Crown D-75 - 6 Circuit Theory; 6.1 Block Diagram Circuit Theory

REV. 0
0-75 POWER AMPLIFIER
6 Circuit Theory
6.1 Block Diagram Circuit Theory
The following cliscussioo re f ers lO the block diagram in
Fig. 6.1.
When using th e XLR Balanced Input.lwo signals, I SO°
out of phase, will be introduced 10 th e Balanced Input
circuioy. Here, th e two s ignals arc added together to
become the Unbalanced o utput of the Balanced input
circuitry,
Thi sc ombincd sign al is th en fed to a s tage of powe r
amp l ifi c ation where it is boos t ed to a l eve l of s uffi c ient
amplitude to drive an Ou t put Load.
A ponion of the output signal is routed to the Signal
Presence cin:uilry. Pr ovided th e ou tput sig nal has J!l
amplitude of at least one vo ll peal.: to peak, the green
s ignal prese nce indicators willlighl and vary in imensily
with Lilc O UlPU L si gna l.
The o utput signai is f ed back to a.'l d com pared with Lile
i npu t signal. An y n onl ineariti es ex i sti ng between th ese
two signals will generate a correction signal to th e
amplifier
and the JOC indi cators on the fronL panel.
~ In pbue . ,..;,t, 1M • i9UI 00QUII1O
The P owe r Suppl)' supp li es th e proper voltages to the
various circuit componeOis within the amplifie r.
P:trz;
UNBAl
POWER
INPUT
A MP
CH,
CH 1
3AlINPUT
I
r8
s~
,-d'
POWER
MONO", I
AC LINE
SUPPLY
SWITCH
MONO
Lf\-
BAlINPUT
I
~
s~
UNBAl POWEM
INP UT
AMP
CH2
CH2
F ig. 6.1 D ·7 5 Block D ia gram
Circuit Theory 5 -1