Ecler SAM412T - Manual (Page 7)

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6. CONSIDERATIONS
6.1. Starting up
This is directly done via the POWER mains switch (10). Even is the power-up noise of SAM412T is
minimal, we highly recommend to power up all equipment in the following order: sound sources, mixing
units, equalizer, processors and finally power amplifiers. The power down sequence is the inverse of the
power up one.
6.2. Equalization
Tone controls (4, 5, 6) provide ±15 dB gain/attenuation for each of the three bands, centered on
100Hz, 2kHz and 10kHz. Given this unit's application philosophy, tone controls are designed to be set
with a screwdriver, thereby preventing accidental manipulation during normal usage.
6.3. VU-meter
The SAM412T has a VU-meter (9) to show the main mixing signal.
6.4. Ground loops, background noise
You should always make sure that the signal sources coming to the unit, as well as all devices
connected to its outputs, do not have their grounds interconnected, that is; ground must never come from
two different devices. Should this ever happen, noises could occur and seriously interfere the sound quality.
Cable shields, when connected to the chassis, must never be linked together. This will avoid
ground loops.
The SAM412T mixer was designed to produce the lowest background noise. Independently from
the electronic design, the resulting background noise directly relies on the correct use and installation of
the mixing unit.
I. e.: setting a channel VOL to "2" and the output to "10" is not the same as the other way round. In
the first case, the signal coming to the mixing amplifier - which has got its own noise - is low, and so is the
signal-to-noise ratio (low signal). When the output amplifier boosts the whole signal we will get a very high
background noise. In the second case - with the channel fader at maximum - the mixing level is high, and
so is the signal-to-noise ratio. When the signal reaches the VOL OUTPUT and is boosted, it will keep a
much better signal-to-noise ratio than in the preceding case.
6.5. Cleaning
The front panel should not be cleaned with dissolvent or abrasive substances because silk-
printing could be damaged. To clean it, use a soft cloth slightly wet with water and neutral liquid soap;
dry it with a clean cloth. Be careful that water never gets into the unit through the holes of the front panel.