Compex Systems AP4530 - Manual (Page 27)

iDR-8 User Guide 27
XLR Analogue Inputs and Outputs
MIC/LINE Inputs
Plug analogue microphone and line
sources in these inputs. The connections are differentially
balanced XLR with pin2 hot (+), pin3 cold (-) and pin 1 ground.
For unbalanced sources link pin 3 to pin 1 at the iDR input.
Phantom power +48V DC can be switched to XLR pins 2 and
3 for powering condenser microphones and other equipment
that needs phantom power. The voltage is fed through a 6.8k
ohm resistor to each pin.
The Input Source window From within the Input
Channels window click on the Source button or the All button.
This opens the window with the input controls. The controls
shown are those associated with the physical input routed to
that channel through the source patchbay. Check that the
physical input number displayed is the same as the XLR input
you are working with.
Selecting phantom power Open on the Source window
to access the +48V switch. If required, select +48V. Read the
warnings below.
To avoid loud clicks make sure that all channels fed
by the input are turned down or muted before you switch
+48V on or off or plug microphones into powered inputs.
Do not connect unbalanced sources or cables to the inputs
when +48V is selected. If phantom power is not required
make sure +48V is turned off.
Selecting PAD Select the -20dB pad if you are plugging
in high level microphone or line sources. Open on the Source
window to access the -20dB switch.
Setting GAIN Open on the Source window to access the
gain control. With audio active adjust the control so that the
meter averages around ‘0’ with loudest peaks no more than
‘+10’. The gain control ranges from +5 to +50dB gain, or -15
to +30dB gain with pad selected. Gain is adjusted in 3dB
steps.
Soft Limiter The limiter is an analogue circuit just before the
ADC converter. It can be switched in or out. It uses an opto
device to automatically limit the maximum signal level sent from
the input preamp to the converter. While the preamp stage can
be clipped, it does prevent clipping of the converter which can
result in the harsh distortion associated with digital equipment
if unexpected transient peaks are allowed to get through. The
limiter starts to work 4dB before clipping. Default setting is
limiter switched out.
Selecting the limiter Open on the Source window to
access the limiter button. Switch it on or off as required.
LINE Outputs
Connect these to line level equipment
such as amplifier inputs. Maximum output is +18dBu. Decide
the normal operating level according to headroom required.
Typical level is 0 or +4dBu. The connections are differentially
balanced XLR with pin2 hot (+), pin3 cold (-) and pin1 ground.
For unbalanced sources link pin 3 to pin 1 at the iDR output.
The Output Source window Click on the XLR within the
Output Select window to open up its Analog Output window.
Check that the source channel number displayed is the one
you want to send to the output XLR.
IN 1
+
-
OUT 1