Manley Labs Stereo Variable MU Limiter Compressor with Mid/Side and T-Bar Mod

Manley Labs Stereo Variable MU Limiter Compressor with Mid/Side and T-Bar Mod

Manley Labs Stereo Variable MU Limiter Compressor with Mid/Side and T-Bar Mod

Important Notice: This item is non-cancelable and non-returnable
Special Order
Expected availability: 7-14 business days 
Free Standard Shipping
Not eligible for Free Expedited Shipping

Product Highlights

  • Sound of the Original Variable MU
  • Mid/Side Mod Adds Stereo Enhancement
  • All-Tube Design
  • 6 x Tubes per Channel
  • Hand-Wound Custom Nickel Transformers
  • Stereo or Dual Mono
  • Hardwire Bypass Switch
  • Side-Chain High-Pass Filter
  • Large Illuminated Sifam Meters
  • Handmade in the USA
Show moreShow less
Man Behind Layer

B&H $1000 Giveaway

Share your most-wanted item with friends & family for chances to win a $1000 B&H Gift Card. It's that easy!

1 new winner announced every week!
Limit 1 entry per day; Come back every day to increase your chance of winning!

Be sure to mention #BHWishList when you share!

Share on Twitter Share on Facebook

Congrats to our winners so far — Mark P., Lauren K. & Daniel M.

Official Rules


NO PURCHASE IS NECESSARY TO ENTER OR WIN. The B&H $1,000.00 Giveaway (the "Giveaway" or "Sweepstakes") is void where prohibited by law and is sponsored by B&H Foto & Electronics Corp., 440 Ninth Avenue, New York, NY 10001 ("Sponsor"). It is not sponsored or endorsed by Facebook or Twitter in any way.

Entry Period/Methods of Entry. The Sweepstakes will run from on or about November 7, 2016 until on or about December 19, 2016 (the "Entry Period"). Entries received outside the Entry Period are void. Enter the Sweepstakes via either one of the following methods. (1) Share your most wanted item on Facebook or Twitter via the dedicated links found on the B&H Website (; or (2) Mail a postcard (postmarked during the Entry Period) containing your name, address, phone number, and email address, and indicate the subject(s), if any, about which you are interested in receiving future emails from B&H (e.g. photo, video, audio, computers, home theater, portable entertainment ) (optional) to: B&H $1,000.00 Giveaway, c/o B&H Foto & Electronics Corp., 440 Ninth Avenue, New York, NY 10001 (either option, an "Entry"). Entries must not, in the sole and absolute discretion of the Sponsor, contain obscene, provocative, defamatory, sexually explicit, or otherwise objectionable or inappropriate content. Entries deemed by Sponsor to be inappropriate will be disqualified. Entries owned by a third party, or the use of any trademarks, service marks, logos, brands, or products owned by a third-party are not acceptable for entry into the Sweepstakes. Limit 1 entry per person, per day.

Winner Selection/Prizes/Odds. The B&H Social Team will randomly select a winner from among all eligible entries every Monday during the Entry Period, for a total three (3) winners (each a "Winner"). Each Winner will receive a B&H Gift Card pre-valued in the amount of $1000.00. No cash or other substitutions will be offered. Winner selection is in the sole and absolute discretion of the B&H Social Team. Any taxes are the sole responsibility of the winner. Winners will be notified and receive their prize to the e-mail address associated with the account to which their Entry was posted or the email account provided with a mail-in entry. The odds of winning depend on the number of eligible entries received.

Identity of Winners/Eligible Participants. Winners will be identified by the e-mail account associated with the Facebook or Twitter account from which their Entry was submitted or the email account provided with a mail-in entry. An e-mail account holder shall mean the natural person assigned to such e-mail account by the internet access or online service provider or other organization responsible for assigning e-mail addresses for the domain associated with such e-mail account. Any issues regarding the identity of a Winner shall be resolved by Sponsor in its sole discretion. The Sweepstakes is only open to residents of the United States that are at least eighteen (18) years of age on their entry date and is not open to employees of Sponsor, their immediate family, any person domiciled with such employees, or any affiliates or subsidiaries of Sponsor.

Entry Ownership/Entrant Agreements. Entrants retain full ownership and copyrights to their Submission. However, by entering the Sweepstakes entrants grant Sponsor permission to use their Entries for promotional purposes on their respective social media channels with proper credit. Entrants also agree: (a) to be bound by these Official B&H $1,000.00 Giveaway Rules; (b) that any claims related to this Sweepstakes shall be resolved individually without resort to any form of class action and that awards, shall be limited to actual out-of-pocket costs incurred in entering the Sweepstakes, and shall not include incidental or consequential damages or attorneys fees; and (c) that any actual or perceived ambiguities in these rules shall be interpreted by Sponsor in their sole discretion.

Limitation of Liability/Sponsor Modification/Cancellation Rights/ Choice of Law/ Venue/ Winners List. Sponsor is not responsible for incomplete entries or for failure to receive entries due to technical failures or human error of any kind. Winners agree that Sponsor will have no responsibility for losses or damage of any kind resulting from the acceptance, possession, or use of the prizes. Except where prohibited, participation in the Sweepstakes constitutes entrant's consent to the publication of his or her name by Sponsor in any media for commercial or promotional purposes without limitation or further compensation subject to Sponsor's respective Privacy Policies. Sponsor may modify or discontinue the Sweepstakes at any time and may disqualify from the Sweepstakes any person it determines, in its sole discretion, to have attempted to or actually tampered with or otherwise abused any aspect of the Sweepstakes. Entrants agree that in the unlikely event a dispute arises in connection with this Sweepstakes, it will be governed by the laws of the State of New York and heard exclusively in a court of applicable jurisdiction in the County and State of New York irrespective of any choice of law provisions to the contrary. To receive names of the winners by U.S. mail, please mail a self-addressed stamped envelope to: B&H Foto & Electronics Corp., Attn: B&H $1,000.00 Giveaway, 440 Ninth Avenue, New York, NY 10001. Any Winners List request must be received by B&H within one (1) year of the date the Sweepstakes is conducted.

Let us know how to reach you if you win!

Privacy 100% guaranteed; email address for contact purposes only


Already have a B&H account? Just log in tomorrow to enter again!

$0.00 Tax Collected Outside NY

You Pay:  $5,130.00

Add to Wish List Item in Wish List
  • 1Description

The Stereo Variable MU Limiter Compressor with M/S and T-Bar Mod from Manley Labs is a dynamic signal processor using two single-pentode tubes wired in triode for peak reduction and compression. The tube circuit is constantly re-biased by the vacuum tube rectified side-chain control voltages, resulting in a smooth change in gain.

The Mid/Side modification (also known as the Vertical/Lateral or Sum/Difference) allows for stereo encoding and decoding, as well as image enhancement processing capabilities. Instead of an active circuit, the left switch changes the wiring of the input transformer, while the right switch changes the output wiring. When both M/S switches are activated, the stereo signal is encoded and decoded providing the ability to compress the mid, sum or mono part of the sound on channel one, while channel two's compressor controls the side or difference. The Mid/Side switches replace the high-pass side-chain position on the front panel. The HP/SC are ganged and moved to the power switch position, while the power switch has been moved to the rear of the chassis.

The T-Bar modification uses a converter board with two 6BA6 single pentodes wired in triode mode to take over the duties of the single-envelope dual-triode 6386 or 5670 tubes. Each of the single-pentode tubes are matched for low noise and low microphonics before being installed onto the adapter board. Direct A/B comparisons and testing have found the sound and performance of the dual 6BA6 to be nearly identical to the original 6386 tube. Comparing the dual 6BA6 to the 5670 sounds less "squashed" with fewer artifacts as the amount of limiting is increased.

The compressor setting offers a soft-knee 1.5:1 ratio, while the limit mode offers a sharper knee with ratios ranging from 4:1 to 20:1. With higher limiting settings, the knee will start to soften. Distortion effects can be achieved by turning up the input and lowering the output while using little or no compression. The side-chain high-pass filter uses a 1-pole, 6 dB/octave filter that attenuates 1 to 3 dB at 100 Hz and 4 to 6 dB at 50 Hz. Once engaged, the compressor / limiter will not respond as strongly to low frequency content and will prevent audible "pumping" when processing bass-heavy music.

The input of the Variable MU is ganged, but can still process two independent channels with separate threshold and output controls. With the link switch engaged, the unit operates in true stereo mode and excels at processing 2-track, final mix, or mastering compression and limiting. Handmade in the USA, the unit is housed in a 2U steel chassis with a CNC-machined 1/4" faceplate that is also inlaid with laser-engraved inserts. The Variable MU ships with an IEC power cable.

  • M/S modification allows various approaches to Mid/Side recording, playback and processing
  • T-Bar Mod replaces the single 5670 tube with two 6BA6 tubes providing the original sound of the Variable MU
  • Manley input and output transformers with nickel laminations in mu-metal cases
  • Balanced inputs and outputs (600 Ω)
  • Independently regulated B+ and heater supplies
  • Bypass Switch: Hardwire true bypass
  • Input Attenuator: -8 to +8 dB stepped Greyhill switch
  • Variable Attack: 25 to 70 ms
  • Threshold: Continuously variable
  • 5-Step Recovery Switch: 0.2, 0.4, 0.6, 4, 8 sec
  • Compression Ratio: 1.5:1
  • Limit Ratio: 4:1 to 20:1
  • Large Illuminated Sifam Meters: Displays the amount of dB gain reduction
  • Stereo link switch
In the Box
Manley Labs Stereo Variable MU Limiter Compressor with Mid/Side and T-Bar Mod
  • IEC Power Cable
  • Limited 90-Day Warranty, Extends to 5 Years with Registration
  • Table of Contents
    • 1Description
    Number of Channels 2
    Inputs 2 x XLR transformer balanced (600 Ω)
    Outputs 2 x XLR transformer balanced (600 Ω)
    Input Level Input Level Switch: -8, -4, -2, -1, 0, +1, +2, +4, and +8 dB
    Compression Threshold Continuously variable threshold for compression and limiting
    Ratio Compressor: 1.5:1
    Limiter: 4:1 to 20:1
    Attack Time Variable Attack: 25 to 70 ms
    Release Time Recovery 5 Steps: 0.2, 0.4, 0.6, 4.0, 8.0 sec
    Maximum Output Level +30 dBu (26 Vrms) 26 dB Headroom
    Make-up Gain +35 dB
    Frequency Response 20 Hz to 25 kHz
    THD & Noise <0.1% THD @ 1 kHz
    Noise Floor: -85 dB typical
    Meter Illuminated Sifam meters
    Tubes per Side Fully Differential All-Tube Circuitry: 5670, 5751 (or 12AX7), 7044 (or 5687), & 12AL5
    (T-Bar mod replaced 5670's with 2 pairs of 6BA6's)
    High Pass Filter HP SC: High-Pass Side-Chain Filter:
    -1 to -3 dB @ 100 Hz
    -4 to -6 dB @ 50 Hz
    Rackmountable 2 U
    Power Supply 120 VAC, 80 W, 60 Hz
    Fuse Mains Fuse Value: 1.25 A
    Mains Fuse Type: MDA or MDL SLO-BLO Time Delay: 1-1/4" x 1/4"
    Dimensions (WxHxD) 19.0 x 3.5 x 10.0" / 48.3 x 8.9 x 25.4 cm
    Power Transformer protrudes 3.5" / 8.9 cm out back of chassis
    Weight 14.0 lb / 6.4 kg

    Manley Labs Stereo Variable MU Limiter Compressor with Mid/Side and T-Bar Mod Review

    Be the first to review this item
    See any errors on this page? Let us know.