Zenith 13K2 Amplifier Manual
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7.2 Operation precautions
- Make sure that the power switch on the amplifier
front panel are set to off before making any input,
output, and also before manipulating the DIP-s w
itches on the rear panel.
- Make sure that the AC mains voltage is correct and
matches the voltage printed on the rear panel of the
amplifier (230V).
- Make sure that no signal is present at the input to
the amplifier when powering up. An input signal
could produce an unintentionally loud initial volume
from the speakers.
7.3 Signal flow and headroom
7.3.1 Signal flow block diagram
The input stage of 13K2 amplifiers has a high
sensitivity to provide ample system headroom. This
in effect means that the input stage is almost
impossible to clip.
Overall amplifier input gain is adjusted using the
input stage DIP-switches. Please note that the gain
setting is global, affecting all channels. Following the
input stage, the dedicated level control on each
channel allows signal attenuation from 0dB to minus
infinity.
The Current Peak Limiter (CPL) section dynamically
limits the input signal based on three parameters:
sensed current level, feedback from the output
stage, and sensed voltage clip from the VPL (and
output amplifier voltage clip if soft clip is activated).
This ensures that power output is maintained within
the design limits of the amplifier.
The adjustable Voltage Peak Limiter (VPL) sets the
maximum output voltage and therefore also the
maximum output power. Eight different voltage
stages are available using the DIP-switches on the
rear panel of all models.
The sophisticated output section monitors faults and
generates appropriate warnings, which are displayed
on the amplifier front panel. In the rare event that
conditions are extraordinarily severe, the amplifier
will shut down until the fault or problem setting has
been rectified or adjusted. These sensing circuits are
also employed to feed back voltage and current level
information, via a side chain, to the limiters. Sensing
circuits also transmit local amplifier module
temperature and power supply temperature to the
appropriate protection mechanisms. Read the
Protection, Faults and Warnings section for further
details.
7.3.2 Headroom, sensitivity and VPL/Gain
settings
The input amplifier and limiter system is designed to
accommodate extremes of performance. Typically,
exceeding maximum input by much as +10dB will
only result in a 1% increase in distortion. The
