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ManleyVariable Mu Mastering Version Limiter Compressor - T-Bar Mod


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Manley Variable Mu Mastering Version

True to its roots with high attention to power and solid performance, the Variable Mu Mastering Version T-Bar mod is Manley's stereo limiter/compressor features a newer take on an original tube and designed towards mastering engineers. With all controls switched to detented switches, this version of the Variable Mu offers easy recall for mastering sessions as well as those looking for less precision and more decision. With the inclusion of the T-Bar mod, the Variable Mu offers the same juiced and dynamic range of reduction as its originator in a new and reliable option. Whether you're working on a detailed mix and need quick and easy choices or applying that last layer of glue to your tracks, the Variable Mu is here to offer its big Manley sound for assistance.

Each step of the way, the Variable Mu takes tube gain staging (hence the Mu), amplification, and leveling with maximum high-voltage headroom for a clean and powerful signal. The input gain is ganged for both channels, but this should be seen more as a pro than a con considering it's general use for mastering. Each channel can be set to a gentle compressor with a 1.5:1 ratio, or be pushed into maximum drive with a limiter that starts off at a 4:1 ratio but pushes up to 20:1 once the gain reduction surpasses 12dB.

Dynamic control is implemented with a stepped threshold control for simple and recallable gain reduction, and depending on the mode determines whether each increment is a half or quarter decibel. Controlling when compression or limiting kicks in and how long it lasts, the attack portion has been enhanced with a wider range of selectable speeds while the quite slow release retains its original timing choices. All three of the controls can be set individually or in a stereo link for one set of controls affecting both channels, and all compression and limiting can be easily viewed via the backlit gain reduction VU meters. The final output controls are unique for each channel making it very easy to dial in the perfect amount of leveling per channel.

Adding the vintage sound of the original Variable Mus, the T-Bar mod offers replacement… to a replacement. The original 6386 tubes used at the compression stage offered a fantastic range of dynamic control but due to their rarity in their original form—alongside being noisey, introducing microphonics, and terrible side-to-side matching—the 6386 was swapped for a 5670. Although a beloved choice as found in the Fairchild 670, the 5670 provides more squashing once pushing limiting past 6dB, making for a unique but not as similar option to the 6386. The T-Bar mod solves the need for what isn't available by inserting a pair of 6BA6 pentodes wired up as single triodes to replace the previous dual triodes. This mod offers an almost identical limiting and reduction curvature to the original 6386, making it the perfect solution for bringing back that vintage vibe without the problematic issues.

Offering quality control both sonically and physically, the Variable Mu Mastering Version T-Bar mod is the perfect solution for mastering engineers that want a modern take on a classic and powerful bus compressor.

Variable Mu Mastering Version Features

  • Stereo tube limiter/compressor
  • All controls are detented for easy recalls on masters
  • T-Bar mod replaces dual triode 5670 with a pair of 6BA6 pentodes wired as single triodes
  • Balanced transformer inputs and outputs with flat frequency response
  • All-tube signal path, including variable gain, amplifying, and output
  • Each channel has a limit/compress switch and a hardware bypass switch
  • Compression is soft knee at a 1.5:1 ratio, Limiter is a sharper knee starting at a 4:1 ratio and can achieve up to a 20:1 ratio
  • Input gain ranges +/-4dB over a 5-position control
  • Threshold is labeled in half-dB steps for a 12dB range on the limiter, compressor reassigns these to quarter-dB steps for a 6dB range
  • Attack time extended on both ends with 11 positions (15to 90ms)
  • 5-position recovery control (200ms to 8 sec)
  • HP SC input sets a 1-pole filter at 100Hz
  • Sep/Link sets whether the threshold, attack, and recovery are individual to the channels or linked controls
  • Output detented to 24 steps of half-dB increments for an 11dB range
  • 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: 15msec-90msec
  • 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.
Manley Variable Mu Mastering Version Limiter Compressor - T-Bar Mod Reviews