L-ACOUSTICS LA15a 115V Manual V1.0 27/01/2003
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6. CONNECTIONS
6.1 INPUT CONNECTIONS
6.1.1 BALANCED INPUTS
XLR Input connectors are active balanced and wired according to IEC 268 (i.e., pin 2 hot) in the
following way:
PIN
1
GROUND/SHIELD
PIN
2
HOT
(+)
PIN
3
COLD
(-)
Figure 4: XLR Input Connector Wiring
Figure 5: Balanced XLR wiring
The Neutrik® Combojack includes a ¼” (6.3 mm) phone jack, which is wired in parallel with the XLR
in the following manner:
TIP HOT
RING COLD
SLEEVE SHIELD/GROUND
Figure 6: ¼” TRS plug
The input impedance is high enough (20 kOhms, balanced) to allow ”daisy-chaining”, or multiple parallel
input connections. The headroom of the input circuits is also high enough to accept the maximum output
level from virtually any low-level signal source. Balanced signals are less sensitive to AC hum and radio
interference. The source impedance should be less than 1 kOhms in order to avoid high frequency loss in
long cables.
Figure 7: LA15a Rear Panel Detail
