Manley Labs Variable MU with MS Modification Option

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.

MID/SIDE MODIFICATION (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 in 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.

• 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)

• HP SC: High Pass Side Chain Filter -3dB @ 100Hz

• 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)

• 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" (chassis occupies 2u) Power transformer protrudes 3.5" out the back of the chassis.

• Shipping Weight: 23 lbs.