Manley Laboratories Stereo Limcom, Variable Mu Limiter Owners manual

MANLEY

LABORATORIES, INC.

OWNER'S MANUAL

STEREO "VARIABLE-MU"

LIMITER / COMPRESSOR

MANLEY LABORATORIES, INC.

13880 MAGNOLIA AVE.

CHINO, CA. 91710
TEL: [phone]
FAX: [phone]

email: [e-mail]

http://www.manleylabs.com

CONTENTS

SECTION PAGE

INTRODUCTION 3

MAINS CONNECTIONS 4

INSTALLATION 5

FRONT PANEL 6

REAR PANEL 7

EXAMPLE SETTINGS 8

FRONT PANEL ADJUSTMENTS 9

OPERATIONAL NOTES 10

TECHNICAL NOTES 11

MASTERING AND M/S MODELS 12

GAIN REDUCTION CURVES 13

SPECIFICATIONS 14

SERVICE ADJUSTMENTS 15

WARRANTY 16

WARRANTY REGISTRATION 17

BLANK TEMPLATE TO STORE SETTINGS 18

INTRODUCTION

THANK YOU!...

for choosing the Manley Laboratories Stereo Variable-MU Limiter Compressor . The
heart of this limiter is the variable gain vacuum tube. In tube-talk MU refers to gain
and only a few types of tubes were ever designed for variable-mu operation. This
limiting circuitry was designed by David Manley over thirty years ago. Our current
version of this unique piece combines that classic sound with the precise cleanliness
of modern componentry. The circuit is entirely differential which tends to cancel
distortion and hum. It can handle a widely varying range of input signals in a rapid­acting manner without introducing audible coloration common in many limiters. The
Attack and Recovery (Release) times have been carefully chosen for todays
applications. These properties make this a superb compressor for both individual
tracks, mixes and final mastering.

GENERAL NOTES

LOCATION & VENTILATION

The Limiter Compressor Amplifier must be installed in a stable location with ample
ventilation. It is recommended, if this unit is rack mounted, that you allow enough
clearance on the top and bottom of the unit such that constant movement of air can
flow through the ventilation holes. There are 8 tubes inside this unit so it does run
quite hot. Good ventilation is definitely encouraged.

WATER & MOISTURE

As with any electrical equipment, this unit should not be used near water or
moisture.

SPECIAL NOTES

Tubes may become loose during transit. Straighten and press down each tube before
plugging this unit into the mains socket. Furthermore, don't touch the tubes after the
unit has been switched on, the tubes become very hot during operation and should
only be handled after the power has been turned off and the tubes have cooled.

WARNING!

TO PREVENT THE RISK OF ELECTRIC SHOCK

DO NOT OPEN THE CABINET

REFER SERVICING TO

QUALIFIED PERSONNEL

!

MAINS CONNECTIONS

TROUBLESHOOTING NOTE: Occasionally we have had units sent to us to service that had no problem. The

symtom was clipping only when the unit was in the processing chain. Remove the unit and distortion
gone. However in the shop - no problem. The cause was a combination of the somewhat low input
impedance of the Limiter/Compressor and the somewhat "wimpy" line driver of the preceding device.
The solution - change the order of processing so that a more professional device fed the Limiter /
Compressor. The input impedance is over 1.2 Kohm and most devices are supposed to drive 600 ohms

(which is twice as hard) but in this era of ICs and semi-pro gear claiming to be pro well.......

Your unit has been factory set to the correct mains voltage for your country. The
voltage setting is marked on the serial badge, located on the rear panel. Check that
this complies with your local supply.

Export units for certain markets have a moulded mains plug fitted to comply with
local requirements. If your unit does not have a plug fitted the coloured wires should
be connected to the appropriate plug terminals in accordance with the following code.

GREEN/YELLOW EARTH terminal
BLUE NEUTRAL terminal
BROWN LIVE terminal

As the colours of the wires in the mains lead may not correspond with the coloured
marking identifying the terminals in your plug proceed as follows;

The wire which is coloured GREEN/YELLOW must be connected to the terminal in
the plug which is marked by the letter E or by the safety earth symbol or coloured
GREEN or GREEN and YELLOW.

The wire which is coloured BLUE must be connected to the terminal in the plug which
is marked by the letter N or coloured BLACK.

The wire which is coloured BROWN must be connected to the terminal in the plug
which is marked by the letter L or coloured RED.

DO NOT CONNECT/SWITCH ON THE MAINS SUPPLY UNTIL ALL OTHER
CONNECTIONS HAVE BEEN MADE.

INSTALLATION

5

Please refer to the REAR PANEL section for a full layout of the rear panel of your
Stereo limiter compressor.

1. Set the voltage change-over switch on the back of the unit to the voltage you
are using.

2. Be certain that the unit has a 2 Amp SLO-BLO (120 Volt operation) or 1 Amp
SLO-BLO (for 240/220 Volt use) fuse.

3. Connect the input signal(s) to the 3 pin female XLR's on the rear panel. The
input XLR's are TRANSFORMER COUPLED balanced wired as follows:

PIN 1: GROUND
PIN 2: (+) POSITIVE GOING PHASE
PIN 3: ( - ) NEGATIVE GOING PHASE

4. Connect a 3 pin XLR cable to the male output XLR on the rear panel. The
output XLR is balanced and the pinout is wired as follows:

PIN 1: GROUND
PIN 2: (+) POSITIVE GOING PHASE
PIN 3: ( - ) NEGATIVE GOING PHASE

The output impedance is 600 Ohms nominal.

5. Connect a standard IEC mains cable to the IEC mains socket on the rear
panel.

6. Check that the power is switched off on the unit.

7. Connect the IEC mains cable to a 50/60 Hz AC source of the proper selected
voltage.

8. Power up the unit and allow it enough time to stabilize before using (approx
15 to 30 minutes).

METER

ADJUST

ATTACK

OUTPUT

THRESHOLD

RECOVERY

COMPRESS

LIMIT

BALANCE

BYPASS

IN

FRONT PANEL

A IN / BYPASS Switched in bypass mode, (down position) all effects of the limiting circuitry are

bypassed and will not affect the audio signal. In the bypass mode , the audio
signal passes from the input directly to the output.

B. COMP. / LIMIT Selects compression ( 1.5:1) or limiting (4:1) function. Compression is soft -knee,

Limit is a sharper knee. At greater than 12dB of limiting the ratio increases (up to
20:1 maximum)

C. RECOVERY Recovery times can be selected between

a. VERY SLOW 8 seconds
b. SLOW 4 seconds
c. MEDIUM .6 seconds
d. FAST .4 second
e. VERY FAST .2 second

D. THRESHOLD Continuously variable gain reduction threshold control.

Determines the necessary amplitude for compression or limiting to take effect.
Most extreme effect is at the MIN (fully counter clockwise) position. The lower
the threshold, the more that gets limited.

E. OUTPUT ATTENUATE Continuously variable attenuation of output signal leaving the amplifier circuitry.

Full attenuation occurs at the full counterclockwise position.
This control is active only in IN mode.

F. ATTACK Continuously variable sensitivity of transient detection. Determines the necessary

length of transient to initiate gain reduction. Fast =25mS, Med =50mS, Slow
=70mS.
Fully counter clockwise at the slowest setting will prevent most percussive
signals from causing limiting or compression.

G. DUAL INPUT Continuously variable attenuation of input signal entering the amplifier limiting

circuitry
Full attenuation occurs at the fully counterclockwise position.
This control is active only in IN mode.

I. LINK When switched to "SEP" left side is independent from the right side. When

switched to "LINK"
both channels are reduced in gain by the same number of dB. This insures that
the stereo image is unchanged. The METERs remain independent to help set
THRESHOLDs.

I. POWER ON/OFF Power is supplied to the unit when switched UP. Meters will illuminate

H. GR METER Measures in decibels amount of reduction

6

8

10

12

MANLEY

LABORATORIES INC.

REDUCTION dB

IN

BYPASS BALANCE

4

2

ADJUST METER

0

MANLEYSTEREO "VARIABLE-MU" LIMITER COMPRESSOR

LIMIT

COMPRESS

RECOVERY

SLOW FAST

THRESHOLD

MIN MAX

OUTPUT

ATTACK

SLOW FAST

DUAL INPUT

SEP LINK

POWER

FASTSLOW

MAXMINFASTSLOW

A H B C D E F G H I E F C D B H A

10

12

MANLEY

LABORATORIES INC.

REDUCTION dB

6

8

4

2

0