Mackie 1402-VLZ3 User Manual

1402-

VLZ3

The balanced-to-unbalanced connection has been 

anticipated in the wiring of Mackie jacks. A 

1

⁄

4

" TS plug 

inserted into a 

1

⁄

4

" TRS balanced input, for example, 

will automatically unbalance the input and make all the 
right connections. Conversely, a 

1

⁄

4

" TRS plug  inserted 

into a 

1

⁄

4

" unbalanced input will automatically tie the 

ring (low or cold) to ground (earth).

Mackie’s single-jack inserts are the three- conductor, 

TRS-type 1⁄4" phone. They are unbalanced, but have 
both the mixer output (send) and the mixer input 
 (return) signals in one connector. See Figure E.

The sleeve is the common ground (earth) for both 

signals. The send from the mixer to the  external unit is 
carried on the tip, and the return from the unit to the 
mixer is on the ring.

If you insert a TS (mono) 1⁄4" plug only  partially (to 

the fi rst click) into a Mackie  insert jack, the plug will 
not activate the jack switch and will not open the insert 
loop in the  circuit (thereby allowing the channel signal 
to continue on its merry way through the mixer).

This allows you to tap out the channel or bus signal 

without interrupting normal operation.

If you push the 1⁄4" TS plug in to the second click, you 

will open the jack switch and create a  direct out, which 
does interrupt the signal in that channel. See Figure F 
on the next page.

NOTE: Do not overload or short-circuit the signal you 

are tapping from the mixer. That will affect the internal 
signal.

RCA-type plugs (also known as phono plugs) and 

jacks are often used in home  stereo and video equip-
ment and in many other applications (Figure D). They 
are  unbalanced and electrically identical to a 1⁄4" TS 
phone plug or jack (see Figure C). Connect the signal to 
the center post and the ground (earth) or shield to the 
surrounding “basket.”

In most studio, stage and sound reinforcement situ-

ations, there is a combination of balanced and unbal-
anced 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 (hot) 
connections are wired to each other, and that 
the balanced signal low (cold) goes to the 
ground (earth) connection at the unbalanced 
input. In most cases, the balanced ground 
(earth) will also be connected to the ground 
(earth) at the unbalanced input. If there are 
ground-loop problems, this connection may be 
left disconnected at the balanced end.

• 

When connecting an unbalanced output to a 
balanced input, be sure that the signal high 
(hot) connections are wired to each other. The 
unbalanced ground (earth) connection should 
be wired to the low (cold) and the ground 
(earth) connections of the balanced input. If 
there are ground-loop problems, try connecting 
the unbalanced ground (earth) connection only 
to the input low (cold) connection, and leaving 
the input ground (earth) connection discon-
nected.

• 

In some cases, you will have to make up special 
adapters to interconnect your equipment. For 
example, you may need a balanced XLR female 
connected to an unbalanced 1⁄4" TS phone 
plug.