Go to Content

Manley Labs Variable MU Stereo Limiter/Compressor

The Manley Variable MU Limiter/Compressor is yet another mastering studio standard used on hit record after hit record


(2 reviews)


Print page
You need Flash player 8+ and JavaScript enabled to view this video.
  • Images (2)
Discounted Price $4,399.00
Order Now! This item is out of stock but will be available soon. You will not be charged until your item ships.

Protect Your Investment! ( More Info )

Discounted Price $4,399.00
Add to Cart
The MANLEY VARIABLE MU LIMITER COMPRESSOR has been Manley's best selling product for many years. It is one of the very few compressors that has become a real standard in Mastering studios and contributed to most hit records over the last decade and probably the next. "Mu" is tube-speak for gain, and Variable Mu is our registered trademark for this limiter compressor. It works by using the "remote cut-off" or re-biasing of a vacuum tube to achieve compression. The precious vintage Fairchild 670 also uses this technique and is one of few all-tube compressor to do so, that we know of. Even the side-chain has glowing rectifier bottles. How's it work? The unique 5670 dual triode is at the center of the peak-reducing and compression action constantly being re-biased by the vacuum tube rectified side-chain control voltages which cause this tube to smoothly change its gain. Just like that.

The COMPRESS mode is soft-knee 1.5 to 1 ratio while the sharper knee LIMIT mode starts at 4 to 1 and moves to a more dramatic ratio of 20 to 1 when limiting over 12dB. Interestingly, the knee actually softens as more limiting is used. Distortion can be creatively used by turning up the Input and turning down the Output while using very little or no compression.

You might notice that the Variable Mu Limiter Compressor has a ganged input control, but do not jump to conclusions that it is mono-unfriendly. Track away! There are separate threshold and output controls to make compensations with plus you can always adjust your individual source levels elsewhere, right? The advantage of the stereo input control becomes dramatically clear when you switch to LINK mode, and that's what Manley's Variable Mu Limiter Compressor does better than anything else: final mix, 2-track, or mastering limiting and compression. Like one reviewer put it: "It's like pouring a bowl of sweet cream over the mix." Mmmmmm. Yummy. Give your music a big hug.

  • 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, 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.

You need this!


Like many landmark moments in a person's life, I remember the first time I heard a Vari-Mu. It was right around the turn of the century and a studio client brought one in to my humble little 48-track analog studio with his favorite preamps and mics. We had one of those well-known British consoles with a built-in buss compressor (really, not a bad one at all). You know the one, with the clunky automation. LOL. So the client says, "hey can we bypass that buss compressor and insert my Manley Vari-Mu on the stereo mix instead?" I'd been mixing music for about 15 years at this point and I thought I'd heard it all. Wow, was I wrong! Immediately on first listendown, it was like I had reached Nirvana (the metaphysical state, not the band). Everything in the mix just became "better." The highs were elevated in the most musical luscious way, I'd ever heard, the mids were pushed out front and center with an immediacy and a "snap" that just reached out of the speakers and gently caressed your eardrum, and the lows pushed me back in my chair, becoming the bold anchor of each track. Everything sit perfectly where it belonged, where I had *intended* it to belong, almost as if the Vari-Mu was reading my musical mind and it knew just what to do. There's only one way to describe that: Magic. Pure magic. I bought one two weeks later and am now the proud owner of my THIRD Vari-Mu! Sell your car if you have to, but buy one of these. Buy it now.

Eric Boyer

The West




Bought the Vari Mu several years ago. It was one of the first high-end hardware pieces I ever purchased. I love it. Some hardware is sold with the rationalization that there is a cumulative effect as gear is introduced into the signal path. The Manley Vari Mu is NOTICEABLE by itself. I've been stymied trying to understand why a mix wasn't sounding good only to find that I left the Vari Mu out of the hardware chain. I actually phoned EveAnna Manley to say thanks & send my compliments on the Vari Mu. It's the best piece of audio hardware I've ever purchased (really).

Music Czar



Variable MU Stereo Limiter/Compressor

5.0 2


Series N/A
Model N/A
Other Features N/A
Information not available