Samson MDR624 User Manual

MDR Series Mixers

MIC IN MIC IN

SIX CHANNEL MIXER

LINE IN

30

GAIN

GAIN

5

60

5

-26

+26

-26

0

HF

55

12K

1010

15

15

15

0

MF

5

5

5

2.5K

1010

15

15

15

0

0

LF

5155

5155

80Hz

1010

15

15

AUX

010

010

0

0

PAN

R

L

L

55

010

010

LEVEL

CHANNEL 2 CHANNEL 3/4 CHANNEL 5/6 CR / PHONES MAIN LEVELCHANNEL 1

LINE IN

LEVEL

3/L

30

4/R

60
+26

0

HF

55

12K

1010

15

0

MF

5

2.5K

1010

15

0

0

LF

80Hz

1010

AUX

0

0

PAN

R

AUX SEND

AUX RET

LEFT/MONO

RIGHT

PHONES

5/L

LINE IN LINE IN

6/R

0

0

HF

55

12K

1010

15

15

15

0

0

MF

5

5

5

2.5K

1010

15

15

15

0

0

0

0

LF

5155

5155

80Hz

1010

15

15

AUX

010

010

0

0

0

0

BAL

R

L

L

55

PEAKPEAKPEAK PEAK

010

010

LEVEL

LEVEL

L

CR OUTPUT

R

L

MIX OUTPUT

R

55

12K

1010

15

MF

5

2.5K

1010

15

80Hz

1010

AUX

BAL

R

HF

LF

2T IN 2T OUT

LEFT

RIGHT

AUX RETURN

5

010

2TK TO MIX

2TK TO C/R

5

010

LEVEL

LEFT

RIGHT

PHANTOM POWER

CLIP

+12

+6

0

-6

-12

-18

-24

LR

OUTPUT LEVEL

5

010

LEVEL

Safety Instructions/Consignes de sécurité/Sicherheitsvorkehrungen/Instrucciones de seguridad

ACHTUNG: Um die Gefahr eines Brandes oder Stromschlags zu verringern, soll-

ten Sie dieses Gerät weder Regen noch Feuchtigkeit aussetzen.Um die Gefahr
eines Stromschlags zu verringern, sollten Sie weder Deckel noch Rückwand des
Geräts entfernen. Im Innern befinden sich keine Teile, die vom Anwender

gewartet werden können. Überlassen Sie die Wartung qualifiziertem
Fachpersonal.Der Blitz mit Pfeilspitze im gleichseitigen Dreieck soll den Anwender

vor nichtisolierter “gefährlicher Spannung” im Geräteinnern warnen. Diese
Spannung kann so hoch sein, dass die Gefahr eines Stromschlags besteht. Das
Ausrufezeichen im gleichseitigen Dreieck soll den Anwender auf wichtige
Bedienungs- und Wartungsanleitungen aufmerksam machen, die im mitgelieferten
Informationsmaterial näher beschrieben werden.

Wichtige Sicherheitsvorkehrungen

1. Lesen Sie alle Anleitungen, bevor Sie das Gerät in Betrieb nehmen.

2. Bewahren Sie diese Anleitungen für den späteren Gebrauch gut auf.

3. Bitte treffen Sie alle beschriebenen Sicherheitsvorkehrungen.

4. Befolgen Sie die Anleitungen des Herstellers.

5. Benutzen Sie das Gerät nicht in der Nähe von Wasser oder Feuchtigkeit.

6. Verwenden Sie zur Reinigung des Geräts nur ein feuchtes Tuch.

7. Blockieren Sie keine Belüftungsöffnungen. Nehmen Sie den Einbau des
Geräts nur entsprechend den Anweisungen des Herstellers vor.

8. Bauen Sie das Gerät nicht in der Nähe von Wärmequellen wie Heizkörpern,
Wärmeklappen, Öfen oder anderen Geräten (inklusive Verstärkern) ein, die
Hitze erzeugen.

9. Setzen Sie die Sicherheitsfunktion des polarisierten oder geerdeten Steckers
nicht außer Kraft. Ein polarisierter Stecker hat zwei flache, unterschiedlich bre­ite Pole. Ein geerdeter Stecker hat zwei flache Pole und einen dritten
Erdungsstift. Der breitere Pol oder der dritte Stift dient Ihrer Sicherheit. Wenn
der vorhandene Stecker nicht in Ihre Steckdose passt, lassen Sie die veraltete
Steckdose von einem Elektriker ersetzen.

10. Schützen Sie das Netzkabel dahingehend, dass niemand darüber laufen und
es nicht geknickt werden kann. Achten Sie hierbei besonders auf Netzstecker,
Mehrfachsteckdosen und den Kabelanschluss am Gerät.

11. Ziehen Sie den Netzstecker des Geräts bei Gewittern oder längeren
Betriebspausen aus der Steckdose.

12. Überlassen Sie die Wartung qualifiziertem Fachpersonal. Eine Wartung ist
notwendig, wenn das Gerät auf irgendeine Weise, beispielsweise am Kabel
oder Netzstecker beschädigt wurde, oder wenn Flüssigkeiten oder Objekte in
das Gerät gelangt sind, es Regen oder Feuchtigkeit ausgesetzt war, nicht
mehr wie gewohnt betrieben werden kann oder fallen gelassen wurde.

WARNING: To reduce the risk of fire or electric shock, do not expose this unit to
rain or moisture. To reduce the hazard of electrical shock, do not remove cover or
back. No user serviceable parts inside. Please refer all servicing to qualified per­sonnel.The lightning flash with an arrowhead symbol within an equilateral triangle,
is intended to alert the user to the presence of uninsulated "dangerous voltage"
within the products enclosure that may be of sufficient magnitude to constitute a
risk of electric shock to persons. The exclamation point within an equilateral trian­gle is intended to alert the user to the presence of important operating and main­tenance (servicing) instructions in the literature accompanying the product.

Important Safety Instructions

1. Please read all instructions before operating the unit.

2. Keep these instructions for future reference.

3. Please heed all safety warnings.

4. Follow manufacturers instructions.

5. Do not use this unit near water or moisture.

6. Clean only with a damp cloth.

7. Do not block any of the ventilation openings. Install in accordance with the
manufacturers instructions.

8. Do not install near any heat sources such as radiators, heat registers, stoves,
or other apparatus (including amplifiers) that produce heat.

9. Do not defeat the safety purpose of the polarized or grounding-type plug. A
polarized plug has two blades with one wider than the other. A grounding type
plug has two blades and a third grounding prong. The wide blade or third
prong is provided for your safety. When the provided plug does not fit your
outlet, consult an electrician for replacement of the obsolete outlet.

10. Protect the power cord from being walked on and pinched particularly at
plugs, convenience receptacles and at the point at which they exit from the
unit.

11. Unplug this unit during lightning storms or when unused for long periods of
time.

12. Refer all servicing to qualified personnel. Servicing is required when the unit
has been damaged in any way, such as power supply cord or plug damage, or
if liquid has been spilled or objects have fallen into the unit, the unit has been
exposed to rain or moisture, does not operate normally, or has been dropped.

PRECAUCION: Para reducir el riesgo de incendios o descargas, no permita que
este aparato quede expuesto a la lluvia o la humedad. Para reducir el riesgo de
descarga eléctrica, nunca quite la tapa ni el chasis. Dentro del aparato no hay
piezas susceptibles de ser reparadas por el usuario. Dirija cualquier reparación al
servicio técnico oficial. El símbolo del relámpago dentro del triángulo equilátero
pretende advertir al usuario de la presencia de “voltajes peligrosos” no aislados
dentro de la carcasa del producto, que pueden ser de la magnitud suficiente como
para constituir un riesgo de descarga eléctrica a las personas. El símbolo de excla­mación dentro del triángulo equilátero quiere advertirle de la existencia de impor­tantes instrucciones de manejo y mantenimiento (reparaciones) en los documentos
que se adjuntan con este aparato.

Instrucciones importantes de seguridad

1. Lea todo este manual de instrucciones antes de comenzar a usar la unidad.

2. Conserve estas instrucciones para cualquier consulta en el futuro.

3. Cumpla con todo lo indicado en las precauciones de seguridad.

4. Observe y siga todas las instrucciones del fabricante.

5. Nunca utilice este aparato cerca del agua o en lugares húmedos.

6. Limpie este aparato solo con un trapo suave y ligeramente humedecido.

7. No bloquee ninguna de las aberturas de ventilación. Instale este aparato de
acuerdo a las instrucciones del fabricante.

8. No instale este aparato cerca de fuentes de calor como radiadores, calenta­dores, hornos u otros aparatos (incluyendo amplificadores) que produzcan
calor.

9. No anule el sistema de seguridad del enchufe de tipo polarizado o con toma
de tierra. Un enchufe polarizado tiene dos bornes, uno más ancho que el
otro. Uno con toma de tierra tiene dos bornes normales y un tercero para la
conexión a tierra. El borne ancho o el tercero se incluyen como medida de
seguridad. Cuando el enchufe no encaje en su salida de corriente, llame a un
electricista para que le cambie su salida anticuada.

10. Evite que el cable de corriente quede en una posición en la que pueda ser
pisado o aplastado, especialmente en los enchufes, receptáculos y en el
punto en el que salen de la unidad.

11. Desconecte de la corriente este aparato durante las tormentas eléctricas o
cuando no lo vaya a usar durante un periodo de tiempo largo.

12. Dirija cualquier posible reparación solo al servicio técnico oficial. Deberá
hacer que su aparato sea reparado cuando esté dañado de alguna forma,
como si el cable de corriente o el enchufe están dañados, o si se han derra­mado líquidos o se ha introducido algún objeto dentro de la unidad, si esta ha
quedado expuesta a la lluvia o la humedad, si no funciona normalmente o si
ha caído al suelo.

ATTENTION: Pour éviter tout risque d’électrocution ou d’incendie, ne pas
exposer cet appareil à la pluie ou à l’humidité. Pour éviter tout risque d’électrocu­tion, ne pas ôter le couvercle ou le dos du boîtier. Cet appareil ne contient aucune
pièce remplaçable par l'utilisateur. Confiez toutes les réparations à un person­nel qualifié. Le signe avec un éclair dans un triangle prévient l’utilisateur de la
présence d’une tension dangereuse et non isolée dans l’appareil. Cette tension
constitue un risque d’électrocution. Le signe avec un point d’exclamation dans
un triangle prévient l’utilisateur d’instructions importantes relatives à l’utilisation
et à la maintenance du produit.

Consignes de sécurité importantes

1. Veuillez lire toutes les instructions avant d’utiliser l’appareil.

2. Conserver ces instructions pour toute lecture ultérieure.

3. Lisez avec attention toutes les consignes de sécurité.

4. Suivez les instructions du fabricant.

5. Ne pas utiliser cet appareil près d’une source liquide ou dans un lieu
humide.

6. Nettoyez l’appareil uniquement avec un tissu humide.

7. Veillez à ne pas obstruer les fentes prévues pour la ventilation de l’appareil.
Installez l’appareil selon les instructions du fabricant.

8. Ne pas installer près d’une source de chaleur (radiateurs, etc.) ou de tout
équipement susceptible de générer de la chaleur (amplificateurs de puis­sance par exemple).

9. Ne pas retirer la terre du cordon secteur ou de la prise murale. Les fiches
canadiennes avec polarisation (avec une lame plus large) ne doivent pas
être modifiées. Si votre prise murale ne correspond pas au modèle fourni,
consultez votre électricien.

10. Protégez le cordon secteur contre tous les dommages possibles (pince­ment, tension, torsion,, etc.). Veillez à ce que le cordon secteur soit libre,
en particulier à sa sortie du boîtier.

11. Déconnectez l’appareil du secteur en présence d’orage ou lors de périodes
d’inutilisation prolongées.

12. Consultez un service de réparation qualifié pour tout dysfonctionnement
(dommage sur le cordon secteur, baisse de performances, exposition à la
pluie, projection liquide dans l’appareil, introduction d’un objet dans le boîti­er, etc.).

Table of Contents

Introduction 2

MDR624 Features 3

Controls and Functions

Front and Rear Panel Layout 4–5
Mono Input Channel Section 6–7
Master Section 8–9

MDR624 Input and Output Connections 10–11

Operating the MDR624 12–13

System Set-ups 14–15

MDR624 Wiring Guide 16

Specifications 17

Block Diagram 18

Notes 18-19

Copyright 2004, Samson Technologies Corp.

Printed January, 2004

Samson Technologies Corp.
575 Underhill Blvd.
P.O. Box 9031
Syosset, NY 11791-9031
Phone: 1-800-3-SAMSON (1-800-372-6766)
Fax: [phone]
www.samsontech.com

2

Congratulations on your purchase of the Samson MDR624 mixer! The MDR624 is a six channel mixer, with two
low noise microphone pre-amps. In addition to the two mono Mic/line inputs, there are two channels with left and
right inputs to handle stereo signals. For added flexibility, you can change the tone quality of your microphones or
other line inputs by using the three-band channel equalizers. Connecting external effects like a reverb or digital
delay to the MDR624 is easy thanks to the Aux send on each channel along with the stereo Aux Return in the
master section. LED indicators for Power, Phantom, Peak and Main Output Level make it easy to keep your lev­els set correctly and minimize distortion. Clean, clear sound reproduction, packaged in a rugged enclosure,
ensure reliable high quality sound from performance to performance. Optimized for recording, live sound rein­forcement and commercial installations, the MDR624 is an ideal mixer solution offering big sound in a compact
package.

In these pages, you’ll find a detailed description of the features of the MDR624 mixer, as well as a description of
its front and rear panels, step-by-step instructions for its setup and use, and full specifications. You’ll also find a
warranty card enclosed—please don’t forget to fill it out and mail it in so that you can receive online technical sup­port and so we can send you updated information about these and other Samson products in the future.

With proper care and adequate air circulation, your MDR624 will operate trouble free for many years. We recom­mend you record your serial number in the space provided below for future reference.

Serial number:

Date of purchase:

Should your unit ever require servicing, a Return Authorization number (RA) must be obtained before shipping
your unit to Samson. Without this number, the unit will not be accepted. Please call Samson at 1-800-3SAMSON
(1-800-372-6766) for a Return Authorization number prior to shipping your unit. Please retain the original packing
materials and if possible, return the unit in the original carton and packing materials.

Introduction

3

MDR624 Features

The Samson MDR624 six channel mixer, is a comprehensive, all-in-one solution for live sound, recording, fixed
installation and post production applications. Here are some of its main features:

• Six channels – Two Mic/Line plus two Stereo inputs.

• Flexible design topology ideal for live sound, recording and post production.

•2 Track To Mix Level control allows you to mix in a CD, DAT, Cassette, Computer Sound Card or Mini
Disk with the channel faders.

• Three-band channel equalizer, +/-15dB at 80Hz, 2.5 KHz and 12KHz provides precise and musical
results in sound shaping.

• An Auxiliary Send for external effects, on stage monitor mix, or headphone mixing.

• Eight segment LED Meter with VU ballistics displays the main MIX output.

• High quality, low noise, discrete microphone pre-amplifiers with 48-Volt phantom power, provide
Maximum Dynamic Range and transparent audio.

• Advanced circuit design using discrete components and high quality, low noise op-amps carefully select­ed at each stage of the signal path.

• Quality build and rugged construction ensure reliable performance from venue to venue and session to
session.

• Three-year extended warranty.

AUX SEND

LINE IN

30

5

60

-26

+26

0

55

1010

15

15

0

5

5

2.5K

1010

15

15

0

0

5155

80Hz

1010

15

AUX

010

0

0

PAN

R

L

010

LEVEL

CHANNEL 2 CHANNEL 3/4 CHANNEL 5/6 CR / PHONES MAIN LEVELCHANNEL 1

AUX RET

LEFT/MONO

RIGHT

3/L

5/L

LINE IN LINE IN

6/R

4/R

0

HF

55

12K

12K

1010

15

15

0

MF

MF

5

5

2.5K

1010

15

15

0

0

LF

5155

80Hz

1010

15

AUX

010

0

0

BAL

R

L

55

PEAKPEAKPEAK PEAK

010

LEVEL

PHONES

HF

15

15

LF

15

L

CR OUTPUT

R

L

MIX OUTPUT

R

0

HF

55

12K

1010

15

0

MF

5

5

2.5K

1010

15

0

0

LF

5155

80Hz

1010

AUX

010

0

0

BAL

R

L

010

LEVEL

2T IN 2T OUT

LEFT

RIGHT

AUX RETURN

5

010

2TK TO MIX

2TK TO C/R

5

010

LEVEL

LEFT

RIGHT

PHANTOM POWER

CLIP

+12

+6

0

-6

-12

-18

-24

LR

OUTPUT LEVEL

5

010

LEVEL

MIC IN MIC IN

LINE IN

30

GAIN

GAIN

5

60

-26

+26

0

HF

55

12K

1010

15

15

0

MF

5

5

2.5K

1010

15

15

0

0

LF

5155

80Hz

1010

15

AUX

010

0

0

PAN

R

L

55

010

LEVEL

4

Controls and Functions

Front and Rear Panel Layout

10

1

2

11 12

MIC IN MIC IN

AUX RET

LEFT/MONO

3

RIGHT

AUX SEND

PHONES

13

L

CR OUTPUT

R

14

15 16

17

18

LINE IN

30

GAIN

5

4

-26

0

60
+26

5

15

15

0

6

7

5

15

15

0

0

5

15

15

8

010

9

0

0

R

L

55

GAIN

HF

55

12K

1010

MF

5

2.5K

1010

LF

5

80Hz

1010

AUX

PAN

LINE IN

30

5

60

-26

+26

0

HF

55

12K

1010

15

15

0

MF

5

5

2.5K

1010

15

15

0

0

5

15

010

L

LF

5

80Hz

1010

15

AUX

0

0

PAN

R

3/L

4/R

15

5

15

5

15

010

L

5/L

LINE IN LINE IN

6/R

0

HF

55

12K

1010

15

0

0

0

0

0

55

15

MF

5

5

2.5K

1010

15

15

LF

5

5

80Hz

1010

15

15

AUX

010

BAL

R

L

PEAKPEAKPEAK PEAK

0

0

0

0

0

0

L

MIX OUTPUT

R

HF

55

12K

1010

15

MF

5

2.5K

1010

15

LF

5

80Hz

1010

15

AUX

BAL

R

2T IN 2T OUT

LEFT

RIGHT

AUX RETURN

5

010

2TK TO MIX

2TK TO C/R

5

LEFT

RIGHT

PHANTOM POWER

CLIP

+12

+6

0

-6

-12

-18

-24

LR

OUTPUT LEVEL

5

19

20

21

22

23

A

010

LEVEL

B

OFF

ON

POWER

MADE IN CHINA

C

010

LEVEL

CHANNEL 2 CHANNEL 3/4 CHANNEL 5/6 CR / PHONES MAIN LEVELCHANNEL 1

PHANTOM

ON

OFF

AC ADAPTOR

010

LEVEL

010

LEVEL

010

LEVEL

010

262728

DESIGNED AND ENGINEERED IN THE UNITED STATES BY SAMSON TECHNOLOGIES

CAUTION

RISK OF ELECTRICAL SHOCK

DO NOT OPEN

RISQUE DE SHOCK ELECTRIQUE

NE PAS OUVRIR

SERIAL NUMBER :

CAUTION: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK

DO NOT REMOVE BOTTOM COVER

NON SERVICEABLE PARTS INSIDE

DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE

REFER SERVICING TO QUALIFIED PERSONNEL

LEVEL

24

25

5

Front and Rear Panel Layout

FRONT PANEL

1 MIC – Input connector for Low-Noise Microphone pre-

amp.

2 LINE –Input connector for Line level inputs.

3 GAIN – Used to set the input level of the mic pre and line

input.

4 HIGH FREQUENCY – Controls the high band of the

Channel Equalizer, +/- 15 dB at 12KHz.

5 MID FREQUENCY – Controls the mid band of the Channel

Equalizer, +/- 15 dB at 2.5KHz.

6 LOW FREQUENCY – Controls the low band of the Channel

Equalizer, +/- 15 dB at 80Hz.

7 AUX – Pre fader auxiliary send that can be used with an

external effects processor, or to create a cue or monitor
mix.

8 PAN – Controls the channel’s position between left and

right in the stereo bus.

9 PEAK – Red LED will illuminate indicating when the

GAIN has been adjusted too high.

10 LEVEL – Audio taper fader provides smooth control over

level changes.

11 RIGHT LINE – 1/4-inch phone input connector for the right

line input for the stereo channels.

12 LEFT LINE - 1/4-inch phone input connector for the Left

Line input for the stereo channels.

13 AUX RET – Input connector from external line level

sources.

14 AUX SEND – Line level output from the Auxiliary bus.

15 HEADPHONE JACK – Connect stereo headphones here.

16 CR OUTPUT– Left and Right Control Room output connec-

tors for connecting a monitor system.

17 MIX OUTPUT – Left and Right main Mix output connec-

tors.

18 2 TRACK INPUTS – Connect the output from a DAT,

Cassette, Mini Disk or Hard Disk Recording system.

19 2 TRACK OUTPUTS – Connect to the input of a DAT,

Cassette, Mini Disk or Hard Disk Recording system.

20 AUX RETURN – Used to mix in level of the effects

return.

21 PHANTOM – Indicates that the 48 Volt Phantom

Power is on.

22 POWER – Indicates the MDR624 is powered up.

23 OUTPUT METER - Eight segment display with VU

ballistics indicates main Mix level.

24 2 TRACK TO MIX - Switch used to mix the 2 track

input with the mix from the channel inputs.

25 2 TRACK TO CR – Switches between the main Mix

and the 2 Track in the Control Room output.

26 MAIN LEVEL – Used to control the overall volume of

the Left and Right main Mix outputs.

27 C ROOM/HEADPHONE – Adjusts the volume of the

control room speakers or headphones.

28 BALANCE – Controls the channel’s position between

left and right in the stereo inputs.

REAR PANEL

A POWER – Switches on the MDR624’s main power.

B PHANTOM – Engages the 48-Volt Phantom power

supply to microphone pre-amps.

CAC ADAPTOR INLET – Connect External AC power

supply here.

Front and Rear Panel Layout

6

Controls and Functions

The following section details each part of the MDR624’s input channels including the GAIN control, 3-BAND EQ,
AUX send, PAN, BALANCE and LEVEL controls. The input channels One and Two on the MDR624 feature high
quality, discrete transistor pre-amps providing transparency and extended dynamic range on standard XLR con­nectors. Channels 3/4 and 5/6 are stereo input channels that accept line level signals on standard 1/4" phone
connectors for either balanced (TRS – TIP/ RING/SLEEVE) or unbalanced (TS – TIP/SLEEVE) connections. A

detailed explanation of the Input, as well as the Output connectors, can be found in the following section “Input and Output
Connections” on page 11 of this manual.

GAIN

The MDR624’s pre-amp stage has a variable GAIN control, which is used to set the sensitivity of the
input. Because the input can accept either a mic or line level signal, the GAIN control operates in two
ranges based on which input is being used. When a microphone is connected to the input, the range is
5 to 60dB, and when a line is connected, the range is –26 to +26dB. For more infor-

mation on using the GAIN control see the section “CONNECTING MICROPHONES AND INSTRU­MENTS” on page 12 of this manual.

CHANNEL EQUALIZER

The MDR624 input channels feature a 3-band equalizer allowing you to adjust the
high, mid, and low frequencies independently on each channel. The channel’s fre­quency response is flat when the knobs are in the "12:00" position. Rotating the
knob towards the right will boost the corresponding frequency band by up to 15dB,
and rotating it towards the left will cut the frequency by up to 15dB. The frequency
centers, range of boost or cut, and equalizer type for each band are as follows:
High: 12KHz +/- 15dB shelving type
Mid: 2.5KHz +/- 15dB peaking type
Low: 80Hz +/- 15dB shelving type

AUX SEND

The AUX section is often used for a monitor mix in a live sound mixing, or for a
headphone mix in a recording application. Each input channel includes an Aux send
which controls the amount of that channel’s signal that is sent to the Aux bus. For

more information on using the AUX control see the section “SENDING AN INDEPENDENT MIX
TO THE MONITOR SPEAKERS” on page 13 of this manual.

G

1

2

1

2

3

3

MONO INPUT CHANNEL SECTION

GAIN

5

-26

30

60
+26

0

15

15

15

0

5

0

0

5

010

15

15

15

55

5

5

HF

12K

1010

MF

2.5K

1010

LF

80Hz

1010

AUX

BALANCE (Stereo Inputs Only)

The MDR624’s BALANCE control is used to place or position a mono
input into the stereo main Left and Right MIX bus. For a stereo input,
the balance control is used to center the sound between the Left and
Right Mix bus. You can create a stereo image by panning some input
signals to the left and others to the right.

PAN (Mono Inputs Only)

The MDR624’s PAN control is used to place or position the mono
signal into the stereo main Left and Right MIX bus. You can create a
stereo image by panning some input signals to the left and others to
the right. The MDR624’s PAN control is a Power-Pan circuit, which
includes a 3dB dip in the center position. This is desirable since
there’s a 3dB increase in gain when the mono input signal is heard in
both the Left and Right MIX bus.

PEAK LED

The MDR624’s MIC/LINE pre-amp also includes a CLIP LED which,
when illuminated, indicates that the signal is peaking or overloading.
To reduce distortion, lower the GAIN control to keep this LED from
staying on.

FADER

The MDR624’s rotary input FADER controls the overall channel level.
The input FADER features an audio taper and no detents for smooth
fades.

5

4

Controls and Functions

6

MONO INPUT CHANNEL SECTION

7

7

7

5

6

4

0

0

L

BAL

R

010

0

0

L

5

010

LEVEL

CHANNEL 1

PAN

R

PEAK

MAIN LEVEL

The master MAIN control is the overall volume control for
the left and right mix bus. The MAIN LEVEL affects both
the Control ROOM signal which is output to the speakers
and the line level signal which is output from the MIX OUT
jacks.

CR / PHONES

The C/ROOM + PHONES control is used to set the level
sent to the control room outputs, and also to the head­phone jack.

2 TRACK INPUT AND OUTPUT

The MDR624’s 2 Track section provides the connections
for playback and recording for an external device such as a
DAT, cassette recorder, CD or Mini Disk.

2TK TO CR

The 2TR TO CR switch is used to assign the
2TR input to the Control Room output. If you
push down the 2TK TO CR button, signal will
be routed into the left and right Control Room
output and will be adjusted by the CR /
PHONES control knob.

2TK TO MIX

The 2TR TO MIX switch is used to assign the 2TR input to
the MAIN mix bus. If you push the 2TR TO MIX button, the
signal present at the 2 TRACK IN will be routed to the left
and right MAIN output and the level will be controlled by
the MAIN LEVEL knob.

10

Controls and Functions

The MDR624’s Master section includes the master level controls for the MAIN mix, AUX and CR (Control
Room) / PHONES output, as well as, 2-track assign switches and LED metering for power and level. The
following section details the function controls and switches in the Master section.

MASTER SECTION

11

8

8

9

11

10

8

9

L

CR OUTPUT

R

L

MIX OUTPUT

R

HF

5

12K

10

15

MF

5

2.5K

10

15

LF

5

80Hz

10

15

AUX

10

BAL

R

PEAK

2T IN 2T OUT

LEFT

RIGHT

AUX RETURN

5

010

2TK TO MIX

2TK TO C/R

5

LEFT

RIGHT

PHANTOM POWER

CLIP

+12

+6

0

-6

-12

-18

-24

LR

OUTPUT LEVEL

5

10

EL

EL 5/6 CR / PHONES MAIN LEVEL

010

LEVEL

010

LEVEL

POWER LED

The Power LED lights up to indicate that the main POWER switch (located on the rear panel) is on.

- Phantom Power LED

This LED illuminates indicating that the 48 volt
phantom power is applied to the microphone
pre-amps enabling use with condenser micro­phones. The +48V LED will light up when the
Phantom Power switch (located on the rear
panel) is switched to the ON position.

Output Level Meter

The OUTPUT LEVEL METER allows you to
monitor the level of the signal which is being
sent to the MIX OUT jacks.

NOTE:

To avoid distortion, adjust the Main Level

control so that the 0 indicator LED lights occa­sionally.

Auxiliary Return

The MDR624 has a stereo auxiliary return,
which can be accessed via the pair of 1/4-inch
phone jacks located on the top panel. The
Auxiliary Return can be used to connect any
stereo line level signal, but they are primarily
used to connect the output of external effects
processors.

AUX RET

This adjusts the amount of signal that is com­ing from the AUX RET jacks to the MAIN bus.

For more information on using the AUX control see
the section “USING AN EXTERNAL EFFECT” on page

13 of this manual.

Controls and Functions

MASTER SECTION - continued

12

13

14

15

9

12

13

14

15

HF

12K

0

LEFT

2T IN 2T OUT

LEFT

MF

2.5K

0

LF

0Hz

0

UX

AL

AK

RIGHT

AUX RETURN

5

010

2TK TO MIX

2TK TO C/R

5

PHANTOM POWER

OUTPUT LEVEL

RIGHT

LR

CLIP

+12

+6

0

-6

-12

-18

-24

5

010

LEVEL

CR / PHONES MAIN LEVEL

010

LEVEL

Microphone Input - Mono Input
Channels

Use these inputs to connect Low Impedance
microphones and low level signals from direct
boxes. The MIC inputs have a nominal operating
level of –50dB through -20dB. The MIC inputs
also feature +48V phantom power, allowing you
to use condenser microphones. The Phantom
Power switch (located on the MDR624’s rear
panel) enables phantom power on all the micro­phone inputs when set to the ON position. XLR
Connector pin-out - Pin 1: Ground, Pin 2: Hot (+),
Pin 3: Cold (-)

Line Level Input - Mono Input Channels

Use these inputs to connect synthesizers, drum machines, effects processors or any line-level signal.
The LINE inputs have a nominal operating level of -40dB through - 10dB. TRS phone jacks Connector
pin-out - Sleeve: Ground, Tip: Hot (+), Ring: Cold (-)

Line Level Input - Stereo Input Channels

You can connect the outputs from stereo devices such as synthesizers, drum machines, effects proces­sors or any stereo line-level signal. Use the LEFT input when connecting a mono input signal to the
Stereo Input channels. The LINE inputs have a nominal operating level of -40dB through - 10dB. TRS
phone jacks Connector pin-out - Sleeve: Ground, Tip: Hot (+), Ring: Cold (-)

10

MDR624 Input and Output Connections

CHANNEL 1 – 6 MIC and LINE INPUTS

The MDR624’s channels 1 and 2 mono input channels each have a 1/4-inch connector for line level inputs and
XLR connectors for the MIC inputs. Channels 3/4 and 5/6 stereo input channels each have 1/4-inch connectors
for line level inputs. By using the GAIN control on channels 1 + 2, you can connect a variety of signal sources
from microphones to line level devices such as synthesizers, and drum machines. All the LINE and MIC inputs
are balanced. The MIC inputs are compatible with microphones with output impedances of 50~600 Ohms and
the LINE inputs are compatible with line level devices of 600 Ohms.

NOTE:

It is not possible to simultaneously use both the LINE and MIC inputs on the same channel. Use only one

of the inputs for the appropriate source on each channel.

Following below is a detailed description of the MDR624’s input and output connectors.

18

MIC IN MIC IN

AUX RET

AUX SEND

16

17

18

16

17

GAIN

LINE IN

5

-26

30

60
+26

GAIN

5

-26

LINE IN

30

60
+26

LEFT/MONO

RIGHT

3/L

LINE IN LINE IN

4/R

PHONES

5/L

6/R

AUX Send

The signal present at the AUX output is sent from the AUX bus, which is fed from the AUX send on the
input channels. The AUX output can be used as the
MONITOR MIX bus in a live sound situation by con­necting the output to a power amp and monitor speak­er.

AUX RETURN LEFT/RIGHT

The AUX RETURN LEFT/RIGHT are stereo inputs that
are generally used to connect the outputs of an effects
processor, but can also accept the signal from any line
level source like a keyboard, recorder and even anoth­er mixer. The signal connected to the AUX RETURN
LEFT/RIGHT will feed the main LEFT/RIGHT MIX bus.
The overall level is controlled by the AUX RET knob
located in the master section on the front panel. Use
the LEFT/MONO input when connecting a mono input
signal to the AUX RETURN.

CONTROL ROOM LEFT/RIGHT OUTPUT

The Control Room outputs are used to connect a stu­dio monitor system. The Control Room outputs have
the same output as the L/R MIX, however, the level
can be adjusted independently from the main mix
using the C ROOM/HEADPHONES control.

MIX LEFT/RIGHT OUTPUT

In a live sound application, the LEFT/ RIGHT MIX outputs are connected to a power amplifier or powered
speakers. In a recording application, the LEFT/ RIGHT MIX outputs are used to connect to the inputs of a
stereo device such as computer sound card, DAT, or cassette recorder.

HEADPHONE OUTPUT

You can connect a standard pair of stereo headphones to the PHONES jack and depending on the posi­tion of the 2T TO CR switch, you will hear either the 2-Track input or the MAIN mix.

2TR INPUT

The MDR624 features dual RCA connectors for the left and right 2-track input. You can use these inputs
to connect a CD, Cassette, Mini Disk, DAT or the output from a computer sound card. To listen to the
input connected to the 2T IN, be sure to check the position of the 2T To Mix and 2T TO CR switches. For

more information on using the 2 Track inputs, see the section “PLAYING BACK A CD USING 2T TO MIX ” on page 13 of
this manual.

2TR OUTPUT

If you want to record the mix from your MDR624, you can use the 2-track OUT connectors. The dual RCA
connectors can be connected to a CD, Cassette, Mini Disk, DAT or recorder, even the input of a computer
sound card for hard disk recording. For more information on using the 2 Track outputs, see the section “RECORDING

A MIX FROM THE MDR624 ” on page 13 of this manual.

11

MDR624 Input and Output Connections

MASTER SECTION INPUT AND OUTPUT JACKS

The MDR624 features several output connectors allowing you to interface a variety of external devices. A stereo
recording device, such as a cassette recorder, can be connected to the 2 Track jacks, and power amplifiers or
powered monitors can be connected to the CONTROL ROOM and MAIN output jacks.

E

19

20

20

21

22

23

21

22

19

23

24

242525

AUX RET

LEFT/MONO

RIGHT

LINE IN LINE IN

0

5

0

5

5

55

15

5

15

5/L

6/R

HF

12K

10

MF

2.5K

10

AUX SEND

PHONES

0

15

0

5

15

L

CR OUTPUT

R

L

MIX OUTPUT

R

HF

55

12K

1010

15

MF

5

2.5K

1010

15

2T IN 2T OUT

LEFT

RIGHT

L

RI

12

Operating the MDR624

BASIC OPERATION

The following section explains the basic operation of the MDR624.

CONNECTING MICROPHONES AND
INSTRUMENTS

1. Before connecting mics or instruments,

make sure that the power of all your sys­tems components, including the MDR624,
are turned off. Also, make sure that the
Left and Right MIX faders are turned all
the way down.

2. Connect the cables to your microphones

and instruments, and insert the other end
of the cable firmly into the appropriate
input on the MDR624.

NOTE

: SETTING THE INPUT GAIN - When

connecting a microphone to channels 1 + 2,
it’s a good idea to start with the Gain Control
turned all the way down. Set the input fader
to the "2 o’clock" position and slowly raise
the GAIN control until you see the CLIP LED
turn on. Now, back the GAIN control down
so that the CLIP LED only lights for a short
time during the loudest input the channel will
see.

3. Switch on the power of any peripheral

devices, and then power up the MDR624.

NOTE

: It is important to remember the

Golden Rule of audio … " LAST ON, FIRST OFF". Translated, this means that when turning on your system, you
should always turn your power amplifiers or powered monitors on LAST, and when turning your system off, turn

your power amps off FIRST. This helps avoid any loud pops caused by inrush current at power up, which can
sometimes damage loudspeakers.

4. Turn on your power amp or powered monitors and raise the level control to the manufacturers’ recommend-

ed operating level.

5. Set the Main Level fader in the MDR624’s master section to the "2 o’clock" position.

6. While speaking into the mic (or playing the instrument), adjust the channel Level control so that the "0" LED

of the MAIN section peak level meter lights occasionally.

7. You can shape the tone of each channel by adjusting the equalizer controls as desired.

S

A

M

S

O

N

R

2

1

Vocal

SIGNAL FLOW

Bass Guitar

SIGNAL FLOW

Direct Box

SIGNAL FLOW

SIGNAL FLOW

Lead Guitar

Signal Processor

Stereo Signal

MIC IN MIC IN

LINE IN

30

GAIN

GAIN

5

60

5

-26

+26

0

HF

55

12K

1010

15

15

15

0

MF

5

5

5

2.5K

1010

15

15

15

0

0

LF

5155

5155

80Hz

1010

15

15

AUX

010

010

0

0

PAN

R

L

55

010

010

LEVEL

CHANNEL 2 CHANNEL 3/4 CHANNEL 5/6 HEADPHONES MAIN LEVELCHANNEL 1

LINE IN

30

60

-26

+26

0

0

0

0

0

0

L

LEVEL

AUX RET

LEFT/MONO

RIGHT

3/L

LINE IN LINE IN

4/R

0

HF

55

12K

1010

15

15

0

MF

5

5

2.5K

1010

15

15

0

0

LF

5155

80Hz

1010

15

AUX

010

0

0

PAN

R

L

55

010

LEVEL

55

1010

15

5

2.5K

1010

15

80Hz

1010

AUX

BAL

R

AUX SEND

5/L

6/R

HF

12K

MF

LF

PHONES

0

55

1010

15

15

0

5

5

2.5K

1010

15

15

0

0

5155

80Hz

1010

15

AUX

010

0

0

BAL

R

L

010

LEVEL

L

CR OUTPUT

R

L

MIX OUTPUT

R

HF

12K

MF

LF

2T IN 2T OUT

LEFT

RIGHT

AUX RETURN

5

010

2TK TO MIX

2TK TO C/R

5

010

LEVEL

LEFT

RIGHT

PHANTOM POWER

CLIP

+12

+6

0

-6

-12

-18

-24

LR

OUTPUT LEVEL

5

010

LEVEL

Keyboards

13

Operating the MDR624

USING AN EXTERNAL EFFECT

If you want to use an external device for effects processing, you can easily connect the unit using the MDR624
AUX bus. Follow the simple steps below to interface your
processor:

1. Set the L/R mix faders to the "2 o’clock" position.

2. Raise the AUX knobs for the channels to which you want
the external effect to be applied.

3. Set the input level of the external effect so that the sound is
not distorted and so that the effect’s input meter does not
indicate a clipped signal.

4. Use the AUX return control to adjust the level of the effects
processed by the external effects device.

PLAYING BACK A CD USING 2T TO MIX

The MDR624 has a dedicated input for playing back a CD,
Tape or Mini Disk, which is heard in the Control Room and
Headphone outputs or the main outputs. Below is a descrip-

tion of how you can play back a CD, Tape or MD using the MDR624’s 2 TRACK INPUT.

• Turn the CONTROL ROOM and MAIN LEVEL knob all the way down.

• If you want to hear the 2-track in the Control Room

outputs, engage the 2T to CR switch. If you want to
hear the 2-track in the the MAIN outputs, engage
the 2T TO MIX switch.

• Start playback on the CD, Tape or MD player.

• Now raise the CONTROL ROOM level or main level

until you reach a comfortable listening level.

RECORDING A MIX FROM THE MDR624

You can record the audio from the MDR624’s mixer section
including the MIC, LINE, TAPE IN and AUX inputs to a
Cassette deck, MD, DAT or any other type of recorder using
the 2 Track outputs. Simply connect the MDR624’s 2-Track
OUT to the input jacks of the recorder as shown in the dia­gram to the right. Connect the recorders outputs to the 2 Track in jacks as shown.

SENDING AN INDEPENDENT MIX TO THE MONITOR SPEAKERS

The MDR624’s AUX send can be used to feed a separate set of amplifiers and loudspeakers for stage monitors.
This lets you build one stereo mix for the amplifiers and speakers facing the audience and the other mono mix for
the amplifiers and monitor speakers facing the musicians.

1. Raise the AUX controls for the channels that you wish to hear from the monitor speakers.

NOTE:

The AUX controls are "PRE-FADER SENDS" which means they are not affected by the FADER
level settings of each channel. This allows you to create a mix for the monitors that is independent of the
main LEFT and RIGHT MIX.

2. In order to get the most gain from your monitor mix, use an external graphic equalizer (like a Samson S curve
131 or E31i) to cut out any frequencies that cause feedback. For more information, see the diagram on pg. 14.

K

AUX

010

010

AUX

AUX

010

AUX

010

2T

AUX RET

LEFT/MONO

RIGHT

/L

LINE IN LINE IN

/R

0

15

15

0

5

15

15

0

0

5155

15

AUX SEND

L

CR OUTPUT

R

PHONES

L

5/L

MIX OUTPUT

6/R

R

0

HF

55

55

12K

1010

15

15

0

MF

5

5

5

2.5K

1010

15

15

0

0

LF

5155

80Hz

1010

15

AUX

HF

12K

1010

MF

2.5K

1010

80Hz

1010

AUX

LF

2T IN 2T OUT

LEFT

RIGHT

AUX RETURN

5

010

2TK TO MIX

PHANTOM POWER

CLIP

+12

+6

LEFT

RIGHT

INPUT

LEFT
OUTPUT

Effects Processor

RIGHT
OUTPUT

PHONES

LINE IN

0

55

15

15

0

5

5

15

15

0

0

5155

15

010

0

0

BAL

R

L

R

L

MIX OUTPUT

R

HF

12K

1010

MF

2.5K

1010

LF

80Hz

1010

AUX

2T IN 2T OUT

LEFT

RIGHT

AUX RETURN

5

010

2TK TO MIX

2TK TO C/R

PHANTOM POWER

CLIP

+12

+6

0

-6

-12

-18

-24

LR

OUTPUT LEVEL

LEFT

RIGHT

OUTPUT

RECORD
INPUT

LR

LR

CD BURNER

14

MDR624 System Set-Ups

This system shows the

MDR624 connected to a

pair of powered speakers

like the SAMSON

Expedition XP200. The

MONITOR OUT is con-

nected to an external

power amp, which is dri-

ving 2 monitor speakers.

For inputs, one micro-

phone is connected to

channel 1’s low-imped-

ance input, and the out-

put of the Bass Direct Box

is also connected to the

Low-Impedance input on

Channel 2. The

Keyboards, as well as the

Lead Guitar’s signal

processor's outputs, are

connected to the

MDR624’s line inputs.

MDR624’s AUX SEND

connected to an external

monitor amp.

MDR624 LIVE SOUND SET-UP

15

MDR624 System Set-Ups

This system shows the MDR624

in a recording set up with the

LEFT and RIGHT CONTROL

ROOM outputs hooked up to

powered studio monitors and

the AUX SEND feeding a head-

phone mix sent to a Samson

S•phone headphone amp. For

inputs, a microphone is con-

nected to channel 1’s low-

impedance input, and the out-

put of the Bass Direct Box is

also connected to the Low-

Impedance input on channel

2. The Keyboards, as well as the

Lead Guitar’s signal proces-

sor's outputs, are connected to

the MDR624s line inputs.

MDR624 RECORDING SET UP

MDR624 Wiring Guide

Unbalanced 1/4” Connector

XLR Balanced Wiring Guide

The are several ways to interface the MDR624 to support a variety of applications. The MDR624 features bal­anced inputs and outputs, so connecting balanced and unbalanced signals is possible.

Balanced TRS 1/4” Connector

16

CONNECTING THE MDR624

MDR624 Specifications

Mono input channels

Microphone input electronically balanced, discrete input configuration
Frequency response 10Hz to 45kHz, +0/- 3dB
Distortion (THD&N) 0.05% at +4dBu, 1kHz
Gain range 5dB to 60dB(MIC)
SNR (Signal to Noise Ratio) 110dB
Line input electronically balanced
Frequency response 10Hz to 45kHz, +0/ -3dB
Distortion (THD&N) 0.05% at +4dBu, 1kHz
Sensitivity range -40dBu to -10dBu

Stereo input channels

Line input balanced
Frequency response 10Hz to 55kHz,+0/-3dB
Distortion (THD&N) 0.05% at +4dBu, 1kHz

Impedances

Microphone input 3.6Kohm
All other inputs 10Kohm or greater
Tape out 1Kohm
All other outputs 120ohm

Equalization

Hi shelving +/- 15dB @12kHz
Mid bell +/- 15dB @2.5kHz
Low shelving +/- 15dB @80Hz

Main Mix Section

Noise(Bus noise) Fader 0 dB, channels muted:100.0dBr (ref.:+4dBu)

Fader 0dB, all input channels assigned and set to UNITY gain:

-90dBr(ref.: 4dBu)
Max output +22dBu balanced
AUX Return gain range 0 to +15dB
AUX Send max out +22dBu

Power supply (AC/AC Adaptor)

Main Voltage USA/Canada 95-120V~,60Hz
Europe 210-230V~,50Hz
U.K./Australia 240V~,50Hz
Power Consumption 10Watts

Physical

Dimension (W, D, H) 187mm 257mm 36/50mm
Net weight 3.7 lb. (1.7 kg) Without Adaptor

17

18

Block Diagram

Notes

19

Notes

20

Samson Technologies Corp.

575 Underhill Blvd.

P.O. Box 9031

Syosset, NY 11791-9031

Phone: 1-800-3-SAMSON (1-800-372-6766)

Fax: [phone]

www.samsontech.com