ManleyVariable Mu Mastering Version Limiter Compressor - MS Mod + T-Bar Mod

Manley Variable Mu Mastering Version

Providing two solid mods that extend and enhance how the Variable Mu works, Manley's Variable Mu Mastering Version MS mod & T-Bar mod is a stereo limiter and compressor for mastering engineers that want the most out of their setup. The control of the unit has been contained to a set amount of possibilities via detented knobs, meant specifically for easy and reliable recalls on mastering sessions. Before diving too deep on what makes this unit so special in the Variable Mu lineup, the core of which this modified mastering edition must be touched upon.

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.

Known as "The Works", the MS and T-Bar mod offer both mid/side encoding and decoding as well as a newer set of tubes to replicate the reduction of the original units' tubes. Able to apply mid/side processing to the input, output, or both, the MS mod offers great extension into stereo processing by offering an easy way to smash the mids while leaving the sides untouched, vice-versa, and everything in between. The T-Bar mod replicates the sound of the rare and original 6386 tubes by wiring up paired 6BA6 pentodes as single triodes, almost identically matching the gain reduction and limiting curves while taking out the known issues of rarity, noise, and microphonics.

These two modifications plus a fantastic way to recall your limiting and compression settings make the compelling and dynamic Manley sound of the Variable Mu a must-have for any mastering engineer's suite.

Variable Mu Mastering Version Features

• Stereo tube limiter/compressor
• All controls are detented for easy recalls on masters
• Mid/side encoding and decoding via input/output switching
• 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