Great River ME1NV

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Microphone Preamp

Published in SOS June 2006
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Reviews : Preamp

Photos: Mike Cameron

Great-sounding mic preamps are in plentiful supply, and many are surprisingly affordable too. Some are designed to be as accurate and faithful to the source sound as possible, while others are carefully 'sculpted' to add a degree of warmth or some other favoured characteristic. The American Great River MP2NV (dual-channel) and ME1NV (single-channel) mic preamps are intended to impart a certain 'vintage' quality and are based on the kinds of discrete circuit designs employed in the Neve consoles from the 1970s. However, these are not just more faithful recreations of the classic 1073, because the design has been tailored somewhat to address some of the perceived downsides of the early Neve design — specifically a tendency to lose some control at the bottom end in certain situations.

The ME1NV is housed in a half-rack 1U box with an internal linear mains power supply. Sowter transformers are employed for the input and output paths, and up to 70dB of gain is available. In addition to the balanced mic input there is a dedicated DI input, and both balanced and unbalanced line-level outputs are provided. Other features include separate input- and output-stage level metering, an unbalanced insert point, and switches to alter the input impedance and output loading.

Front-panel Controls

The unit is finished with a durable black paint, through which the panel markings appear to be etched. The controls comprise just a pair of black knobs and five grey buttons. There's a mains power switch, with associated blue On/Off LED, while the other four buttons each have an associated green LED to make their status obvious. Most signal switching is performed by sealed relays, and the internal construction is to a high standard.

The input gain is switched in precise 5dB increments from 5dB to 60dB with the larger of the two rotary controls. The smaller rotary control adjusts the output level and is continuously variable. The front-panel markings suggest a range of ±10dB relative to a centre Cal (calibration) marking, while the handbook says the range is -22dB to +10dB and the specifications claim -25dB to +10dB. This imprecision is compounded by the fact that there is no centre detent on the output-gain control, so the actual calibrated level position is rather vague anyway. When I measured the level control's range I found it went up to +11.5dB and down to -15dB, so none of the published figures are right! However, regardless of the panel markings and claimed specs, the control actually covers a useful range and performs its task of level matching with other equipment perfectly well — just don't rely on the markings to set levels!

The preamp circuitry design is such that, as the input gain is increased, so too is its 'vintage character', and this arrangement provides a range of tonal options. If you want a fairly transparent sound, for example, it pays to crank up the output gain control to benefit from that stage's cleaner sound, and back off the input gain control. For a thicker and slightly more coloured sound, turn the output level down and wind in more front-end gain. We are not talking guitar-amp levels of overdrive distortion here, but the effect and the way it is controlled are broadly similar.

Variable Microphone Input Impedance

The input impedance seen by the microphone can be switched with one of the grey buttons between 1200(omega) (out) and 300(omega) (in). The impedance change is achieved by re-configuring the input transformer's windings to alter the turns ratio, although this inherently also changes the gain slightly. I measured a 2.5dB increase when switching to the 300-Ohm mode. For most mics, most of the time the 1200(omega) mode is fine, although the majority of modern preamps present a higher figure, and most modern transformerless mics are probably designed with a higher figure in mind — 2400(omega) is pretty common these days, for example.

The 300(omega) mode may suit some ribbon mics better though, and will certainly result in a change in sound quality when used with most dynamic mics — typically a tilting of the frequency response to give a thinner and brighter sound. However, the actual changes are a little unpredictable and depend on the complex relationship between the mic's output transformer and the preamp's input transformer, combined with the mic cable's attributes. In other words, it's a case of pushing the button and seeing if you like the results! Most capacitor mics (and buffered dynamics and ribbons) with transformerless outputs will remain largely unaffected by changing the input impedance — although in some cases the lower load may result in increased transient distortion and reduced headroom.

The front-panel DI input overrides the rear mic input and presents a 1.2M(omega) input impedance, which is ideally suited to electric guitars and basses. This input employs an active FET buffer stage before the signal is routed through the mic transformer. Consequently, as with the mic input, changing the input impedance will have a tonal affect on the DI signal and is worth experimenting with. The input has been designed to provide some musical colour to the signal — this definitely isn't a squeaky-clean DI — and the lower impedance setting seemed to enhance the coloration nicely!

Two of the remaining grey switches apply 48V phantom power and invert the output signal polarity. Phantom power measured at 48.4V with perfect symmetry, and the preamp was able to deliver the full current rating without any obvious voltage sagging. The polarity inversion only affects the XLR output — the unbalanced -10dBV output is completely unaffected by this switch, which is a shame. This restriction of the unbalanced output is noted in the handbook, but may still catch some people out. From a practical point of view it would have made more sense to have reversed the input transformer's connections rather than the output transformer's so that both outputs would be affected.

Inputs, Outputs & Termination

The last grey button disconnects the standard 600(omega) load across the output transformer. Most output transformers have a high-frequency resonance peak that requires a specific loading to control it. In the case of this particular Sowter transformer the peak is at about 50kHz and the optimum loading is 600(omega). This is an old-fashioned concept now, which has largely been forgotten in this day and age of electronically buffered outputs, but it has a usefully creative side effect. Switching off the termination when driving the preamp's output into a high-impedance input will result in gently rising high-frequency region, adding a sense of 'air' and brilliance to the sound (plus a small increase in the mid-range distortion).

When correctly terminated, the frequency response measures flat to 20kHz and drops gently above that to about -1.5dB at 35kHz and -3dB at 50kHz. However, with the 600(omega) termination switched out and feeding a high-impedance device the high-frequency response rises gently to roughly +1dB at 20kHz, +3dB at 35kHz, and +5.5dB at 50kHz (the resonance). The precise results in any given situation will actually be dependent on the input characteristics of the receiving device and the connecting cable, so it's another case of trying the switch in both positions to see what works best with the particular source sound.

The final front-panel element to mention is a pair of LED bar-graph meters, each with four green, one yellow, and one red LED. There are no level markings, but the meter seems to have something resembling a VU meter response. The bottom green LED comes on at -22dBu, with the other greens illuminating at roughly -12dBu, -2dBu, and +2dBu. The yellow LED lights at +10dBu, and the red glows at +20.5dBu.

The rear panel of the ME1NV is neatly laid out, with XLRs for the mic input and balanced +4dBu output. The XLR output is transformer balanced and fully floating, while a quarter-inch socket provides an unbalanced output at -10dBV. Since this output doesn't pass through the output transformer, it is fractionally cleaner than the balanced output, although the lower level means that it won't be able to drive some A-D converters fully, and it also misses out on the polarity inversion switch.

A second quarter-inch socket provides an insert point (labelled Patch) using the familiar tip-send/ring-return configuration. The nominal signal level is -10dBV and the insert point is immediately prior to the output stage. Mains power is connected via the usual IEC connector, with integrated voltage selection and fuse holder.

Alternatives The ME1NV is attractively priced, given its facilities and sound quality, but it isn't a true Neve 1073 clone. The manufacturers would suggest that their refinements offer an advantage, and in the right circumstances I would broadly agree. However, you can still buy the modern Neve 1073 module in various forms, and there are plenty of pretty accurate clones around if you simply must have that sound, but they cost significantly more than the ME1NV. One of my favourites is the Chandler 1073 LTD, but the same company also make preamps based closely on another vintage console, the EMI TG. The Chandler TG2 is a really nice preamp that is sonically more flexible, in some ways. While, again, more expensive than the ME1NV, it does offer a different yet equally desirable sound character. For a cleaner sound, it's hard to beat the DAV Electronics BG1, which is based on vintage Decca design principles, but uses a modern integrated-circuit front end. It is very well engineered, performs superbly for the price, and remains one of my firm favourites.

Vintage Sounds

The ME1NV is not the cleanest or quietest mic preamp in the world, but it does have a subtly rich character that many users will really appreciate. It sounds a tad more 'modern' than most vintage preamps to my ears, but still has more than a hint of the scale and body of a typical 'vintage' preamp — all those transformers and high-current discrete Class-A circuitry make sure of that.

The separate input-gain and output-level controls allow the overall level to be balanced against the required amount of 'drive' to provide a usefully creative range of sound characters. The ability to tinker with the input and output impedances adds further to the sonic versatility of the unit, and the dual metering allows the internal gain structure to be optimised sensibly.

There is plenty of gain available, and I was able to use the Great River preamp with a couple of different Chinese ribbon mics during the review period to great effect. Changing the input impedance changed the sound in fairly subtle ways, and was different for the two mics as well. With most of my capacitor mics — nearly all of which have transformerless outputs — the impedance switch seemed to have little or no effect, much as expected.

The DI is surprisingly effective, especially on bass. Driving the front end quite hard gives a nice richness and character to the sound that seems to work well. However, a little care is needed not to clip the front end, because that doesn't produce a very nice sound at all! I didn't use the insert point in earnest, although I did check that it worked as advertised. For anyone who still likes to track through a compressor or with some EQ, this facility allows a suitable outboard unit to be integrated with the preamp, before the processed output signal is dispatched through the preamp's output transformer. The provision of separate balanced and unbalanced outputs can be useful in some situations, and one suggested application is to provide a zero-latency monitoring output to feed a monitoring mixer or similar.

This is a nice little preamp, well worth investigation for anyone recording rock and pop material where a degree of coloration is a desirable thing. It wouldn't be my first-choice preamp for classical or 'serious' music applications, although it is capable of delivering a fine performance if the mics are chosen carefully and the gain structure is set up thoughtfully. Overall, I found the ME1NV to be a good-sounding and musically versatile preamp, and the sonic impression is indeed reminiscent of the vintage designs, but it sounds a little more open and modern to my ears, which will certainly appeal to many people. It is also cheaper in the UK than most Neve 1073 clones and includes a very usable DI input, adding further to the attraction.