Installation; Connections - Omnitronic PAA Series User Manual

4 Installation

This amplifier is built for 19" racks (483 mm) but can also be used as a tabletop unit. In order to ensure
sufficient cooling of the amplifier, air must always be able to flow freely through all air vents. For rack
installation, the amplifier requires
space between the devices. Insert the heaviest units into the lower part of the rack.
The hot air given off by the amplifier must be dissipated from the rack; otherwise heat will accumulate in the
rack which may not only damage the amplifier but also other units in the rack. In case of insufficient heat
dissipation, install a ventilation unit into the rack.

5 Connections

Speakers
High voltage at terminals when using PA systems. Installation by skilled personnel only! Turn off
amplifier before connecting.
Either PA speakers with 70 V or 100 V audio transformer or 4-16 Ω speakers or speaker groups with a total
impedance of at least 16 Ω can be connected.
• Connect PA speakers to the terminals "COM" (negative pole) and "100 V" or "70 V".
• Connect low-impedance speakers to the terminals "COM" (negative pole) and "4Ω", "8Ω" or "16 Ω"
(positive pole).
• When connecting, observe the correct polarity (positive and negative connections). The terminal "COM" is
always the negative pole. The positive connection of the speaker cables is always specially marked.
The total load must not exceed 120 W
otherwise the amplifier may be damaged by overload.
Notes
The input impedance of the speaker systems should at least be the same or even higher than the output impedance of
the amplifier. Refer to this example for the calculation number of speakers/impedance:
Number of speakers
1 speaker at 8 Ω
2 speakers at 8 Ω each
2 speakers at 8 Ω each
3 speakers at 8 Ω each
3 speakers at 8 Ω each
4 speakers at 8 Ω each
Choosing appropriate speaker cables
• Speaker systems must only be connected via sufficiently dimensioned cables. Thin cables lead to cable heatup or
enormous power loss and loss in sound quality. For all speaker systems up to 400 Watts, we recommend a cable
diameter of 2.5 mm², for all other speaker cables 4 mm².
• A high damping factor of your amplifier supplies a clear sound reproduction. Unnecessarily long and thin cables will
influence the damping factor and thus the low frequencies in a negative way. In order to safeguard good sound quality,
the damping factor should lie around 50. The longer a cable has to be, the thicker it should be. In this respect, a
damping factor of 200 will be reduced to 47 (8 ohms) when using a 10 m long, 2.5 mm² speaker cable. The power loss
at 8 ohms is 1.63 %, at 4 ohms 3.25 % and at 2 ohms even 6.5 %.The maximum cable length is 30 meters.
General information on installing cables
• Always treat cables carefully and protect them from damages during transportation.
• Install cables always in a structured way and protect them from damage.
• Cables must be installed in a way that no person can stumble over them. Always fix cables with an appropriate tape.
• Cables should be installed directly (no loops, S-shaped overlengths).
• Always install cables far away from power cables (never closely parallel).
• Never put heavy objects like speaker systems, flightcases etc. on cables.
• Never operate cables wound up.
2 U. If several units are to be installed, make sure that you leave 1 unit
DANGER TO LIFE!
(PAA-120), 240 W
RMS
≙ Impedance
8 Ω
4 Ω (parallel)
16 Ω (in line)
2.66 Ω (parallel)
24 Ω (in line)
2 Ω (parallel)
16 • EN
(PAA-240) or 360 W
RMS
(PAA-360),
RMS