Rca Plugs & Jacks; Unbalancing A Line; Special Connections; Trs Send/Return Insert Jacks - Mackie 8-submaster mixer Owner's Manual

TIP (RETURN)
TIP (SEND)
In most cases, the plug must be inserted fully
to activate the switch. Mackie takes advantage of
this in some circuits, specifying circumstances
where you are only to partially insert the plug.
Once again, see Special Mackie Connections, on
the next page.
RCA PLUGS AND JACKS
RCA "phono" plugs and jacks are often used in
home stereo and video equipment and in many
other applications (Figure 10). They are unbal-
anced, and electrically identical to a 1/4" TS
phone plug or jack. Connect the signal to the cen-
ter post and the ground or shield to the
surrounding "basket." There are no RCA jacks on
the Mackie 8•Bus Series Mixing Consoles. Adapt-
ers to convert an RCA male plug to male 1/4" TS
plug are available at any electronic shop, like
Radio Shack.

UNBALANCING A LINE

In most studios, there is a mix of balanced and
unbalanced inputs and outputs on the various
pieces of equipment. This usually will not be a
problem in making connections.
• When connecting a balanced output to an
unbalanced input, be sure the signal high
connections at each end are wired together,
and the balanced signal low goes to the ground
connection at the unbalanced input. In most
cases, the balanced ground will also be
connected to the ground at the unbalanced
input. If there are hum or radio frequency
ground-loop problems, this connection may be
left disconnected at the unbalanced end.
• When connecting an unbalanced output to a
balanced input, be sure that the signal high
connections at each end are wired together.
The unbalanced ground connection should
be wired to the low and the ground connec-
tions of the balanced input. If there are
ground-loop problems, try connecting the
"Y" insert cable
RING (IN)
FROM
PROCESSOR
OUTPUT
TO
PROCESSOR
INPUT
Figure 11 : Hybrid connector with Send & Return com-
bined on a TRS plug with the separate Send & Return on
the TS plug ends (Plugis Insertis Hybridus)
unbalanced ground connection only to the
input low connection, and leaving the input
ground connection disconnected.
In some cases, you will have to make up spe-
cial adapters to interconnect your equipment. For
example, you may need a balanced XLR female
connected to an unbalanced 1/4" TS phone plug.
SPECIAL MACKIE CONNECTIONS
The balanced-to-unbalanced connection has
been anticipated in the wiring of the Mackie
8•Bus Series jacks. A 1/4" TS plug inserted into a
1/4" TRS balanced input, for example, will auto-
matically unbalance the input and make all the
right connections. Conversely, a 1/4" TRS plug
inserted into a 1/4" unbalanced input will auto-
matically tie the ring (low) to ground.

TRS Send/Return Insert Jacks

The Insert Jacks on both the 8•Bus input
channels and on the Submaster and Main Mix
buses are the three-conductor, TRS type 1/4"
phone. They are unbalanced, but have both the
mixer output (send) and the mixer input (re-
turn) signals in one connector (Figure 11 above).
The sleeve is the common ground for both sig-
nals. The send from the mixer to the external unit
is carried on the tip, and the return from the
external unit to the mixer is on the ring.
Using the Send Only on an Insert Jack
If you insert a TS (mono) 1/4" plug only
partially (to the first "click") into an 8•Bus Se-
ries Insert Jack, the plug will not activate the
jack switch and will not open the insert loop in
the circuit.
This allows you to borrow the channel or bus
signal at that point in the circuit, without inter-
rupting normal operation. Note: Do not overload
or short-circuit the signal you are tapping from
the mixer. That will affect the internal signal in
the 8•Bus Series.
RING TIP
(RETURN) (SEND)
TIP (OUT)
TO MIXER
CHANNEL INSERT
47
ADD-ONS
SPECS
ETC.