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4. CONSIDERATIONS
4. 1 Ground loops, background noise
You should always make sure that the signal sources coming to the mixer, 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 FXSA-041 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.
Adjust, where appropriate, the gain of each input for an adequate operating level and then adjust
the VOL controls on the front panel to obtain the desired input mix. Finally, adjust the VOL control
of the main mix output to get the relevant output volume for your installation, and also enable the
TK switches for priority inputs (a signal detection on these priority inputs will attenuate the signal
of non-priority inputs).
Important note on mix level adjustment: setting for example a channel VOL control to "2" and the
output VOL control to "10" is not the same as the opposite. In the first case, the signal entering the
mixing amplifier is weak, but even so it contains a background noise, so the signal/noise ratio is
low (low signal). When the output amplifier equally amplifies both parts as a whole, the output has
a very high background noise. In the second case, as the channel VOL control is set to the
maximum, the signal received by the mixing amplifier has a high level and therefore also a high
(good) signal/noise ratio, so when this signal reaches the output VOL control and is amplified, the
signal/noise ratio remains better than in the previous case.
4. 2 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.
