The Great River MP-2NV is a stereo preamp built on the foundations established by the classic British console preamps with modern improvements to provide the "big iron" sound of the '70s with modern performance and transparency.
Neither a clone or a reissue, the Great River MP-2NV is a modern take on the classic design, with significant improvements that combine the vintage British harmonic structure with modern performance and transparency. A classic for the modern age, the MP-2NV achieves its remarkable performance with two proprietary discrete Class-A gain stages. A front-panel DI routed through an FET and BJT buffer through the input transformer (also unique to Great River preamps) gives you a must-hear-to-believe sound from any and all Hi-Z instruments, and a discrete high-current Class-A "big iron" transformer-coupled output amplifier. The MP-2NV has an internal power supply suitable for operation on any power grid. A simple change of fuse and proper positioning of a voltage selector will adjust the unit for any voltage between 100 and 240 V AC.
Great River MP-2NV preamp—Just the Facts:
- Multiple In/Out connections: XLR balanced; 1/4" -10dbV output for 'no-latency' DAW monitoring; high-Z input on front panel (disconnects mic input): TRS 1/4" insert patch point for compressor or equalizer ahead of the output amplifier
- Adjustable gain stages: input in 5dB steps to 60dB; output from -25 to +10dB; maximum overall gain 70dB; two to three stages of single ended solid state amplifier gain blocks, depending on gain structure; high-current 70ma Class A bias on output stage
- Input and output meters on each channel (dual-stage metering is a Great River exclusive)
- Front-panel switches: polarity; phantom power; input impedance (1200 / 300 ohm); output loading (600 ohm resistor across output transformer)
- High-quality, custom-wound Sowter transformers
- Gold-plated switching contacts
- Local power supply regulation on each channel
- 110 or 220-volt operation with external selection, either 50 or 60Hz
- Three-year warranty with registration
- Single rack space with internal power supply
Great River ME-2NV Benefits
- “Big Iron” vintage sound from custom-wound transformers
- No-latency' output monitoring for DAW users
- High-Z input is ideal for bass, guitar, and sound modules (FET-buffered and routed into the input transformer, a Great River exclusive)
- Gain stage monitoring via dual meters (also a Great River exclusive)
- Ultra quiet noise floor for outstanding performance at any gain setting
- Excellent stereo imaging (nearly identical phase response channel-to-channel)
Great River MP-2NV—Under the Hood
The NV Series preamplifiers offer comprehensive gain staging capabilities, which are controlled by two knobs on the front panel. The large gain knob adds an increment of 5dB 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 Tip: 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 1.2meg ohm 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 Tip: 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.
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 Tip: 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.
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 Tip: 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”. Be sure to check the polarity of all of your mic inputs when doing a multiple input mix, such as a drum kit, or a guitar amp with several mics. For instance, if you are miking the top and bottom of a snare simultaneously, the bottom mic should have it’s polarity reversed in relation to the rest of the set. If you are miking an open backed guitar amp from in front and in back, the rear mic should have it’s polarity reversed. Listen both ways, at least, to determine what works best for the track.
The input load for the microphone and the Hi-Z buffer can be switched from 1200 ohms to 300 ohms. When the button is in the out position, the input load is 1200 ohms. When the button is pushed in, the input load is 300 ohms.
Great River Tip: Most microphones will work best with the 1,200-ohm setting. Best isn’t always what you want though. With most microphones, the result of using the 300-ohm setting will be a roll off of the lowest frequencies and a tilt upwards of the highs. This effect is highly dependent on the particular microphone, and the only way to know for sure is to try it.
Keep in mind that the impedance change is accomplished by changing the step-up ratio of the input transformer, so a gain change happens as well. Don’t let the volume difference mask the tonal difference when determining your preference.
In general, the best mics to try changing the impedance selection effect on are dynamics and ribbons. Condenser microphones have built in amplifiers, and the usual effect of running them into a lower impedance than they like to see is just a large increase in distortion and lower headroom, with minimal tonal changes.
The DI is similar to a condenser microphone, in that it doesn’t change tonally much, but has much different distortion characteristics with the different loads presented by the two impedance selections. This can be used to great advantage when recording electronic instruments that need a little more body.
This button controls the output termination relay. When in the out position, the output transformer is unloaded. When pushed in, a 600-ohm resistor is connected across the secondary.
Great River Tip: The output transformer has an inherent resonant peak that affects the frequency response at high frequencies. This peak is at approximately 50kHz, and is about 6db up from flat and is cable and load dependent. The amplifier is designed to be correctly loaded by 600 ohms for best flatness in both frequency and phase response, but some interesting effects happen when un-terminated.
A gentle high-frequency lift, like an “air band” EQ and a bit grittier midrange are the effects you should hear when the loading button is out.