Manley Langevin Dual Vocal Combo User Manual

OWNER'S MANUAL

LANGEVIN

DUAL VOCAL COMBO

MANLEY

LABORATORIES, INC.

MANUFACTURED BY:

MANLEY LABORATORIES, INC.

13880 MAGNOLIA AVE.

CHINO, CA. 91710 USA

TEL: [phone]
FAX: [phone]

email:[e-mail]

http://www.manleylabs.com

REV. 5-01-01; "P" SUFFIX

CONTENTS

SECTION PAGE

INTRODUCTION 3

FRONT PANEL 4, 5

BACK PANEL 6

MIC PRE BASICS 7

CONNECTING YOUR PREAMPLIFIER 8, 9

OPERATION NOTES 10, 11

SPECIFICATIONS 12

TROUBLESHOOTING 13, 14

INTERNAL ADJUSTMENTS 15

INTERNAL LAYOUT 16

REPLACING FUSES 17

MAINS CONNECTIONS 18

WARRANTY 19

WARRANTY REGISTRATION 20

APPENDIX A: WIRING YOUR OWN CABLES 21

APPENDIX B: TEMPLATE FOR STORING SETTINGS 22

INTRODUCTION

THANK YOU!...

for choosing the Langevin Dual Vocal Combo. Manley Labs bought all the rights to the Langevin
name and circuits in 1992. Manley uses the Langevin name for its solid state products including
versions of an all discrete Pultec and Electro-Optical Limiter, and Mic Preamp.

The Dual Vocal Combo is the result of a suggestion to combine the "Langevin Dual Mono
Microphone Preamplifier with EQ" with the "Langevin Dual-Channel Electro-Optical Limiter" for
a competitively priced stereo or 2 channel VoxBox-like product. Both the mic preamp and the
Langevin EL-OP are recognised as great values and serious high performance all-discrete professional
units. While the combination is not quite a "solid state VoxBox" because it doesn't have some of the
compressor & EQ functions and no de-esser, it is 2 channels of the "essentials" for half the price.

The "Combo" is 100% discrete transistor in the signal path and there are no op-amps except to drive
the LEDs in the Opto circuit, and the Meter circuit. Negative feedback is minimal, only one
transformer (mic input) per channel and much of the components are the same as in the Manley tube
gear. While we were planning this unit we upgraded the front panel Instrument Inputs for higher input
impedance (150K ohms) and higher gain (25 dB more) so virtually all guitars, bassers and synths and
drum machines could be recorded direct-to-tape comfortably.

Thank you again, and please enjoy!

WATER & MOISTURE

As with any electrical equipment, this equipment should not be used near water or moisture. If liquid
enters the preamplifier, it must be immediately returned to your dealer for servicing.

SERVICING

The user should not attempt to service this unit beyond that described in the owner's manual. Refer
all servicing to Manley Laboratories.

WARNING!

!

TO PREVENT THE RISK OF ELECTRIC SHOCK

DO NOT OPEN THE CABINET

REFER SERVICING TO

QUALIFIED PERSONEL

3

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

OFF

POWER

ON

IN

BYPASS

INPUT

H.F.

L.F.

12 KHz

EQ IN

Hz

Hz

EQ IN

12 KHz

L.F.

H.F.

INPUT

Hz

ATTENUAT

KHz

+10

+10

PHANTOM

+10

+10

KHz

Hz

ATTENUAT

REDUCTIO

GAI

METER

OUTPUT

REDUCTION

METER

OUTPUT

REDUCTIO

REDUCTIO

GAI

LINK

SEP

DIRECT

INPUT

DIRECT

INPUT

by Manley Laboratories Inc.

(PULLON)

(PULLON)

PHANTOM

LIMITER

DUAL VOCAL COMBO

EQ OUT

EQ OUT

BYPASS

IN

INPUT

8080Hz

EQ IN

L.F.

12 KHz

H.F.

(PULLON)

PHANTOM

POWER

OFF

ON

PHANTOM

(PULLON)

8080Hz

L.F.

EQ IN

H.F.

12 KHz

INPUT

ATTENUAT

E

DIRECT

INPUT

by Manley Laboratories Inc.

4040Hz

IN

BYPASS

EQ OUT

REDUCTIO

-1-10 +10

NGAI

OUTPUT

REDUCTIO

METER

8 KHz

DUAL VOCAL COMBO

SEP

LINK

N

LIMITER

4040Hz

OUTPUT

REDUCTION

+10

-1-10

N

-1-10 +10

REDUCTIO

EQ OUT

N GAI

+10

-1-10

8 KHz

ATTENUAT

E

IN

BYPASS

DIRECT

INPUT

NMETER

J K L M N O P 0 N M L K J

The Dual Vocal Combo has 2 channels which are mirror images of each other and is further divided into top
and bottom sections which correspond to the Mic Pre with EQ and the Opto-Limiter Sections. Don't let the
mirror image aspect confuse you!

A) INPUT ATTENUATE. This is the basic GAIN control which can also be considered MIC GAIN or INPUT
LEVEL. The range is from "off" to 50 dB of gain. Don't be afraid of turning this knob as loud as is needed. It is
the first component (other than the mic transformer) in the signal path so exceptionally loud signals can be
attenuated enough to prevent clipping in almost all situations.

B) 80 Hz / 40 Hz. Sets the corner frequency for the L.F (Low Frequency) Shelf EQ. Mostly frequencies below
the setting get affected but the gentle slope means that some frequencies higher than the corner also get
boosted or cut.

C) L.F. How much boost or cut is applied to the lows. The range is from -10 dB to +10 dB. It is intended as a
safe, smooth basic tone control and not as a comprehensive 'do everything' EQ but is very effective at
compensating for the proximity effect from Cardioid pattern mics.

D) EQ IN / EQ OUT. EQ OUT Bypasses the EQ stage and EQ IN allows boosting and cutting.

E) H.F. How much boost or cut is applied to the highs. The range is from -10 dB to +10 dB. Also intended as
a safe, smooth basic tone control and very effective for adding that 'air' or 'sparkle' when needed.

F) 12kHz / 8 kHz. Sets the corner frequency for the H.F (Low Frequency) Shelf EQ. Mostly frequencies above
these points get boosted or cut but some effect is still heard below these points. Watch out for sibilance
problems.

G) PHANTOM POWER. Puts 48 volts on the mic XLR connector to power certain mics. The LEDS (H) next to
the switches will glow when PHANTOM power is ON. THIS SWITCH MUST BE PULLED TO TOGGLE.This
is to prevent accidents like blowing your speakers. ALWAYS turn down the INPUT ATTENUATE before
hitting this switch. Mic signals are typically one hundredth of a volt and phantom is 48 volts so expect it to
POP unless the INPUT is turned down. The big POP can also happen if you change a mic, mic cable, mic
patch, etc. Turning down the monitors, headphone levels, etc is the alternative but get into the habit of turning
it down with mics even when you aren't using Phantom. Also note that if you have slightly intermittant or dirty
connectors in the mic path, that noises will be far worse.

Phantom power is only required for solid state condensor mics and not dynamic mics, tube mics and
especially not for old ribbon mics. Some vintage ribbon mics can be damaged with Phantom. FET condensor
mics will generally be silent without phantom. With most mics, phantom power will have no effect, not make
them sound worse, unless there are dirty connectors.

I) POWER ON / OFF. When power is turned ON the VU Meters will glow. If not, then make sure the power
cable is plugged in or the fuse has not blown.

4

J) DIRECT INPUT. This is for plugging in an electric guitar, bass, synth, etc into the Dual Vocal Combo. The
input impedance is high (150 kOhms) appropriate for these instruments and there should be plenty of gain
available. Electric guitars and basses may need a fair amount of H.F. Boost to sound comparable to an amp
because there happens to be a lot of H.F. boost going on in the innards of most amps. A jack plugged into
this input will interrupt the normal mic XLR input.

OPTO-LIMITER SECTIONS

K) IN / BYPASS. BYPASS turns off the limiter and its controls. IN allows limiting or levelling. This should be
the most used control on the limiter. Always compare the original sound to the sound after the limiter to verify
you are not accidentally over-squashing. Remember that sound is compised of pitch, duration and volume or
dynamics. The point is not to throw away one element (dynamics) just tame it and control it as needed.

L) GAIN. This is the 'Make-up Gain' after the limiter. It is usually set so that there is no volume change when
switching IN / BYPASS to allow easy A/B comparisons OR as the final output level to optimise how hard the
signal is hitting tape or to optimise the level to an A to D convertor.

M) REDUCTION. This sets the THRESHOLD of limiting and the amount of limiting. Turning it clockwise,
creates deeper limiting. We generally advise that 4 to 6 dB of limiting (levelling) is fine for vocals and most
individual intruments and 1 to 3 dB is good for percussive sounds and mixes. Too much limiting on a mix will
usually first make the drums quieter which is not generally desirable. The amount one should 'level' vocals
depends mostly on the singer's technique and talent, the musical style and the thickness of the arrangement.
Sometimes with very dynamic vocals, loud dense tracks and a mix that is not vocal forward significantly more
levelling might be needed. We have heard of people using 10 to 12 dB of vocal limiting with good results but a
bunch more extra care will be needed. In the pauses between lines, the gain will rise that 10 or 12 dB along
with headphone leakage, air conditioning rumble, throat noises, etc. Don't forget that if you are like many
engineers, you will be limiting the vocal again in the mix, so don't feel you have to do all the limiting during the
recording - play it safe. There is no Un-Do button, and the alternative is the dreaded Re-Do. Questionble EQ,
you can fix, over limiting is very difficult to fix later.

N) METER OUTPUT / REDUCTION. This switch is for the VU meters. In METER OUTPUT, the VU's show
the final output level like most VU meters. In REDUCTION mode the meters show how much limiting is
occurring in dBs. Because VU meters are not lightning-fast, you may not see all the limiting that is actually
happening with fast transient sounds.

O) VU METERS. These are smaller versions of standard Sifam VU meters. It is worth pointing out that VU
meters were always intended to correspond to apparent 'volume' similar to how our ears work and are not like
the 'peak' meters you have on your digital recorders. VU meters work great for analog tape, but for digital use
the 'LED ladders' on your A to D or digital machine. The meters should glow when power is on.

P) SEP / LINK. This switch allows the 2 limiters to act independently (SEPARATE) or to 'track' together in
LINK mode. SEP is used if each channel has different types of sounds going through it. LINK is used for
stereo sounds. When limiters or compressors are linked and a loud signal on one side forces limiting then,
both limiters pull down the same amount of dBs. This is so that the center image doesn't tug one direction
then the other, which is a bit distracting and wrong sounding. With this unit, set up BOTH channels for normal
limiting then switch to LINK. Some limiter compressors just use the just left channel controls in LINK mode
and while convenient is not really the right way. Those limiters "mono" the audio that controls the limiting
which gives excess limiting for sounds in the center and no limiting for out-of phase sounds, meanwhile peaks
in either channel can overload the A to D. The Langevin and Manley units combine the control voltages rather
than the audio and provide a more useful limiting function but not quite as conveniently.

5

IN

IN

CHASSI

GROUND

CIRCUI

CHANNEL 1

- R

SERIAL NUMBER

N9512423

OUT

OUT

UNBALANCED

ONLY

MIC IN

FAX

BALANCED

LINE OUT

PREAMP OUT

LIMITER

EXPOSE THIS

ISK OF ELECTRIC

AN

[phone]

TO REDUCE THE RISK OF ELECTRIC

SHOCK DO NOT

EQUIPMENT TO RAIN OR MOISTURE

POWER

CAUTION

SHOCK. DO NOT OPEN.

REFER SERVICING TO QUALIFIE

PERSONNEL ONL

EVEANNA MANLEY PRODUCTION

MANLEY LABORATORIES

13880 MAGNOLIA AVE., CHINO, CA 91710

PHONE [phone]

email: [e-mail]

REPLACE FUSE

WITH SAME

TYPE AND

RATIN

BALANCED

OUT

UNBALANCED

ONLY

LINE OUT

MIC IN

CHANNEL 2

PREAMP OUT

LIMITER

ONLY

BALANCED

LINE OUT

MIC IN

CHANNEL 1

A

B

PREAMP OUT

LIMITER

BALANCED

MIC IN

IN

CHANNEL 2

LINE OUT

OUT

UNBALANCED

ONLY

REPLACE FUSE

WITH SAME

TYPE AND

G

RATIN

AN

EVEANNA MANLEY PRODUCTION

MANLEY LABORATORIES

13880 MAGNOLIA AVE., CHINO, CA 91710

PHONE [phone]

POWER

FAX

-R

ISK OF ELECTRIC

SHOCK. DO NOT OPEN.

PERSONNEL ONL

EXPOSE THIS

[phone]

Y

email: [e-mail]

CAUTION

REFER SERVICING TO QUALIFIE

TO REDUCE THE RISK OF ELECTRIC

SHOCK DO NOT

EQUIPMENT TO RAIN OR MOISTURE

UNBALANCED

N9512423

m

CIRCUI

GROUND

STCHASSI

D

SERIAL NUMBER

C D E F G H E D C

A) PREAMP OUT. This balanced output comes directly from the mike pre and allows you to use the mike pre
separate from the limiter. Inserting a TRS plug into this jack breaks the normal signal path between the mike
pre output and the limiter input. TIP= +, hot or positive going signal

RING= -, or negative going signal

SLEEVE= Ground (shield)

B) LIMITER IN. This balanced input allows you to insert a signal directly into the opto-limiter, bypassing the
mike pre and EQ. Utilizing the PREAMP OUT and LIMITER IN jacks with a patch bay allows the mike pre
and limiter sections to be used independently or linked externally. With no plugs inserted in either of these
jacks, the mike pre and opto-limiter sections are automatically linked together.

C) MIC IN. This is where you plug in the mic cable. Because this input has up to 50 dB of gain and can have
Phantom power, we strongly suggest that the INPUT ATTENUATE and/or monitor level is turned way down to
avoid huge pops or thumps when you plug a cable in here.

Pin 1 = Ground (shield)
Pin 2 = +, hot or positive going signal
Pin 3 = -, low or negative going signal

PREAMP OUT

LIMITER

IN

D) BALANCED LINE OUT. This is the final output after the Mic Pre, EQ and Opto-Limiter. It is ONLY meant to

drive balanced inputs. If you are driving an unbalanced input, use the OUT UNBALANCED ONLY jack.

E) OUT UNBALANCED ONLY. Use a regular 1/4" plug here to connect to an unbalanced or balanced input.
The nominal output here is +4dBm and not the -10dBu "consumer" level found on some budget semi-pro
gear. To feed that kind of input, you have to turn down the INPUT ATTENUATOR or better yet, the Limiter's
GAIN and ignore the VU meter which is set up for +4 levels.

TIP = +, hot or positive going signal
SLEEVE = Ground (shield)

F) FUSE. This is a 1/4" 1 amp slo-blo fuse. The fuse is a protection device intended to protect you and the
unit in case something is very wrong. Sometimes it is just the fuse that fails for some unknown reason, so if it
blows and you can't power up the unit, try another fuse (same type and value). If it blows too, prepare to send
in the unit for repair.

G) POWER. This is where the power cable gets plugged in. You Dual Vocal Combo should come with an IEC
power cable appropriate for your country and voltage.

H) GROUND TERMINALS. These 'ground posts' are intended to help in some installations particularly where
a special audio grounding scheme is used. The top post is the audio circuit ground and the bottom is chassis
and AC third pin ground. For almost all applications these posts are connected together with a strap or solid
piece of wire. If you are getting hums and buzzes, this is a good place to start experimenting, and why we
include them.

6

MIC PRE BASICS

This Microphone Preamp, like most mic preamps, is pretty easy to use. First we can discuss why
outboard mic pre's have become "a must have item" in almost every studio even though your console
probably has a bunch of them and that manufacturer claims that they are really great and you don't need
outboard mic pre's. Then, why is everybody buying them, using them, and why are most people going back
to tubes or vintage transistor based circuits?

Good question. The signal from a typical mic is very low - anywhere from 20 to 70 dB below your
normal line level signals. 95% of the time 30 to 40 dB of gain is all that is needed to boost the signal to line
levels. Where you really need a lot of gain is with most ribbon mics and when you are recording chamber
music from a distance. Mic signals are fragile and raw. The fragility is apparent when one compares various
mic pre's - each preamp seems to sound different - no EQ, no compression, nothing elaborate - just basic
gain. Maybe it is the mic reacting different into different circuits. Each preamp, tube or solid state seems
to impart a flavour or color (or personality) of its own. Some of these flavours are subtle and some are not.
A few engineers have an array of mic pre's and use them almost like effects - using each for a certain flavor
as needed. The rest of us only have the budget for one or two great mic pre's so we tend to choose one that
sounds "best", or is priced for us, or is used by "xxxxxx". The Langevin Microphone Preamplifier is superb
sounding - probably because it has a simple all discrete gain stage with a minimum of components and a
minumum amount of negative feedback. Specifications, while important, will not be truly indicative of an
audio product's "sound" until methods of determining the transient accuracy are established. Transient
accuracy is not a "spec" and test benches don't produce hit records. The transient details are important for
reproducing the true character of the instrument, the room and stereo image. Most solid state circuits use
a large amont of negative feedback to lower noise and distortion at the cost of transient accuracy. This
preamplifier started out clean and quiet so minimal negative feedback was necessary.

Op-amp based designs, by comparison, have dozens of transistors in each "chip" (its easier to
fabricate a transistor than a resistor on silicon), hundreds of dB's of negative feedback and sometimes a few
discrete transistors to provide performance that an "IC" simply cannot. The result is good specs - but that
harsh, hard, cold sound that makes shakers sound like pink noise, makes vocals sibilant in an unpleasant
way, and can only render a 2 dimensional image at best. We prefer tubes or simple discrete circuits.

We mentioned mic signals are fragile and raw. Some consider that the "headroom" factor is the most
important issue in mic pre's. We believe that it is just one of a number of issues including the harmonic
character of the distortion. Except for the final output, all circuits are "Class A" which is usually associated
with zerocrossover distortion and near clipping will be even order distortion and less upper harmonics.This
Preamplifier has more headroom than most solid state mic pre's because of the 48 volt power supply used,
compared to 30 volts (+/- 15V or 24 volts) used in other designs. If overdriven, which is not easy, it starts
to clip in a gentle, smooth way.

Another consideration above and beyond technical concerns when it comes to the art of
recording music is that every preamp seems to have some comparative influence on the
"sound" of the mic signal. When we have a choice, we tend to use the preamp that either best
flatters the singer or instrument or gets closest to the desired final sonic goal. Sometimes, the
choice is the clean & pristene pre and sometimes it is the vintage or aggressive box but it
seems to be getting rarer that we choose the basic console mic preamps. The Dual Vocal
Combo is typically considered "clean but vintage" and not as "dry" as many all-discrete mic
preamps. People have used the words "smooth" and "strong" to describe it but undoubtedly
you will find your own words to descibe it compared to your console and other units.

7