Extron electronics MLS 304MA User Manual page 18

Installation, cont'd
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2-10 MLS 304 Series, MLS 406 Series • Installation
• The Preamp connector outputs a variable, line level audio signal for
use with a powered amplifier or self-powered speakers. The volume
can be controlled (attenuated) via the front panel knob or RS-232
communication. The volume range is 0 (mute) through 100.
Lineout and Preamp outputs can be set up as
• unbalanced, -10 dBV (-7.8 dBu, 0.316 Vrms, default) for consumer level
devices such as VCRs, DVD players, and stereo receivers
or
• balanced, +4 dBu (+1.8 dBV, 1.228 Vrms) for professional devices such
as mixers, signal processors, and power amps
depending on how the connector is wired and how the MLS is set up (via the
control software). See the following wiring diagrams and chapter 4, Serial
Communication.
Tip
NO GROUND HERE.
Sleeve(s)
Tip
NO GROUND HERE.
Unbalanced Stereo Output
CAUTION
For unbalanced audio, connect the sleeve(s) to
the center contact ground. DO NOT
the sleeve(s) to the negative (-) contacts.
Tip
NO GROUND HERE.
Sleeve
Unbalanced Mono Output
Connect the sleeve to ground (Gnd). Connecting the sleeve to a negative
(-) terminal will damage the audio output circuits.
For mono output, wire either the left or the right side, not both.
Do not bridge mono outputs. The left and right input signals are
summed, and each mono output channel carries the same combination
signal.
If the output is wired for balanced output, the level is +6 dB higher than the
level for unbalanced output wiring. The balanced/unbalanced level difference
occurs no matter which line level output setting is chosen via RS-232. See
page 4-10.
After the audio inputs and outputs are connected, see chapter 3, Operation
and Setup for instructions on how to adjust the per-input audio sensitivity
levels and optimize Lineout and Preamp output.
If the Loudness feature is turned on, the gains for bass and treble frequencies
are affected for all outputs whenever volume is adjusted.
Amplified output (MLS 304MA, MLS 406MA only) — Cable speakers to this
5-position screw terminal for a mono amplified audio output. This provides a
mono output signal even if the input is a stereo signal. For stereo output, use
the non-amplified Lineout and Preamp outputs instead.
The 4 ohm/8 ohm direct connection circuit and the 70 V/100 V transformer
connection are mutually exclusive: only one circuit (direct or transformer) can
be active at a time.
Do not short the terminals to ground or the amplifier will be damaged.
Do not bridge mono outputs. Bridging could damage the amplifier.
Tip
Left
Ring
Sleeve(s)
Tip
Right
Ring
Balanced Stereo Output
connect
Tip
Left
Ring
Sleeve
Right
Balanced Mono Output
Left
Right
Left
Right