The MANLEY VARIABLE MU LIMITER COMPRESSOR has been our best selling product for many years. It 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. “Mu” is tube-speak for gain, and Variable Mu® is our 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. See the gain reduction curves here!
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 plus 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 our Variable Mu® Limiter Compressor does better than anything else: final mix, 2-track, or mastering limiting and compression.
Maximum gain: 35dB
Max. output: +30dBu (26Vrms) 26dB Headroom
<0.1% THD @ 1KHz Noise floor: -85dB typical
Input/Output Impedance: Balanced 600 Ohms
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
Power Consumption (120/240VAC): 80 watts
Shipping Weight: 23 lbs.