Crown 1160ma Guía Del Usuario

For the sake of simplicity, only channel one of 
the amplifier is described. 

Signal is presented to the amplifier through one 
of three connectors when using the standard 
input module. Each channel is outfitted with a 
balanced XLR connector 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 rear-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 com-
prised of a symmetrical window detector, a 
buffer amplifier, and the gating op amp which 
uses several small components to set the com-
pressor’s attack and decay characteristics. The 
actual compressing is accomplished by an 
opto-isolator which affects the gain in the sig-
nal path.

The signal then travels either through the HP 
filter module or is bypassed around it depend-
ing on the position of the channel operation 
switch. In the CH1 and CH2, with the switch set 
in the 70V position, the filter is enabled. The fil-
ter is an 18 dB-per-octave high-pass with a –3 
dB rolloff at 70 Hz. This provides a measure of 
protection to step-down transformers used in 
distributed speakers installations. With the 
switch set in the 4/8 Ohm setting, the filter is 
bypassed.

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.

Following the error amp is the LVA stage, where 
the low-voltage referenced signal gets trans-
lated to the output high-voltage rails. The last 
voltage amplifier, in conjunction with a boot-
strap 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 ampli-
fier’s notch distortion to a minimum.

The predrivers provide enough signal to acti-
vate 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 is referred to as 
the Triple-Deep Darlington Output Stages. 

The output transistors are protected by the Time 
Dependent Voltage & Current circuit. This cir-
cuit protects the devices from extending 
beyond their safe area of operation, but allows 
the devices to provide high bursts of peak 
power when needed. This amplifier output 
topology offers a good combination of low qui-
escent amplifier heating, great distortion per-
formance at high powers, and relative 
simplicity, with impressive reliability and value.

All output power is delivered through a chan-
nel-independent, dead front barrier block on 
the back panel. When the Channel Operation