mxr M87 User Manual

92503010480 revA

M87 BASS COMPRESSOR

SCORE/FOLD SCORE/FOLDSHORT TRIM

Dunlop Manufacturing, Inc.

150 Industrial Wa y
P.O. Box 846
Benicia, CA 94510
Phone: [phone]
Fax: [phone]

WARNING: The information contained
in this document is the intellectual
property of Dunlop. Any use and/or
reproduction, in whole or in part, must
have the written permission of Jim
Dunlop Manufacturing, Inc.

M87 bass coMpressor

4/4 coLor process

DUNLOP PART #: 92503010480REVA
UPC #: N/A

FILE NAME:

92503010480REVA_M87_MANUAL.INDD

FILE DATE: 02/16/11
DIELINE DOES NOT PRINT

FLAT SIZE: W= 8” X L= 4.875“
FINISHED SIZE: W= 4” X L= 4.875”

PRINT MATERIAL: 100# DULL COVER
PRINTING SIDE 1: 4CP = CMYK
PRINTING SIDE 2: 4CP = CMYK
FONTS: (ALL FONTS OUTLINED)
LINKED IMAGES: N/A
BINDERY: SCORE & FOLD
NOTES:

CONCEPT

REVISED

PROOF

QUOTE

FINAL ART

PROJECT DIRECTOR: GRAHAM SHAW

DESIGNER: HANK ALVA

CONTACT: [e-mail]

92503010480revA_M87_man.indd 1-3 2/16/11 10:53 AM

M87 BASS COMPRESSOR

DESCRIPTION

• CHT™ Constant Headroom
Technology for clear,
clean performance

• A studio classic in an MXR pedal

• True bypass

• Ten Gain Reduction status LEDs

POWER

The M87 Bass Compressor can
be powered by one 9 volt battery
(accessed by removing the bottom
plate of the pedal), a Dunlop
ECB003 AC adapter (ECB003E in
Europe) or a Dunlop DCB10 DC
Brick power supply.

DIRECTIONS

• Set Release, Attack, Output
and Input to 12 o’clock, and
Ratio to 4.

• Run a cable from your bass to
your Bass Compressor’s Input
jack and run another cable from
the Bass Compressor’s output
jack to your amplier.

• Turn the effect on by depressing
the footswitch (Blue LED lit).

• Observe the LED Meter while
playing normally and set the
INPUT knob so that the rst 3
to 7 green gain reduction LEDs
light, clockwise to light more
and counterclockwise to light
fewer LEDs.

• Adjust the OUTPUT knob to set
the desired output signal level
of the compressor, clockwise
for more output signal level and
counterclockwise for less. Going
between Compressor bypass and
ON is very helpful when adjusting
the OUTPUT level.

• Use the ATTACK knob to set how
quickly your Bass Compressor
responds to your signal and
starts to reduce gain, from 800
microseconds fully counterclock­wise to 20 microseconds
fully clockwise. Fast ATTACK
settings create abrupt and tight
compression, while slow ATTACK

SPECIFICATIONS

Input Impedance 1 MΩ
Output Impedance 600 Ω

Max Input Level +14 dBV
Max Output Level +8.5 dBV

Frequency Response

20 Hz to 20 kHz, +/- 1 dB
Signal to Noise Ratio* > 90 dBV
Total Harmonic Distortion** > 0.5%
Gain 31 dB

Compression Ratio
4:1, 8:1, 12:1, 20:1

Attack Time 20 µs to 800 µs
Release Time 50 ms to 1.1 s

Bypass True Hardwire

Current Draw
LEDs off 14 mA
LEDs on 19 mA
Power Supply DC 9 volt

Housing Material Aluminum
Housing Dimensions
4-3/4” x 2-3/4” x 1-9/32”
Weight 8.4oz.

0 dBV = 1Vrms,
*A-Weighted, all controls at mid position
**20 dB gain reduction, 1.1 s release setting,

50 Hz to 20 kHz

settings sound more relaxed.

• Use the RELEASE knob to set
how long it takes your Bass
Compressor to return to
uncompressed or 0dB gain
reduction level (no meter LEDs
lit), adjustable from 1.1 seconds
fully counterclockwise to 50
milliseconds fully clockwise. Fast
RELEASE settings create less
compression on the attack of
notes played in fast succession.
Slow RELEASE settings produce
smooth compression
on sustained notes.

• Use the RATIO knob to select
compression ratio. The 4 setting
selects a 4:1 ratio, meaning that
if the input level rises 4 decibels
above threshold, the output level
will only rise by 1 decibel. There­fore, gain has been reduced by 3
decibels. The 8 setting selects an
8:1 compression ratio, 12 selects
12:1, and 20 selects 20:1

COMPRESSION

Standard studio dynamic range
reduction can be achieve with
Attack and Release at their 12
o’clock settings, a 4:1 or 8:1
ratio, and by adjusting the input
control to consistently light the -3
to -7 dB LED during note attacks.
Then, to only soften note attacks,
dial in a faster attack time (CW)

DUNLOP MANUFACTURING, INC.

P.O. BOX 846 BENICIA, CA 94510 U.S.A.

TEL: [phone] FAX: [phone]

CONTROLS

METER precisely displays

gain reduction level and
Compressor response time
when the input signal reaches
the compression threshold

RELEASE adjusts how quickly

the Bass Compressor returns
to uncompressed gain level

ATTACK adjusts the time the

Bass Compressor takes to
respond to an input signal
and reduce gain

OUTPUT used to set the

desired output level of the
Bass Compressor

RATIO sets the degree of

compression, from mild 4 (4:1)
to extreme 20 (20:1)

INPUT adjusts the input signal

level relative compression
threshold and sets the amount
of gain reduction

FOOTSWITCH toggles Bass

Compressor on/bypass

and reduce the input control
(CCW) to light only the -3 to

-5 dB LEDs during note attacks.
Or to accentuate note attacks,
dial in a slower attack time
(CCW) and a faster release
time (CW). To hear a more
compressed sound, set the
input control to a higher level
(CW) to light more gain reduction
LEDs with a slow release time
and a fast attack time.

LIMITING

Compression and Limiting are
similar in process but differ in
degree of compression. High
compression ratios 12:1 or 20:1
with fast attack and release
settings are considered to be
limiting. With your Bass
Compressor, the 12:1 ratio setting
produces ‘soft’ limiting, while
the 20:1 produces ‘hard’ limiting,
or ‘brick wall’ limiting with the
fastest attack and release
settings. In contrast, to get the
classic ‘squishy’ limiting effect,
dial in a slow release time
(CCW) with a fast attack.

METER
Short string taps are an easy

way to see the METER display
Compressor reaction time and
can be helpful in setting Attack
and Release controls.

SCORE/FOLD SCORE/FOLD SHORT TRIM

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