Reference Manual
Page 6
5. Clip/Limiter LED
Each channel has a LED that light at the real clipping point (more than 0.5% T.H.D.) and also
indicates the input signed is compressed by amplifiers.
6. Protect LED
Each channel has a Protect LED that will light when the load connected is lower than 1 Ohm
or amplifier broken.
7. Bridge LED
The Yellow active LED illuminates to indicate that the amplifier is
bridge mode.
8. Power LED
The green active LED illuminates to indicate that the amplifier is turned on, and works
correctly.
9. AC power switch
Use this to switch on the amplifier. A soft-start system limits the start-up surges.
10. Fan exhaust ports
Heated air exits the amplifier through the exhaust ports, located on the rear of the amplifier
chassis. Be sure not to block this ports, especially when rack mounting the amplifier.
11. Input connectors
XLR female is provided on each channel for balanced or unbalanced input. Unfortunate
wiring, in the proximity of dimmers or other generalised phase controls, motors, trans-
former, etc. can cause interference into your system. You will hear loud humming or a
bumping noise in the loudspeakers. Balanced wiring suppresses these noises quite
significantly.
12. Selectable Limit function
The switch enable the Limit circuit located on settings board.
13. Input Sensitivity/Gain
The standard settings are:0.775V/1V/1.4V,selection is independent for each channel. Use
this function to match the amplifier's
sensitivity/gain with the other connected equipment.
As option, is possible adjust the unit for any sensitivity/gain.Note that every increase of the
gain will decrease the S/N ratio.
14. Mode operation switches
Setup these switches for the desired operation mode.
15. Speakon output connectors
The unit has four Speakon connectors as outputs: CH 1 and CH 2. Every one permit the con-
nection of both channels for stereo operation or parallel mode. For bridge operation the
CH1 connector should be used.
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Reference Manual
Page 7
17. S.N. label
Every unit has a label indicating: the model, and the barcode serial number.
Operation
Connecting Power and Circuit size requirements
Amplifier's
power requirement are rated at idle, at 1/8 and 1/3 power ("severe" music con-
dition).The maximum power current draw rating is limited only by the internal fuses.
Consult the specification at the end of this manual for the power each amplifier will
demand. Mains voltage must also be correct and the same as that printed on the rear of
the amplifier. Damage caused by connecting the amplifier to improper AC voltage is not
covered by any warranty.
Note: always switch off and disconnect the amplifier from mains voltage before making
audio connections, and as an extra precaution, have the attenuators turned down during
power-up.
Cooling Requirements
Amplifier use a forced air cooling system to maintain a low, even operating temperature.
Drawn by a infinitely variable speed fans mounted inside the unit, air enters through the
front grills with dust filter, and courses through the cooling fins of the heatsinks, which dis-
sipates power transistor heat, before exiting through the rear panel ports. Make sure that
there is enough space around the front of the amplifier to allow air to enter, and around
the units to allow the heated air to exit. If the amp is rack-mounted, do not use doors or cov-
ers on the front and rear of the rack; the air must flow through the amplifier without resis-
tance.
Note: whatever type of rack you are using, make sure that the heated air can escape freely,
and that there is not resistance to the intake of cool air through the front grill.
Configuration
Use the configuration switch and the internal jumpers to configurate the amplifier to meet
your requirements. The setup must be done with the unit switched off. With the switches
and jumpers is possible to configurate the amplifier for the following functions:
Stereo Mode (standard)
In stereo mode, the channels operate independently, with their input attenuators control-
ling the respective channel's
level. Recommended minimum nominal load impedance for
stereo operation is 4 or 2 Ohms per channel (as indicated on the specifications).
Loudspeakers are connected to the speakon outputs CH 1 or CH 2. For reference see
Bridged Mono Mode
In Bridged Mono mode, both amplifier channels work with the same input signal, but with
inverse phases.The result is a doubling of the output voltage and thus double the power
on the double impedance. If the amplifier is to be operated in Bridged Mono mode, ONLY
one input may be used CH1. We recommend that you set them to the -0dB (full) position.
Loudspeakers are connected to the speakon output CH 1. For reference see Figure 1.
Figure 1
16. A.C. Power cable
The unit have one A.C. power cable. Before connection, be sure that the cable is not frayed
or broken. The connection must be made only in a plug with the electrical ground wire system.
PLX Series
PLX Series