Manley Laboratories Stereo Variable Mu Limiter Compressor Varimu

The Variable Mu Limiter Compressor is the GLUE that holds the mix together while crystallizing it into a professional, final product. All-tube, all transformer, an all-American legend. High Pass Side Chain mod now comes as standard.

The Manley Variable Mu® Limiter Compressor has defined professional stereo buss compression since 1994. This all-tube, transformer-coupled design utilizes the remote cut-off technique—re-biasing vacuum tubes to achieve gain reduction—delivering smooth, musical compression that unifies mix elements without audible artifacts. With custom hand-wound Manley transformers featuring nickel laminations and a fully differential signal path, the Variable Mu® provides exceptional transparency across its 20 Hz to 25 kHz frequency response.

• All-tube, transformer-coupled design using remote cut-off tube technology
• Musical compression with Compression (1.5:1) and Limit (up to 20:1) modes
• Custom Manley IRON® transformers with nickel laminations in mu-metal cases
• Hand-assembled in California to this day

• Ratios: 1.5:1 (Compress), 4:1 to 20:1 (Limit)
• Frequency Response: 20 Hz – 25 kHz, ±0.1 dB
• Max Output: +30 dBu
• Noise Floor: -85 dB
• Tubes: 5670, 5751, 12BH7 unit dependent
• Dimensions: 19″ × 3.5″ × 10″ 2U

Tube Complement & Compression Features
• MANLEY input & output transformers with nickel laminations in mu-metal cases with flat frequency response from 20Hz-25KHz
• BALANCED INPUTS & OUTPUTS (600 Ohms)
• Fully differential ALL-TUBE circuitry
• Variable Gain vacuum tube: 5670 x2 Standard or 6BA6 x4 T-BAR Mod
• Amplifying vacuum tubes: 5751 or 12AX7 x2
• Output vacuum tubes: 12BH7 x2 current production since 4/2016
• Output vacuum tubes: prior to MSLC94006 use 7044 or 5687 x2
• Side Chain Rectifier Diodes: 12AL5 x2
• Independently regulated B+ and Heater supplies
• Hardwire 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)
• STEREO LINK SWITCH - Several units can be linked for Surround (custom order)

Audio Performance & Power Specifications
• 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.