Connection To The Mains; Stereo Operation - US Blaster USB 7120 Manual Del Usuario

the amplifier into the rack. Put the heaviest devices into the lower part of the rack. Be aware that fas-
tening the amplifier with four screws on the front panel is not enough. In order to ensure safety, addi-
tional fastening by using ground and is de bars is necessary. If racks are to be transported or used for
mobile use, additionally fasten the devices by connecting the rear brackets with the side or ground bars
of the rack. In this way, the amplifier cannot be pushed backwards. The front panel alone is not designed
to absorb acceleration forces occurring during transportation.
INPUTS
A good cable run improves the sound quality remarkably. Input cables should be short and direct, since
high frequencies will be mostly be absorbed if the cables are unnecessarily long. Besides that a longer
cable may lead to humming and noise trouble. If long cable runs are unavoidable, you should use bal-
anced cables. The inputs of your US BLASTER amplifier are equipped with 6.35mm and XLR jacks.
OUTPUTS
The high damping factor of your amplifier supplies a clear sound reproduction. Unnecessarily long and
thin cables will influence the damping factor and thus the low frequencies in a negative way. In order to
safeguard good sound quality, the damping factor should lay around 50. The longer a cable has to be,
the thicker it should be. The outputs of your US BLASTER amplifier are equipped with
Screw/clamp/speakon jacks.

CONNECTION TO THE MAINS

Connect the US BLASTER amplifier only after having made sure that the right voltage (110/230V) is sup-
plied and that the ground lead is earthed. This device falls under protection class I. Do not detach the
ground lead from the housing!

STEREO OPERATION

Connect the input signal to the input jacks/XLR on the rear panel. Connect your speakers to the
Screw/clamp/speakon jacks Output Channel ch1 and ch2.
Caution: The impedance of the speakers must be between 4 and 16 Ohm.
Caution: Before switching on your amplifier, please refer to the explanations under Operation. Adjust the
level of each channel with Gain control CH1 and CH2 on the front panel. 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 dis-
torted and your speakers are damaged.
OPERATION
After having connected your amplifier to the mains, turn both gain controls counter-clockwise to null-
position. The last device to be switched on is the amplifier. The "power on" LED lights 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. 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 neverthe-
less, check the connecting cables between the pre-amplifier and the amplifier. Now adjust the volume
with the gain controls CH1 and CH2.
All important operating information of the amplifier are displayed on the front panel.
CLIP short-circuit or impedance too low or signal distorted
protect :active during stabilisation period after switching on or when one of
the protective circuits started
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