Applied Research and Technology (ART) MPA Gold Owner's Manual
ART MPA Gold™ Microphone Preamplifier
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TABLE OF CONTENTS
Introduction ............................................................................................ 3
Introduction .......................................................................................... 3
Features ............................................................................................... 3
Front Panel Controls ...............................................................................4
Input Gain Control................................................................................ 4
Input Impedance Control ..................................................................... 5
Analog Output Control ......................................................................... 5
HPF Control ........................................................................................ 5
Gain Switch.......................................................................................... 5
Phantom Switch ...................................................................................6
Phase Switch ...................................................................................... 6
Plate Voltage Switch ............................................................................ 6
Meter Switch ........................................................................................ 7
Tube Warmth Meter ............................................................................. 7
Front Panel Connections.........................................................................8
Instrument Inputs ................................................................................. 8
Rear Panel Connections ......................................................................... 8
Balanced Inputs ................................................................................... 8
Balanced Outputs ............................................................................... 8
Signal Path ...............................................................................................9
Signal Path Flow Diagram ....................................................................9
Signal Path Flow................................................................................. 10
Operating Instructions ......................................................................... 10
Obtaining the best noise performance ............................................... 10
Adjusting the input impedance........................................................... 10
Setting the tube plate voltage ............................................................ 11
Warranty Information ........................................................................... 12
Service .................................................................................................. 12
Specifications ....................................................................................... 13
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ART MPA Gold™ Microphone Preamplifier
MPA GOLD INTRODUCTION
The ART MPA Gold™ microphone preamplifier features a new low noise, high
performance preamplification circuitry designed for superior audio fidelity. Building upon
the quality and success of great sounding products like the Pro MPA, ART engineers
set out to develop the next generation of professional microphone preamplifier. The
MPA Gold is the culmination of years of research and development, and sets a new
standard for quality and value. Professional features and spectacular tone are what
make the MPA Gold a world-class microphone preamplifier.
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MPA GOLD FEATURES:
• Variable input impedance for flexible microphone voicing (150 Ohms to 2400 Ohms).
• Selectable plate voltage
• Large VU meters
• Front accessible meter trim
• Meter selectable between –10dB and +4dB ranges
• Tube warmth LED meter
• Improved discrete class A input microphone preamplifier
• Lower noise at low gains
• Lower THD
• Wider frequency response
• Front accessible Instrument Input Jack
• Very high input impedance
• Automatically switches to the instrument input when you plug in
The MPA Gold is an attractively styled processor, with a light gold colored front panel
and matching knobs. Its Switch caps are illuminated when activated.
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ART MPA Gold™ Microphone Preamplifier
FRONT PANEL CONTROLS
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Input Gain control
This control optimizes the input signal level before the tube gain is applied. Both
Microphone and Instrument input gains remain the same and are affected by this
adjustment. Input gain can be adjusted from 0dB (for line level signals) to 45dB of gain.
The analog meters are used to see the effects of the input gain setting.
Additional gain is available via the Gain switch (+20dB) and the Analog Output control
(+10dB) for a maximum of 75dB total.
The combination of these controls allows the user to adjust the signal level through the
tube section, providing more or less “tube” sound as needed. To obtain more “tube’
sound, increase input gain, use the +20dB Gain switch, “normal” plate voltage, and less
Analog output gain.
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ART MPA Gold™ Microphone Preamplifier
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Both the microphone and instrument inputs are optimized for their respective sources as
far as signal levels and noise performance. Running most of the gain on the input
generally provides the best performance of the MPA Gold. Refer to the section titled
“Obtaining the best noise performance with the MPA Gold” for more detailed
instructions on setting the Input Gain control for the best results.
Input Impedance control
This knob controls the Mic/line input amplifier impedance. This function allows variable
voicing of any microphone.
Refer to the application section titled “Adjusting the Input Impedance” for more
information on making the most of this function.
The ¼” instrument input is NOT affected by this control, and remains high (>1M Ohm)
impedance.
Analog Output control
The output signal level at the rear output jacks is adjusted by this control. It can provide
from +10dB of gain (fully clockwise) to completely muted. You can see the effects of this
adjustment reflected in the analog meters when the meter switch is set to “output”.
HPF control
The HPF is a single tuned High Pass Filter that is frequency tunable. The input signal
can be filtered to remove “pops” or other extraneous low frequency information. This
control moves the rolloff frequency from 10 Hz (fully CCW) to 200 Hz (fully CW). Since
it is single tuned, it preserves some low frequency content so its use is less obtrusive. It
is especially useful in close mic’d applications.
Gain switch
The Gain switch is used in conjunction with the input gain control to adjust signal levels
through the MPA Gold. When depressed, the tube circuit provides 20dB more gain in
the signal path. This also has the effect of driving the tube harder and making the tube
the dominant source of gain and overload character.
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