the point where they exit from the
AR-15 Voltage Regulator / power conditioner
AR-15. To prevent risk of fire or injury, damaged cords and cables should be replaced
5. Clean the AR-15 with a damp cloth only. Do not
use solvents or abrasive cleaners. Never pour
any liquid on or into the unit.
6.When left unused for a long period of time,
the power cord of the AR-15 should be unplugged from the outlet.
7.The AR-15 should be serviced by qualified
service personnel when:
a. The power supply cord or the plug has
been frayed, kinked, or cut.
b. Objects have fallen or liquid has spilled
into the unit.
c. The AR-15 has been exposed to rain or
other moisture.
d. The AR-15 does not appear to operate
normally or exhibits a marked change in
e. The AR-15 has been dropped, or the
enclosure damaged.
8.The AR-15 requires that a safety ground be
present for proper operation. Any attempt to
operate the AR-15 without a safety ground
is considered improper operation and could
invalidate the warranty.
9.There are no user serviceable parts in the
AR-15. Refer servicing to qualified service
personnel only.
Voltage Regulation
Furman Voltage Regulators are intended to
protect sensitive electronic equipment from
problems caused by AC line voltage irregularities—brownouts or overvoltages that can
cause audio tonal changes, digital equipment
malfunction (such as loss of MIDI programs or
other data), or, in extreme cases, permanent
damage. They accept input voltages over a
wide AC voltage range and convert them to a
steady, stable output at the desired standard
voltage, plus or minus five volts. Voltages approximately ±10% beyond that range may be
converted to usable levels, depending on the
requirements of the equipment. This stable
voltage protects equipment and allows optimal
performance. See graphs on the back page.
The AR-15 has eight outlets on the rear panel,
and one convenience outlet on the front panel.
All are functionally interchangeable. The outlets
are regulated, surge-suppressed, and linearly
filtered, making the unit a full-function power
conditioner. The AR-15 has no controls except
an on-off switch and the switch for the optional
rear rack light.
Note: The AR-15 is for use with AC voltage
only. DC voltages should never be applied to
them. Also, it does not change or regulate line
frequency. The output frequency will always be
the same as the incoming frequency.
SMP+ (Series Multi-Stage Protection
Traditional surge suppression rely on circuits
that “sacrifice” themselves when exposed to
multiple transient voltage spikes, requiring the
dismantling of your system, and repair of your
surge suppressor. Not so with SMP+. With
Furman’s SMP+, damaging transient voltages
are safely absorbed, clamped, and dissipated.
No sacrificed parts, no service calls, no down
time. Unique to Furman’s SMP+ is its unparalleled
clamping voltage. While other designs offer
clamping voltages that are well above 330 Vpk,
AR-15 Voltage Regulator / power conditioner
Furman’s SMP+ clamps at 188 Vpk, (133 VAC
RMS). This unprecedented level of protection
is only available with Furman’s SMP+ technology. Additionally, Furman’s trusted over-voltage circuitry protects against all too frequent
accidental connections to 208 or 240 VAC, by
shutting off the incoming power until the over
voltage condition is corrected.
LiFT (Linear Filtering Technology)
Unfortunately, traditional AC filter - conditioners
have been designed for unrealistic laboratory
conditions. Prior technologies could actually harm audio and video performance more
than they help, due to the resonant peaking
of their antiquated, non-linear designs. Under
certain conditions, these designs can actually
add more than 10 dB of noise to the incoming
AC line! Furman’s SMP+ with LiFT takes another approach, ensuring optimal performance
through linear filtering and no leakage to
ground. With this exclusive filtration technology, all connected equipment will be free of
noise and contamination and will operate at
optimum performance levels.
Extreme Voltage Shutdown Indicator
This LED is normally off. It monitors a hazard
common in the entertainment industry: wiring
faults – for example, accidental connection
to 220VAC where 120VAC is expected, or an
open neutral from a 208 or 240VAC feed. The
Series II SMP+ circuit senses voltages that
are so high that operation would be impossible
and shuts the power down before damage
can occur. Upon initially applying power to
these units, the Extreme Voltage indicator
LED will light if the input voltage is above the
extreme voltage cutoff, and power will not be
applied to the unit’s outlets. If the unit has been
operating with an acceptable input voltage
and subsequently that voltage exceeds 145150V, it will shut off power to the outlet and the
Extreme Voltage LED will light.
NOTE: If the mains power is above the high
cutoff voltage and has caused the unit to
remove power from its outlets, it cannot restore
power without the operator manually turning
the unit off, then on again. Avoid turning the
unit back on, without first checking the source
of the problem, and perhaps changing the AC
Protection OK Indicator
Although the Furman SMP+ circuit assures
virtually protection from transient voltage
spikes and surges, nature has a way of
occasionally creating electrical forces that are
beyond the capabilities of any TVSS device to
absorb without some degree of damage. In
the rare instance that this occurs, the green
“Protection OK” LED indicator located on your
front panel will dim. If this happens some level
of protection from voltage surges will remain,
but the Furman’s clamping voltage rating will
be compromised. The unit must be returned
to Furman Sound, or an authorized Furman
Service center for repair.
Fuses and Circuit Breakers
There is one fuse and one circuit breaker in the
AR-Series. In the event that the unit appears to
be completely dead (neither the Power switch
nor any LED’s light up), unplug the power cord
and the load and check the breaker. If the circuit breaker is tripped, a white button will pop
up. Push it back in to reset it. The purposes of
these circuit protection devices are:
1. A fast-blow 15 amp circuit breaker is accessible at the rear panel without removing the
AR-15 Voltage Regulator / power conditioner
unit from the rack. This breaker will trip if the
unit’s 15 amp capacity is exceeded at any
2.A fast-blow 1/4 amp fuse is located inside
the unit. This fuse will blow if the unit has
been connected to a voltage that is above
the range of the Extreme Voltage Shutdown circuitry. To replace it, the unit must
be completely disconnected from all power
and removed from its rack. The six hex head
screws and two Phillips head screws holding
the top cover must be removed. The internal
fuse is located in a holder on the printed circuit
board. Replace the fuse only with the exact
same type (1/4 fast blow).
Input Voltage Monitoring
The row of ten LED’s at the left of the front
panel make up a meter that indicates INPUT
VOLTAGE. Only one LED will light up at a time.
There are two red LED’s at the endpoints. When
lit, they indicate that the input voltage may
be above or below the point where it can be
restored to the selected nominal output voltage (though it may still be restored to a usable
level) but is not high or low enough to cause an
extreme voltage shutdown.
Output Voltage Monitoring
indicates proper function (i.e., that the output voltage is within ±5V of the selected output voltage).
Your equipment will always work normally when
this light is on, and often will work satisfactorily
even when it is off.
The AR-15 offers a 10-LED bargraph line voltage
meter to monitor the incoming line (the Voltage
Regulator output).
Because of their toroidal transformer design,
Furman Voltage Regulators may be positioned near most other equipment without fear
that the other equipment will be disrupted by
leakage of a strong 50/60 Hz magnetic field.
Nevertheless, suggested rack locations would
be either at the top or bottom.
As with any rackmount equipment, be sure to
use 10-32 machine screws for mounting in the
rack’s tapped holes (this is not a metric size).
In particular, beware of 10-24 screws, which
may fit if forced but which will strip the threads.
To avoid marring the front panel finish, use
plastic washers under the screw heads.
The AR-Series uses a design based on an
eight-tap toroidal autoformer. The toroidal design assures minimal leakage of stray magnetic
fields, and, because of its high efficiency, a very
compact size for its rating. The Voltage Regulator’s circuitry monitors the incoming line voltage
with each cycle, comparing it to an extremely
precise voltage reference, accurate to ±0.15%.
If a voltage fluctuation requires that a different
tap be selected, the new tap is electronically
switched exactly at the zero-crossing, to avoid
distorting the AC waveform. If necessary, it can
switch taps as often as once each cycle. Most
commercial voltage regulators using multipletapped transformers switch taps at uncontrolled
times, thereby creating voltage spikes and
clicks that can leak into the audio! Hysteresis in
the switching circuits avoids “chatter” or unnecessary switching back and forth between adjacent taps. Unlike those voltage regulators that
employ ferro-resonant transformers, Furman
Voltage Regulators are not sensitive to small
AR-15 Voltage Regulator / power conditioner
errors in line frequency, making them ideal for
use with generators.
Maximum and Minimum Load
The AR-15 can handle loads totalling up to 15
amperes as long as the input voltage is equal
to or above 124 volts. For voltages below that
level, its capacity must be derated at approximately 113 milliamperes per volt. (See graphs
on back page.) As a practical matter, therefore,
to cope successfully with worst-case brownout conditions, you should plan your total load
so that it does not exceed 12 amps, or 1400
watts. Please note that this refers to the aggregate power requirement of all equipment
plugged into the Voltage Regulator, not to each
individual item.
NOTE: While there is no minimum load requirement for the AR-15 you may experience an
audible mechanical hum coming directly from the
unit when the POWER switch is on with nothing
plugged in. This effect will sometimes disappear
as soon as you plug in any equipment drawing 40
to 50 watts total.
is a number indicating the nominal electrical
potential that has been adopted in a region
for powering electrical equipment of all kinds.
In most of North America it is 117 volts AC; in
Japan, 100 volts; and in many other countries
220, 230, or 240 volts. The actual voltage can
fall below or rise above this nominal level due
to brownouts, power cutbacks, use of substandard wiring, and other causes. These deviations can cause poor performance or a malfunction. A regulator is a device which, through
use of a transformer, corrects the voltage
deviation by stepping it up or down so that it is
as close as possible to the nominal level.
SPIKE: A pulse of energy on the power line.
Spikes can have voltages as high as 6000
volts. Though they are usually of very short duration, the energy they contain can be considerable, enough to damage sensitive solid-state
components in audio and computer equipment.
Spikes can also foul switch contacts and degrade wiring insulation. They are an unavoidable component of electric power. They are
caused unpredictably by electric motors switching on or off (on the premises or outside), utility
company maintenance operations, nearby
lightning strikes, and other factors. Spikes (also
called surges or transients) are absorbed by
special components called MOV’s in the ARseries to provide safe voltage levels to protect
your equipment.
(Radio Frequency Interference) or EMI (Electro
Magnetic Interference) involves lower voltages
and less energy than is found in spikes, but it is
continuous rather than transient in nature. It is
not likely to cause physical damage, but it can
certainly be annoying, producing static in audio
circuits, “snow” on video screens, or garbled
data in computers. Noise can be introduced into
AC lines by nearby radio transmitters, certain
kinds of lighting, electric motors, and others.
Because noise occurs at higher frequencies
than the 50 or 60 Hz AC line, it can be effectively reduced through use of low-pass filtering.
Three-Year Limited Warranty
Furman Sound, LLC., having its principal place
of business at 1690 Corporate Circle, Petaluma,
CA 94954 (“Manufacturer”) warrants its AR-15
(the “Product”) as follows:
AR-15 Voltage Regulator / power conditioner
Manufacturer warrants to the original Purchaser
of the Product that the Product sold hereunder
will be free from defects in material and workmanship for a period of three years from the
date of purchase. The Purchaser of the product
is allowed fifteen days from the date of purchase
to complete warranty registration by mail or online at the Furman website. If the Product does
not conform to this Limited Warranty during the
warranty period (as herein above specified),
Purchaser shall notify Manufacturer in writing of
the claimed defects. If the defects are of such
type and nature as to be covered by this warranty, Manufacturer shall authorize Purchaser
to return the Product to the Furman factory or to
an authorized Furman repair location. Warranty
claims should be accompanied by a copy of the
original purchase invoice showing the purchase
date; this is not necessary if the Warranty Registration was completed either via the mailed in
warranty card or on-line website registration.
Shipping charges to the Furman factory or to
an authorized repair location must be prepaid
by the Purchaser of the product. Manufacturer
shall, at its own expense, furnish a replacement
Product or, at Manufacturer’s option, repair the
defective Product. Return shipping charges
back to Purchaser will be paid by Manufacturer.
AND FITNESS FOR A PARTICULAR PURPOSE. Manufacturer does not warrant against
damages or defects arising out of improper
or abnormal use of handling of the Product;
against defects or damages arising from improper installation, against defects in products
or components not manufactured by Manufacturer, or against damages resulting from such
non-Manufacturer made products or components. This warranty shall be cancelable by
Manufacturer at its sole discretion if the product
is modified in any way without written authorization from Furman Sound. This warranty also
does not apply to Products upon which repairs
have been affected or attempted by persons
other than pursuant to written authorization by
and exclusive obligation of Manufacturer shall
be to repair or replace the defective Product in
the manner and for the period provided above.
Manufacturer shall not have any other obligation
with respect to the Products or any part thereof,
whether based on contract, tort, strict liability or
otherwise. Under no circumstances, whether
based on this Limited Warranty or otherwise,
shall Manufacturer be liable for incidental,
special, or consequential damages. Manufacturer’s employees or representatives’ ORAL OR
relied upon by Purchaser, and are not a part of
the contract for sale or this limited warranty. This
Limited Warranty states the entire obligation of
Manufacturer with respect to the Product. If any
part of this Limited Warranty is determined to be
void or illegal, the remainder shall remain in full
force and effect.
Before returning any equipment for repair,
please be sure that it is adequately packed
and cushioned against damage in shipment,
and that it is insured. We suggest that you
save the original packaging and use it to
ship the product for servicing. Also, please
enclose a note giving your name, address,
phone number and a description of the
NOTE: All equipment being returned for repair must have a Return Authorization (RA)
Number. To get an RA Number, please call
the Furman Service Department, (707) 7631010, ext. 2370 or 2377, between 8 a.m.
and 5 p.m. U.S. Pacific Time, or fax to (707)
763-1310. Please display your RA Number
prominently on the front of all packages.
Spike Protection Modes:
Line to neutral, zero ground leakage
Spike Clamping Voltage:
188 Vpk @ 3,000 amps, 133 VAC RMS
(tested to UL-1449 6,000 Vpk @ 3,000 amps)
Response time:
10 dB @ 10 kHz
40 dB @ 100 kHz
100 dB @ 10 MHz
Linear attenuation curve from 0.05 - 100 ohms line impedance
Shutdown Range:
Above 137 VAC typically
19 “ W x 11.63” D x 1.75” H
1 nanosecond
(48.26 x 29.54 x 4.45 cm)
Maximum surge current:
6,500 amps
14.5 lbs. (6.58 kg)
Current Rating:
Voltmeter Accuracy: The AR-15 II is capable of 15 amps for input voltages
of 124V (104V in 100V mode) or higher; derate at 113
mA per volt to a minimum of 12:3A
“In Regulation” Ranges:
AR-15 II: Provides regulation ±5V in 120V mode from
97 to 137V
Three Year Limited Warranty:
The AR-15 is protected by a limited three-year warranty covering defects
in materials and workmanship.
Noise attenuation:
Furman Sound, LLC. • 1690 Corporate Circle • Petaluma, CA 94954-6919 USA
Phone: 707-763-1010 • Fax: 707-763-1310 • Web: • E-mail:
Made in China