SWITCHED 1�4" PHONE JACKSgoes to the ground (earth) connection at
1the unbalanced input. In most cases, theSwitches can be incorporated into �4"
balanced ground (earth) will also be
phone jacks, which are activated by inserting
connected to the ground (earth) at the
the plug. These switches may open an insert
unbalanced input. If there are ground-looploop in a circuit, change the input routing of
problems, this connection may be left
the signal or serve other functions. Mackie
disconnected at the balanced end.
uses switches in the channel insert and bus in-
sert jacks, input jacks and AUX returns. WeY When connecting an unbalanced output to
also use these switches to ground the line-levela balanced input, be sure that the signal
inputs when nothing is plugged into them.high (hot) connections are wired to each
In most cases, the plug must be insertedother. The unbalanced ground (earth)
fully to activate the switch. Mackie takesconnection should be wired to the low
advantage of this in some circuits, specifying(cold) and the ground (earth) connections
circumstances where you are to insert the plugof the balanced input. If there are ground-
only partially. See Special Mackieloop problems, try connecting the
Connections, later in this section.unbalanced ground (earth) connection
only to the input low (cold) connection,
RCA PLUGS AND JACKSand leaving the input ground (earth)
RCA-type plugs (also known as phonoconnection disconnected.
plugs) and jacks are often used in home stereoIn some cases, you will have to make up
and video equipment and in many other appli-special adapters to interconnect your equip-
cations (Figure D). They are unbalanced andment. For example, you may need a balanced
electrically identical to a 1�4" TS phone plug orXLR female connected to an unbalanced 1�4"
jack (See Figure C). Connect the signal to theTS phone plug.
center post and the ground (earth) or shield
SPECIAL MACKIE CONNECTIONS
to the surrounding Obasket.�
The balanced-to-unbalanced connection has
UNBALANCING A LINE
been anticipated in the wiring of Mackie jacks.
In most studio, stage and sound reinforce-A 1�4" TS plug inserted into a 1�4" TRS balanced
ment situations, there is a combination of
balanced and unbalanced inputs and outputsringOtip�SEND to processor
tipsleeve(TRS plug)
on the various pieces of equipment. This usu-
ally will not be a problem in making
This plug connects to one of the
connections.mixerOs Channel Insert jacks.Oring�RETURN from processor
Y When connecting a balanced output to an
Figure F
unbalanced input, be sure the signal high
(hot) connections are wired to each other,
and that the balanced signal low (cold)
43 |
ACEC
