Manley NU MU Owner's Manual

OUTPUT

THRESHOLD

MIN

SLOW FAST

MAX

SLOW FAST

RECOVERY

ATTACK

ST ER EO LI MI TE R C O MP RE S S OR

+3dB

-3dB

dB0

HIP

GR

METER

OUTPUT

HP SC

INPUT

LEVEL

V U

CHANNEL 1CHANNEL 2

INPUT 2 INPUT 1OUTPUT 2 OUTPUT 1

INSERT 2 INSERT 1

VACUUM TUBE STEREO LIMITER / COMPRESSOR

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TM

OWNER’S MANUAL

Contents

i) Introduction 1

ii) Manual Conventions 1

iii) Copyright Notice 1

1. Important Safety Instructions 2

2. Getting Started 2

3. Front Panel 3-4

4. Rear Panel 5

5. Operational Notes 6-7

6. Advanced Tricks 8

7. Questions & Troubleshooting 9

8. Servicing 10

9. Calibration Procedure 11-13

10. Specifications 14

11. Recall Sheet 15

PAGECHAPTER

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This equipment has been tested and found to comply with the limits for a class B digital device, pursuant
to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful
interference in a residential installation. This equipment generates, uses and can radiate radio frequency
energy and if not installed and used in accordance with the instructions, may cause harmful interference
to radio communications. However, there is no guarantee that interference will not occur in a particular
installation. If this equipment does cause harmful interference to radio or television reception, which can
be determined by turning the equipment off and on, the user is encouraged to try to correct the
interference by one or more of the following measures:
* Reorient or relocate the receiving antenna.
* Increase the separation between the equipment and receiver.
* Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
* Consult the dealer or an experienced radio/TV technician for help.

ii) Manual Conventions

Please take a few moments to read through this manual carefully. It contains essential information for the
proper operation of your Manley Nu Mu Limiter & Compressor.

Also in the following pages you will find useful hints and tips, allowing us to help you achieve the utmost
performance from your equipment.

Below are the following conventions, used to pick out particularly important parts of the manual. The
symbols are found in the margin next to the body of text of interest.

!

Especially Useful Tip

Important Information. Read Carefully

Caution! Pay Attention!

Refer to another section in this Manual

iii) Notice

This manual provides general and technical information for use, installation, and operating instructions for
the Manley Nu Mu Limiter & Compressor. Manley Laboratories, Inc. reserves the right to make changes in
specifications and other information contained in this publication without prior notice. Manley
Laboratories, Inc. shall not be liable for errors contained herein or direct, indirect, incidental or
consequential damages in connection with the furnishing, performance, or use of this material. No
statement contained in this publication, including statements regarding suitability or performance of
products shall be considered a warranty by Manley Laboratories, Inc. for any purpose or give rise to any
liability of Manley Laboratories, Inc.

© 2016 COPYRIGHT Manley Laboratories, Inc. All rights reserved.

This manual and any associated artwork, product designs, and design concepts are subject to copyright
protection. No part of this document may be reproduced, in any form, without prior written permission of
Manley Laboratories, Inc. Nu Mu, and the Manley Laboratories, Inc. logo are trademarks of Manley
Laboratories, Inc.

TM

Thank you for selecting the Manley Nu Mu Stereo Vacuum Tube, Limiter & Compressor. The Manley Nu Mu

builds upon the legacy of the Variable Mu, combining the “T-Bar” vacuum tube front end used in the Variable

Mu with a new discrete FET output stage. This marriage of tubes and solid-state electronics gives the Nu Mu a

remarkable tonal character which will always make it a hit in the studio!

Using the new “HIP” control gives the engineer more freedom, allowing more of the music to come through. This

function raises soft dynamics without squashing the louder passages.

Your Nu Mu is powered by our highly developed audiophile switched-mode power supply, offering super low

impedance, rigid regulation and very, very low noise. Congratulations on your new purchase! Don’t forget to

register your warranty with us.

Thank you for choosing our MANLEY Nu Mu. Enjoy!

1

i) An Introduction To The Manley Nu Mu Limiter & Compressor

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2

1. Important Safety Instructions

1. Water and Moisture – Do not use The near any source of water or in excessively moist

environments.

2. Object and Liquid Entry – Care should be taken so that objects do not fall, and liquids are not

spilled, into the enclosure through the openings.

3. Heat & Ventilation – When installing The in a rack or any other location, be sure there is

adequate ventilation. Improper ventilation will cause overheating, and can damage the unit.
The unit should be situated away from heat sources, or other equipment that produce heat. As
a general rule with tube equipment, it is wise to keep a 1U gap below and above if possible.

4. Power Sources – The has a universal power supply which can operate in any country. It

has an input voltage range of 90-260 VAC at 50/60 Hz.

5. Cleaning - The can be cleaned with just a damp cloth, or alcohol/methylated spirits for

more stubborn marks.

6. Damage - If after unpacking your there are signs of shipping damage, contact your

dealer.

7. Servicing - Do not attempt any servicing without consulting your dealer or Manley

Laboratories, Inc. The user should not attempt to service the unit beyond that described in the
operating instructions. All other servicing should be referred to qualified service personnel.
This unit has high voltages present, even after the power has been switched off.

8. DO NOT connect the AC supply cord until all other connections have been made. Afer initial

power up the VU Meter will “blink” for thirty seconds. The unit remains in MUTE until this
warm up period has elapsed.

Nu Mu

Nu Mu

Nu Mu

Nu Mu

Nu Mu

2. Getting Started

Unpacking your MANLEY

The Nu Mu is secured in its packing carton by two end-caps.

Hold the unit by the middle and simply lift the unit vertically straight out of the box.

After it has been unpacked, check that nothing is loose inside when handling the unit. The unit is
shipped with the vacuum tubes installed. Make sure they are not loose by looking through the vent
holes on the top cover. Ensure they are standing upright in their sockets.

It is advisable to keep the original packaging. In the event of servicing or relocating, the original
packaging ensures that the unit will always be shipped safely.

This package contains the following;

1 x Manley Nu Mu Reference Channel Strip
1 x Manley Nu Mu Owner’s Manual
1 x IEC Power Cable
1 x Warranty Registration Card
1 x Warranty Statement

Nu Mu:

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3

3. Front Panel

1

2

3

4

5

6

OUTPUT CONTROL

The OUTPUT control is available on both the left and the right channel. It adjusts the output level of that
audio channel. Unity gain is about the ninth marking, or 11 o'clock.

THRESHOLD CONTROL

The THRESHOLD control is available on both the left and the right channel. THRESHOLD or gain reduction
sets the necessary amplitude for compression or limiting to take effect. The most extreme effect is when
the control knob is set to MIN or fully counter-clockwise.

COMPRESS / LIMIT SWITCH

This switch allows the Nu Mu to use two different compression ratios. Offering either Compression at
approximately 3:1 when the switch is engaged and illuminated or Limiting at approximately a 10:1 ratio.

IN / BYPASS SWITCH

The BYPASS switch in the Nu Mu is a ‘Hardwire’ bypass for maximum performance. This switch dictates
whether your audio flows through the Limiter/Compressor or just straight through the unit, even if the unit
is switched off audio will still flow through the unit. If the switch is engaged and illuminated to the “IN”
position the audio will pass through either the Limiter or Compressor, so all the front panel controls will
function. Use this switch to verify that the limiting or compressing is not messing up the original sound but
enhancing it or at least leveling the volume.

VU METER

The Large custom VU meters allow easy tracking of both channels with the Nu Mu. It shows the amount of
gain reduction in dB from the 0 dB mark, when the switch (7) is set to REDUCTION. When this switch is
selected to O/P and illuminated, the meter measures the output in decibels.
Note: VU meters and PEAK meters rarely agree, digital recorders usually use peak meters - Rely on those for
a precisie recording. VU meters are standard with analog tape machines and big consoles because they
correspond well with perceived loudness.

HIP CONTROL

The "Hip" control allows compression to happen at lower volumes (lower in the dynamic range spectrum) but
leaves the louder dynamics alone while still compressing the overall signal. You get louder soft sections and
original dynamics of the louder sections. Previously the only way to get around this issue has been parallel
compression, where the compressed signal is mixed with the uncompressed signal. Our "Hip" control
achieves a similar effect while being easier to use, requiring less hardware (no need for extra mixing
externally)

More notes on the HIP control in Chapter 5 Operational Notes

Diagram 1

LIMIT

BYPASS

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OUTPUT

OUTPUT

THRESHOLD THRESHOLD

MIN

MIN

SLOW

SLOW

FAST

FAST

MAX

MAX

SLOW FAST

RECOVERY

SLOW FAST

RECOVERY

ATTACK

ATTACK

STER EO L IM ITE R CO MP RES SO RHAN DCR AF TE D IN C AL IFO RN IA U SA

COMPRESS

IN

LINK

+3dB

-3dB

dB0

+3dB

-3dB

dB0

INPUT
LEVEL

HIP

GR

METER

OUTPUT

HP SC

INPUT
LEVEL

V U

1 12 23 4 5 6

9 910 11 11 12 13

7

8 8

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3. Front Panel

4

METER SELECT SWITCH

The Meter select switch allows the user to monitor either Gain Reduction or the Output of the unit. When the
switch is engaged and illuminated, the output of the particular channel you are monitoring is visible in the
corresponding VU Meter.

ATTACK CONTROL

The
Attack control is continuously variable and determines the necessary length of a transient to initiate gain
reduction.

With 63% gain reduction: SLOW 0.13s, MID 0.07s, FAST 0.013s.
With 90% gain reduction: SLOW 0.64s, MID 0.35s, FAST 0.064s.

Fully counter clockwise at the slowest setting will prevent most percussive signals from causing limiting or
compression. It is available on both the left and the right channel.

RECOVERY CONTROL

HP SC SWITCH

The High Pass Side Chain filter is factory set a 100Hz. When this switch is engaged and illuminated, everything
above 100Hz will have the effect of limiting or compression. Useful if you want the bass to come through with full
impact and limit or compress everything else.

POWER SWITCH

The Power Switch glows a soft blue color when an IEC power lead is connected to the unit. This indicates that the
Nu Mu is in STANDBY mode. Engaging the power switch takes the Nu Mu out of standby mode and into warm-up
mode. The power switch will illuminate to a brighter blue and the backlit VU meters will start to flash. This warm­up process last 30 seconds after which the MUTE relays will lift and the VU meters will stop flashing.

The ATTACK control determines how long the compressor takes to respond to signals above the threshold.

The RECOVERY control determines how long the compressor takes to recover after the signal falls below the
threshold level.
With 63% gain reduction recovery, five selections: 0.1s, 0.16, 0.32, 0.64s, 1.7s.
With 90% gain reduction recovery five selections: 0.227s, 0.368s, 0.736s, 1.6s, 3.87s.

LINK FUNCTION

When The LINK function is used it links the two Stereo channels together. The Left channel controls become the
master linking THRESHOLD, ATTACK & the RECOVERY CONTROLS.

INPUT LEVEL SWITCH

The Input Level is controlled by a toggle switch. There is an Input Level control for each cannel. Three levels of
attenuation are available. +3dB, 0dB and -3dB.

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8

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10

11

12

13

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