NU MU MANUAL REV 1.0 WEB MANUAL.des

NU MU MANUAL REV 1.0 WEB MANUAL.des
OUTPUT
THRESHOLD
HIP
METER
OUTPUT
MIN
+3dB
0 dB
-3dB
INPUT
LEVEL
VU
mu
MAX
RECOVERY
ATTACK
GR
SLOW
FAST
HP SC
nu mu
TM
SLOW
FAST
S T E R EO L I M I T E R C O M P R E S S O R
VACUUM TUBE STEREO LIMITER / COMPRESSOR
CHANNEL 2
CHANNEL 1
PRESSOR
ES INC.
O, CA 91710
256
om
INPUT 2
OUTPUT 2
OUTPUT 1
INSERT 2
INSERT 1
USA
OWNER’S MANUAL
INPU
Contents
CHAPTER
nu mu
PAGE
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.
Specifications
11
10.
Recall Sheet
12
i) An Introduction To The Manley Nu Mu Limiter & Compressor
Thank you for selecting the Manley Nu MuTM 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!
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.
nu mu
1
1. Important Safety Instructions
1. Water and Moisture – Do not use The Nu Mu 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 Nu Mu 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 Nu Mu 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 Nu Mu can be cleaned with just a damp cloth, or alcohol/methylated spirits for
more stubborn marks.
6. Damage - If after unpacking your Nu Mu 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.
2. Getting Started
Unpacking your MANLEY Nu Mu:
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
1
1
1
1
nu mu
x
x
x
x
x
Manley Nu Mu Reference Channel Strip
Manley Nu Mu Owner’s Manual
IEC Power Cable
Warranty Registration Card
Warranty Statement
2
3. Front Panel
1
2
OUTPUT
3
4
5
6
7
2
THRESHOLD
OUTPUT
THRESHOLD
COMPRESS
1
HIP
LIMIT
MIN
IN
RECOVERY
ATTACK
nu mu
MAX
BYPASS
SLOW
FAST
LINK
SLOW
METER
OUTPUT
+3dB
0dB
-3dB
MIN
+3dB
0 dB
-3dB
INPUT
LEVEL
INPUT
LEVEL
SLOW
SLOW
H A N D C R A F T E D I N C A L I FO R N I A U S A
8
1
9
10
ATTACK
FAST
HP SC
VU
FAST
MAX
RECOVERY
GR
FAST
S T E R EO L I M I T E R C O M P R E S S O R
11
Diagram 1
11
12
9
8 13
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.
2
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.
3
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.
4
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.
5
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.
6
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 9 Operational Notes
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3
3. Front Panel
1
2
OUTPUT
3
4
5
6
7
2
THRESHOLD
OUTPUT
THRESHOLD
COMPRESS
1
HIP
LIMIT
MIN
IN
RECOVERY
ATTACK
nu mu
MAX
BYPASS
SLOW
FAST
LINK
SLOW
METER
OUTPUT
+3dB
0dB
-3dB
MIN
+3dB
0 dB
-3dB
INPUT
LEVEL
INPUT
LEVEL
SLOW
SLOW
H A N D C R A F T E D I N C A L I FO R N I A U S A
8
7
9
10
ATTACK
FAST
HP SC
VU
FAST
MAX
RECOVERY
GR
FAST
S T E R EO L I M I T E R C O M P R E S S O R
11
Diagram 1
11
12
9
8 13
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.
8
ATTACK CONTROL
The ATTACK control determines how long the compressor takes to respond to signals above the threshold. 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.
9
RECOVERY CONTROL
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.
10 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.
11 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.
12 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.
13 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.
nu mu
4
4. Rear Panel
7
RIGHT
LEFT
CHANNEL 2
CHANNEL 1
PIN CONNECTIONS
1/4” JACK
MAINS VOLTAGE SHOWN
ON SERIAL TAG
WARNING! : TO REDUCE
THE RISK OF FIRE OR
ELECTRIC SHOCK, DO
NOT EXPOSE THIS UNIT
TO RAIN OR MOISTURE
CAUTION! : RISK OF
ELECTRIC SHOCK. DO
NOT OPEN. REFER
SERVICING TO QUALIFIED
PERSONNEL ONLY.
TIP : SEND
RING : RETURN
SLEEVE : GROUND
XLR
PIN 1: SHIELD/GROUND
PIN 2: POSITIVE PHASE
PIN 3: NEGATIVE PHASE
nu mu
STEREO LIMITER COMPRESSOR
MANLEY LABORATORIES INC.
SERIAL No.
INPUT 2
OUTPUT 2
13880 MAGNOLIA AVE. CHINO, CA 91710
PHONE +1 (909) 627-4256
service@manleylabs.com
www.manley.com
OUTPUT 1
INSERT 2
INSERT 1
6
5
INPUT 1
HAND CRAFTED IN THE USA
2
Diagram 2
4
1
XLR INPUT 1 (TRANSFORMER BALANCED) (CH1, LEFT)
PIN 1: GROUND
PIN 2: (+)
PIN 3: (-)
2
XLR INPUT 2 (TRANSFORMER BALANCED) (CH2, RIGHT)
PIN 1: GROUND
PIN 2: (+)
PIN 3: (-)
3
XLR OUTPUT 1 (IMPEDANCE BALANCED) (CH1, LEFT)
PIN 1: GROUND
PIN 2: (+)
PIN 3: (-)
4
XLR OUTPUT 2 (IMPEDANCE BALANCED) (CH2, RIGHT)
PIN 1: GROUND
PIN 2: (+)
PIN 3: (-)
5
INSERT INPUT CH1, LEFT
3
1
This TRS 1/4” jack interrupts the connection between the PREAMP/COMPRESSOR OR
LIMITER sections, allowing external gear to be inserted into the signal path.
The pinout is TIP: SEND, RING: RETURN, SLEEVE: GROUND.
6
INSERT INPUT CH2, RIGHT
This TRS 1/4” jack interrupts the connection between the PREAMP/COMPRESSOR OR
LIMITER sections, allowing external gear to be inserted into the signal path.
The pinout is TIP: SEND, RING: RETURN, SLEEVE: GROUND.
7
IEC MAINS CONNECTOR
Standard IEC mains connector for 50 /60 Hz AC.
(INPUT MAINS VOLTAGE 90 V AC - 250 V AC)
nu mu
5
7. Operational Notes
The MANLEY NU MU LIMITER / COMPRESSOR is
designed for multiple purposes. The unit can be
used in stereo or as 2 individual channels of
limiting or compression. With higher input gain
settings the unit can be used to create gentle
tube distortion if desired. Modest settings will
often enhance the signal in ways difficult to
describe however the range includes "tube
warmth", richness and enhanced clarity and
magic.
The attack and recovery controls are important
to understand. The response to transients and
percussive sounds are affected by the attack
control. Recovery is the time it takes for the
gain to return to normal or zero reduction. This
is called "RELEASE" on some limiters.
We can use a typical mix with dynamic vocals,
drums and bass for an example. With this
example a fast attack setting will react to the
drums and reduce the overall gain. If the
recovery is very fast then the gain will return to
normal quickly. This will have an audible effect
of reducing some of the level and attack of the
drums in the mix. As the recovery is set slower
the gain changes so that the drums might be
heard as "pumping". Now these gain changes
caused by the drums are pulling down vocals,
some bass and causing volume changes. Slower
recovery settings will usually keep the gain
changes more inaudible but will also lower the
perceived volume.
A slow attack setting will tend to ignore drums
and other fast signals but will react to the
vocals and bass in our example. A slow attack
might also let a hard kick drum transient distort
the next piece of equipment in the chain. We
have set up the unit so that medium settings of
both controls provide good gain control and
little change in mix values.
LIMITING OR COMPRESSION
Two basic rules of thumb with any compressor
or limiter should be reminded. Typical amounts
of gain reduction shown by GR meter should be
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2 to 6 dB. The more that the needle swings the
more likely the gain changes will be audible.
Listen for objectionable "pumping" with fast
settings.
Use your ears to determine optimum settings
more than the meters. Some limiters add
unpleasant artifacts with any reasonable
looking setting. This limiter may give some
magic at unexpected settings. It may help to
use the bypass switch to compare the original
input with the processed output to verify that
an improvement is real. Then, because the
peaks are reduced, the final output can be
adjusted a little louder than the input.
It should be borne in mind that the intended
usage, and function therefore, is very different
between limiting and compression. In limiting
mode we are seeking to control PEAK
overshoots or the 'ceiling' level as inaudibly as
possible, normally in the 2 to 4 dB area. By
using compression we seek to "fold in" a ratio
of, say, 20 or more into 10 dB. Both limiting
and compression can produce the effect of
increasing the average levels and background
noise - depending on the degree or amount of
limiting / compression used. Because dynamic
range and peaks can be reduced, often overall
loudness can be increased at the output. This is
called MAKE-UP GAIN on some compressors and
is simply the OUTPUT ATTENUATOR with this
unit.
Limiters often are designed for very fast attack
times only. This assumes that the unit will
almost always be used to prevent electronic
clipping or overload. Typically the release with
these is slow to prevent audible damage to the
mix.
With this unit you can adjust the attack,
release and even the overload point in musical
ways. Distortion can be creatively used by
turning up the INPUT and turning down the
OUTPUTs while using very little or no
COMPRESSION.
6
7. Operational Notes
HIP CONTROL
The cleanest settings are easiest to set up and
most recommended for mixes. Set the
THRESHOLD near "MIN", set the ATTACK near
"FAST" and adjust the INPUT for 2 to 4 dB of
LIMITING, then adjust the OUTPUTS to reach
the levels you want or by comparing with
BYPASS.
You can fine tune the ATTACK, RECOVERY and
THRESHOLD to taste from this. Compression
with this unit begins at the same threshold so
to achieve similar amounts of gain reduction
you may have to turn up the INPUT or turn the
THRESHOLD to "MIN".
We also suggest while in "LINK" that both
channels are set up the same or similar. LINKing
with one channel in LIMIT and the other in
COMPRESS is not possible.
The gain control chain is technically called a
feedback circuit. Most modern compressors use
a feed foward circuit which sounds unmusical
to us but for features sake usually offers a
Ratio control. Some engineers get great results
from blending the output of the limiter with
the "straight" signal. This trick obviously is
easier to do on individual tracks and sounds like
a very gentle compressor that lifts quiet
sections.
The general goal of compression is to reduce
the overall dynamic range of the signal.
Traditional compression reduces the loudest
sections of the music which can squash the
most exciting transients.
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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) - all while keeping a
constant Manley color/tone to the music since
there is no mixing between the wet and dry
signals through the dynamics of the music.
Users of our Variable Mu often want to just kiss
the sound with a bit of compression while
getting the "Manley Sound", the hip control
makes this easier, when using the Nu Mu.
When the "HIP" control is active, you will want
to adjust the Threshold control so that
compression is active more often than you are
used to. It should release on quieter passages,
but you should see constant compression on
louder passages.
You can also think of the "HIP" control as Safety
or Easy mode - it will keep you from over
compressing the signal, even if the controls
aren't quite set right. You can get the Manley
Sound without excessive compression.
7
6. Advanced Tricks
Here are a few tricks that are not really for rookies.
They come from guys doing major records for years
and won’t work unless you’ve mastered the basics.
In other words if we gave you a Strat and Marshall it
won’t make you another Jimi. Also we don’t suggest
that you try these out while paying big-time studio
rates - they may not be easy to get right at first.
Trick#4
Drive the compressor from an AUX send and return it
to a channel. Once you have some limiting, carefully
turn up that aux send on the return channel to “feed
back” into the limiter. Watch out for real howling
feedback and over the top limiting. If you are lucky it
won’t scream during the quiet parts.
Trick#1
Each compressor or device in the chain has certain
flavors and characteristics and with experience we
grab the ones we like because of the sound - not
because “it is a compressor”. The idea is to use
several cool compressors in a chain getting flavors
from each depending on how much GR (gain
reduction) is used in each and how hard they are
driven. It’s this second concept that can be tricky.
The key is balancing the faders, track auxes, the
return auxes, the thresholds, and make-up gains. The
technique can get pretty crunchy and wild. Works
best with not-so-clean compressors, but is interesting
with the Nu Mu.
How far to turn up each Make-up Gain to overdrive
or not overdrive the next unit - and still not get
flooded with noise when the music stops. You can
chain the two channels of the Nu Mu and turn up the
make-up of the first channel. This works best with
classic discrete and tube units and usually IC units
are to be avoided.
The finesse comes from which order they are
patched. See how long it might take to get best
results.
Trick#2
This one is easier, but also requires serious listening.
Rather than just “inserting” a limiter, try driving the
limiter from the tape patch (pre EQ), returning it to
a spare fader and mixing it with the original.
So what is so tricky ? How you EQ and automate and
add effects to these channels. You can also have fun
phase reversing one of the channels. You get
cancellation but only at a certain level. It is sort of
like gating, but different - it is a way of controlling
the “ambiance”.
Trick#3
Using one track to “duck” another. This may work
better with compressors with attack and release and
ratio controls if you are thinking drums. Bass and
vocal is very cool with the Nu Mu. Set it up like
trick#2 with bass in one channel and vocal in the
other (in LINK mode) and experiment with each
threshold.
Two guitar tracks also work here sometimes.
Obviously, we pull out this trick when two tracks are
stepping on each other and EQ isn’t making enough
room for clarity.
nu mu
Trick#5
This one is a way to get a very good single channel
De-esser from the Nu Mu or other compressor good
enough for lead vocals. Split the Insert send of the
vocal to the Nu Mu and to a spare channel. EQ the
snot out of that second channel -boosting the 5 or 6
kHz band and chopping everything below that.
Use the insert from this channel to drive the other
channel of the Nu Mu, but it is unlikely that you want
this fader up. Set the Nu Mu to Link. The threshold of
the first channel sets compression and the second
channel sets de-essing.
Unlike some de-essers it will not chop highs, but
reduce wide-band which is less obvious. The only
drag is that the release is a little slow. Remember
good de-essing is not to remove esses - the idea is to
reduce esses and make them natural sounding.
BTW if you need to de-ess, you might want to rethink your choice of gear. There are 3 main reasons
we get horrible esses:
1) a gap in the singer’s teeth or just a strange voice,
2) too much or wrongly chosen EQ, or,
3) gear that distorts the highs.
If the cause is “1”, try sticking some dental wax in
the gap. No joke! If the cause is “2” then we can tell
you some EQs allow one to boost highs with less
problems with the esses or you might try boosting a
higher freq, or less during tracking. If it is “3” you
may want a better mic or sell off some of that cheap
IC gear that seems to be distorting the top in a way
that you don’t like.
Actually we have heard some pretty expensive gear both tube and solid state - that has this particularly
ugly distortion. If in doubt, try some tough percussion
through it like shakers or tambourines, and see how
they sound...
8
7. Questions & Troubleshooting
Q: No Power, No Indicators ?
Ensure the IEC plug at the rear of the unit is inserted all
the way. Wait at least five minutes before trying the power
switch again. If the unit does not power up then check the
fuse on the PSU. (See Servicing, Diagram 3)
Q: The Unit Is Switched On, No Sound ?
First try plugging the IN and OUT cables into some other
piece of gear to verify that your cables are OK. Next check
the front panel, try BYPASS. If you have sound now it might
be a good idea to turn up the output levels to about 1
o’clock (rather than fully counterclockwise which is “minus
infinity”.
Q: Levels Seem To Be Wrong, No Bottom ?
Several possible scenarios. Manley uses the professional
standard of +4 dBm = Zero VU = 1.23 volts AC RMS. A lot of
semi-pro gear uses the hi-fi reference of -10 dBm = Zero
VU. This is a 14 dB difference that will certainly look odd
and may tend to distort. Often there are switches on semipro gear to choose the pro reference level. We do not
provide that kind of switch because of inevitable
compromises in the signal path. If the loss looks close to 6
dB and it sounds thin then one half of the signal is lost. The
cause is probably wiring again. One of the two signal
carrying wires (the third is ground / shield on pin 1) is not
happening. Check the cables carefully because occasionally
a cable gets modified to work with a certain unit and it
seems to work but its wrong in other situations. If only one
side of the Nu Mu exhibits this problem, it may be a
problem in the unit itself.
!
Q: Only One Channel Is Functioning ?
This may be due to a faulty tube. Most Manley gear is two
channel, meaning you can swap tubes to determine the
faulty tube. Switch one pair at a time. VT1 & VT2, VT3 &
VT4 are matched pairs.Leave the unit switched off for at
least 15 minutes before removing any covers. If upon
examination you see a white topped tube instead of a
silver top this tube is likely to have cracked its glass
envelope, fracturing the vacuum, this tube will need to be
replaced.
Q: How Can I Cure Low Frequency Hum?
Method 1- The most likely cause is a ground loop. This can
be cured by lifting the chassis to signal ground lift jumpers
which are located inside the unit. Please refer to the
Servicing Chapter, Diagram 3.
Method 2 - Cutting the shield on one side of the cable (PIN
1). This is done by some studios at every female XLR to
“break” all loops. You may get a loop simply from the
rack. All the other gear in the rack is “dumping” ground
noise onto the rack rails. Try removing the Nu Mu from the
rack so that it is not touching any metal. You may have
cured a non-loop hum. Some gear radiates a magnetic field
and some gear (especially if it has transformers) might
receive that hum.
nu mu
Method 3 -Another method of reducing all sorts of hum and
noise is to use a 60-0-60 balanced AC power transformer.
Hum is more likely with the unbalanced inputs and outputs
because these signals are ground referenced. A common
situation is using the Nu Mu in a way that significantly
boosts the low level signals and what may have started out
as a little hum becomes nasty. Check out the gear feeding
the Nu Mu or use less limiting and make-up gain.
Q: Why is my Nu Mu Not Completing its Power-Up Cycle?
The Nu Mu utilizes a custom designed, sophisticated high
voltage switched-mode power supply. This power supply
features protection circuitry to stop any damage being
caused to itself. If at anytime the unit will not power-up
the protection circuitry may have been triggered. It is in
protection mode if after switch-on the power LED blinks for
a fraction of second then after a pause it blinks again. The
PSU is now in protection mode as the supply is trying to
reset. This condition will occur if the unit suffers excessive
heat exposure or there is a damaged tube or component.
Allow the unit to cool and try powering-up again. If the
protection mode persists, the unit will have to be returned
for service.
Q: Nu Mu Makes Noises When The Front Panel Is Tapped?
Some tubes become microphonic over time. That means
they start acting like a bad microphone. Vibration and aging
has caused the supports for the small internal parts in the
tube to loosen and now the tube is sensitive to vibration.
The only remedy is to replace the tube.
Q: I am Hearing a lot of Hiss?
This is again a common tube symptom. You could swap
tubes to find the culprit but an educated guess is OK too.
Generally the first tube in the path is the one with the most
gain and dealing with the softest signals. VT1 (5751) is the
first tube in the signal path. (See Servicing Chapter,
Diagram 3)
Q: Nu Mu Sounds Distorted?
This might be a tube. Swapping is a good way to find out. It
may be a wiring issue or mismatch. Wiring problems usually
accompany the distortion with a major loss of signal.
Mismatches are a bit tougher. The Nu Mu has a high input
impedance (HI Z) but some of our gear has a reasonably low
input impedance. Without even explaining the term
“impedance” it is enough to say that a lot of gear is simply
not capable of driving pro levels and low impedances. It will
sound like lost headroom, early clipping, distortion on
peaks. Often changing the order of processors will do the
trick. Also check your patch bay in case there is a problem
there too.
9
9. Servicing
1
2
P3
6BA6
RIGHT
6BA6
LEFT
VT1
VT2
VT3
VT4
1
2
KEY
Chassis Ground Lift
PSU FUSE 2A(T)
Diagram 3
VACUUM TUBES
The Nu Mu utilizes two 6BA6 tubes per channel, which are hand matched at the factory. The life
span of these tubes is in the order of 5000-6000 hours, after which time the tubes should be
replaced. If the Nu Mu has become noisy, this could be related to tube wear. Consult your dealer or
purchase new tubes from Manley Labs. We suggest low noise and graded quality. Simply hold the
tube firmly at its base and vertically pull upwards, freeing the tube from its socket. When inserting
a new tube ensure all the pins are straight and align with the receptacles of the tube base before
pressing down firmly to locate the tube correctly. In most cases the unit will require calibration
after a tube change. Consult the Manley website or contact us for the calibration procedure required
after a tube change.
1
GROUND LIFT JUMPER
If necessary the Circuit Ground can be disconnected from the Chassis Ground. This practice is usually
required if hum-loops cannot be cured in any other way. Removing both jumpers JP6 will break the
chassis signal ground.
2 PSU FUSE
The PSU fuse is a safety fuse rated at 2A (T) 250V AC. If this fuse fails the switched-mode PSU has
suffered a catastrophic failure and it is unlikely that it can be repaired. The unit will have to be
returned for service.
nu mu
10
10. Specifications
MANLEY Nu Mu STEREO ELECTRO-OPTICAL VACUUM TUBE LIMITER / COMPRESSOR
Ÿ Fully differential front end, with Manley IRON input transformers
Ÿ All tube audio path, with 2 pairs of hand matched 6BA6's vacuum tubes per channel.
Ÿ New solid state output stage. High voltage, discrete transistor design with high headroom for a smooth,
punchy and dynamic action
Ÿ Hard-wire BYPASS switch
Ÿ Transformer BALANCED INPUTS.
Ÿ Impedance BALANCED OUTPUTS.
Ÿ INPUT LEVEL switch: -3dB, 0dB, +3dB
Ÿ Silent Conductive Plastic, continuously variable OUTPUT controls.
Ÿ MIN: -40dB~11 O'clock: 0dB (+/- 1 indent mark)MAX: +10dB
Ÿ RECOVERY 5 steps switch:
Ÿ 63% gain reduction recovery: 0.1s, 0.16, 0.32, 0.64s, 1.7s.
Ÿ 30% gain reduction recovery: 0.227s, 0.368s, 0.736s, 1.6s, 3.87s.
Ÿ Continuously variable ATTACK control:
Ÿ 63% gain reduction: SLOW 0.13s, MID 0.07s, FAST 0.013s.
Ÿ 90% gain reduction: SLOW 0.64s, MID 0.35s, FAST 0.064s.
Ÿ Continuously variable THRESHOLD control.
Ÿ LIMIT/COMPRESS Mode switch.
Ÿ LIMIT (1.5:1 to 12:1) or COMPRESS (1.2:1 to 3:1)
Ÿ HP Side Chain Filter: 6dB per octave, approximately -3dB at 100Hz.
Ÿ STEREO LINK SWITCH Left Channel Master. Links threshold, attack & recovery controls.
Ÿ HIP control function: Raises soft dynamics without squashing louder passages
Ÿ Large Illuminated Stereo VU meters. Reads Output level or Gain reduction.
Ÿ Sidechain INSERT: Insert point for limiter/compressor sidechain. Two Stereo Phone Jacks
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
nu mu
Ÿ
(TIP= Send, RING= Return, SLEEVE= ground)
For Unity Gain set: Input level switch to “0” and, Output control to ~11: O'clock. (Input source Z= 150 Ohms
Output load Z= 100k Ohms)
Maximum Input level: (1 kHz Sine, <0.3% THD+N)
Ÿ -3= +25 dBu
Ÿ 0 = +21 dBu
Ÿ +3= +18 dBu
Maximum gain: 13dB
Gain Make-Up: 10dB (gain above unity)
Output Headroom: 23dB (Reference to +4dBu)
Maximum output: +27dBu (18Vrms) 100K Ohm load, +24.5dBu (13Vrms) 600 Ohm load. (1kHz Sine, < 0.3%
THD+N, BW 20Hz- 20kHz).
Frequency Response: - 0.8dB @ 20Hz, -0.5dB @ 50kHz
Total Harmonic Distortion: <0.05% THD+N (1kHz Sine, +4dBu, BW: 20Hz - 22kHz)
Noise floor: -85dB typical (BW: 20Hz - 22kHz)
Dynamic Range: 112dB
Signal to Noise Ratio: 89dB (referenced to +4dBu, BW 20Hz – 20kHz)
Common-Mode Rejection Ratio (CMRR): 74dB (BW: 20Hz - 22kHz, +4dBu, 1kHz Sine)
Output Impedance: 100 Ohms
Input Impedance: -3= 1k, 0= 2.5k, +3= 4.5k Ohms
Sidechain Insert: Send output Z= 50 Ohms, Return Input Z= 50k Ohms
“Warm-Up” mute timer: ~30 Seconds
Universal high voltage switched mode power supply custom designed for our vacuum tube audio circuits.
Mains Voltage & Frequency: Operates worldwide 90-250V~ AC 50/60 Hz.
Power Consumption (120/240VAC): 25 Watts
Standby power on switch.
Standby Power Consumption (120/240VAC): 0.5W
11
nu mu
FAST
SLOW
RECOVERY
FAST
MAX
INPUT
LEVEL
FAST
SLOW
RECOVERY
FAST
MAX
INPUT
LEVEL
MIC NOTES
+3dB
0dB
-3dB
SONG
LINK
BYPASS
IN
LIMIT
COMPRESS
INSTRUMENT / TRACK
H A N D C R A F T E D I N C A L I FO R N I A U S A
SLOW
ATTACK
MIN
THRESHOLD
ARTIST
nu mu
OUTPUT
MIC NOTES
+3dB
0dB
-3dB
SONG
LINK
BYPASS
IN
LIMIT
COMPRESS
INSTRUMENT / TRACK
H A N D C R A F T E D I N C A L I FO R N I A U S A
SLOW
ATTACK
MIN
THRESHOLD
ARTIST
nu mu
OUTPUT
VU
VU
INPUT
LEVEL
INPUT
LEVEL
+3dB
0 dB
-3dB
+3dB
0 dB
-3dB
HP SC
GR
METER
OUTPUT
HIP
HP SC
GR
METER
OUTPUT
HIP
SLOW
RECOVERY
FAST
MAX
SLOW
ATTACK
OUTPUT
FAST
MAX
SLOW
ATTACK
OUTPUT
ENGINEER
DATE
S T E R EO L I M I T E R C O M P R E S S O R
RECOVERY
THRESHOLD
ENGINEER
DATE
S T E R EO L I M I T E R C O M P R E S S O R
MIN
SLOW
MIN
THRESHOLD
FAST
FAST
11. Recall Sheet
12
OUTPUT
THRESHOLD
COMPRESS
LIMIT
MIN
IN
RECOVERY
ATTACK
nu mu
MAX
BYPASS
SLOW
+3dB
0dB
-3dB
FAST
LINK
SLOW
INPUT
LEVEL
VU
FAST
H A N D C R A F T E D I N C A L I FO R N I A U S A
Designed & Hand Crafted in the USA
Manley Laboratories, Inc.
13880 Magnolia Avenue
Chino, CA 91710 USA
T: +1 (909) 627-4256
www.manley.com
PIN CONNECTIONS
MAINS VOLTAGE SHOWN ON
SERIAL TAG WARNING! : TO
REDUCE THE RISK OF FIRE OR
ELECTRIC SHOCK, DO NOT
EXPOSE THIS UNIT TO RAIN
OR MOISTURE CAUTION! :
RISK OF
ELECTRIC SHOCK. DO NOT
OPEN. REFER SERVICING TO
QUALIFIED PERSONNEL ONLY.
1/4” JACK
TIP : SEND
RING : RETURN
SLEEVE : GROUND
XLR
PIN 1: SHIELD/GROUND
PIN 2: POSITIVE PHASE
PIN 3: NEGATIVE PHASE
nu mu
STEREO LIMITER COMPRESSOR
MANLEY LABORATORIES INC.
SERIAL No.
13880 MAGNOLIA AVE. CHINO, CA 91710
PHONE +1 (909) 627-4256
service@manleylabs.com
www.manley.com
HAND CRAFTED IN THE USA
Rev. 1.0 ZF 2016
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