The Manley Vari MU is an all valve compressor and limiter designed for stereo buss compression.

The Manley Vari Mu takes its name from the patented technology used in this compressor, in which the valve is the gain reduction element. The compression works by using the “remote cut-off” or re-biasing of the 5670 dual triode vacuum tube. 

In compression mode, the Vari MU starts with a soft-knee 1.5:1 ratio, while in Limit mode the ratio starts at 4:1 and increases all the way up to 20:1 when pushed over 12dB of gain reduction. As more limiting occurs, the knee softens. This explains why it possible to push the Manley Vari Mu further than any other compressors.

Although it was originally designed as a mixbuss compressor to sweeten the final mix, it is nonetheless possible to use it as a dual mono with both sides having their own sets of controls including threshold, attack, recovery and output.

Manley Vari MU 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 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)
• STEREO LINK SWITCH
• 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.