13
Sensitivity
Your amplifier is a linear device operating with a fixed input to output voltage
gain (less attenuation). The maximum output voltage swing is determined by
the applied mains voltage, load, load type and the duty cycle of the
applied signal. The
input sensitivity
for your
IS
Series amplifier when the
attenuator is at maximum position (fully clockwise) is determined by the Input
Sensitivity switch.
There are 3 settings for rated power into a 4 ohm load.
0.775V in for rated power out
1.0V in for rated power out
1.44 V in for rated power out.
Each channel of your
IS
Series amplifier has a nominal balanced
input
impedance
of 20kOhms (@1kHz) and should not present a difficult load for
any signal source. (i.e. the equipment feeding signal)
.
Hum Problems
Most equipment is designed for minimum hum when used under ideal
conditions. When connected to other equipment and to a safety earth in an
electrically noisy environment, problems may occur. The three ”E”s of hum
and hum related noise which can plague your audio system are:
a) Electrostatic radiation,
b) Electromagnetic radiation, and
c) Earth loops
Electrostatic
radiation capacitively couples to system elements, causing an
interference voltage that mainly affects higher impedance paths, such as
amplifier inputs. The source is generally a nearby high voltage, such as a
mains lead or a speaker lead. The problem can usually be reduced by
moving the offending lead away, or by providing additional electrostatic
shielding (i.e. an earthed conductor which forms a barrier to the field).
Electromagnetic
radiation induces interference currents into system elements
that mainly effect lower impedance paths. Radio transmitters or stray
magnetic fields from mains transformers are often the cause of this problem.
It is generally more difficult to eliminate this kind of interference, but again,
moving the source away or providing a magnetic shield (i.e. a steel shield)
should help.
Summary of Contents for IS1200
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