Connecting The MPL 1640
The actual connections you’ll make to and from the MPL 1640 will vary accord- ing to the environment you use it in and the particular equipment you have. In the “Applications” sections at the conclusion of this manual (pages 24 - 27), you’ll find some suggested setups. Here we present a few basic rules concern- ing MPL 1640 connections that will apply in pretty much all situations:
•In general, it’s best to make all connections with the MPL 1640 and all power amplifiers turned off. If you must make connections with the power on, make sure that both the Main Mix and 3/4 output levels are completely down. Whenever powering down, turn both output levels completely down and then turn off all power amps first. Wait a few seconds for their power supplies to discharge and then turn off all connected equipment, turning the MPL 1640 off last.
•Try to use balanced connectors and cabling wherever possible. These kind of connections do a better job of rejecting extraneous noise and hum and generally provide a cleaner signal. Although the MPL 1640 will accept unbalanced connectors throughout, it specifically provides electronically balanced connectors for all sixteen mic and line inputs and for its Main Mix outputs. The wiring diagram below shows how 1/4" TRS (Tip/Ring/Sleeve) plugs should be wired for use with these inputs and outputs:*
SLEEVE
TIP
RING
TIP +
GROUND RING -
Unbalanced cables use standard 1/4" phone plugs, wired as follows:
| + SIGNAL |
+ SIGNAL |
|
GROUND | GROUND |
•Make one connection at a time and then monitor the incoming signal. If you hear a distinct hum or buzz, you may have a grounding problem with that particular device. See the section on page 15 entitled “Grounding Techniques” for information on how to avoid grounding problems.
•NEVER connect a microphone and line level input to the same channel
3 - SIGNAL
1 GROUND 
TO MIXER 2 + SIGNAL
* You’ll also find this information
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