IT-20 II - Owner’s Manual
IntroductIon
InstallatIon
Thank you for your purchase of a Furman IT- The power source to which the IT-20 II is
20 II 20 amp Balanced Power Conditioner, connected must be adequate for use at 20 amps.
and congratulations on your choice. This We recommend a ꢀ0 amp circuit, wired with
specially wound and shielded toroidal isolation 10 gauge wiring, if continuous operation near
transformer is designed specifically to reduce 20 amps is anticipated. A dedicated (nothing
hum pickup by sensitive equipment when ultra- else connected) 20 amp circuit is the minimum
low-noise is a must.
acceptable to comply with NEC requirements.
Consult a qualified electrician if in doubt. The IT-
20 II is designed for mounting in a standard 19
inch equipment rack. Because of its weight, the
best position for it is the bottom slot of the rack.
Its toroidal transformer minimizes magnetic
leakage, but nevertheless, due to its high
capacity, it will radiate an appreciable magnetic
field. Therefore, we recommend that it not be
positioned adjacent to sensitive, low level signal
processors, especially mic preamps, mixers,
tape recorders, etc. Power amps may be more
suitable “rack neighbors.”
descrIptIon
Designed for the most critical, ultra-low noise
installations, the IT-20 II can supply 20 amps
of Balanced AC power for recording studios,
broadcast stations, or video production facilities.
To understand the incredible need for clean
noise-free AC power, it’s important to note that
today’s sophisticated studio equipment features
tremendous dynamic range. Most of the signal
content that defines high resolution such as
harmonics, instrument timbre, high frequency
extension, spatial cues, and fast transient
attacks in audio are inherently low in signal
level. Further, when AC noise is induced into
audio processors, pre-amplifiers, microphones,
powered monitors, computers, and mixing
consoles, the all important low level signals are
distorted or masked. Once signals are masked
there is no way to retrieve the lost content.
Advanced AC filtering is critical when audio or
video resolution is at stake. With Furman’s IT-20
II, for the first time you will hear audio content
and see video images as they were meant to be
- pristine. Add to this our SMP+ non-sacrificial
surge suppression, E.V.S. protection, Linear
FilteringTechnology(LiFT), andlaboratorygrade
digital voltmeter and you will be assured that AC
noise and surges are a thing of the past.
The maximum benefit is derived from balanced
power when it powers ALL equipment in an
installation. Therefore, try to position the IT-20
II in a central location so its power can be easily
distributed everywhere it’s needed. If the total
power consumption of all equipment exceeds 20
ampsat120volts,deletehighlevelormechanical
devices first (such as power amps, motors). If
possible, physically isolate any equipment that
has to be powered with conventional power
through a different circuit, and route their AC
cords away from all other cabling. The balanced
power produced by the IT-20 II is restricted to
use with electronic equipment only. Balanced
power may not be used for lighting equipment,
and access must be limited to use by qualified
personnel only.
If you are installing the IT-20 II in a rack that
has rear as well as front mounting rails, you may
wish to order adjustable rear rack ears from
Furman. These allow the IT-20 II to be securely
attached in both the front and back. Order model
RRM-2.
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IT-20 II - Owner’s Manual
manyAC noise contaminants may be present on
theAC ground wire. For these reasons Furman’s
IT-20 II contains a Ground Lift Switch.
operatIon
cIrcuIt Breaker/swItch
The IT-20 II has a large black switch on the front
panel that is both a precision circuit breaker and
an on-off switch. If circuit breaker is tripped,
manually reset the unit by turning it off and then
back on, to restore power.
This switch floats the output ground, eliminating
ground noise and also, in many instances, the
hum and buzz associated with ground loops.
The IT-20 II’s GFCI protection circuit assures
that even when utilizing the power conditioner
in this mode, operation is safe and secure.
In fact, even if a connected component has
a catastrophic failure, less than 5 milliamps
current imbalance from line to ground or neutral
to ground will instantly disconnect the voltage
output from the IT-20 II. This is far safer than
any conventional 120 VAC outlet, and it has
numerous noise reducing advantages.
Ground Fault Interrupter (GFcI):
The GFCI on the IT-20 II’s front panel is a special
kind of circuit breaker that detects an imbalance
in the current flowing in the two hot legs. The
“missing” current is presumed to be flowing
through the ground conductor (the round pin on
an AC outlet).
However, ground wiring in any studio, broadcast
or club environment can be complex. Because
all 14 outlets of the IT-20 II are in parallel,
it is still possible to have a ground loop if the
two offending products are simultaneously
connected to a single IT-20 II. Use of multiple
IT-20 II’s may be necessary in extreme cases.
Also, for studio and broadcast use, separating
all digital processing products from all analog
devices is highly recommended and can be
accomplished by using two IT-20 II’s.
Ground current often indicates a dangerous
partial or full short circuit. If an imbalance is
detected, the GFCI trips and cuts off power not
only to itself, but to all the IT-20 II’s outlets. If
this occurs, the button on the GFCI marked
“R” (Reset) will pop out. To restore operation,
correct the fault and push the button in. You may
test the proper operation of the GFCI at any
time by simulating a ground fault by pushing the
button marked “T” (Test). If the GFC1 is working
properly, this will cause the “R” button to pop
out and cut off power. You can restore operation
after a test by pushing the “R” button in.
Intheend, itisbesttoexperimentwiththisswitch.
Whichever position yields the least noise or
clearest audio / video recording or reproduction
is the position that should be utilized.
Ground lIFt swItch
Balanced ac power
Ground loops are fairly common in many
installations because AC cords with safety
ground are rarely connected to a single low-
resistance buss bar. When there is a significant
In much the same way that balanced audio lines
can reduce the pickup of hum and other types
of electromagnetic interference (EMI), the use
of balanced AC power lines in sensitive audio,
video, or computer installations can make an
enormous difference in system noise and signal
integrity. But power distribution in NorthAmerica,
unfortunately, is not balanced. The distribution
standards currently in use were derived from
difference in voltage between
a
source
component’s neutral and ground and a load
component’s neutral and ground, the buzz and
hum associated with this type of ground current
noise (or loop) may take place. Additionally,
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IT-20 II - Owner’s Manual
practices established over a century ago, when Asymmetrical noise, or what is called “differential
electric power use was limited to lighting and mode,” is responsible for well over half the noise
motors, long before any AC noise sensitive present in today’s AC lines. For this reason we
applications existed. The emphasis then was on employ our exclusive Linear FilteringTechnology
convenience (from the power utilities’
(LiFT). This assures that your audio, video, or
standpoint)andsafety,butnotnoisecancellation. computer signals are as pure and uncorrupted
The result was a three-wire distribution scheme as possible.
in which 120V branch circuits have a hot wire
and a neutral wire, with the neutral tied to a third
wire connected for safety to an earth ground.
The third wire does not carry any current
unless there is a fault. This unbalanced scheme
can create hum in audio circuits for two main
reasons. First, the current flowing in the hot wire
induces hum in any other nearby wires, which
may carry vulnerable low-level audio or video
signals. Second, because the impedance of
chassis and cable shielding to ground is always
greater than zero ohms, ground current flowing
from power supply capacitors and from EMI
pickup causes a voltage drop at 60Hz and its
harmonics. This low level noise becomes part of
the audio signals.
lInear FIlterInG technoloGy (lIFt)
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! Worse still, lost digital data, the need to
re-boot digital pre-sets, or destroyed digital
converters are frequently caused by excessive
voltage spikes and AC noise contaminating the
equipment ground. Furman’s LiFT takes another
With a center-tapped isolation transformer, the approach,ensuringoptimalperformancethrough
AC power feeding a studio can be balanced at linear filtering and no leakage to ground.
its source. The current-carrying wires then are
no longer “hot” (120V) and “neutral” (0V), but
two 60V lines of opposite polarity (referenced
to ground connected to the center tap), whose
serIes MultI-staGe protectIon plus
(sMp+)
difference is 120V. This type of power, when
Traditional surge suppression relies on circuits
run around a room, does not induce hum into
that “sacrifice” themselves when exposed to
nearby audio wiring because the two conductors
multiple transient voltage spikes, requiring
induce equal and opposite voltages that cancel
the dismantling of your system and repair of
your surge suppressor. With Furman’s SMP+,
however, damaging transient voltages are
safely absorbed, clamped and dissipated. No
sacrificed parts, no service calls, no downtime.
AlsouniquetoFurman’sSMP+isitsunparalleled
clamping voltage. While other designs offer
clamping voltages that are well above ꢀ00Vpk,
each other. Similarly, ground currents are all
but eliminated by the same common-mode
cancellation effect. No longer is it necessary to
adopt cumbersome and expensive star-ground
systems or use massive bus bars or heavy
ground rods. Further, with features such as our
center tap ground lift, ground induced noise may
be reduced even further.
Furman’s SMP+ clamps at 188Vpk, 1ꢀꢀ VAC
Of course Balanced AC Power is only the
beginning of a system free of AC noise.
RMS, even when tested with multiple 6000Vpk,
3000 amp surges! This unprecedented level of
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IT-20 II - Owner’s Manual
• The power supply cord or plug has been
frayed or cut
protection is only available with Furman’s SMP+
technology.
• Objects have fallen or liquid has spilled into
the unit
extreMe VotlaGe shutdown (e.V.s.)
• The IT-20 II has been exposed to rain or
other moisture
When voltage rises to extreme levels because
of a lost neutral line or an accidental connection
to 208 or 240 VAC, Furman’s Extreme Voltage
Shutdown kicks in, automatically powering down
all equipment quickly and safely to prevent
damage from occurring. An indicator LED will
then illuminate, alerting you to the situation until
the over voltage condition is corrected by turning
the unit off and then back on.
• The IT-20 II does not appear to operate
normally, or exhibits a marked change in
performance
• The IT-20 II has been dropped, or the
enclosure damaged
The IT-20 II requires that a safety ground be
present for proper operation. Any attempt to
operate the IT-20 II without a safety ground
is considered improper operation and will
invalidate the warranty.
dIGItal VoltMeter:
This LED digital voltmeter is an accurate, self-
checkingACvoltmeterthatcontinuallymeasures
the IT-20 II’s input AC voltage.
power source
The power source to which the IT-20 II is
connected should be adequate for use at 7
amps. Typical household outlets will have a
current capacity of at least 10 - 15 amps.
saFety InForMatIon
and warnInGs
Please read and observe all of the safety and
operating instructions before the IT-20 II is
operated. Retain these instructions for future
reference.
warranty
Furman Sound, LLC., having its principal place
of business at 1690 Corporate Circle, Petaluma,
CA 94954 (“Manufacturer”) warrants its IT-20 II
(the “Product”) as follows:
• Do not disassemble or modify in any way.
No user-serviceable parts inside
• Keep away from moisture and avoid
excessive humidity
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 on-
line 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
• Do not allow liquids or foreign objects to
enter the unit. Household lighting equipment
may not be connected to the IT-20 II because
its sockets are not designed for use with
symmetrical power and may present a shock
hazard. We recommend that only audio,
video and computer processing equipment
be connected to the IT-20 II
The IT-20 II should be serviced by qualified
service personnel when:
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IT-20 II - Owner’s Manual
the claimed defects. If the defects are of such with respect to the Products or any part
typeandnatureastobecoveredbythiswarranty, thereof, whether based on contract, tort, strict
Manufacturer shall authorize Purchaser to liability or otherwise. Under no circumstances,
return the Product to the Furman factory or to whether based on this Limited Warranty or
an authorized Furman repair location. Warranty otherwise, shall Manufacturer be liable for
claims should be accompanied by a copy of the incidental, special, or consequential damages.
original purchase invoice showing the purchase Manufacturer’s employees or representatives’
date; this is not necessary if the Warranty ORAL OR OTHER WRITTEN STATEMENTS
Registration was completed either via the mailed DO NOT CONSTITUTE WARRANTIES, shall
in warranty card or on-line website registration. not be relied upon by Purchaser, and are not
Shipping charges to the Furman factory or to a part of the contract for sale or this limited
an authorized repair location must be prepaid warranty. This Limited Warranty states the
by the Purchaser of the product. Manufacturer entire obligation of Manufacturer with respect to
shall, at its own expense, furnish a replacement the Product. If any part of this Limited Warranty
Product or, at Manufacturer’s option, repair the is determined to be void or illegal, the remainder
defective Product. Return shipping charges back shall remain in full force and effect.
to Purchaser will be paid by Manufacturer.
THE FOREGOING IS IN LIEU OF ALL
OTHER WARRANTIES, EXPRESS OR
serVIce
IMPLIED, INCLUDING BUT NOT LIMITED
Before returning any equipment for repair,
TO THE IMPLIED WARRANTIES OF
please be sure that it is adequately packed and
MERCHANTABILITY AND FITNESS FOR A
cushioned against damage in shipment, and
PARTICULAR PURPOSE. Manufacturer does
that it is insured. We suggest that you save the
not warrant against damages or defects arising
original packaging and use it to ship the product
out of improper or abnormal use of handling of
for servicing. Also, please enclose a note giving
the Product; against defects or damages arising
your name, address, phone number and a
from improper installation, against defects in
description of the problem.
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 Manufacturer.
NOTE: All equipment being returned for repair
must have a Return Authorization (R/A) number.
To get an R/A number, please call the Furman
Service Department at 707.763.1010 extensions
113 and 133. Please display your R/A number
prominently on the front of all packages.
THIS WARRANTY IS EXCLUSIVE. The sole
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
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specIFIcatIons
AC Current Output:
20 Amps (2400 watts at 60/120V)
Shutdown Voltage:
At 1ꢀ5-140 VAC
Inlets:
Heavy duty power cord with 20A three-pronged plug
Outlets:
12 rear (isolated), 2 front (GFCI) each rated at 20 amps
Spike Protection Modes:
Line to neutral, zero ground leakage
Spike Clamping Voltage:
188 Vpk @ ꢀ,000 amps, 1ꢀꢀ VAC RMS
(Tested to UL-1449 6,000 Vpk @ 3,000 amps)
Response Time:
1 nanosecond
Maximum Surge Current:
6,500 amps
Differential Noise Attenuation:
10dB @ 10kHz
40 dB @ 100 kHz
100 dB @ 10 MHz
Common Noise Attenuation:
Greater than 80 dB @ 20Hz to 20 KHz
Greater than 40 dB @ 20Khz to MHz
Linear attenuation curve from 0.05-100 ohms line impedance
Turns Ratio:
1:1, windings separated with Faraday Shield
Transformer Regulation:
ꢀ% at full load
Power Consumption:
12 watts for display and control circuits
Voltmeter Accuracy:
± 1V
Furman Sound, LLC
1690 Corporate Circle.
Petaluma, California 94954-6919 USA
Phone: 707-763-1010
Dimensions:
19” W x 5.25” H x 17” D, 80 lbs.
Fax: 707-763-1310
E-mail: [email protected]
051206-C
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