Sound Devices MM-1 User Manual

MM-1

Microphone Preamplifier

with Headphone Monitor

User Guide and Technical Information

Sound Devices, LLC

E7556 State Rd. 23/33 • Reedsburg, WI • USA
[phone] • fax: [phone]
Toll-Free: [phone]
www.sounddevices.com
[e-mail]

MM-1 User Guide and Technical Information

General Description

Sound Devices MM-1 combines a high-performance microphone preamplifier with a flexible
headphone monitor.

The full-featured, transformer-balanced microphone preamp produces low-noise, low-distortion
gain at all switch positions. Its dual-stage limiter and high-pass filter prevent occasional signal
extremes from overloading down-stream equipment.

The MM-1 is at home in a range of applications—film sound (boom operators), high-definition
television production, corporate/industrial environments, radio/television announce booths, and
music production. With its headphone monitoring function the MM-1 is a benefit in applications
where communications channels and mix-minus feeds need to be monitored in headphones. The
user can monitor both microphone audio and external audio sources in headphones with level
control.

The MM-1 is designed for durability. Its extruded aluminum chassis, rugged end panels, machined
knobs, and panel mounted connectors assure reliable mechanical operation.

Features

High Performance Microphone Preamplifier

• Maximum of 66 dB of gain, in eleven discrete steps for accurate, repeatable gain settings.

• Dynamic range exceeding 120 dB

• 10 Hz to 50 kHz audio bandwidth.

• High immunity to RF interference due to transformers, RF filtering, and all-metal construction

• High current line output driver capable of driving very long cable runs.

• Premium Lundahl input transformer with superior sonic quality and freedom from interference prob­lems.

• Extended range peak limiter via dual opto-isolators makes preamplifier virtually “unclippable”.

• Selectable 48-volt / 12-volt phantom power or 12-volt T-power for condenser microphones.

• High-pass filter with two selectable corner frequencies, 80 and 160 Hz, 6 dB per octave.

Headphone Monitoring

• Headphone monitoring of microphone audio, external monitor audio, or a mix of both.

• Monitor input accepts balanced or unbalanced mono line-level inputs on 1/4-inch tip-ring-sleeve connec­tor.

• Separate level control of Monitor gain and overall headphone gain.

• Split ear function via DIP switches.

Portable

• Internal battery power (two-AA) for convenient, low cost power.

• Excellent battery life with alkaline or lithium primary cells.

• External 5–17 VDC powering (plug included).

Durable Mechanical Construction

• High strength aluminum chassis withstands punishing field conditions.

• Panel-mounted connectors for strength and reliability.

• Easy access battery compartment for quick battery changes.

• Durable belt clip and end panels.

2

Features and specifications are subject to change. Visit www.sounddevices.com for the latest documentation.

Specications

-6

+1

-5

-4

-3

-2

-1

+0

d
B
u

10 100k20 50 100 200 500 1k 2k 5k 10k 20k 50k

MM-1 User Guide and Technical Information

Gain: (Mic to Line)

Gain Accuracy (Mic - Line)

Frequency Response

(Mic - Line)

Equivalent Input Noise: (Mic)

Output Clipping Level: (Line)

Input Clipping Level: (Mic)

Dynamic Range: (Mic to Line)

THD + Noise:

Common Mode Rejection Ratio:

Input (Mic):

Input: (Monitor)

Output: (Line)

Headphone Output Impedance:

Frequency Response: (Monitor In)

Frequency Response (headphones):

Input Clipping Level: (Monitor In)

High-Pass Filter:

Phantom Power:

T-Power:

Limiter:

Internal Voltage Rails:

Power:

Polarity:

Weight: (unit only)

Dimensions: (unit only)

Included Accessories:

0 dB to 66 dB input to output, switch selectable

+0.6, –0.1 dB with reference to front panel gain markings
(150 ohm source, 100k ohm load impedances)

20 Hz –20 kHz, +0.1, -0.5 dB, –1 dB at 50 kHz (relative to 1 kHz level with 150 ohm source)

MM-1 Frequency
Response

-- w/80 Hz HP

·· w/160 Hz HP

–126 dBu (–128 dBV) maximum
(150 ohm source, flat weighting, 22 Hz – 22 kHz bandwidth gain setting 36 dB or greater)

+22 dBu minimum with 100k ohm load
+20 dBu minimum with 600 ohm load

+4 dBu minimum at the 0 or +18 dB gain setting

122 dB minimum at the +18 dB gain setting

.05% maximum (from 50 Hz – 22 kHz @ +4 dBu output level, 22 Hz – 22 kHz filter bandwidth,
+46 dB gain setting

100 dB minimum at 80 Hz
60 dB minimum at 10 kHz

Transformer-balanced, 2k ohm input impedance

Electronically-balanced, 22k ohm input impedance

Transformer-balanced, 130 ohm output impedance

Unbalanced, 200 ohms

10 Hz – 50 kHz, ±0.5 dB, gain at 50 %

10 Hz – 50 kHz, ±0.5 dB, gain at 50%

Greater than +30 dBu

80 Hz or 160 Hz (switch selectable), 6 dB per octave

12 V or 48 V (switch selectable), will supply 10 mA per DIN 45 596 specification

12 V via 180 ohm resistors, will supply 10 mA

Limits to +17 dBu output level, 10:1 limiting ratio
5 ms attack time, 100 ms release time
Amber/Red LED indicates limiting/clipping

±15 V, regulated

Internal: 2 x AA batteries
External: 5–17 VDC via threaded coaxial jack, (5.5 mm outer diameter, 2.1 mm inner diameter),
pin positive, sleeve negative.

Voltages above 17 VDC cause no damage to unit but will open an internal poly fuse. Poly fuse will
reset when voltage is removed.

All inputs to all outputs are non-inverting
XLR – pin-2 = hot, pin-3 = cold, pin-1 is ground
TRS – Tip = hot, ring = cold, sleeve = ground

0.64 kg, 1.42 lbs.

49 mm x 95 mm x 166 mm (h x w x d)
(1.95” x 3.75” x 6.55”)

Mating DC coaxial power connector, 4 rubber feet

3

MM-1 User Guide and Technical Information

Block Diagram

Front Panel Controls and Connectors

2

1

1) Preamp Gain Switch (Rotary)

Selects the amount of gain from input to
output, adjustable in 11 increments.

2) High-Pass Filter Switch

Three-position switch inserts an 80 Hz
or 160 Hz corner frequency filter, 6 dB
per octave. Off position removes the
filter from the signal path.

3) Limiter Switch

Activates the peak limiter. Limits to +17
dBu output.

4) Limiter/Peak LED

Bi-color LED illuminates red at 3 dB
below clipping; illuminates amber to
indicate limiter activity.

5) Monitor In Gain

Controls the level of Monitor Input
signal.

4

3

6

5

7

6) Phones Gain

7) Headphone Connector

8) Power LED

9) Power Switch

9

8

Controls the overall headphone monitor
level of both preamp audio and monitor
audio.

1/4-inch TRS mono headphone output;
microphone audio and/or monitor
audio in headphones.

Bi-color LED illuminates green when
the unit is powered and changes to
red when approximately four hours of
battery life remain.

Selects the power source for the unit,
either Internal (battery) or External
power.

4

Features and specifications are subject to change. Visit www.sounddevices.com for the latest documentation.

Back Panel Controls and Connectors

MM-1 User Guide and Technical Information

1) Line Out

Transformer-balanced line-level output.
+22 dBu peak output level.

2) Mic In

Transformer-balanced XLR input accepts
microphone level signals.

3) Balanced Monitor Input

Active-balanced ¼-inch connector
accepts balanced or unbalanced line
level signals from -10 dBu to +24 dBu.

4) Phantom Voltage Switch

Selects phantom voltages between 48 V
or 12 V for mic powering.

Bottom Panel Switches

1

2

4

3

75

6

5) Microphone Power Switch

Three-position switch selects Phantom
power, T-power (12 Volts), or no power
(DYN position).
WARNING: Do not use T-powering
with phantom powered or dynamic
microphones (see “Microphone
Powering”).

6) Battery Compartment

Requires two AA batteries for operation.
Insert positive (+) end of battery first

7) External DC Input Connector

Accepts 5–17 VDC,
pin (+), sleeve (–). .

1

1) DIP Switches

The “Split Ear” setting allows the a
signal to be sent to the left headphone
earpiece and a monitor signal to be sent
to the right earpiece. Also, S2-B can
mute the mic audio to the headphones.

The bottom panel switches are
accessible when the belt clip is
removed. Use a 1/16-inch allen­head wrench.

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