10
7.8. MUTE - REMOTE LED indicator
The MUTE LED indicator on the front panel also indicates when signals sent with the remote
handset are received by the infrared detector: it lights up in green when infrared signals are received
and in orange when you try to increase or decrease the volume beyond its maximum/minimum limits,
with the remote control or the encoder.
7.9. Ground loops, background noise
You must always avoid interconnected grounds between signal sources. It means grounds
must never arrive by two or more different ways, since this could produce "hum" ("ground loop") that
would even interfere with the sound reproduction quality.
Cable shielding, when connected to the chassis, must never be interconnected, so as to
avoid ground loops.
The PKUB amplified mixer has been conceived to obtain the lowest possible background
noise. Independently of the electronic design the background noise will directly depend 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.
7.10. 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.
