A single-channel microphone preamp with a rich feature set.
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Jonathan Little of Little Labs continually pushes the boundaries of analog technology with his unique products. His small company boasts some of the most innovative and highly regarded gear available, and the new Lmnopre microphone preamplifier is no exception.

Face Value

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FIG. 1: The Lmnopre''s many features come in a tight package that is remarkably easy to use.

For a single-channel microphone preamp without EQ or compression, the Lmnopre has more features than you can shake a dozen sticks at. And somehow Little managed to fit them all into a 1U faceplate. The controls are as elegant and pleasing to the eye as they are functional and easy to manipulate (see Fig. 1). Starting at the faceplate's left are an XLR mic input and a switch that disables the rear XLR input and conveniently doubles as a mute switch. To their right are two separate ¼-inch DI inputs, one active and one passive; using internal jumpers, you can configure whichever jack you're not using as a thru for feeding an amplifier. In addition to a DI-enable switch, another switch isolates the ground of the DI inputs to eliminate potential ground-loop hum.

The next three switches are standard preamp fare — a 20 dB pad, 48V phantom power, and a 6 dB-per-octave highpass filter starting at 120 Hz. But because the Lmnopre is a Little Labs device, of course, the highpass has a twist: engaging the filter allows you to use a separate low-frequency resonance feature that employs a different coupling capacitor to give you a low-frequency boost (more about that later). The preamp has two knobs for controlling gain, one for lower levels (20 to 48 dB) and one for higher levels (40 to 74 dB). A switch for choosing the gain range lies below the indicator LED, which glows green for low and red for high.

The low-frequency resonance controls come next — an enable switch and a knob controlling the amount of boost. To their right are the 180-degree polarity-flip switch and the phase-align switch and knob; the latter determines the amount of phase shift.

The output section has a trim knob; when engaged, it allows you to drive the preamp harder without overloading the next device downstream from the Lmnopre. A switch for bypassing the output transformer further expands the Lmnopre's sonic palette. At the end of the line are two clip-indicator LEDs, one for the preamp section and one for the phase circuit.

The backplate has the lion's share of the Lmnopre's I/O, including another mic input, a 5-pin jack for your own external transformer (in the manual, Little recommends a few to try), and a pair of insert jacks that essentially allow you to split the device in half by separating the preamp and the phase-alignment tool (see Fig. 2). Also on the rear are a master output jack and a 4-pin jack for the Lmnopre's hefty lump-in-the-line power supply. All rear-panel jacks are XLRs, including the power supply input. Switches on the backplate let you select the external transformer and activate the insert jacks.

In the Thick of It

Over the course of the review, I paired the Lmnopre's fully differential preamp section with a variety of microphones and sound sources. From snare drum and vocals to electric bass and guitar, the Lmnopre gave me the sound I wanted every time.

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FIG. 2: The Lmnopre''s back panel contains most of the vital I/O, including a 5-pin XLR to connect your own input transformer.

When I directly compared the Lmnopre with similarly priced solid-state preamps, such as the Millennia Media TD-1's HV-3 mic preamp, I heard very slight differences that I couldn't label as better or worse. In A/B comparisons, I heard a general tightness, as opposed to the HV-3's airiness; although the Lmnopre didn't sound dull or lacking in any particular frequency range, the HV-3 sounded a little more open. The Lmnopre sounded a bit more compressed and slightly thicker in the midrange, but that's what I expected, because the HV-3 is transformerless. All the nice, custom-wound iron in the Lmnopre's transformers thickens up its sound somewhat.

If you want a cleaner signal path, you can patch out of the insert-send jack on the back, bypassing the phase circuit and the output transformer. You can even run the Lmnopre transformerless using the 5-pin jack on the back (you need to know what you're doing if you want to try that out, though, as it could void your warranty).

Both DI inputs, which run through a separate custom-wound transformer, yielded equally satisfying results when compared to the TD-1, which is renowned for its DI. I slightly favored the active version, perhaps because my basses and guitars all have passive electronics.

More Than Just a Phase

The phase-align circuit is one of the preamp's most unusual features. In essence, it allows you to line up the waveform of the signal running through it relative to a similar signal to minimize phase cancellation. (That capability is useful only when two or more signals are representing the same source, as a waveform can only be out of phase relative to another waveform.)

The Lmnopre's phase-align circuit uses allpass filters and other analog voodoo to actually change the audio's phase characteristics. Although it is based on the circuitry in Little Labs' exalted IBP (In-Between-Phase) tool, it's a bit simpler than the IBP's. A switch for engaging the circuit and a knob for determining the amount of phase shift are the only two controls that got ported over.

The results of using this circuit are usually not subtle. When I used it on a bass DI next to a signal from a miked cabinet, or on one of two mics on a guitar amp, or on one mic in a 2-mic bass drum setup, I could find the sweet spot where the phase lines up to yield the best sound, second only to timely microadjustments in mic placement. The effect is magic — it's almost like equalizing the signal across the whole frequency spectrum at once.

You can also use the phase-align control as a special effect. Outside of the sweet spot are many areas where a guitar, for instance, thins out in a certain cool way. The Lmnopre opens up a whole new world of sonic possibilities, and all before your sound even gets to the recording medium. However, if you're feeling dodgy about committing your phase-aligned signal to tape, you can always use the phase circuit at line level during mixdown, thanks to the insert points provided on the Lmnopre's backplate. I do have one small gripe, though: the insert switch is on the back, which is a minor inconvenience if you have the box in a rack.

The only real problem with the phase-align circuit is that because it uses filters to achieve the effect, it substantially decreases the entire device's headroom. The manual claims that this decrease is no more than 12 dB, but I ran an oscillator through it and found that it's more like 13 dB, and 16 dB with the output transformer bypassed. If you switch the phase-align circuit in after you've set your levels, you'll probably need to readjust your gain to avoid nasty distortion (as opposed to the quite pleasant distortion the unit achieves when pushing the transformers above and beyond). The loss of headroom is by no means a showstopper; it merely requires some diligence in gain staging, which is worth the trouble to have access to the Lmnopre's brilliant phase tool.

A Certain Resonance

The low-frequency resonance circuit is yet another unique feature. Without adding active circuitry to the signal path, it lets you add girth to your audio, from a subtle rise in the sound's body to a woofy, woolly low-end boost.

Even when I pushed this circuit to its extreme, it sounded better than a standard low-end EQ boost. It's similar to the proximity effect achieved by moving cardioid mics close to the sound source, in that an enhanced presence accompanies the boost in low end.

Spells a Winner

The Lmnopre's $1,500 street price is an awfully fair one to pay for so much audio mojo. The unique design, attention to detail, excellent customer service, and pristine audio quality that have all become part and parcel of the Little Labs product line make this preamp extremely enticing for studios of all sizes. If it's in your budget, you'd do well to get the Lmnopre in your rack ASAP.

Eli Crews is often found reciting the alphabet at New, Improved Recording (, his studio in Oakland, California.



microphone preamp



PROS: Many innovative features. Aesthetically and functionally well designed. Top-notch audio quality. Informative and educational manual. Excellent product support.

CONS: Rear-mounted switch to separate phase-align circuit from preamp. Phase circuit decreases headroom considerably.


Little Labs