Soundtube MA3501t User Manual

Ma3501t, Warning

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Install Instructions For:


© 2014SoundTube Entertainment, Inc. All rights reserved. PN INS-MA3501t Rev06.13.14






SoundTube products must be installed by a professional audio installer/contractor. For safety and for
optimum audio performance, installer must follow all directions issued by SoundTube Entertainment.








• 350W at 4 ohms direct or 25V, 70V, 100V isolated outputs
• Efficient Class G high current mono-block amplifier
• Large Torroidal power transformer and audio output transformer
• Selectable high pass/subsonic filter
• Euro block balanced and dual unbalanced RCA inputs
• Selectable 12V and auto signal sense remote turn on and stand
by options
• Selectable peak/clipping limiter
• High current euro block output connectors
• Dual 115VAC/230VAC operation
• Wind tunnel flow through cooling with variable speed
thermostatically controlled fan
• Overload, short circuit and thermal protection circuits
• Power/standby, clipping and protection LED indicators
• Compact 2U Rack space chassis


The SOUNDTUBE MA3501t audio distribution amplifier is a high
performance audio amplifier that is designed for continuous use in
commercial applications. The high efficiency Class “G” amplifier
design offers high performance in a compact design and utilizes 2
large and efficient toroidal transformers in the amplifier power and
audio output sections. The power transformer is a very high current
design for sustained high power output and can operate with
multiple input mains voltage and is thermally protected.
The audio output transformer is a very low distortion design that
provides very clean audio output at high power levels for 25V, 70V
or 100V audio distribution systems.

The MA3501t amplifier also has a direct speaker output option that
bypasses the transformer for those applications where it is
necessary to operate 4-16 ohm speaker systems. All of this

performance is in an amplifier that is only 2RU in height.

Other application and performance features of the SOUNDTUBE
MA3501t amplifier are flexible audio inputs connections for both
balanced and unbalanced audio signals. The balanced input
features a Euro Block, Phoenix style connector and the
unbalanced inputs are 2 RCA style jacks that will allow the mix
down of a stereo input signal to a summed mono output.
The amplifier offers a switchable peak limit anti-clipping circuit to
help keep the audio clean and undistorted at high output levels
and also a switchable high pass filter to avoid over driven bass
distortion and speaker line transformer saturation from low
frequencies. The MA3501t also provides the installer with remote
turn on and off provisions that can either be switched by an
external 12VDC source with loop through provisions or set to a
program input sensing position that provides turn on and standby
operations in the presents or absents of an audio signal. Both of
the remote features mute the amplifier audio output when no signal
is present to avoid any stray hum or noise being reproduced in the
standby mode.

The SOUNDTUBE MA3501t amplifier is designed to provide long
term reliability of operation and includes several features to insure
many years of trouble free operation. Besides the oversized
torroidal power and audio transformers the amplifier features a
thermostatically controlled cooling fan with ducted heat sink
cooling for the power stage. The protection circuitry includes
thermal shut down over temperature protection for the power
transformer and the power amplifier, input power overload
protection, short circuit, DC output and over load protection and
low impedance protection with relay switching to kill the speaker
output and provide protection for speakers systems connected to
the amplifier.