Furman PRESTIGE Série Guide De L'utilisateur page 7

In the end, it is best to experiment with the Ground Lift Switch. Whichever position yields the least noise or clearest audio / video
recording or reproduction, is the position that should be utilized.
Ultra-Low Resistance Magnetic Power Switch / Circuit Breaker:
Furman's Prestige Series 20 amp capacity power switch is specifically designed to stand up to the enormous high in-rush current de-
mands of many power amplifiers. Additionally, Furman magnetic circuit breakers are not sensitive to temperature, nor do they raise
the AC impedance as many less costly thermal breakers will do. If the 20 amp RMS current capacity of the P-2400 IT is exceeded,
the spring tensioned switch will immediately switch to the off position. You will need to switch the toggle back to the on position
once the problem is corrected (typically by eliminating one component, or until the RMS current does not exceed 20 amps or 2400
watts).
Extreme Voltage Shutdown Indicator:
The Extreme Voltage LED indicator is normally off. It is located within the meter lens assembly directly above the blue voltage / cur-
rent LED's, though during normal use it will NOT be visible.
The Extreme Voltage Shutdown (EVS) indicator monitors a hazard common in the entertainment, remote broadcast, and AV contrac-
tor industries:wiring faults. For example, accidental connection to 208VAC where 120VAC is expected, or an open series neutral
from a 208 to 240VAC electrical service. The Furman EVS 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 the P-2400 IT, the Extreme Voltage indicator will illuminate to a bright red if the input voltage is
above the extreme voltage cutoff. When this occurs, power will not be applied to the outlets. If the unit has been operating with
an acceptable input voltage and subsequently that voltage exceeds 140V, it will shut off power to the outlets and the Extreme Volt-
age LED will light.
NOTE: If the mains power is above the high cutoff voltage and has caused the EVS circuit to remove power from the outlets, it can-
not 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 source.
Protection OK Indicator:
Although the Furman SMP circuit assures virtually maintenance free 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 (such as a direct lightning hit in an outdoor application). In the rare instance that this occurs, the green "Protection OK"
LED indicator (located at the bottom right of the meter display), will no longer illuminate. 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 Fur-
man.
USB Charger:
The Furman P-2400 IT's USB charger provides an easy way to recharge many popular electronic accessories as well as cellular com-
munication devices by simply plugging the re-charge cord into the front panel socket. Please note: because there are currently
many standards for USB, some devices may not be compatible with our charger.
How Balanced AC Power Works:
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 North America, unfortunately, is not balanced.
The distribution standards currently in use were derived from practices established over a century
ago, when electric power use was limited to lighting and motors, long before any AC noise sensitive applications existed. The em-
phasis then was on convenience and safety, but not noise cancellation.
The result was a three-wire distribution scheme 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 60 Hz and its harmonics. This low level noise becomes part of the audio signals.
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