Manley Stereo Variable MU Mastering Compressor

The Manley Stereo Variable MU Mastering Compressor 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!

The Mastering Version of our Variable Mu Limiter Compressor incorporating detented and logable steps built with 1% metal film resistors on sealed gold-contact Grayhill switches is available. The Mastering Version of the Variable Mu Limiter Compressor uses expensive Greyhill rotary switches with gold contacts where conductive plastic pots were used. The steps are determined with a large number of 1% precision metal film 1/2 watt resistors. The best conductive plastic pots only have 10% or 20% tolerance. The ten fold improvement in precision helps a great deal in left-right matching. There is a subtle audible improvement with stepped switches as well. Audiophile HI-FI often uses that technique to wring the last drop of performance out of a preamplifier. And I bet you wanted stepped switches mostly for resets.

The INPUT LEVEL is a five position switch with a generic optimum setting of “0” in the 12:00 position. Each step in either direction is 2 dB. For reference, Unity Gain is "0". The OUTPUT Attenuators are in half dB steps. Reference Unity is -11.5 or fully counter-clockwise. You might think of these as "gain makeup". They are marked technically, in that “0” or fully clockwise has zero attenuation in the circuit. The tube circuit actually has 15.5 dB of gain. The Input attenuator at "0" removes 4 dB and the Output attenuator removes the last 11.5 producing "unity". With a little compression the "gain make-up" available with the Output Attenuator is very handy. The Threshold is in half dB steps calibrated to LIMIT mode. In Compress the steps are approximately 1/4 dB. There are 24 steps so LIMIT gets a 12 dB range and Compress has a 6 dB range of adjustment. In some cases it is common to use the Input Attenuator to find a good starting point. Some Mastering engineers find using the combination of Input, Output and Threshold to achieve a little different "drive". Another good reason for stepped gains. The Attack Time has been slightly extended in both directions compared to a regular Variable Mu and divided into 11 steps. The Recovery 5 position switch is exactly the same as a regular Variable Mu.

Manley Stereo Variable MU Mastering Compressor Switches

• Input: -4 to +4 in 2 dB steps
• Output: -11 to 0 in 1/2 dB steps (24 detents)
• Threshold: -11 to +1 in 1/2 dB steps (24 detents)
• Attack: 11 positions
• Release: 5 positions

Manley Stereo Variable MU Mastering Compressor Options

• MS Mod - Manley offer a Mid/Side mod upgrade (aka. Vertical/Lateral or Sum/Difference) to the Variable Mu Limiter Compressor, which opens the door to stereo encoding and decoding as well as exciting image enhancement processing capabilities. For instance, setting to compress only the in-phase information allows the augmentation of the stereo image as the out-of-phase content is left untouched. Or, conversely, if you need a "more-mono" mix for broadcast, or vinyl-cutting for instance, you can set it to kill off more of the out-of-phase info which leaves more in-phase material in the final result.
• T-Bar Mod - Newer Manley Variable Mu Compressors use the 5670 tube instead of the 6386. In terms of sound, up to about 6db of limiting it's about the same for these two tube types. After that point, the 5670 version tends to sound more "squashed" than the original 6386 version. Some like it better, some don't-- depends on what you're trying to do. To solve all these problems, Paul at Manley came up with a really good solution: The T-Bar Mod. The T-Bar Mod uses a pair of 6BA6 pentodes wired as single triodes to replace each dual triode 5670 (or 6386). the 6BA6 TBAR Mod is the preferred system to use in the Manley Variable Mu for reasons of ability to perfectly match each phase-halve section and each stereo set, ability to select for lo-noise and lo-microphonic sets for a low cost, and because the action of the 6BA6's so closely resemble the smooth 6386 limiting curves. In other words, the T-Bar Mod converts later 5670 units to have the same limiting characteristics of the original 6386 for smoother operation.

Manley Stereo Variable MU Mastering Compressor Specifications

• 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, 7044 or 5687, & 12AL5 per channel
• Independently regulated B+ and Heater supplies
• Hard-wire bypass switch
• Silent conductive plastic dual input attenuator
• 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)
• 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 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 Stereo Variable MU Mastering Compressor Includes

• Manley Stereo Variable MU Mastering Compressor
• IEC Power Cable
• Manual
• Manufacturers Warranty