Featuring a hybrid tube/solid-state design, switchable input levels, and Manley IRON balanced-input transformers, the Nu Mu is a dual-channel compressor and limiter suitable for use on the stereo buss. The unit itself comes stocked with the same tube front-end of the well regarded Variable Mu—four hand-matched 6BA6 vacuum tubes on the valve side—while offering a FET solid-state amplifying and output stage, which provides its faster, punchier path. As such, it’s a compressor well suited for electronic pop productions, or other mixes where one desires a more transparent stereo-buss compressor, rather than a color piece.
The Nu Mu provides output controls for both the left and right channels, as well as independent bypass, threshold, ratio, attack, and recovery selectors. Both the attack and recovery settings are continuously variable, reacting to the music pumped through the channels. Still, you can roughly dictate how slowly or quickly these controls operate. You’ll note the independent three-position toggle switches, which dictate the input level, giving you a choice of +3, 0, or -3 dB. Separate VU meters can be configured to read gain reduction or overall output levels.
On the left of the unit, you’ll find a link button, which will turn the left channel into the master channel, thereby ganging threshold, attack, and recovery controls. In this way, you can achieve a cohesive stereo picture when processing a dual-channel source. On the right, you’ll note the HP SC switch, which operates the internal sidechain detector circuit, factory set to 100 Hz. This global control is useful for allowing bass signal to pass through the NU MU without triggering gain reduction, thereby securing yourself a fuller, more bass-heavy sound.
The unit provides two different ratios, one offering compression at approximately 3:1, and the other offering limiting at 10:1—or thereabouts; the ratio, like the attack and recovery times, is program dependent.
Perhaps the most interesting feature of this unit is the Hip control, accessible on the right side of the front panel. When engaged, the Hip control does not operate as hard on intrinsically louder signals as it does on audio with a lower amount of level, effectively allowing your louder material to shine through uncompressed. Using this circuit can obviate the need for parallel compression in certain situations. The unit takes up 2 RU of rack space and comes with its own power supply.
Features at a Glance
•2 ratios for compression or limiting
•Hip control for preserving dynamics of loud sections
•Suitable for use as a stereo-buss compressor on electronic production, or other material where clean, punchy gain-reduction is called for
•4 x hand-matched 6BA6 vacuum tubes with FET solid-state amp and output stage
•Stereo link establishes left-master dynamic control
•Illuminated stereo VU meters read gain reduction or output level
•High-voltage SMPS custom designed for Manley Labs' vacuum tube audio circuits