00031120.DOC, Version 1.0
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5.6 Operation modes
Stereo operation
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 operation-mode-switch is correctly set.
Calculation number of speakers – impedance
E.g. 1 speaker à 8 Ohm = 8 Ohm
2 speakers à 8 Ohm = 4 Ohm (parallel)
2 speakers à 8 Ohm = 16 Ohm (in line)
3 speakers à 8 Ohm = 2.66 Ohm (parallel), only for amplifiers capable of handling 2 Ohms
2 speakers à 8 Ohm = 24 Ohm (in line)
4 speakers à 8 Ohm = 2 Ohm (parallel), only for amplifiers capable of handling 2 Ohms
N.B.:
The input-impedance of the speaker-systems should at least be the same or even higher than the output-
impedance of the amplifier.
Parallel operation
Possibility to run the amplifier in mono-mode, i.e. via one input channel. In parallel operation mode, the
voltage remains the same, the current is doubled. Consequently, the output impedance is limited to the
minimum value of one individual channel.
Connect the input signal to the input-plug CH-1.
Make sure that the amplifier is disconnected from the mains before you set the operation-mode-switch to
parallel.
Bridge the red pole sockets of Output Channel 1 and Output Channel 2.
Connect your speakers to the Speaker-socket Output CH-1.
Caution!
Before switching on your amplifier, please refer to the explanations under Operation.
Adjust the level with the gain-control CH-1 on the frontpanel.
Bridging
Possibility to run the amplifier in mono-mode, i.e. 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-plug CH-1 on the rearpanel.
Make sure that the amplifier is disconnected from the mains before you set the operation-mode-switch on the
frontpanel to Bridge.
Connect your speakers to the Binding post Mono Bridged.
Caution!
Before switching on your amplifier, please refer to the explanations under Operation.
Adjust the level with the gain-control CH-1 on the frontpanel.
6. OPERATION
After having connected your amplifier to the mains, turn both gain controls counter-clockwise to Min-position.
The last device to be switched on is the amplifier. The "SIGNAL" and "PROTECT" LED light up now. If it
does not, check if the amplifier is connected to the mains correctly.
After the turn-on delay the speakers are activated (PROTECT-LED is off).
After having set the volume controls of the pre-amplifier in null-position, turn the gain controls of your
amplifier to mid-position. You must not hear any loud humming. If there is humming nevertheless, check the
connecting cables between the pre-amplifier and the amplifier (switch off components before). Now adjust
the volume with the gain controls CH-1 and CH-2.
Caution!
Increase the level of each channel only so far that the CLIP-LED lights up shortly. Thus, you avoid
that the output signal is distorted and your speakers are damaged.
All important operating modes of the amplifier are arranged on the frontpanel.
SIGNAL
output level
CLIP
short-circuit or impedance too low or signal distorted
