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Consumer equipment generally uses un-balanced connections such as RCA and phone jack connectors. Quite
simply balanced audio has three connections, a Plus, Minus and Ground (or shield). Un-balanced audio has
two connections - Plus and Ground.
For your convenience a console will arrive with one MIC INPUT cable (B501), one LINE INPUT cable
(B502) and 4 RJ45 to open leads (B500) which may be used for inputs and outputs.
With so many optional connections in both the professional and consumer audio market, it is impossible to
provide cabling to meet every individual need. We have provided a sampling of the cables, which are
available as options.
RJ45 jacks contain eight wires each. Six of these are used for balanced audio input and the other two provide
+/- 15 VDC to the B series of input amps. (see inside front cover)
The input wiring is clearly labeled on the bottom cover of the unit and are identical for each mixer (see the
console outline drawing for general location).
REMEMBER: There is +/- 15VDC present on the RJ45 Connections. PLEASE check all diagrams before
wiring your own cables.
4.5.1 General Installation Comments
Connect one audio source at a time, and check for RF interference and other problems before proceeding. It
is advisable to connect a sensitive voltmeter or oscilloscope to the console Program output to monitor signal
quality as each input is connected to the console. Any noticeable degradation in the console's noise floor
should be investigated and eliminated before moving on to the next input.
Remember that FM RF interference usually is caused by rectification of a high RF signal level; AM RF
interference usually is caused by a system ground loop (see Section 4.4). Telephone lines are often the cause
of noise problems, and a 600:600 ohm isolation transformer is recommended at the console input for direct
connection to the phone line. In high RF fields, proper grounding techniques are absolutely necessary.
Important: Never apply a phone line directly to the console. The presence of a ring voltage will cause
damage to the circuitry.
4.5.2 Wiring the Inputs and Outputs Using the B500 Cable
RJ45 wiring is standard T568B and should be readily available at your local computer or phone supply store.
LPB offers a series of pre-made input cables and amplifiers. Information is located on the inside of the front
cover of the manual.
Pin 1 White/Orange Left +
Pin 2 Orange/White Left –
Pin 3 White/Green Right +
Pin 4 Blue/White GND
Pin 5 White/Blue GND
Pin 6 Green/White Right –
Pin 7 White/Brown -15VDC (not available on B500 Cables)
Pin 8 Brown/White +15VDC (not available on B500 Cables)
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