6
The LED indicator “
XOVER
” on the front panel lights up when this function is activated via the switch on the
rear panel (15).
3.5. Limiter circuit
This provides additional protection and is always activated on amplifiers in the LPA series. This “ANTICLIP”
circuit constantly analyzes the harmonic distortion produced by the excessive clipping of the signal in the amplifier
output, and reduces the input level automatically to keep the level of distortion below 0.5% approximately.
The clear advantage of a limiting system in front of conventional compressors is that the former does
practically not alter the dynamic range, acting only when the distortion threshold is reached.
3.6. Output connections
See diagram 6.1. for output connection possibilities.
The output section on the rear panel features both Speakon® connectors (18) and threaded connection
posts (17).
If you need to operate the amplifier in BRIDGED mode, you should place the “MODE” (16) switch in BRIDGE
position. Input signal should be fed into Channel 1 of the amplifier and the output appears at the 2+ and 2- pins of
the Speakon® connector and/or at the red connection posts. Before the amplifier is started, it checks that the total
impedance of the set of loudspeakers connected to the amplifier (operating in BRIDGE mode) is not lower than 8
Ω
.
ATTENTION: Terminals 1+ and 1- should only be used in case of “STEREO” or “PARALLEL” mode
and terminals 2+ and 2- in “BRIDGED” mode. Any other combination may impair final audio quality
The connection cable that joins the amplifiers outputs and the loudspeakers must be of good quality,
sufficient section and as short as possible. This is most important when the distances to cover are long ones i.e. up
to 10 meters it is recommended to use a section not inferior to 2.5mm
2
and for superior distances 4mm
2
.
4. OPERATION AND USAGE
4.1. Start up
When the power-on switch is pressed (10), the blue “ON” LED and the two red “PROTECT” LEDs light up (2).
Around 10 seconds later, all of the voltages have already stabilized and the amplifier is operational, so the
“PROTECT” LED indicators go off.
In a complete audio installation, it is important to start up the equipment in the following sequence: sound
sources, mixer, equalizers, active filters and finally power amplifiers. To turn them off the sequence should follow
an inverse pattern.
4.2. Input attenuators
These devices are controlled from the two rotary controls on the front panel (1).
Their function is to adjust the intensity of the signal received by the amplifier from an external signal source
connected to INPUT 1 / INPUT 2 by setting it to the maximum listening level desired and/or permitted by the system’s
loudspeakers.