Manley stereo 10DV Limiter / Compressor » The Alan Wilder / Depeche Mode Collection Historic equipment, vinyl & memorabilia auction

General information :	Select Show
The Manley stereo 10DV Limiter / Compressor 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. “Mu” is tube-speak for gain. 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. 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. 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. The Variable Mu® Limiter Compressor has a ganged input control, but do not jump to conclusions that it is mono-unfriendly. There are separate threshold and output controls to make compensations with plus you can always adjust your individual source levels elsewhere. The advantage of the stereo input control becomes dramatically clear when you switch to LINK mode, and that’s where the Manley scores better than anything else: final mix, 2-track, or mastering limiting and compression. The Basics The Manley Variable-Mu is an all-tube compressor/limiter featuring real transformer balanced input and outputs and three dual triodes in a fully symmetrical all-tube circuit. This is the basic circuit configuration made famous by the hard to find and outrageously expensive Fairchild 670. Although originally designed around a 6386 variable MU tube, Manley switched some years ago to the more easily obtainable 5670. A 7044 or 5687 is used in the output section, which features a higher output current and better consistency than the original 12BH7 that was used. The unit is built like a tank, yet with a craftsmanship and precision way beyond the norm — which is the level of quality we’ve come to expect from Manley. The meters, attenuators, and input and output transformers were all custom designed, with the all-important mu-metal encased transformers wound in-house at the Manley Lab’s magnetics department (a very impressive part of the facility). And, indeed, the specs are equally impressive, with the input of the Vari-Mu capable of up to +36 dB (that’s 52 volts RMS) with only 1% distortion. Output is capable of +30 dB, which, in this world of transformerless output stages, is an impressive spec that harkens back to pre-IC days. Though brief, the manual is one of the best in the industry, covering everything from installation to example settings and operational tips, to service adjustments, and even including a section about correct interfacing and cable wiring. Simple Features One thing about the Vari-Mu is that it’s not over the top feature-wise. In fact, the unit has exactly what’s needed to get the job done — nothing more and nothing less. Essentially, there are two channels that are mostly independent except for one important exception — they share a common input gain control (more on this later). Each channel has a threshold control, output gain, attack and recovery (release), and a switch that selects between compression at about a 1.5:1 ratio and limiting at about 4:1. The ratios are deceiving in that they actually increase as the amount of compression/limiting increases, with the ratio climbing up to 20:1 at 12 dB of limiting, hence the name “variable-mu” or variable gain. A nice thing about the Attack and Recovery controls is that they have “slow” and “fast” panel designations that make them much easier to quickly set than those on other units that only have timing numbers. The envelope section provides quite a lot of control with the Attack settings available from “fast” at 25 ms, to “medium” at 50 ms, and the “slow” position at 70 ms. The Recovery control switches between five selections, starting with “very slow,” with a time base of eight seconds, to “very fast,” with a recovery time of 2 ms. There’s also a hard-wire bypass and two large precision meters that indicate gain reduction. A link switch connects the left- and right-channel control circuits for stereo operation, although the individual controls aren’t over-ridden, so you still need to set up both channels to similar parameters. There are several hot-rod options available for the Variable-Mu from the factory: the mastering version features precision 1% metal film resistors, Greyhill rotary switches with gold contacts, and stepped threshold attenuators and output controls. The surround version enables three units to be linked together via a common detector (see the upcoming review in Surround Professional on this version). Another version contains a true M/S feature that allows for Mid/Side recording, playback, and processing. And, lastly, the M/S or Vertical/Lateral Mod allows for Mid/Side recording, playback, and processing, which can be used to give a wider sound by making the unit only compress the in-phase information, leaving the out-of-phase info unscathed. Conversely, as in the Fairchild 670, one can achieve a more mono sound (helpful in disc cutting to minimize groove liftout) by setting the Vari-Mu to compress more out-of-phase info. In Use On bass, the tubes of the unit help round out the sound, while controlling the peaks and evening out the quieter notes. On vocals, the tubes enhanced the sonics in a way that only tubes can do, adding both clarity and warmth. As stated before, the left and right channels share a common input gain control, which means that you have to adjust the source feed into the channel and work the threshold control a bit more than usual when in dual-mono mode, but this isn’t much of a problem after you get the hang of it. But it’s across the mix bus where the unit shines. At 4 to 6 dB of limiting, you don’t even know that the unit is there (except for its effect on the dynamics); it’s that transparent. Kick it up to something obscene, like 15-20 dB, and it squeezes the track like a silk glove, getting the effect without any nasty artifacts. There’s something to this unit that just glues everything together and makes the track sound, for want of another term,”better.” No wonder it’s been the secret weapon of mastering engineers around the world for so long.

General information :

The Manley stereo 10DV Limiter / Compressor 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. “Mu” is tube-speak for gain. 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. 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.

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.

The Variable Mu® Limiter Compressor has a ganged input control, but do not jump to conclusions that it is mono-unfriendly. There are separate threshold and output controls to make compensations with plus you can always adjust your individual source levels elsewhere. The advantage of the stereo input control becomes dramatically clear when you switch to LINK mode, and that’s where the Manley scores better than anything else: final mix, 2-track, or mastering limiting and compression.

The Basics

The Manley Variable-Mu is an all-tube compressor/limiter featuring real transformer balanced input and outputs and three dual triodes in a fully symmetrical all-tube circuit. This is the basic circuit configuration made famous by the hard to find and outrageously expensive Fairchild 670. Although originally designed around a 6386 variable MU tube, Manley switched some years ago to the more easily obtainable 5670. A 7044 or 5687 is used in the output section, which features a higher output current and better consistency than the original 12BH7 that was used.

The unit is built like a tank, yet with a craftsmanship and precision way beyond the norm — which is the level of quality we’ve come to expect from Manley. The meters, attenuators, and input and output transformers were all custom designed, with the all-important mu-metal encased transformers wound in-house at the Manley Lab’s magnetics department (a very impressive part of the facility). And, indeed, the specs are equally impressive, with the input of the Vari-Mu capable of up to +36 dB (that’s 52 volts RMS) with only 1% distortion. Output is capable of +30 dB, which, in this world of transformerless output stages, is an impressive spec that harkens back to pre-IC days.

Though brief, the manual is one of the best in the industry, covering everything from installation to example settings and operational tips, to service adjustments, and even including a section about correct interfacing and cable wiring.

Simple Features

One thing about the Vari-Mu is that it’s not over the top feature-wise. In fact, the unit has exactly what’s needed to get the job done — nothing more and nothing less. Essentially, there are two channels that are mostly independent except for one important exception — they share a common input gain control (more on this later). Each channel has a threshold control, output gain, attack and recovery (release), and a switch that selects between compression at about a 1.5:1 ratio and limiting at about 4:1. The ratios are deceiving in that they actually increase as the amount of compression/limiting increases, with the ratio climbing up to 20:1 at 12 dB of limiting, hence the name “variable-mu” or variable gain.

A nice thing about the Attack and Recovery controls is that they have “slow” and “fast” panel designations that make them much easier to quickly set than those on other units that only have timing numbers. The envelope section provides quite a lot of control with the Attack settings available from “fast” at 25 ms, to “medium” at 50 ms, and the “slow” position at 70 ms. The Recovery control switches between five selections, starting with “very slow,” with a time base of eight seconds, to “very fast,” with a recovery time of 2 ms. There’s also a hard-wire bypass and two large precision meters that indicate gain reduction. A link switch connects the left- and right-channel control circuits for stereo operation, although the individual controls aren’t over-ridden, so you still need to set up both channels to similar parameters.

There are several hot-rod options available for the Variable-Mu from the factory: the mastering version features precision 1% metal film resistors, Greyhill rotary switches with gold contacts, and stepped threshold attenuators and output controls. The surround version enables three units to be linked together via a common detector (see the upcoming review in Surround Professional on this version).

Another version contains a true M/S feature that allows for Mid/Side recording, playback, and processing. And, lastly, the M/S or Vertical/Lateral Mod allows for Mid/Side recording, playback, and processing, which can be used to give a wider sound by making the unit only compress the in-phase information, leaving the out-of-phase info unscathed. Conversely, as in the Fairchild 670, one can achieve a more mono sound (helpful in disc cutting to minimize groove liftout) by setting the Vari-Mu to compress more out-of-phase info.

In Use

On bass, the tubes of the unit help round out the sound, while controlling the peaks and evening out the quieter notes. On vocals, the tubes enhanced the sonics in a way that only tubes can do, adding both clarity and warmth. As stated before, the left and right channels share a common input gain control, which means that you have to adjust the source feed into the channel and work the threshold control a bit more than usual when in dual-mono mode, but this isn’t much of a problem after you get the hang of it.

But it’s across the mix bus where the unit shines. At 4 to 6 dB of limiting, you don’t even know that the unit is there (except for its effect on the dynamics); it’s that transparent. Kick it up to something obscene, like 15-20 dB, and it squeezes the track like a silk glove, getting the effect without any nasty artifacts. There’s something to this unit that just glues everything together and makes the track sound, for want of another term,”better.” No wonder it’s been the secret weapon of mastering engineers around the world for so long.

Technical spec :	Select Show
MANLEY input & output transformers with nickel laminations in mu-metal cases FREQUENCY RESPONSE -1dB: 20Hz-75KHz screenshot BALANCED INPUTS & OUTPUTS (600 ohms) Fully differential ALL-TUBE circuitry using one each 5670, 5751, 7044 or 5687, & 12AL5 per channel 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 (older units before serial number MSLC61642 shipped before 12/2003 use: 26V 1.2W FESTOON LAMPS; Manley’s Part Number: VAR016B) Order spare bulbs using our parts order form. (newest units after serial number MSLC61642 shipped after 12/2003 use white LED lighting) 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 Unit is factory set for 100V, 120V or 220-240VAC operation for original destination country’s mains voltage. Operating Mains Voltage changeable with power transformer changeover switch and fuse value change. Mains Voltage Frequency: 50~ 60Hz Dimensions: 19” x 3 1/2” x 10” (chassis occupies 2u) Power transformer protrudes 3.5″ out the back of the chassis. Shipping Weight: 23 lbs.

Technical spec :

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Alan's comments :	Select Show
“All I can say is that it sounds wonderfully warm and inviting, and has been the outboard compressor that I turn to most for a variety of applications, from drums to guitars to vocals. The results can be heard on all Recoil material since ‘Liquid’.”