Manley Stereo Variable Mu® Mastering Limiter Compressor – Tube Dynamics for Mastering
The Manley Stereo Variable Mu® Mastering Limiter Compressor is a high-end, all-tube dynamics processor designed specifically for mastering applications. Renowned for its musical compression, rich harmonic distortion, and unparalleled tonal smoothness, the Stereo Variable Mu® is a staple in top-tier mastering studios worldwide. It delivers the perfect combination of subtle dynamic control and analog coloration, adding warmth and presence to the final master.
At the heart of the Stereo Variable Mu® is a real variable gain tube circuit, which makes it stand out from traditional compressors. The unit uses 5670 dual triode vacuum tubes in its gain stages, providing natural, smooth compression with a variable threshold and gain range. Its all-tube signal path, combined with carefully selected components and a robust build, ensures that your masters maintain musicality while adhering to the technical precision required in professional mastering.
Key Features
- All-tube, hand-wired stereo limiter/compressor for mastering
- True variable mu design with 5670 vacuum tubes for musical and transparent compression
- Switchable Limit (hard knee) and Compress (soft knee) modes
- Adjustable compression ratios from 1.5:1 to 20:1
- Independent threshold and gain controls per channel
- Bypass switch per channel for easy comparison of processed vs. unprocessed signals
- Balanced XLR and 1/4” TRS inputs and outputs
- Solid, professional build with custom Manley transformers
Technical Specifications
- Channels: 2 (Stereo or Dual Mono)
- Compression Ratios: Variable from 1.5:1 to 20:1 (depending on mode)
- Attack Time: 25 ms – 70 ms (program-dependent)
- Release Time: 0.2 sec – 1.5 sec (program-dependent)
- THD: < 0.3% @ +20 dBu output
- Noise Floor: -85 dB typical
- Inputs/Outputs: Balanced XLR and 1/4” TRS
- Tubes: 2x 5670 (gain), 2x 5751 (sidechain), 2x 7044 or 12BH7 (output)
- Power: 90–250 VAC, 50/60 Hz (universal input)
- Dimensions: 2U rackmount (19″ x 3.5″ x 10″)
- Weight: Approx. 16 lbs (7.3 kg)
Ideal For
- Mastering engineers requiring smooth, musical compression for final masters
- Mix engineers needing analog glue and tone for stereo bus compression
- Studio owners looking to add an analog compressor to their mastering chain
The Manley Stereo Variable Mu® Mastering Limiter Compressor is an essential tool for any mastering engineer looking to add a unique analog character to their final output, ensuring that the master is balanced, cohesive, and musical.