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Review: Maselec Master Series MLA-2 Precision Stereo Compressor

The optically controlled, mastering-grade MLA2 offers impeccable specs, precision gain control and compelling sound.

The Maselec MLA2 is an “old school”-inspired compressor with modern refinements. Its designer, Leif Masses, who is both an electronics engineer and a recording engineer, brings his studio experience to bear on how a compressor should behave in the wild. As with other offerings in the Maselec Master Series, the primary design goals are flexibility, simplicity of operation, transparency, wide bandwidth, low distortion, low noise and immunity to electronic hostilities in the signal path. The device’s adaptive time constants are intended to reduce unwanted artifacts that can occur when program compression is in use. The MLA2 is successful on all of these counts.


With its independent left and right channel controls, the MLA2 can function as a stereo or dual mono device. All settings are hard-switched, facilitating accurate recall. Gain reduction is implemented with optical sensors and a classic feedback circuit topology; hence the old school personality of the device. The individual optical elements for each channel are hand-selected and tightly matched for precise left and right tracking. Compression ratios range 1.4:1 to 8:1. Interestingly, attack and release settings are given as time per decibel. Attack values range from .005 ms to 1.5 ms per dB and release values range from .02 to 1 sec per dB. Calibrating the time constants in this manner gives detailed information to the user. For example, it’s easy to see that at the MLA2’s slowest attack setting, 6 dB of gain reduction will occur in 9ms. An innovative accelerator circuit enables the MLA2 to achieve fast attack times that are generally out of reach for an optically controlled attenuator.

The actual attack and release times are adaptive; they vary from their nominal settings in response to the program to reduce unwanted pumping. Input peaks of quicker duration automatically shorten the release time to avoid ducking the program in response to large transients. Traditional feedback-based compressor designs exhibit a side effect where the attack time gets slower as the compression ratio is decreased. The MLA2 includes a proprietary circuit to keep the attack time at the selected nominal value for all available ratios.

The MLA2 uses an operational drive principle. The user sets the input level to determine the amount of gain reduction as opposed to adjusting the compressor’s threshold. The actual threshold values are fixed at a high or low range by the position of a rear panel switch. The high level is intended for program mastering and the low position for individual instruments during tracking. The input drive is switched in 1 dB steps from -20 dB to 0 dB. In other words, the input control is an attenuator with the advantage of making it virtually impossible to clip the device at the input stage.

The output control is also switched in 1 dB steps but applies gain from 0 dB to +20 dB. I found this to be a useful arrangement because rotating the input and output controls by the same number of clicks results in the program level remaining fairly constant while the amount of gainreduction changes. This makes gauging the ideal amount of compression somewhat easier by minimizing the misleading effect of too much change in the final perceived level as adjustments are being made.

The front-panel switch complement includes compression in/out, channel link, power, and a selector for the VU meters to display gain reduction or output level. Powering the unit off results in a hardbypass so that signal flow will not be interrupted nor will anything connected the device’s transformerless inputs be loaded down in the absence of power: a nice feature to have in installations where the device is normalled to a signal bus. The channel link control has the unusual feature of being dynamically modified by the program. Peaks of short duration relax the linkage of gain-reduction between channels resulting in less ducking and louder perceived output.

Also on the front panel is a pair of dualcolor indicator lamps that turn from green to red when the threshold is exceeded on the corresponding channel. The indicators are useful for balancing stereo compression and for informing the operator of how left/right level differences are affecting compression.

In Use

On first auditioning the MLA2, it becomes immediately apparent that the optical gain control principle as applied here yields very smooth dynamic control. The sound is clear, solid, deep and up front. I set up a threeway shootout between a well-regarded analog mastering compressor, an outboard digital unit from a company that known for its best-in-class mastering processors and the MLA2. The first program up was a well-mixed rock power ballad with plenty of dynamic range. I set up the MLA2 for its slowest attack time, a 2:1 ratio, and next to shortest release time. Gain reduction averaged about 1.5 to 2.5 dB.

After carefully matching levels, compression and ballistics on all three units, the listening proved no contest. The digital unit, as you’d expect, provided good control and clarity, and would have sufficed, except in comparison. The alternate analog compressor sounded hard and somewhat thin compared to the MLA2. The MLA2 produced a full, rich sound with greater apparent volume and a solid bass/bass drum impact. The lead vocal remained as natural and emotionally engaging as it was in the original mix. This was a slam-dunk of surprising proportions: the MLA2 sounded huge on this mix.

Next up was a vintage-inspired track from singer Catherine Russell and guitarist Matt Munisteri — two fantastic musicians dedicated to bringing back the great songs of early jazz with a fresh attitude, musical virtuosity and modern fidelity. The differences were stark. When switching away from the MLA2 to one of the alternatives, the mix seemed to collapse even at matched levels. The MLA2 did especially well on keeping a resonant acoustic bass in check without tampering with the balance of the vocals and horns through over-modulation. The vocal tone was as sweet and full as it was in the uncompressed mix.

The MLA2 did not disappoint in other situations that called for compression. I found the precision of the controls and metering to be very helpful in guiding my way to a good starting point for each new situation. The one nit I would pick is the choice to locate the threshold range setting on the rear of the unit. Today’s reality is that rooms need to be multipurposed. Changing the unit over from tracking mode to mastering mode should ideally not require going behind a rack. Nonetheless, it’s a relatively small hoop to jump through for a compressor that sounds this good.


The MLA2 lives up to its moniker as a mastering-grade compressor. It offers impeccable specs, precision gain control, and compelling sound. The soft-blue lights under the VU meters add a nice visual touch and the heavyweight construction feels solid to the touch. Its performance is faster and more versatile than what is usual for an optically controlled compressor, yet it retains the smoothness and absence of distortion that are the hallmarks of classic optical devices. The MLA2 sounds fantastic and can do justice to a great mix.

Price: $4,200

Contact: Prism Sound |

NYC-based mastering engineer Alan Silverman is a two-time Grammy nominee in the Album of the Year category for mastering.