Cloud Electronics MPA626 - Manual (Page 6)

MPA-626: Installation and Operation Manual 5
5 Music Equalisation
One set of independent bass and treble controls is provided for the music signals. These pre-
set controls are located on the rear panel adjacent to the line input sockets. The treble control
has a range of ±10dB at 10kHz and the bass control has a range of ±10dB at 50Hz.
6 Music Priority
When a Juke Box or Spot Announce Player is connected to the MPA-626, fully automatic
priority over any selected line input can be achieved by using the Line 6 input and setting the
rear panel switch L6/PR to ON. When this mode of operation is selected, the unit will operate
normally until a signal is detected on line 6, this causes the selected signal (usually background
music) to mute, allowing the signal on line 6 to operate with priority. Once the signal on line 6
ceases, the selected signal will smoothly restore to its former level. The time taken for the
selected signal to be restored can be set at 3, 6 or 12 seconds by repositioning jumper J13 on
the upper rear printed circuit board.
7 Microphone Inputs
Two microphone inputs are provided, the microphone amplifiers are an electronically balanced,
transformer-less design configured for optimum low noise performance. The input impedance is
greater than 2k
Ω and is suitable for microphones in the 200Ω to 600Ω range. Inputs are via gold
plated 3-pin XLR type latching connectors, which are positioned on the rear panel. For balanced
microphones, connect the cable screen to pin 1, the in phase signal to pin 2 and the reverse
phase to pin 3. To operate the channel in the unbalanced mode, connect pin 3 to pin 1 (ground)
inside the XLR cable plug. Use pin 2 as hot and pin 1 as screen (ground), see diagram below: -
Phantom power facilities are provided; either of the inputs can be configured to operate with
15V phantom power by setting the relevant jumper to the ON position. Jumper details and
locations are shown in the following diagram : -
Care should be taken to ensure that phantom power is activated only when the microphone
connected to the input requires external phantom power
7.1 Gain Control
A pre-set gain control is provided adjacent to the XLR input connector. The gain can be
adjusted from 20dB to 60dB. A high overload margin is maintained at all gain settings
7.2 Microphone Access Inputs
The microphone access inputs are primarily intended to provide compatibility with paging
microphones and their associated switching arrangements. When these inputs are left open
circuit the microphone inputs are muted. When either terminal 1 or 2 is connected to the 0v
terminal the respective microphone channel will become open for use.
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