Grace m502 Owner's Manual

m

502

500 series Opto Compressor Module

owner’s manual Rev A

all contents © Grace Design/ Lunatec LLC

2434 30th Street, Boulder, CO 80301 USA

tel [phone] fax [phone]

[e-mail] / www.gracedesign.com

Welcome and thanks for purchasing the Grace Design m502 optical compressor. We build all of

our products to be completely reliable and easy to use, so you can concentrate on making great
recordings. While you will nd the m502 is completely straightforward to use, we do ask that you
spend a little time reading this manual to help avoid any common user diculties.

In the event that you do encounter any technical diculties with this or any of our products, feel free
to call us at 303-443-7454. Our oce hours are 9:00 to 5:00, Monday through Friday, MST, or you may
e-mail any technical questions to: [e-mail]. Also, please check out our web site for
complete product information, owner’s manuals and technical documents.

Grace Design has been building audiophile quality products for the recording industry for over
18 years. The technology in the m502 is the result of extensive listening, eld-testing and careful
renement. Your m502 represents a combination of absolutely pristine audio performance, robust
mechanical construction and complete reliability at a reasonable price.

We sincerely hope our products help you achieve a new level of excellence in your work!

- The Grace Design Team

Contents

Important Safety Information 3

Safety Marking Symbols 3

Features 4

Front Panel Controls / Features 4

Installing and Connecting 5

Operation 6

Diagrams 9

Specications (Preliminary) 11

Warranty 12

Manual Revisions 13

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Important Safety Information

GENERAL

Indoor use only

Ordinary Protection: This equipment should not be exposed to dripping or splashing.

Avoid placing objects lled with liquids, such as vases or glasses, on this equipment.

Mains supply voltage uctuations are not to exceed ±10% of the nominal supply voltage.

Pollution Degree 2

Maximum Relative Humidity: <80%

Operation temperature range: 10 °C to 40 °C

Storage and transportation temperature range –40 °C to 70 °C

Maximum altitude: 3000m (9843 ft.)

Equipment suitable for continuous operation

Weight: 316g / 0.7 lb

SAFETY

Please be sure to power o your 500 series rack before installing or removing this or any
500 series modules. Hot swapping could cause connection sparks at the card-edge
connector that could damaging this or other equipment.

SERVICE INFORMATION

The Grace Design m502 contains no user serviceable components. Contact Grace Design for repair
and upgrade information. In the event that your Grace Design m502 needs to be returned to the
factory, please contact us for a return authorization number.

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Features

• Elegantly simple, purist feedback design optical compressor for signal leveling with a minimum of
sonic artifacts

• Subtle dynamic control to heavy compression, the sonic character of the source remains intact

• Comprehensive control set includes input level, threshold, attack, release, ratio and makeup gain

• Bright, easy to read 10 segment LED gain reduction meters

• Bi-color output peak LED lights green with signal present and red 6dB before clipping

• Pin 7 & 9 connections to Radial Workhorse™ and Purple Sweet Ten™ auxiliary connectors

• Pin 11 unbalanced audio out connection to Radial Workhorse™ BussFeed

• Five year transferable warranty on parts and labor

• Made in the USA

Front Panel Controls / Features

COMP IN SWITCH - This switch

THRESHOLD - This knob sets the

minimum level at which the

compressor circuit is activated, with a

range of +15dB to -15dB.

activates the compressor circuitry.

INPUT - This switch selects between
three input levels: -10dB, 0dB, and
+10dB.

ATTACK (milliseconds) - This knob sets

how quickly (or slowly) the compressor

circuit attenuates the incoming signal.

RELEASE (seconds) - This knob sets

how quickly (or slowly) the compressor

circuit releases its attenuation of the

incoming signal.

RATIO - The ratio control determines

the input/output ratio for signals

above the threshold level. Higher

ratios result in more aggressive gain

reduction while lower ratios will result

in more gentle gain reduction.

OUTPUT - The output control provides

20dB of variable level control at the

output of the m502, from -10dB to

+10dB. This control is useful for small

level adjustments during tracking or

for compression gain makeup.

LINK - This switch is to activate either
a) linking of two m502’s for use in
stereo compression scenarios, or b) to
activate external side chain control of
the compressor for ducking, de-essing
etc.

GR METER - This 10 segment meter
displays the amount of gain reduction
being applied to a signal in the
compression circuit.

PEAK INDICATOR - The LED peak
indicator, which monitors the signal
at the output of the compressor,
illuminates green at -10dBu and red at
+20dBu (6dB before clipping).

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