Great River Electronics MP-2NV User Manual

– NV Series –

– Microphone Preamplifier –

&

– DI –

User’s Guide

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Introduction

The MP-2NV and the ME-1NV are professional quality microphone preamplifiers designed to re­create the vintage sound characteristics of the early 1970s large consoles. Modern components
give the NV Series more clarity, punch and performance under normal use. In addition, features
like metering before and after the major gain stages let the user drive them “hard” to greatly
expand the range of sonic options. All microphones will benefit from the power of the NV series
preamplifiers, including dynamic, condensor and especially ribbon types.

On the MP-2NV, each channel is an independent system. All power supply regulation is
duplicated on each audio channel card. For both units, gain staging, phantom power, polarity,
impedance and loading are individually controlled. In addition, each channel is equipped with
dual LED meters and a true HI-Z instrument jack with its own input amplifier.

The ME-1NV uses the same audio and metering circuit boards as the MP-2NV, only the power
supply is smaller due to the reduced demands of the single channel. All specifications and
performance details are identical with the exception of size and weight.

Be sure to register your NV series microphone preamplifier online at
www.greatriverelectronics.com. We welcome and look forward to your comments.

To best understand and utilize your NV, please read the following user’s guide.

Definitive AA

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Front Panel Controls and Buttons

Gain Staging

The NV Series preamplifiers offer comprehensive gain staging capabilities, controlled by two
knobs on the front panel. The large gain knob adds an increment of 5db of gain with each step,
while the small output knob, the pot, delivers continuous adjustment of the output level. The
input range of the large knob is 0db to 60db and the output range of the small knob is
approximately -22db to +10db relative to the "CAL" marking on the front panel. The overall
maximum gain is 70db in the 1200 ohm input impedance mode.

Great River Tips

Generally, the signal will be affected the least by keeping the large knob turned down and the
small one up. More coloration occurs when the input stage does most of the work, so cranking
the large knob and trimming back the output control will tend towards a thicker sound. When
the input stage clips, it gets ugly, so keep an eye on it.

Hi-Z (Direct Injection)

The Hi-Z or Direct Injection (DI) jack presents approximately 1.2 megohm impedance and utilizes
a unique FET/Bipolar buffer amplifier to drive the input transformer. This presents the proper
input load to an instrument, yet allows tonal shaping by changing the load on the input buffer
with the impedance switch.

Great River Tips

Many instruments will benefit from the added coloration of this input. More coloration will
happen sooner with the impedance button in.

This is an “instrument” level input, not “line” level, so putting a full “+4dBu” signal into it is
likely to distort on peaks.

Phantom

When the phantom button is pushed in, a 48v supply to the microphone is activated. This supply
is compliant with the P48 standard, it supplies a full 48v, the resistors are matched 6.81K, and
will withstand a short circuit indefinitely.

Great River Tips

Be sure you use the phantom supply only with microphones or DI boxes that require powering.
It is possible to damage some devices plugged into the preamp if long-term application of
phantom power is allowed.

Polarity

When the polarity button is pushed in, the polarity of the output XLR jacks is reversed. Note, this
does not invert the polarity of the –10dBv output.

Great River Tips

The polarity is inverted by a relay that cross connects pins 2 and 3 of the output XLR. Try the
polarity button when doing vocals, many times the quality of the signal fed to the headphones
can be dramatically improved for the singer by getting the polarity “right”.

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