The Manley Labs Variable-Mu® is a stereo tube compressor that brings music to life with its smooth compression profile and tube-generated harmonic warmth. Sweet, silky and polished; it is considered by many to be the gold standard for mixing and mastering.

The Variable-Mu® is Manley’s flagship compressor and one of the few modern devices to earn favorable comparisons to the legendary Fairchild 660/670. As is characteristic of its tube design, it sits on the slower, gentler side of compression devices and is aimed at providing a sense of ‘glue’ and finish to a track.

Each channel has independent control over Threshold, Attack and Release though the Input gain is shared between the two for easy adjustment of how the stereo source hits the compressor. Separate input, threshold and output controls work together to allow the tubes to be pushed into overdrive without adding much gain reduction, increasing the sense of ‘tube warmth’ by adding gradual saturation. A high pass sidechain filter gives control over the way in which the compressor responds to low frequencies expanding its suitability to different program material and allowing it to retain its smoothness even with high energy in the low end.

The Vari-Mu’s flattering high fidelity tone and easy handling of program material makes the it an excellent final-stage compressor for tracks in both mixing and mastering applications.

MANLEY input & output transformers with nickel laminations in mu-metal cases with flat frequency response from 20Hz-25KHz
Fully differential ALL-TUBE circuitry using one each 5670, 5751 (or 12AX7), 7044 (or 5687), & 12AL5 per channel
Independently regulated B+ and Heater supplies
Hard-wire BYPASS switch
Stepped switch INPUT attenuator as of 10/2011. (older units use Silent dual-ganged potentiometer)
RECOVERY 5 steps: 0.2s, 0.4s, 0.6s, 4sec., 8sec.
Variable ATTACK: 25msec-70msec
Continuously variable THRESHOLD
LIMIT (4:1 to 20:1) or COMPRESS (1.5 to 1)
HP SC: High Pass Side Chain Filter -3dB @ 100Hz
Large ILLUMINATED Sifam METERS (older units before serial number MSLC61642 shipped before 12/2003 use: 26V 1.2W FESTOON LAMPS; Manley's Part Number: VAR016B) Order spare bulbs using our parts order form. (newest units after serial number MSLC61642 shipped after 12/2003 use white LED lighting)
Several units can be linked for Surround (custom order )
Maximum gain: 35dB
Max. output: +30dBu (26Vrms) 26dB Headroom
<0.1% THD @ 1KHz Noise floor: -85dB typical
Power Consumption (120/240VAC): 80 watts
Unit is factory set for 100V, 120V or 220-240VAC operation for original destination country's mains voltage.
Operating Mains Voltage changeable with power transformer changeover switch and fuse value change.
Mains Fuse Value for 100~120VAC operation:replace with 1.25A as of 10/2011
Mains Fuse Value for 220~240VAC operation: replace with 0.6A (600mA) as of 10/2011
Mains Fuse Type: MDA or MDL SLO-BLO Time delay 1 1/4" x 1/4"
Mains Voltage Frequency: 50~60Hz
Dimensions: 19” x 3 1/2” x 10” (chassis occupies 2u) Power transformer protrudes 3.5" out the back of the chassis.
Shipping Weight: 23 lbs.

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