Output Connections; Subsonic Filter; Operation; Starting Up - Ecler DT 4800 Notice D'emploi

3.4. Output connections

The "OUTPUT" section on the back panel is provided with Speak-on connectors (11). This
amplifier can only be operated in stereo mode. Due to its floating output structure, bridging both
output connectors is not possible.
The cable between the amplifier outputs and the loudspeakers must be of good quality, enough
cross-section and as short as possible. This is very important when the distance is long and the load is low
(4-8Ω). We recommend a section of 2.5 mm
for longer distances. An easy way to known the required cross-section, assuming a 4% loss, is:
Cross - section in mm

3.5. Subsonic filter

This filter cuts off inaudible frequency components which when amplified suppose a risk of damage
to the low frequency speakers as they generate excessive excursions of the woofer's diaphragm. The filter
has a Butterworth shaped response with 18 dB/oct slope and a cut-off frequency of 20Hz. The subsonic
filter can be inhibited internally (see figure). This operation must be performed by a qualified technician.

4. OPERATION

4.1. Starting up

To start up the amplifier, turn on the "POWER" switch (7). The "POWER ON" LED will light up
together with the two "STANDBY" (2) and the two "OVERLOAD" (3) leds. After a short while, the voltages
will have stabilised and the "OVERLOAD" AND "STANDBY" leds will go off.
During this period, the automatic gain control processor progressively raises the amplifiers input
gain.
In any complete sound installation it is very important to start up the audio chain in the following
sequence: sound signals, mixer, equalizers or active filters and, finally, power amplifiers. To stop the chain
follow the reverse sequence.

4.2 Input attenuators

These are based on rotative potentiometers placed on the front panel (6). The
attenuators allow the use loudspeakers of less rated power than the amplifier in a safe
way, without damaging them by a misuse of the preamplifier and/or mixer volume. The
amplifier is supplied with two transparent plastic caps that let you lock the input gain
controls. Once inserted they can only be removed with a sharp object.

4.3 Gain selectors

These are located on the rear panel (12) and establish the gain of each amplifier
channel. The factory setting is 1V, meaning that to obtain maximum output power, the
amplifier should be fed with an 0dBV 1V audio signal.
2
or more for distances up to 10m and a section of 4 or 6 mm

2
=
Loudspeaker impedance in Ω
Lenght in m
2
5
4 6
7
3
2 8
1
9
CH1
0 10
5
4
6
3 7
2 8
1
9
CH2
0 10
1V
32dB
26dB
24dB
GAIN
7