IMG STAGE LINE STA-3000 Instruction Manual Download Page 7

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English

necting several speakers, special attention has to
be paid to the correct connection of the positive
and negative terminals .

Important:

At rated power, the total imped-

ance at each output must not fall below 4 Ω in
stereo and parallel operation, and 8 Ω in bridge
operation!

As long as, in the stereo mode or parallel

mode, the RMS output power does not exceed
1250 W per channel, operation with 2 Ω loads is
also supported . Operation in the bridge mode at
a 4 Ω load is possible for an RMS output power
of up to 2500 W .

5.3 Power supply

The mains cable supplied for the mains con-
nection can be used for a power consumption
of 3680 VA (16 A) . Thus, the maximum output
power at 8 Ω speakers is reached . For a high
output power at 4 Ω or 2 Ω, a mains connection
of higher capability must be made by specialized
personnel .

First connect the PowerCon plug to the

mains jack (14) and turn it clockwise until it locks
and then connect the mains plug to a socket . To
separate it from the mains, first disconnect the
mains plug and then, for removing the Power-
Con plug, retract its latch lock and turn the plug
counter-clockwise .

6 Operation

6.1 Selecting the operating mode

Select the desired operating mode with the DIP
switches MODE Nos . 1 to 6 (10):

Stereo mode

–

display:

MODE STEREO

In stereo mode, both channels are operated in-
dependently of each other .

switch configuration
STEREO

Parallel mode

–

display:

MODE PARALLEL

Parallel mode is recommended to provide PA
applications e . g . for two rooms with the same
mono signal and to be capable of adjusting the
volume individually .

The input signal is internally switched from

the left channel additionally to the right channel .
A signal at the right input is ignored . The volume
is separately adjusted for both outputs .

switch configuration
PARALLEL

Bridge mode

–

display:

MODE BRIDGE

The bridge mode (BRIDGE) is used to obtain a
higher power at one speaker .

For this purpose, both amplifier channels

are combined to one mono amplifier: The input
signal of the left channel is additionally switched
to the right channel in an inverted way . Thus, the
voltage at the output is doubled if the speaker
is connected for bridge mode, as described in
chapter 5 . A signal at the right input is ignored .
The volume is adjusted with the left control (1)
together for both outputs .

switch configuration
BRIDGE

Filter

The integrated filter can be used as a cross-
over network for 2-way speaker systems (sub-
woofer / satellite) . Select the function correspond-
ing to the connected speaker with the switch
FILTER (9) .

Position

Filter

SUBWOOFER

Low pass filter with −6 dB at 120 Hz for

bass speakers

SATELLITE

High pass filter with −6 dB at 120 Hz for

mid-high range speakers

FULLRANGE

No filter for full range speakers

6.2 Switching on / off

To prevent loud switching noise, always switch
on the power amplifier in an amplifier system
after all other units have been switched on and
switch it off first after operation . Prior to first
switching-on, set the controls (1 and 5) to the
left stop to “−80 dB” .

Switch on the amplifier with the POWER

switch (6) . The ACTIVE LEDs (2, 4) serve as a
power indication and the display (3) shows the
selected operating mode . After switching-on,
the red LEDs PROTECT (2, 4) light up for a short
time . During this time, the switch-on delay is
activated to protect the speakers .

6.3 Level adjustment

Adjust the output of the mixer or preamplifier to
its rated level (0 dB) or the maximum undistorted
output signal . Turn up the controls (1 and 5) until
the maximum desired volume is reached . The
LEDs “−25 dB”, “−20 dB”, and “−15 dB” (2, 4)
show the adjusted input level . If the red LEDs
LIMITER light up, the limiter circuit is active and
prevents overload of the amplifier . In this case
slightly turn back the controls .

CAUTION

Never adjust the amplifier to a
very high volume . Permanent
high volumes may damage your
hearing! The human ear will get

accustomed to high volumes which do not
seem to be that high after some time . There-
fore, do not further increase a high volume after
getting used to it .

6.4 Groundlift switch

If an interfering hum noise can be heard without
a music signal, a ground loop may be the reason
for this . Ground loops may occur when two units
have contact both via the signal ground and via
the earthed conductor of the power supply or
a conductive connection of the housings in the
rack . To separate the ground loop thus occurring,
set the DIP switches No . 7 and No . 8 (10) from
the upper position to the lower position .

switch configuration
Groundlift

7 Protective Circuits

The protective circuits are provided to prevent
damage to the speakers and to the amplifier . The
integrated level limiter reduces the input signal
when the limit level at the output is reached .
Thus, in case of overload of the amplifier, distor-
tions can be prevented which might damage the
speakers . If the limiter is active, the LED LIMITER
(2, 4) of the corresponding channel lights up .

An additional protective circuit separates

the speakers from the output of the channel
concerned . If it is active, the corresponding red
LED PROTECT (2, 4) lights up:
1 . for a short time after switching-on (switch-on

delay)

2 . in case of overload / overheating (e . g . also by

short circuit at the output or when exceeding
the admissible output power in 2 Ω stereo/
parallel mode or 4 Ω bridge mode)

3 . if a DC voltage occurs at the output
During normal operation, the temperature at
the power transistors is shown on the display (3)
separately for both channels . With higher tem-
peratures, the fan control ensures that the fan of
the channel concerned runs at a higher speed .

In case of a defect, e . g . a short circuit at an

output, the display changes to

SHORT CIR.

PROT, OVERLOAD&FAULT

(in addition, the

LED PROTECT of the channel concerned lights
up) . – In this case, or if the LED PROTECT is not
extinguished after switching-on, or if the protec-
tive switch (11) has been released, the amplifier
must be switched off and the cause for the de-
fect must be eliminated . If required, reset the
protective switch by pressing it down .

8 Specifications

RMS output power

(1 kHz, 0.1 % THD + N)

Stereo, parallel at 4 Ω

Stereo, parallel at 8 Ω

Bridge mode at 8 Ω

2 × 1500 W

2 × 1000 W

3000 W

Maximum admissible RMS output

power at lower load impedance

Stereo, parallel at 2 Ω