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NOTICE D'UTILISATION ET DE DEPANNAGE / OPERATION & MAINTENANCE INSTRUCTIONS
AMPLIFICATEURS / AMPLIFIERS
9. low pass filter
A low pass filter (-3dB at 15kHz) -J28, (Fig : 4), can be obtained through configuration 4b (Fig : 3).
10. Input signal levels
The level of each input can be selected, separately, as following (Fig : 3) :
· Configuration 5b :
· Configuration 5a +7a :
· Configuration 5a +7b :
11. Inputs modes
· Line level inputs (0dB or -10dB) is always set up as unbalanced mode (6a) (Fig : 3).
· Microphone level inputs can be configured as balanced (6b) or unbalanced (6a) mode (Fig : 3).
·
Caution :When microphone level is configured as unbalanced mode, cable between microphone and
amplifier input must be very short and well protected against perturbation .
· Balanced inputs by transformer can be obtained by the use of external transformers :
· MTM code 2247 micro level
· MTL code 2249 line level
Important : Use transformer to balance inputs whenever you have any doubt about the quality of links &
their environmental conditions, for protection against all perturbations, due to the quality of the links, as
all undesirable effects such as hums and electronic oscillation will disappear or will be heavily attenuated.
B Turn on
· Select configurations as per above according to your request.
· For safety reason, keep cover and bottom when amplifier is used outside rack.
· The position of the rack must allow for natural ventilation in the vertical direction .Don't hide ventilation openings
provided on top and bottom covers. In case many amplifiers are superposed or in case of high ambient
temperature, use forced ventilation ( fan units).The best position for fan unit is in between . Bad ventilation shall
deteriorate the characteristics of the amplifier, before leading to thermal cut off.
· Before installing the amplifier in a rack, please remove top &bottom covers. Use fixation brackets
EQ8722&EQ8723(2U) et EQ EQ8721(3U).
· 24V DC power supply consumption must not exceed 200mA.
· Before connecting speakers line(s), check line impedance for a good impedance matching between line(s) and
amplifier .The total power delivered to the speakers must be equal or lower than the amplifier nominal power.
· Before connecting the sources to the appropriate inputs, according to manufacturer's specifications, check the
quality of links & cable layouts . Check if coupling is correct (signal levels, impedances, balanced, unbalanced ).
· Before connecting the amplifier to mains, make sure that the amplifier power transformer tap is set up according
to mains voltage.
· When amplifier is switched on, LED N° 11 (Fig : 1), will turn on.
· Set up inputs level controls in order to get the appropriate sound level, while avoiding any signal clipping.
· Avoid any excessive or not appropriate use of tone controls.
2 TROUBLE SHOOTING
1. Amplifier off :LED N° 11 (FIG : 1) off :
· Check mains,
· Disconnect speakers lines and make sure that short circuit or overloading is not happening.
· If fault is not removed, check for appropriate ventilation.
2. Amplifier out of order : Check critical voltages as per following table (fig : 10).
3. External 24 V DC not available : Check Fuse F2 (Fig : 4).
4. in case of electronic oscillation, check the links (grounding, shielding, environmental perturbation due to cables
layout near other cables or equipments).Activation of the low pass filter (J28) cofiguration 4b (Fig : 4) may solve,
in some cases, problems due to links.
5. In case of hums or high noise level, check the continuity of grounds (links, frame and chassis). The use of input
transformers or a microphone with preamplifier shall reduce hums and oscillation due to the links .
DO3-51-2443-AMG-5EC-V191203
-60dB
-10dB
0dB
AMG 50 5EC 2443
AMG 100 5EC 2444
AMG 200 5EC 2445
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