ATI DM500 User Manual

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© Copyright 2011, ATI Audio Inc.

DM500

DIGITAL AUDIO MONITOR

OPERATION AND MAINTENANCE MANUAL

ATI Audio Inc. ■ Tel: [phone] ■ Fax: [phone] ■ [e-mail] ■ www.

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DESCRIPTION

The DM500 is a portable, battery powered instrument that monitors AES/EBU, IEC958 and S/PDIF
formatted digital audio lines and displays any digital errors. It includes a 24 bit, 27 to 96kHz D-to-A
converter feeding a high quality stereo headphone amplifier for audible monitoring and quality
assessment. The DM500 also includes a balanced 600 ohm stereo line level output to drive external
power amplifiers, console inputs, etc.

The DM500 allows you to meter digital headroom (displayed as dB down from 0dBFS) to warn of
possible overdrive at the signal source. The balanced audio line output is also metered with a
conventional reference level of +4dBm at 0dB on its meter scale. The DM500 can be used at the
end of a digital audio line with internal line termination switched in, or can be inserted in a digital
audio path with no appreciable loading of the signal (termination OFF). Input and loop-thru
connectors are provided for balanced XLR, RCA S/PDIF and BNC.

The DM500 comes complete with a weather protected padded carry case with shoulder strap and 9
volt battery power pack (batteries not included). Other mounting configurations are available, as
listed below. The basic NanoAmp™ internal chassis can be used freestanding, desk mounted or
rack mounted with other NanoAmps up to three across in one RU of rack space.

PERFORMANCE

The DM500 provides dynamic range in excess of 90dB (IEC-A weighted) and THD below .01 %
measured at the analog line outputs for all but the lowest sampling rate of 32kHz. All measurements
are noise limited at -90dB (20Hz to 20kHz bandwidth). Response is ±0.25dB, 20 to 20kHz, at all
but the lowest sampling rate.

INPUTS

The DM500 accepts AES/EBU and S/PDIF digital audio signals from either an XLR female 110­ohm line or a BNC or RCA 75 ohm line as selected by the front panel INPUT switch. Inputs from

0.10 to 10Vp-p are properly detected. The selected digital input is transformer isolated, floating and
DC blocked to eliminate ground loop hum and jitter. All inputs are properly terminated for
minimum signal reflection when the rear panel INPUT termination switch is activated.

The XLR female digital input loops through to an XLR male output connector. BNC and RCA
inputs also simultaneously loop through to the BNC and RCA outputs. Opening the rear panel
termination switch allows the DM500 to bridge, or loop through, digital lines without loading. The
last device should always terminate the line.

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RECEIVER

The DM500 handles incoming digital audio at sampling rates from 27kHz to 100kHz. The digital
receiver circuit, U1, a Crystal Semiconductor CS8414, automatically recovers the clock from the
input data and illuminates an LED to indicate the received standard sample rate (Fs) of 32 to 96kHz.
The receiver circuit outputs serial data (SDATA), serial clock (SCK) and frame sync (FSYNC).
FSYNC is configured as left/right clock (LRCLK). The receiver master clock output (MCK) is
divided in U3 and becomes MCLK to the D/A converter at 128XFs.

DIGITAL TO ANALOG CONVERTER

U5 is a Crystal Semiconductor CS4334, 96kHz, 24bit DIA Converter. The CS4334 is rated at over
90dB dynamic range and -88dB THD+N ratio (.004%). The CS4334 utilizes one bit, delta-sigma
D/A converter technology driving an ultralinear internal analog low pass filter. The converter does
not provide digital de-emphasis.

HEADPHONE DRIVER

A high compliance stereo headphone driver (U9, U10) is controlled by the front panel PHONES
volume control. The headphone amplifier will drive up to 20Vp-p into high impedance phones and
up to 120mAp-p into low impedance phones. The headphone output will provide a comfortable
listening level of 1 mW at 12 o'clock on the volume control for most headsets. The amplifier is
capable of driving many headsets up to DANGEROUS LEVELS over 120dBSPL. If you can hear
distortion, it's TOO LOUD and can cause PERMANENT HEARING DAMAGE! BE CAREFUL!
Treat your ears with tender loving care and they will follow you anywhere. The DM500 is designed
to drive TRS (Tip-Ring-Sleeve) connected stereo headphones between 32 and 600-ohm impedance.
Do not use TS connected mono phones.

LINE OUTPUTS

Analog line level outputs for balanced or unbalanced audio lines of 600 ohms or greater impedance
are available on a two-piece Phoenix type rear connector. Ground sensing output drivers (U7, U8)
allow either the HI or LO output line to be grounded by unbalanced loads. Grounding one side of an
output pair shuts off drive to the grounded line and doubles the output signal on the ungrounded
side, thus maintaining normal circuit operation and gain. Front panel trimpots set the nominal line
output level to +4dBu (1.25V) at 0dB on the line output meter that allows 18dB headroom up to the
peak output level of +22dBu.

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METERING

The DM500 allows front panel selection of two metering modes. The D/A mode measures the direct
output of the D/A Converter and is calibrated (internal adjustments M2L, M2R) to just indicate
0dBFS maximum at full digital input count. 0dBFS on the D/A meter corresponds to +22dBm line
output level. The D/A scale measures five additional steps down from 0dBFS, calibrated at -6, -12, ­15, -18 and -24dB.

The LINE mode meters the audio line output and is calibrated to read 0dB at +4dBm line output
level with internal calibration adjustments M1L and M1R. The LINE meter scale measures 12dB
above and below the 0dB point.

The ballistics of the meter displays are designed to closely follow the requirements of DIN45406 for
PPM response in order to best indicate audible peaks.

DISPLAY

The DM500 displays the input signal sample rate Fs (if within +1and -4% of the standard
frequency) on a set of five front panel LED indicators (32, 44.1, 48, 88.2 and 96kHz). A green data
VALID readout indicates that the received data was correct when sent and that there are no
subsequent parity or bi-phase coding violations or an out-of-lock PLL clock receiver. Out-of-range
or no-signal conditions blank these indicators. The DM500 indicates the following data errors with
separate red LEDs:

Bi-Phase Error—Indicates incorrect bi-phase signal coding
CRC Error—Cyclic Redundancy Check (CRC) value calculated for the receiver signal does not

match the CRC byte of the channel status word

No Lock Error—Signal contains no data or is corrupted beyond recoverable limits
Parity Error—Indicates a parity error due to mismatched ones and zeroes in the audio data

subframe

POWER

The DM500 operates from four 9-volt batteries installed in the removable battery pack. The battery
pack cable should be inserted into either of the DC input connectors present on the rear of the main
chassis. Note that the outer shell of the DC power cable connector is Positive with respect to the
center pin. Models DM500-1 and DM500-2 are supplied with an external 24VDC power module for
operation from 120VAC and 230VAC, respectively. The main chassis loop-thru DC connectors
allow multiple NanoAmp units to operate from a single external power module. Allow one power
module for every two DM500-1 or DM500-2 units. Accessory power modules WA100-1 and
WA100-2 and loop-thru cables 20602-1 are available.

A front panel POWER switch and LED Power indicator are provided.

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DM500 TECHNICAL SPECIFICATIONS

INPUT

DATA FORMATS

AES/EBU and S/PDIF, 27 to 96kHz sample rates

LEVEL

0.1 Vp-p minimum

IMPEDANCE

Transformer isolated, balanced and floating, XLR 110Ω, BNC/RCA 75Ω; terminations

may be switched off for loop-thru operation

CONNECTORS

XLR or BNC/RCA (Front panel selection), paralleled for loop-thru expansion

OUTPUTS

D/A CONVERTER

16 to 24 bit conversion

HEADPHONE

Drives 32 to 600Ω stereo headphones (TRS) to 100mW peaks, 1mW nominal; front

panel ¼" phone jack and volume control

LINE LEVEL

Balanced, +24 dBm peak, +4dBm nominal, 600 ohms; drives balanced or unbalanced
line; individual left and right front panel gain controls

FREQUENCY
RESPONSE

20 to 20kHz ± .25dB

DISTORTION

.10% at peak levels, .01% at nominal levels, 20 to 20kHz

CONNECTOR
(LINE)

Two piece screw clamp, Phoenix™ type

INDICATORS

SAMPLE RATE

LED Display indicates 32, 44.1, 48, 88.2 or 96kHz if incoming signal is within +1
to -4% of standard; all dark indicates no signal

SIGNAL VALID

Indicates that signal is free of transmission errors

BI-PHASE ERROR

Indicates incorrect bi-phase signal coding

CRC ERROR

Cyclic Redundancy Check (CRC) value calculated for the receiver signal does not match

the CRC byte of the channel status word

NO LOCK ERROR

Signal contains no data or is corrupted beyond recoverable limits

PARITY ERROR

Indicates a parity error due to mismatched ones and zeroes in the audio data subframe

POWER ON

Indicates power is on and unit is operational

METERING

Stereo, LED, switchable between D/A converter and analog line output

DIGITAL D/A OUT

Headroom indicators for 0, 6, 12 15, 18 and 24dB, with 0dBFS = digital clipping

ANALOG LINE
OUT

Indicators for +12, +6, 0, -3, -6 and -12dB with 0dB = +4dBm output

SIZE

2.75” (7cm) H x 6.25” (15.9cm) W x 8.5” (21.6cm) D

WEIGHT

3 pounds (1.4kg) net; 4 pounds (1.8kg) shipping weight

POWER

4 x 9-volt batteries required for portable operation (not supplied); loop-thru power
connectors; order accessory power supply WA100-1 for 120VAC 60Hz; use WA100-2
for 230VAC 50-60Hz

WARRANTY

Limited, One Year Warranty

MODELS AND ACCESSORIES AVAILABLE:

DM500 Complete portable unit, as shown on front cover
DM500-1 Desktop mounting, includes external 120VAC power supply
DM500-2 Desktop mounting, includes external 230VAC power supply
21075-501 19” 1RU Rackmount, holds three DM500-1 or DM500-2 units
21097-501 1/3 Rackmount Filler Panel
20602-1 DC power loop-through cable

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One Year Limited Warranty

ATI warrants this product to be free from defects in materials and workmanship to its original owner for a
period of one year from date of purchase. ATI will repair or replace such product or part thereof, which upon
inspection by ATI, is found to be defective in materials or workmanship.

The Proper Return Authorization Number must be obtained from ATI in advance of return. Contact ATI at
856-626-3480 or email [e-mail] to receive the number and instructions for return of your unit.

A written statement providing the name, address, daytime telephone number and email address of the
original owner, together with receipt from the original purchase, and a brief description of any claimed
defects, must accompany all returns. Parts or product for which replacement is made shall become the
property of ATI.

The customer shall be responsible for costs of transportation and insurance to the factory of ATI, and shall
be required to prepay such costs.

ATI shall use reasonable efforts to repair or replace any product covered by this limited warranty within thirty
days of receipt. In the event repair or replacement shall require more than thirty days, ATI shall notify the
customer accordingly. ATI reserves the right to replace any product that has been discontinued from its
product line with a new product of comparable value and function.

This warranty shall be void in the event a covered product has been damaged, or failure is caused by or
attributable to acts of God, abuse, accident, misuse, improper or abnormal usage, failure to follow
instructions, improper installation or maintenance, alteration, or lightning, power fluctuations and other
incidental or environmental conditions. Further, product malfunction or deterioration due to normal wear is
not covered by this warranty.

ATI DISCLAIMS ANY WARRANTIES, EXPRESS OR IMPLIED, WHETHER OF MERCHANTABILITY OF
FITNESS FOR A PARTICULAR USE, EXCEPT AS EXPRESSLY SET FORTH HEREIN. THE SOLE
OBLIGATION OF ATI UNDER THIS LIMITED WARRANTY SHALL BE TO REPAIR OR REPLACE THE
COVERED PRODUCT, IN ACCORDANCE WITH THE TERMS SET FORTH HEREIN. ATI EXPRESSLY
DISCLAIMS ANY LOST PROFITS, GENERAL, SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES
WHICH MAY RESULT FROM BREACH OF ANY WARRANTY, OR ARISING OUT OF THE USE OR
INABILITY TO USE ANY ATI PRODUCT.

Some states do not allow the exclusion or limitation of incidental or consequential damages or limitation on
how long an implied warranty lasts, so the above limitations and exclusions may not apply to you.

This warranty gives you specific legal rights, and you may also have other rights that vary from state to state.
ATI reserves the right to modify or discontinue, without prior notice to you, any model or style product.
If warranty problems arise, or if you need assistance in using your product contact us.