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It is standard practice to ground all input shields at the console end of the line, and leave the shield
disconnected at the source equipment end. Console output shields are normally left open at the console end,
and grounded at the load end. The AC safety (chassis) grounds of all external equipment (as well as the
console's) should be returned to the same physical and electrical point in the studio for optimum operation.
In areas of intense RF interference, shields with one end un-terminated may pick up RF and radiate it into the
console. In this case, the open end of the shield should be connected to ground with a small 0.1 ufd capacitor
(see Figure 4.2); the capacitor will act as a short to RF frequencies, but will appear as an open circuit at 60
and 120 Hz.
Special care should be taken when integrating equipment with unbalanced (consumer) inputs and outputs
into the system. Much of this equipment has no provisions for chassis grounding at all. In this case, one
audio cable shield must be terminated at both ends, or the audio circuit will not work for lack of a ground
reference. If you are using the LPB B520 Line Input Beissel, do not add grounding to the consumer
equipment. Unbalanced equipment with a grounded chassis (such as some professional power amplifiers)
should be installed normally, i.e., with shields open at the console end, and the chassis returned to ground by
a grounding cable. Alternatively, an isolation transformer may be used at the input of the unbalanced device.
Some devices feature a ground link or jumper for strapping the chassis ground to the audio ground. Be sure
these links are connected in accordance with your grounding plan.
The console and all external equipment are usually grounded to a grounding bus, or copper strap, with an
individual grounding conductor, such as copper wire, strap or braid. The grounding bus is securely
connected to an effective electrical ground.
the open end of the shield.
capacitor from shield to ground at
connect a compact ceramic disc
may pick up RF. To avoid this
presence, shields left open at one end
heavy RF
In areas of
mfd
0.1 Shield
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+
Figure 4.2
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