Mackie 1604-VLZ4 User Manual - Page 28

1604VLZ4 Unbalanced RCA Connector TRS Send/Receive Insert Jacks RCA-type plugs (also known as phono plugs) and jacks are often used in home ­stereo and video equipment and in many other applications. RCA plugs are ­unbalanced. Connect the signal to the center post and the ground (earth) or shield to the surrounding "basket." Be sure the cables are wired per AES (Audio Engineering Society) standards: Unbalanced RCA Connector Sleeve - Shield (Ground) Tip - Positive (+ or hot) Single-jack inserts are 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 the illsutration below. The sleeve is the common ground (earth) for both signals. The send from the mixer to the e­ xternal unit is carried on the tip, and the return from the unit to the mixer is on the ring. ring tip sleeve (TRS plug) SEND to processor tip SLEEVE TIP SLEEVE TIP This plug connects to one of the mixer's Channel Insert jacks. ring RETURN from processor Unbalanced 1/4" Insert Connectors Unbalanced RCA Connector Unbalancing a Line In most studio, stage and sound reinforcement situations, there is a combination 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 (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. Special Connections The balanced-to-unbalanced connection has been anticipated in the wiring of 1604VLZ4 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). Using the Send Only on an Insert Jack If you insert a TS (mono) 1⁄4" plug only ­partially (to the first click) into a VLZ4 ­insert jack, the plug will not activate the jack switch and will not open the insert loop in the c­ ircuit (thereby allowing the channel signal to continue on its merry way through the mixer). • When connecting an unbalanced output to a This allows you to tap out the channel or bus signal balanced input, be sure that the signal high without interrupting normal operation. (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 If you push the 1⁄4" TS plug in to the second click, you will open the jack switch and create a d­ irect out, which does interrupt the signal in that channel. See the illustration on the next page. 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. 28 1604VLZ4