Manley Stereo Variable-Mu Rare 6386 version!
Industry's all-time favorite tube compressor.
Legendary first revision 6386 collectors item Manley Vari-Mu. Real Fairchild 670 tubes. Meld your mix together with molten Manley tone.
She operates on the same principle as several top-notch vintage tube limiters, and since this is an original Manley version 1, it uses the same 6386 input tube as the Fairchild, Gates, and others. This tube is the one that actually performs the gain reduction; it, more than any other component, determines the sonic signature of these units.
This Version 1 uses 6386 input tubes and 12BH7 output tubes. These have round (Sowter brand) input transformers. There are 3 power transformers inside the unit. Version 1 units have series-connected heaters for the two 6386 tubes. These were manufactured from 8/1994 until around 3/1996, serial numbers MSLC001 through MSLC123. This unit is serial# MSLC102
The 6386 dual triode was designed as a cascode RF/IF gain-controlled amplifier, and as such, had many characteristics ideally suited for use as a gain-controlled audio amplifier. However, it seems this tube was used more in commercial/industrial applications rather than high volume consumer applications (like in radios and TV’s).
This Version One units guts have SOWTER input and output transformers:
There's a reason this compressor can be found across mix-busses and in mastering labs around the world; it sounds incredible, injecting that important finishing glue in to the program.
"Mu" is tube-speak for gain, and Variable Mu® is Manley's registered trademark for this limiter compressor. It works by using the "remote cut-off" or re-biasing of a vacuum tube to achieve compression. The precious vintage Fairchild 670 also uses this technique and is one of few all-tube compressor to do so, that we know of. Even the side-chain has glowing rectifier bottles. How’s it work? The unique 5670 dual triode is at the center of the peak-reducing and compression action constantly being re-biased by the vacuum tube rectified side-chain control voltages which cause this tube to smoothly change its gain. Just like that.
The COMPRESS mode is soft-knee 1.5 to 1 ratio while the sharper knee LIMIT mode starts at 4 to 1 and moves to a more dramatic ratio of 20 to 1 when limiting over 12dB. Interestingly, the knee actually softens as more limiting is used. Distortion can be creatively used by turning up the Input and turning down the Output while using very little or no compression.
You might notice that the Variable Mu® Limiter Compressor has a ganged input control, but do not jump to conclusions that it is mono-unfriendly. Track away! There are separate threshold and output controls to make compensations with, and you can always adjust your individual source levels elsewhere, right? The advantage of the stereo input control becomes dramatically clear when you switch to LINK mode, and that’s what the Variable Mu® Limiter Compressor does better than anything else: final mix, 2-track, or mastering limiting and compression.
Specifications: - BALANCED INPUTS & OUTPUTS (600 ohms)
- 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
- 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
- Dimensions: 19” x 3 1/2” x 10” (occupies 2u)
- Shipping Weight: 23 lbs.
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