Crown PIP-PA Reference Manual page 9

P .I.P .–PA
MONO mode. Remember to fol-
low the instructions in your
amplifier's Reference Manual.
Then connect the mono input wir-
ing to the mic and/or line input of
Channel 1 only. Do not use the
input of Channel 2 while the
amplifier is in BRIDGED-
MONO or PARALLEL-MONO
mode and keep the amplifier's
Channel 2 level control turned
down.
Input Cable Routing
Because the gain of a Crown
amplifier equipped with a P.I.P.-
PA can be quite high (as high as
90 dB) it is very important to exer-
cise care when routing the input
and output cables.
IMPORTANT: Use shielded wire
for mic input cables and avoid
routing them near the output
cables or noise and/or feedback
oscillation may result. It is wise to
take similar precautions with line-
level inputs cables too.
To avoid hum, do not route the
input cables near power cables.
Switching Between Mic/Line
The line-level inputs are the de-
fault inputs if no switch is attached
to select the mic inputs. In this
case, each mic input is attenu-
ated 54 dB while each line input is
delivered to the amplifier.
When the remote switch connec-
tion is shorted (that is, a switch is
installed and turned on) the line-
level input is attenuated 30 dB
and the mic input is delivered to
the amplifier.
A timed fader circuit causes the
switch from line to mic and mic to
line to be a smooth transition. The
intent is to create a more pleasing
transition for situations where the
line-level input is used to feed
background music and the mic
input is used for paging.
When the switch is activated, the
line-level input is muted after a
delay of 10 msec. Because it is
muted only 30 dB it is still barely
audible. The mic input turns on
almost immediately to insure that
no syllables of speech are lost,
giving an abrupt transition from
background music to paging.
avoid avoid
avoid avoid
When the switch is opened the
mic input is quickly muted 54 dB
in about 3 msec. The line-level
input is turned back on after a
lengthy delay of 1.5 seconds, pro-
viding a more pleasing fade back
to music after the page.
The remote line can also be con-
trolled with a +5 to +24 VDC logic
line. For example, you could use
the Auxiliary control feature of an
IQ–P.I.P. or an MPX/SMX-6 multi-
plexer to control the mic/line
switching with an IQ System
do this, add a 20 K ohm "pull
down" resistor across each re-
mote line. When the logic line is
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