HQ Power QUBIC 2900 Notice D'emploi page 8

9. Operating Modes
Speaker Impedance
Following table shows the impedance for different speaker combinations – each speaker has an individual
impedance of 8 ohms:
# of Speakers
1
2
2
2
4
4
Stereo Operation
This is the normal operation mode of an amplifier, in which every channel gets its own signal. The most commonly
used mode of amplifiers is stereo operation at 4 ohms. Make sure that the mode selector is correctly set (see
"7.b.7").
Remark: The input impedance of the speaker system should at least be the same or even higher than the output
impedance of the amplifier.
Parallel operation
In parallel operation mode the voltage remains the same but the current is doubled. Consequently, the output
impedance is limited to the minimum value of one individual channel. Connect the input signal with the input of
channel 1 (make sure that the amplifier is disconnected from the mains before you set the mode selector to
parallel). Bridge the red pole socket of output channel 1 and output channel 2.
CAUTION! Before switching on your amplifier, please refer to the explanations under "10. Operation". Adjust the
level with the gain control CH-1 on the front panel.
Bridged Operation
Possibility to run the amplifier in mono via one input channel. In bridged operation mode, the voltage is doubled.
Consequently, the output impedance is doubled.
For stereo operation, 2 amplifiers are needed. Connect the input signal to the input CH-1 on the rear panel. Make
sure that the amplifier is disconnected from the mains before you set the operation mode switch on the rear panel
to bridge. Connect your speakers to the red mono bridged speaker socket.
CAUTION! Before switching on your amplifier, please refer to the explanations under "10. Operation". Adjust the
level with the gain control CH-1 on the front panel.
10. Operation
After connecting your amplifier to the mains, turn both gain controls in an anticlockwise direction to the minimum
position. The last device to be switched on is the amplifier. The POWER and PROTECT LED light up now. If not,
check if the amplifier is properly connected to the mains.
After the activation delay the speakers are activated (PROTECT LED is off).
After setting the volume controls of the pre-amplifier in the minimum position, turn the gain controls of your amplifier
to the midway position. If there is any humming, check the connection cables between the pre-amplifier and your
amplifier (switch off components first). Now adjust the volume with gain controls CH-1 and CH-2.
VPA2900MB
Wiring Mode
/
parallel
in line
parallel
in line
parallel
Total Impedance
8
4
16
2.66 (only for amplifiers capable of handling 2 )
24
2 (only for amplifiers capable of handling 2 )
8 HQ POWER