Specifications

Page 41
CE-Series Amps with an Attitude!
Page 40
CE-Series Amps with an Attitude!
Reference Manual
Reference Manual
Fig. 5.8
Tamper-Resistant
Hole Plugs Installed
in a CE-Series
Amplifier
To remove the hole plugs, simply pry the plug away from the
amplifier case using a small, flat-blade screwdriver. To help to
ensure adequate security, the plugs have been designed to
be more difficult to remove than to place into position. If neces-
sary, additional hole plugs can be purchased separately from
Crown’s Parts Department (Part # 103234-1).
Store your knobs in a safe location should you need to make
level adjustments in the future.
Optional 0.775-V Input Sensitivity Setting
The CE-Series amplifier also provides an optional 0.775-V in-
put sensitivity setting. If you determine your application re-
quires this sensitivity setting, please contact Crown Technical
Support for more information.
6 Principles of Operation
For the sake of simplicity, only channel one of the amplifier is
described.
Signal is presented to the CE-Series through one of three con-
nectors when using the standard input module. Each channel
is outfitted with a balanced XLR / phone jack, and a barrier
strip. These connectors are wired in parallel, which allows
daisy chaining when needed. The signal is then converted
from balanced to unbalanced in the Balanced Input Stage
where it also receives RFI protection. Signal then flows into the
Variable Gain Stage where the front panel level controls are
allowed to affect the gain.
Following this stage, the signal is put under the control of a full-
time compressor circuit comprised of a symmetrical window
detector, a buffer amplifier, and the gating op amp which uses
several small components to set the compressor’s attack and
decay characteristics. The actual compressing is accom-
plished by an opto-isolator which affects the gain in the signal
path.
The signal next enters the main amplifier error amp where it is
mixed with a small portion of the output signal in such a way as
to control the amplifier’s overall output performance.
Warning:
Details of closed loop amplifier design are beyond the scope
of this description and if discussed, would surely put most
readers to sleep!
Following the error amp is the LVA stage, which is where the
low-voltage referenced signal gets translated to the output
high-voltage rails. The last voltage amplifier, in conjunction with
a bootstrap current source, drives both predrivers and the bias
servo. The bias servo is mounted in such a way as to translate
the output heatsink temperature into a controlled bias current
to prevent thermal runaway and hold the amplifier’s notch dis-
tortion to a minimum.
The predrivers provide enough signal to activate the drivers,
which together operate in the class AB range. For the major
output current requirements, the drivers feed the various num-
bers of paralleled output transistors which operate in a class B
mode. This we call the Triple-Deep Darlington Output Stages.
Tamper-Resistant Hole Plugs
Your CE-Series amplifier comes with a set of tamper-resistant
hole plugs, which allow you to “protect” the level controls
against unauthorized adjustment. To use, simply pull off the
control knobs from the front of the amp, and slip the hole plugs
into place (see Figure 5.8). The plugs should slide easily into
position, without forcing. Once in place, the plugs will help to
avoid most accidental or intentional tampering (some situa-
tions may require additional security measures).