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Manley Labs Langevin Dual Vocal Combo Mic Pre/EQ/Limiter

The new Langevin Dual Vocal Combo is a combination of two successful products - the Langevin Dual Mono Mic Preamplifier with shelving EQ and the Langevin Dual-Channel Electro-Optical Limiter.

Manley Labs, one of the most respected names in high-end audio, purchased the rights to the Langevin name and circuit designs in 1992. Manley reserves the Langevin name for all its solid state products.
Product PointsApplications: Studio; project studio; broadcast; live sound

Key Features: Two-channel discrete microphone preamp/EQ/electro-optical limiter; XLR I/O and TRS limiter line input; switchable phantom power

Price: $2,000

Contact: Manley Labs at 909-627-4256;


+ Classy Manley electro-optical limiting

+ Great-sounding preamp

+ Reasonable price


– No mic/line input switch – requires manual patching

– Confusing front panel layout

– No phase reverse switch

The Score: Overall, a superb value at $1,000 per channel of excellent preamplification, EQ and limiting.
The new Langevin Dual Vocal Combo is a combination of two successful products – the Langevin Dual Mono Mic Preamplifier with shelving EQ and the Langevin Dual-Channel Electro-Optical Limiter.


The 20-pound Dual Vocal Combo’s signal path is 100 percent discrete. There are no op-amps in the signal path. In fact, the only op-amps in the unit are those used to drive the LEDs in the opto circuit and the meter circuit. The box’s microphone input transformer is custom wound by Manley Labs in its in-house magnetics department.

Each channel includes a front panel accessible high-impedance (150 k-ohms) 1/4-inch jack for the direct input of bass and electric guitars, synths, samplers, drum machines, etc. The rear panel XLR input is interrupted when a cable is inserted into this jack.

The microphone preamplifier and equalizer are roughly based on the vintage Langevin AM-4 channel strip. This section has a frequency response of +/-0 dB from 10 Hz to 20 kHz and <0.05 percent THD at 1 kHz. The limiter is the same as the Manley Electro-Optical Limiter (also similar to the limiters found in the acclaimed Manley VoxBox) except with a discrete transistor gain make-up stage rather than a vacuum tube gain make-up stage.

The rear panel of the Dual Vocal Combo includes a female XLR connector for each channel’s microphone input, two male XLR connectors for the balanced line outputs and two 1/4-inch jacks for unbalanced line outputs. There are also two TRS 1/4-inch jacks to directly patch into the limiter and bypass the microphone preamplifier and EQ. This allows the limiter to be used in conjunction with another mic pre, or in a mix situation.

The problem is, as soon as you insert a plug into the Limiter In jack, it breaks the normal from the EQ into the limiter. This is fine if you always have easy access to the rear panel of your Dual Vocal Combo. I don’t like having to climb behind the rack every time I want to switch from one input to another. I wish Manley had added an additional front panel switch for each channel that selected either microphone or line input. Having female XLR connectors for line input instead of 1/4-inch TRS would be more convenient as well.

A standard IEC connector on the rear panel provides power to the box. Two ground terminals are also included on the rear panel. These posts are intended to assist in installations where a special grounding scheme is being used. The top post is the audio circuit ground and bottom is the chassis/AC ground.

The front panel is beautifully finished in brushed red aluminum and is factory-guaranteed to get plenty of second looks. The knobs and switches are, in typical Manley fashion, all of the highest quality.

Input Attenuate is the input gain control for the microphone preamp. Its range goes from off to 45 dB of gain. The phantom power switch activates 48V phantom power for each respective channel. This is a special locking switch that must be pulled out before it can be turned on or off to prevent accidental switching. Each phantom power switch has an LED that glows when phantom power is on.

Each EQ section has a bypass switch and two frequency select switches. One switch sets the corner frequency for the low frequency shelf as either 80 Hz or 40 Hz shelf and another sets the corner frequency for the high frequency shelf as either 12 kHz shelf or 8 kHz. LF and HF knobs allow the EQ to be adjusted from -10 dB to +10 dB.

In LA-2A fashion, the limiter controls are minimal, allowing for speedy setup and ease of use. The In/Bypass switch takes the limiter in and out of the signal path. The Reduction knob adjusts the limiting threshold. The optical limiter’s attack and release times are fixed at 20 milliseconds and 500 milliseconds, respectively. The Gain knob controls the make-up gain after the limiter.

In the center of the box’s front panel are two VU meters. The meters are smaller versions of standard Sifam VU meters. Each meter has a corresponding switch that determines whether the VU meter monitors final channel output (if Meter Output is selected) or how much limiting is occurring (if Reduction is selected). The Sep/Link switch lets the two limiters act independently (if Sep is selected) or collectively (if Link is selected).

The manual is well written and easy to understand. It includes a helpful section on cable wiring as well as a recall sheet that can be copied and used to document settings. All Manley and Langevin owner’s manuals can be found online at

In use

Initially I found it a bit confusing that the left and right channels are exact mirror images of each other, with the exception of the EQ, which follows the same footprint (LF controls on the left and HF on the right).

The left EQ knob adjusts low-frequency EQ for both channels but the left limiter knob adjusts Gain on the first channel and Reduction on the second.

It would make better sense to me if the left limiter knob on both channels adjusted the Reduction and the right adjusted the Gain. Once I became used to this oddity, however, I stopped cranking the gain of the first channel every time I wanted to adjust the threshold. I also found the lack of a phase reverse switch disappointing.

After extensive use, I concluded that, despite these minor flaws, the Dual Vocal Combo is an extraordinary machine. It sounds great and is easy to use and extremely fast to achieve the end result.

I’ve been putting the box to the test over the last several weeks, using it in a wide variety of circumstances. I have yet to be disappointed. The DVC sounds wonderful on electric guitars. The preamp is punchy and full with a tight bottom end and the EQ allowed me to add top-end sparkle without getting harsh.

It worked equally well with bass guitar. I especially like the low-end definition I was able to attain. When boosting the low frequency, the bottom got bigger without getting muddy or undefined.

I used the Dual Vocal Combo along with a pair of Earthworks SR77 microphones and a Steinway Grand piano to achieve an amazing piano sound for a jazz album I recently completed. The limiter worked especially well with the piano giving the precise amount of control without sucking the life out of the performance.

I used the Brauner VM1 Klaus Heyne Edition microphone (PAR, 10/00, p. 22) through the Dual Vocal Combo, yielding what is perhaps one of the finest vocal sounds I have ever achieved. I also had exceptional results using the Sony C-800G to record vocals through the Combo.

With the limited flexibility of the Dual Vocal Combo’s equalizer there were times when I found it necessary to add my GML equalizer between the Combo and tape (or hard disk in some instances) to allow me to attain the desired sound. The lack of any midrange equalization and the lack of ability to adjust the equalization bandwidth is the only real sonic limitation I found in the box. As long as the original sound source is of reasonably good quality and the microphone is decent, the box will work great. If you are looking for the kind of EQ that will really let you tweak and twist a sound into something that it isn’t, however, this is not the machine to use.

The mic preamp and EQ also sound superb on drums and percussion, although I found the limiter was typically too slow to be effective on kick, snare and toms. The limiter is very “LA-2A-ish” in its compression characteristics – it tends to work best on vocals (thus the name Vocal Combo), bass, guitars and keyboards.


At $2,000, the Manley Dual Vocal Combo is a fantastic bargain offering a superb performance-to-price ratio. Two channels of vintage Langevin AM-4 modules, without any limiting whatsoever would likely cost well over $2,000 if the price included rack-mounting and fitting the box with a power supply.