-Microphones: The Mic input (29), have a nominal input level of 0'316 to 31'6mV and are
equipped with 1/4" jack connectors.
These inputs allow for the use of balanced wires. Connections are as follows:
Low impedance (200 to 600Ω) monophonic microphones must be used. For non balanced
microphones we recommend monophonic jack plugs although stereo ones are also suitable if the
ring is shortcircuited to the sleeve.
-Compact Disc, Magnetophone, Cassettes, tuner and Video: These signals can be
connected to any CD or LINE input. All these inputs can handle line level signals, but the SMAC
PRO20 has dedicated CD (26) and LINE (25) inputs. The CD input sensitivity is +5dBV (1.778V) and
the LINE input sensitivity is –5dBV (562mV) so that nowadays sound sources requirements are
completely fulfilled.
4. OPERATION AND USAGE
4.1. Start up
To switch the mixer on just push the switch labeled POWER (20) and the green pilot-light
inside the switch will light up. Although the switching noise produced by the SMAC PRO20 is very
low and almost inexistent when starting up the SMACs with the OUTPUT (3-4) control down, we
highly recommend the "safe power-up sequence": sound sources, mixer, equalizers, active filters
and, finally, power amplifiers. Powering off should be done by following the exact reverse sequence
in order to avoid any possible damage to the loudspeakers.
4.2. Prelistening
The SMACs are equipped with a prelistening system that enables the monitoring of the
different inputs through the VU-meter and the headphones.
Pressing any of the PFL (Pre Fader Listening) switches (9), the signal(s) present at the
input(s) will be heard on the headphones (30) and seen on the VU-meter (16).
If the PFL lever switches are at the OFF position, then the signal present at the main MIX
bus (before the last amplification step, OUTPUT) will be heard on the headphones and seen in the
VU-meter so that an indication of the output signal will be available.
6
HOT or direct signal
COLD or inverted signal
GROUND
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Tip
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Ring
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Sleeve