Manley Stereo Variable Mu® Limiter Compressor
- Signal Chain
The Variable Mu Limiter Compressor is the GLUE that holds the mix together while crystallizing it into a professional, final product. All-tube, all transformer, an all-American legend.
$6,299.00
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. Like one reviewer put it: “It’s like pouring a bowl of sweet cream over the mix.” Mmmmmm. Yummy. Give your music a big hug.
THE T-BAR MODIFICATION
Backstory: The newer Variable Mu units use 5670 tubes instead of the 6386. By now the availability of the original USA GE 6386 is poor; we don't have any left at all, and what we do have are not usable due to noise, microphonics, bad side-to-side match, etc.
So does the 5670 sound different? Well, up to about 6db of limiting it's about the same. 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 came up with a really good solution: the T-Bar Mod. This uses a pair of 6BA6 pentodes wired as single triodes to replace each dual triode 5670 (or 6386). The 6BA6 T-Bar 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.
MID/SIDE (a.k.a. Vertical/Lateral, or Sum/Difference)
This modification 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. Read more about the MS Mod on page 12 of the Owner's Manual.
In order to add both M-S and the HP SC mods, we move the power switch to the rear panel and install both channels' HP SC switch to the center hole where the power switch was. The M-S switches then flank this switch.
The MANLEY brand has been around since the late 1980's. Manley's first commercially available products were upper echelon high-fidelity vacuum tube amplifiers and preamplifiers constructed at the old Vacuum Tube Logic of America factory.
In this history lesson, we'd like to direct special focus on our people at Manley Labs. The people whose years of dedication, service, and expertise bring you people, our customers, these products. It's all about the people...
On January 30, 1989, a 20 year old EveAnna on sabbatical from her studies at Columbia University met the crew and was hired on to the production team. Baltazar Hernandez, already with two years experience, taught her how to solder in those first few days. It was in 1989 that the first Manley professional products were developed, starting with the original 1u Reference 60dB Microphone Preamplifier and soon followed by our Manley Enhanced Pultec and Mid Frequency Equalizers. Baltazar and EveAnna, busy building gear, were soon joined by Saulo and Ramiro. Just next door, Elias was employed by a printed circuit board maker later brought into the Manley Labs fold when in 1993, Manley Laboratories, Inc. became a separate entity apart from VTL. The new Manley Labs factory at 13880 Magnolia Ave. in beautiful and bovine Chino, California was outfitted to house the Manley HiFi and Pro Studio manufacturing as well as the Langevin production lines, our newly acquired machine shop, and printed circuit board facilities.