USB 7127 - 7128
Professional Power Amplifiers
INTRODUCTION
Congratulations for choosing this US Blaster professional power amplifier. You purchased one of the
finest stereo amplifiers on the market today. This unit was developed using the expertise of professio-
nal sound engineers and working musicians. You will find that your new US Blaster amplifier has supe-
rior performance and greater flexibility than any other amplifiers in its price range. Please read this
manual carefully to get the most out of your new unit.
Offering top power, superior performance and full professional operating features in a roadworthy com-
pact chassis, the US Blaster amplifiers are perfect for even the most demanding sound reinforcement
installation and touring applications.
The operating amplifier instructions in this manual are for the USB 7124, USB 7125 and USB 7126 pro-
fessional power amplifiers. The operation and functions of these units are the same, except as noted.
• Full operating features: detent volume controls; parallel balanced XLR and 1/4" TRS inputs; stereo
(dual channel), parallelinput, or bridged mono operating modes with selector switch; Independent user
defeatable clip limiters (compressor) 3 selectable input sensitivities, ground lift switch, binding post
(banana plug) and speakon outputs.
• Full safety / liability features: 2 dual speed fans for cooling; soft start turn on, noise-free on-off; inde-
pendent DC and thermal overload protection on each channel; short circuit and speaker protection;
built-in current limiter.
Front panel led indicators: Active, Signal, Limit and protection
• Roadworthy, rugged steel chassis (2U) . Modular construction for easy servicing
This manual contains important information on operating your US Blaster amplifier correctly and safely.
Please read it carefully before operating your amplifier. If you have any questions, contact your US
Blaster dealer.
UNPACKING
Carefully open the shipping carton and check for any noticeable damage. Every US Blaster amplifier is
completely tested and inspected before leaving the factory and should arrive in perfect condition. If you
find any damage, notify the shipping company immediately. Be sure to save the carton and all packing
materials for carrier inspection.
RACKMOUNTING
US Blaster amplifiers are designed for standard 19" rack mounting as well as "stack" mounting without
a cabinet. Use 4 screws and washers for mounting to the front rack rails. It is also a good idea to sup-
port the amps also in the rear, especially for mobile use where the amps will be subjected to strong
vibrations.
AMPLIFIER COOLING
Pay close attention to the cooling requirements. Never block the air vents in the back side and front of
the amplifier. Do not install the amplifier in a location that is exposed to direct sunlight, or near hot appli-
ances or radiators. Excessive heat can adversely affect the cabinet and the internal components.
Installation of the amplifier in a damp or dust environment may result in malfunction. If installed in a
rack please be sure to open the back door completely. Periodically remove the internal dust by using
compressed air through the external ventilation holes.
© US Blaster Europe BV