Specifications

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.