Sound Devices MP-1 Portable Mic Preamp

(Originally published in Audio Media Magazine USA& UK)

Since the quest for tools that improve the quality of our work often leave us bleeding on the cutting edge, it’s nice to occasionally find a new one that’s actually a better choice. Such is the case with the MP-1 portable microphone preamp by Sound Devices.

In my world of location sound, there are a variety of scenarios that need a single microphone boosted to line level with high quality. For example, in sports television production the need may be to send the mic signal from a sidelines announcer or a parabolic dish down a very long line, sometimes a mile or more while competing with noise from power lines, etc.

In film production, the need may be to boost the mic level signal of remote mounted wireless receivers. Or, when using a palm sized DAT recorder, there is certainly the need for a high quality phantom powered mic pre or two.

Being "on location" not only creates the need, it also creates special challenges for the equipment needed; a far cry from what would be expected from rack mounted studio equipment. For instance, on location often means being away from AC power, exposed to the elements, constant moving, packing and setting up. Therefor, the equipment has to be very rugged, battery powered, small, and lightweight, while still delivering the highest professional quality. The MP-1 addresses all of these requirements very well, obviously the results of the designers taking pride in their product.

Rugged to the point of having a military appearance, the housing is made of extruded aluminum and uses long screws to keep the heavy gauge end panels securely in place. Small steel handles mounted on the front of each edge protect the front panel from damage and reduce the chances of accidentally changing the settings. The battery compartment is hefty stainless steel with a stiff contact spring. Translation: This is one piece of equipment that will not get crushed, fall apart, or loosen up, and it will always work.

The unit measures 1.7" x 3.7" x 5.5". A peek inside reveals that this space is used very well considering the relatively large, high current line output transformer capable of driving very long cable runs. The circuit board is beautifully laid out and uses surface mount components. It would be nice if it was a little smaller, but will easily fit in most field bag compartments and is a good size for belt clip use. It does not come with a belt clip, but I believe one could easily be installed.

Two AA batteries inside its stainless steel battery compartment will deliver a +4dB signal into 600 ohms for twenty-four continuous hours. When phantom powering a condenser microphone, the battery life is reduced somewhat, depending on the current consumption of the microphone. You can select 48 Volts or 12 Volts phantom, as needed, to help manage battery life. From a practical standpoint, the important thing is that you can pop in to AA’s in the morning and forget about it for the rest of the day, regardless or how you’re using it.

While the first priority with any equipment is that is work when it is supposed to, and the MP-1 certainly will, the second consideration is: How does it sound? In our shop the standard for portable low noise high gain preamps are those found on the Cooper CS-106 portable mixer. The Cooper preamps have considerably more available gain, but when set to deliver the same gain as the MP-1’s maximum (66dB), the MP-1 has slightly less noise. So, for 98% of most field requirements it can hold its own with the very best. The MP-1 has a peak limiter that can be switched on from the front panel. With a fixed threshold of +17dB (3dB before clipping) and a ratio of 10:1, I would plan to use it only as a peak limiter (as intended), not a compressor. But, because its attack time is a very quick 5ms and uses dual opto-isolators it is virtually unclippable with anything less than +4dB. For this reason, it actually could be successfully used as an extreme compressor when used, for example, with an announcer in very loud environments such as NASCAR race events. While I prefer a steeper roll off than the 6 dB per octave that the MP-1 uses, the three position low-cut switch is properly placed, in my opinion, at 80Hz (handling noise), 160Hz (wind noise), and flat.

The Sound Devices MP-1 represents an excellent balance in utility, reliability and cost ($420) and will no doubt be welcomed into a number of places, but I see it mostly appreciated by video production trucks, news crews, and portable DAT recordists. However, I already have a wish list for what I would like to see on subsequent versions. For a number of reasons, the most useful would no doubt be a bridging headphone output (even the guy holding the parabolic dish on the fifty yard line likes to here what he’s doing). Second, for use with dynamic mics or very low-level recording, a few dB more gain could sometimes come in handy. Lastly, the name "MP-1" just screams for an "MP-2" stereo version, winning the ears of even more DAT recordists. Maybe later. But for now, the MP-1 can be counted on to do what it was designed for very well, even in a rugged professional environment. When considering all the options, it’s the one I’d reach for.

–Glen Trew