JBL SYNTHESIS S5160/230 User Manual page 9

2.0
INTRODUCTION
AND FEATURES
Quiet Cooling
The S5160 utilizes a fan to cool the amplifier channels,
ensuring long-term reliability. To reduce fan noise to an
absolute minimum, a thermal sensing and control circuit
has been incorporated in the Synthesis S5160 that sens-
es increases in temperature within the amplifier and pow-
ers a fan at a speed proportional to that temperature
increase. When the S5160 is used at lower volume levels,
the fan turns very slowly – and quietly. At high listening
levels (and the higher operating temperatures this creates
within any amplifier), the sensing circuitry causes the fan
to turn faster, producing increased cooling. As a result, the
fan is never turning faster than necessary, and most of the
noise that is generated is masked by the program being
listened to.
Comprehensive and Isolated Circuit Protection
The S5160 amplifier employs a sophisticated protective
circuit (one for each channel) that senses many possible fault
conditions, such as shorted loudspeaker wires or excess
power demand, and turns the affected channel(s) and their
blue front panel indicators off until the fault condition is
removed, at which time normal operation is automatically
restored. While protection of this sort is not uncommon in
today's well-designed amplifiers, a remarkable feature of
the Synthesis S5160's protective circuits is that they are
optically-coupled to the signal circuit; there is no direct
electrical connection between the signal path and the pro-
tective circuitry.
As a result, there can be no coloration of the
music, no interaction between protection and
amplification, until certain thresholds are
exceeded, at which point the channel(s) turn off
completely.
9
2.0
INTRODUCTION
AND FEATURES