Benchmark DAC3 B Instruction Manual

Benchmark DAC3 B

Instruction Manual

Reference Stereo

PCM and DSD D/A Converter

with

ESS9028PRO Conversion System

(Version 1.x Firmware)

Safety Information

Fuses

CAUTION: FOR CONTINUED FIRE

HAZARD PROTECTION ALWAYS REPLACE
THE FUSES WITH THE CORRECT SIZE
AND TYPE (0.5A 250 V SLO-BLO
MM – LITTELFUSE® HXP218.500 OR
EQUIVALENT). THE FUSE DRAWER
INCLUDES TWO FUSES. ALWAYS
REPLACE BOTH FUSES AT THE SAME
TIME.

AC Input Voltage Range

NOTE: THE DAC3 IS EQUIPPED WITH A

UNIVERSAL POWER SUPPLY. THERE IS
NO VOLTAGE SELECTION SWITCH. AC
VOLTAGE RANGE IS 88-264 VAC, 47-63
HZ. THE PRODUCT MAY ALSO BE
OPERATED FROM DC POWER OVER A
VOLTAGE RANGE OF 125-373 VDC.

Power Cord

CAUTION: ALWAYS USE A GROUNDED

POWER CORD. THE PRODUCT IS
EQUIPPED WITH A STANDARD IEC
POWER ENTRY MODULE. USE AN IEC
POWER CORD THAT IS EQUIPPED WITH
THE APPROPRIATE CONNECTOR FOR
YOUR LOCATION. CORDS ARE AVAILABLE
FROM YOUR DEALER.

®

5 X 20

Modifications

CAUTION: DO NOT SUBSTITUTE PARTS

OR MAKE ANY MODIFICATIONS
WITHOUT THE WRITTEN APPROVAL OF
BENCHMARK MEDIA SYSTEMS, INC.
MODIFICATION MAY CREAT E SAF E TY
HAZARDS AND VO I D THE WARRANTY.

CAUTION: CHANGES OR MODIFICATIONS

NOT EXPRESSLY APPROVED BY
BENCHMARK MEDIA SYSTEMS COULD
VOID THE USER'S AUTHORITY TO
OPERATE THE EQUIPMENT UNDER FCC
REGULATIONS.

Repairs

CAUTION: DO NOT SERVICE OR REPAIR

THIS PRODUCT UNLESS PROPERLY
QUALIFIED. ONLY A QUALIFIED
TECHNICIAN SHOULD PERFORM
REPAIRS.

Instruction Manual for DAC3 B with 1.X Firmware Page 2

Contents

Safety Information 2

Fuses 2
AC Input Voltage Range 2
Power Cord 2
Modifications 2
Repairs 2

Features 4
Introduction 5

Applications 5

DAC3 vs. DAC2 5
DAC3 vs. DAC1 5
DAC3 Technologies 5

Front Panel 8
Rear Panel 8
Quick Start Guide 9

Audio Inputs 9
Remote Control (optional) 9
Front Panel Controls 10
Front Panel Display 11

Operational Details 13

AUTO-ON Function 13
CONTROL-LOCK Function 13
Bi-directional 12V Trigger 14
HPA4, LA4 Compatibility 16
USB MODE Sele ction 16
High-Current Outputs 16
Driving Power Amplifiers 16
Digital Pass-Through 17
Firmware Version Identification 18

Rear Panel 19

Inputs 19
Outputs 22
AC Power-Entry and Fuse Module 23

Internal Settings 24

Jumper-Configured Options 24
Removing Top Cover 24
XLR Output Pads 25
Digital PASS-THROUGH Function 26

Rack Mounting 27

Benchmark Rack Mount T ray 27
Benchmark ½-Wide Blank Plate 27

DAC1, DAC2 and DAC3 Family History 28

DAC1 Series 28
DAC2 Series 28
DAC3 Series 29

Benchmark Technologies 30

Native DSD Conversion 30
High Headroom DSP 30
32-bit SABRE-PRO D/A System 31
Diagnostic Displays 31
Bi-Directional 12 Volt Trigger 31
Distributed Power Regulation 32
Differential Amplifiers 32
Jitter-Immune UltraLock3™ 32
Multi-Mode Asynchronous USB Audio 35

USB Driver Installation 37
Performance Graphs 42
Specifications 57

Audio Performance 57
Group Delay (Latency) 58
Digital Audio Inputs 58
Jitter Tolerance 58
Balanced Analog Outputs 59
Unbalanced Analog Outputs 59
Status Display 59
AC Power Requirements 60
Dimensions 60
Weight 60

Regulatory Compliance 61

FCC and RoHS Compliance Statements 61
FCC Notice (U.S. Only) 61
RoHS Compliant Information 61
CE Certificate of Conformity 62

Warranty Inf o rmation 63

Benchmark 1-Year Warranty 63
Benchmark Ext en ded Warranty Opt ions 64
Notes on Warranty Repairs 64

Instruction Manual for DAC3 B with 1.X Firmware Page 3

Features

 Fixed Gain Calibrated Outputs – XLR outputs are calibrated to +24 dBu at 0 dBFS (pads at 0

dB), RCA outputs are calibrated to 2 Vrms at 0 dBFS (calibration is equivalent to "HT MODE" or
"CALIBRATED MODE" on other DAC3 models)

 CONTROL LOCK - Disables keypad and remote control to prevent accidental changes
 Low-Impedance Passive Output Pads – 0, 10, and 20 dB – optimize output level to power

amplifiers and other downstream devices to maximize system SNR (Page 25

 SABRE PRO - 32-bit PCM D/A conversion system, four 32-bit D/A converters per channel
 SABRE PRO – Native DSD D/A conversion system, four 1-bit DSD D/A converters per channel
 Benchmark Ultra Lo ck3™ Jitter Attenuation System – eliminates jitter-induced distortion
 High Headroom DSP - provides 3.5 dB of analog and digital headroom above 0 dBFS to

completely eliminate the clipping of intersample peaks

 Multi-Mode Asynchronous USB Audio 2.0 – 24 bit/192 kHz, DSD (DoP 1.1)
 Driverless Asynchronous USB Audio 1.1 – 24-bit/96 kHz
 Sample Rate Display – displays the measured sample rate, and format (PCM or DSD)
 Word Length Display – displays the measured word length
 2 Coaxial Digital Inputs – 24-bit/192 kHz PCM, DSD (DoP 1.1)
 2 Optical Digital Inputs – 24-bit/96 kHz PCM

)

 1 Coaxial Digital Output – digital pass through from USB, Coax, and optical inputs when

function is enabled (Page 26

 2 Stereo Analog Outputs – 1 pair balanced (XLR), plus 1 pair unbalanced (RC A )
 IR Remote with metal housing provides control of all functions (optional)
 Automatic De-Emphasis – automatically responds to consumer pre-emphasis bit (44.1, 48

kHz)

 12V Trigger I/O – bi-directional 12V trigger can act as input, output, or both (Page 14
 AUTO-ON Function - can be programmed to turn on when AC is applied (Page 13)
 Power Switch – very low standby power , <0.5 W at 120 VAC
 High-Efficiency Low-Noise Power Supplies – only 12-15 W, 88-264 VAC, 47-63 Hz
 Meets FCC Class B and CE emissions requirements
 Tested for immunity to radiated and conducted RF interference

)

)

Instruction Manual for DAC3 B with 1.X Firmware Page 4

Introduction

Applications

The DAC3 B is the ideal converter to use in
front of Benchmark's HPA4 headphone
amplifier or LA4 line amplifier. It is a lso ideal
for many professional studio applications. It
delivers the full performance of the flagship
DAC3 HGC, but eliminates the volume
control, the analog inputs, the mute and
polarity controls, and the headphone
amplifier.

The DAC3 B is a professional reference-grade
audio digital to analog converter with a fixed­gain output. The DAC3 B supports 24-bit D/A
conversion of PCM at sample rates up to 192
kHz. It also supports direct conversion of 1­bit DSD at a 2.8224 MHz sample rate. It is
designed to be very transparent and this
makes it well-suited for critical monitor ing in
studio control rooms and mastering rooms.

The DAC3 B provides D/A conversion and
digital source selecti on . The DAC3 B is ideal
for use with the Benchmark HPA4
headphone/line amplifier or the LA4 line
amplifier. These devices provide a very high­performance analog volume control that is a
perfect complement to the fixed-gain output
of the DAC3 B.

The fixed-gain DAC3 B has many applications
in a professional environment where a
calibrated output is required. The CONTROL
LOCK function can be enabled to prevent
accidental changes to the settings.

DAC3 vs. DAC2

The DAC3 builds upon Benchmark’s highly
successful DAC2 product family. The DAC3
maintains the familiar DAC2 form factor, but
adds the higher performance available from
the new ES9028PRO D/A converter. The
DAC3 offers the following improvements over
the DAC2:

• Active 2nd Harmonic Compensation

• Active 3rd Harmonic Compensation

• Lower THD

• Lower passband ripple

• Improved frequ en cy response

• Increased Dynamic Range

• Faster PLL lock times

• Faster switching between inputs

DAC3 vs. DAC1

The DAC3 and DAC2 add these features that
are not found on the DAC1:

• Asynchronous 192kHz USB Audio 2.0

• 32-bit D/A conversion system

• Word Length Display

• Sample Rate Display

• Polarity Control

• Direct DSD D/A Conversion

• -20 dB DIM

• Bi-Directional 12V Trigger

• Power Switch with Auto-On Function

• Digital Pass-Through

• High-Headroom D SP

• Additional I/O

DAC3 Technologies

4:1 Parallel Conversion Structure

The conversion system in the DAC3 achieves
a 6 dB signal to noise improvement through
the use of 4:1 summing. The ES9028PRO D/A
is an 8-channel 32-bit converter. In the
DAC3, four channels are summed in the
analog domain to form each of the two output
channels.

The 4:1 summing also improves the THD. The
non-linearities in individual conversion
channels are av era ged across the fou r
summed channels and incoherent non­linearities are attenuated by 6 dB.

Harmonic Compensation

The ES9028PRO has two distortion
compensation systems that independently
remove most of the 2nd and 3rd harmonic
distortion in the D/A converter. Benchmark's
ultra-clean analog output stages allow these
systems to be fully leveraged in the DAC3.

Instruction Manual for DAC3 B with 1.X Firmware Page 5

High-Headroom Digital and Analog
Processing

The DAC3 B has generous amounts of analog
and digital headroom. The analog clip point is
above 29 dBu. The digital clip point is +3.5
dBFS and is aligned to 27.5 dBu. The factory
calibration is +24 dBu at 0 dBFS. This means
that the DAC3 B has 3.5 dB of digital
headroom above 0 dBFS, and another 1.5 dB
before reaching analog clip. The digital
headroom prevents the clipping of
intersampl e ove rs. The analog headroom
allows accurate reproduction of inters ample
peaks without clipping.

line-frequency components in the output
spectrum of the DAC3. This also means that
the DAC3 can be placed in close proximity to
any audio component without causing
interference with the other component.

UltraLock3™ Clock System

UltraLock3™ provides the outstanding jitter

attenuation of Be nchmark's UltraLock2™
system while providing virtually instantaneous
(6 ms) lock times.

Dual-Mode USB Input

No Clipping of Intersample Overs

The DAC3 is one of very few D/A converters
that can accurately reproduce intersample
overs without clipping. Intersample peaks can
reach +3.01 dBFS and commonly occur many
times per second in most 44.1 kHz and 48
kHz recordi n g s. When r ecordings are ripped
using lossy compression systems (such as
MP3), additional intersample overs are often
created. Most converters (including the
DAC1) produce bursts of distortion at every
occurrence of an intersample over. In
contrast, the DAC2 and DAC3 converters
cleanly reproduce all intersample overs
without clipping.

Low-Noise Power Supplies

The DAC3 uses high-efficiency low-noise
power supplies. Each critical subsystem also
has at least one dedicated low-noise
regulator. Th e high-efficiency supplies deliver
the substantial power required by the low­impedance circuits and the output line
drivers. A power switch is included. The
standby power consumption is less than 0.5
W when the unit is off.

Low Magnetic Emissions

The magnetic components in the DAC3 power
supplies operate at over 800 kHz. This allows
the use of very small magnetic components
that emit correspondingly small magnetic
fields . This virtually eliminates all traces of

The DAC3 has a USB input that can be
operated in two modes; driverless USB

Audio 1.1, and a high sample rate USB
Audio 2.0. Both use asynchronous clocking

to eliminate the USB interface as a source of
clock jitter.

Note: To provide full backward and forward

compatibility, the DAC3 uses the DAC2 USB
drivers. This prevents the need to install two
different sets of drivers. Please note that the
DAC3 USB input will be identified as
"Benchmark DAC2" in your computer control
panels. This is inte ntional.

Asynchronous USB Audio 2.0

The USB Audio 2.0 interface supports DSD
and 192 kHz, 24-bit PCM. No drivers are
required for Apple or Linux operating
systems. Drivers are provided for Win d ow s
operating systems at:

BenchmarkMedia.com/drivers

Native Asynchronous USB 1.1

The DAC3 has a driverless USB Audio 1.1
mode that supports 96 kHz, 24-bit PCM with
all operating systems. This mode provides a
quick and easy connection to a wide variety of
computers and tablets without installing a
driver.

Instruction Manual for DAC3 B with 1.X Firmware Page 6

Low-Impedance Passive Attenuators

Bi-directional 12V Trigger

Like the DAC1 and DAC2, the DAC3 includes
low-impedance passive attenuators on the
XLR outputs. These attenuators can be
adjusted to optimize the interface with
preamplifiers, power amp lifiers or powered
monitors. Thi s optimization places the system
volume control in its best operating range.
This exclusive Benchmark feature can provide
substantial improvements in the performance
of the playback signal chain.

Native DSD Conversion

The DAC3 supports native DSD conversion.
This feature was not available on the DAC1.
DSD signals can be delivered to the USB or
Coaxial inputs in DoP 1.1 fo rmat. The DSD
signal is then routed directly to a bank of 1­bit DSD D/A converters. Four balanced 1-bit
converters are summed together for each
balanced output.

Digital Pass-Through

The 12 Volt trigger can be connected to other
audio components so that an entire audio
system can turn on and off in a sequenced
fashion. The DAC3 trigger I/O can be
connected to a preamplifier, power amplifier,
or both. The DAC3 will pull the trigger I/O to
12 volts DC while the DAC3 is on. If the
DAC3 is off and an external device pulls the
trigger I/O to 12 volts, the DAC3 will turn on.

Auto-On Function

The DAC3 can be programmed to
automatically turn on when AC power is
applied. (Page 13

)

The second coaxial input (D4) can be
reconfigured as a digital output. When
operating as an output, any selected digital
input is passed through to D4 without any
processing. Optical, coaxial, and USB inputs
can be passed through to the D4 connector.
This even includes special signals such as
DoP, DTS, Dolby Digital, even when these
signals cannot be decoded by the DAC3.

Instruction Manual for DAC3 B with 1.X Firmware Page 7

Front Panel

• IR Sensor

• Power Button

• Control-Lock Button and Indicator

• Input Select Buttons

• Input Indicators

• Word-Length Indicators

• Sample-Rate Indicators

Rear Panel

• Balanced Outputs

• Unbalanced Outputs

• Digital Inputs

• 12V Trigger I/O

• IEC Power Entry with Fuses

Instruction Manual for DAC3 B with 1.X Firmware Page 8

Quick Start Guide

OFF

Turns the unit off. Any devices

ON

Turns the unit on. Any devices

sequence.

VOLUME

Not used.

DIM

Not used.

MUTE

Not used.

INPUT

Not used.

D1

Selects optical digital input D1.

D2

Selects optical digital in p ut D2.

D3

Selects coaxial digital input D3.

D4

Selects coaxial digital input D4.

USB

Selects USB input.

USB 1.1 and USB 2.0 modes.

Analog

Not used.

Audio Inputs

The DAC3 B features five stereo digital inputs
(2 coaxial, 2 optical, and 1 USB). The coaxial
and optical inputs accept professional (AES)
and consumer (S/PDIF) data formats at word
lengths up to 24-bits.

slaved to the 12V TRIGGER will
also turn off in a controlled
sequence.

Press and hold the OFF button for
3 seconds to force the 12V
TRIGGER off (only necessary
when another device is ac t ing as a

TRIGGER BUS MASTER).

Tip: We recommend using the coaxial or USB

inputs for sample rates above 96 kHz. Optical
interfaces are not always reliable at sample
rates above 96 kHz.

Remote Control (optional)

slaved to the 12V TRIGGER will
also turn on in a controlled

Tip: The remote control is designed to have a

long operating range. In most applications it
is not even necessary to point the remote
directly at the DAC3. The IR sensor is located
above the POWER button.

The chart at the right summarizes the

functions of the optional IR remote
control.

Instruction Manual for DAC3 B with 1.X Firmware Page 9

Press and hold the USB button for
3 seconds to toggle between the

Tip: To provide system compatibility with the

Benchmark HPA4 and LA4, the DIM, MUTE,
VOLUME UP/DOWN, INPUT UP/DOWN
and ANALOG keys are not used by the

DAC3 B.

Tip: The CONTROL-LOCK button disables

the remote control and all other buttons on
the front panel.

Front Panel Controls

POWER

Turns the unit on or off. Any

seconds to turn the unit off.

CONTROL

Press and hold for 3 seconds to

disabled.

INPUT

Press to select inputs.

2.0.

devices slaved to the 12V
TRIGGER will also turn on or
off in a controlled sequence.

Starting with the unit off, press
and hold the POWER button
for 3 seconds to set the AUTO-
ON function.

Starting with the unit on, press
and hold the POWER button
for 3 seconds to clear the

AUTO-ON function.

Tip: The CONTROL-LOCK button disables

the remote control and all buttons on the
front panel. Use this function in dedicated
applications to prevent loss of audio. If you
are not using the 12V TRIGGER I/O, you
will also want to activate the AUTO-ON
feature because the POWER button is
disabled.

Tip: When AUTO-ON is enabled, a switched

AC outlet can be used to turn your system on
and off. The 12V TRIGGER I/O can be used
as a trigger output to control the power state
of additional components.

Tip: The IR remote control sensor is located

directly above the POWER button.

The chart at the right summarizes the
functions of the front-panel controls.

LOCK

If AUTO-ON is set, the
POWER button is disabled.

If CONTROL-LOCK is on,
press the POWER button for 3

toggle CONTROL-LOCK on or
off.

When the CONTROL-LOCK
light is on, the front panel keys
and remote control are

If CONTROL-LOCK is on, the
INPUT buttons are disabled.

Press and hold both input
buttons for 3 seconds to toggle
between USB 1.1 and USB

Instruction Manual for DAC3 B with 1.X Firmware Page 10

Front Panel Display

U

A solid blue light indicates that the USB

computer has not been established.

D1

A solid blue light indicates that optical

is not being received.

D2

A solid blue light indicates that optical

is not being received.

D3

A solid blue light indicates that coaxial

is not being received.

D4

A solid blue light indicates that coaxial

is not being received.

Slow Flash

(2Hz)

No digital signal (output
muted)

Med. Flash

(7Hz)

Data transmission errors or
Non-PCM (output muted)

Rapid flashes

(14Hz)

Non-audio data is being
received (output muted)

Intermittent

Some data corruption is

cable.

There are twelve status indicator lights on the
front panel. At least one light will be
illuminated whenever power is on.

Input Indicators

The input indicators show
which input is selected.

A flashing light indicates an
error on a digital input.

Instructions for configuring this jumper­selected function c an be found in the

Internal Settings

(Page 26).

Input Error Codes

The input indicators flash when errors are
present on the selected digital input. There
are no error indications for analog inputs. Use
the following table to diagnose the problem:

flashes

section of this manual

occurring, converter may be
interpolating to replace
invalid samples, check the

input is selected and operating normally.
A blinking blue light indicates that the
input is selected but a connection to a

input D1 is selected and operating
normally. A blinking blue light indicates
that the input is selected but audio data

input D2 is selected and operating
normally. A blinking blue light indicates
that the input is selected but audio data

input D3 is selected and operating
normally. A blinking blue light indicates
that the input is selected but audio data

input D4 is selected and operating
normally. A blinking blue light indicates
that the input is selected but audio data

Tip: Common causes of input errors:

• Disconnected or fa u lty cable

• Use of excessively long digital cables

• Use of analog cables for digital signals

• Use of optical cables for sample rates

exceeding 96 kHz

• Incompatible data type (AC3, ADAT, etc.)

• Non-audio data is being received

Note: D4 cannot be selected if the Digital

Pass Through function is enabled.

Instruction Manual for DAC3 B with 1.X Firmware Page 11

Digital Format Indicators

16 Only

Measured input word length is
16 bits.

16 and 24

Measured input word length is
17 to 23 bits.

24 Only

Measured input word length is
24 bits.

Both Off

Measured input word length is
less than 16 bits.

44 Only

The input format is PCM at a
sample rate).

48 Only

The input format is PCM at a
used with video).

44 and 2X

The input format is PCM at a

format).

48 and 2X

The input format is PCM at a
resolution audio format).

44 and 4X

The input format is PCM at a

format).

48 and 4X

The input format is PCM at a
resolution audio format).

DSD

The input format is 1-bit DSD

streamed in DoP format.

All Off

Digital signal is not present or
is not in a supported format.

Two lights indicate the
measured word length of
the selected digital input.

Four lights indicate the
sample rate and format of
the selected digital input.

Tip: Computers, disk players, and streaming

devices often subject the digital signal to
sample rate conver sion, changes in word
length, PCM to DSD conversions, and other
forms of digital processing that may degrade
the quality of the audio. This display makes it
easy to detect these processes.

Format indicators

The 44, 48, 2X, 4X, and DSD lights in d icate
the sample rate and format of the selected
digital input as follows:

sample rate of 44.1 kHz (CD

sample rate of 48 kHz (often

sample rate of 88.2 kHz
(high-resolution audio

Word Length Indicators

The 16 and 24 lights indicate the measured
word length of the selected digital input. The
DAC3 detects active data bits and displays
the results as follows:

sample rate of 96 kHz (high-

sample rate of 176.4 kHz
(high-resolution audio

sample rate of 192 kHz (high-

at a sample rate of 2.8224

(4x and 2X)

MHz (high-resolution audio
format). Note: DSD must be

Instruction Manual for DAC3 B with 1.X Firmware Page 12

Operational Details

CONTROL-LOCK Function

AUTO-ON Function

The DAC3 can be programmed to
automatically turn on whenever AC power is
applied. This function allows automation using
switched AC outlets. When AUTO-ON is
enabled, the DAC3 cannot be turned off
without removing AC power.

The AUTO-ON function is programmed by
pressing and holding the POWER button on
the front panel for three seconds. This
function cannot be programmed from the
remote control. This limitat ion prevents
accidental access to this special feature.

Tip: The AUTO-ON function cannot be

changed if the CONTROL-LOCK is on. Turn
the CONTROL-LOCK off before attempting to
change the AUTO-ON function.

Enabling AUT O -ON

The CONTROL-LOCK function
disables the remote control and
all buttons on the front panel.

Use the CONTROL-LOCK
function when the DAC3 will be
used in a dedicated application
using just one digital input. This
feature prevents accidental loss

of audio in these dedicated applications.

Controls are locked when the CONTROL-
LOCK light is on.

Press the CONTROL-LOCK button for 3
seconds to toggle this function on or off.

Tip: If CONTROL-LOCK is on, but AUTO-ON

is off, the unit can be powered down by
pressing and holding the POWER button for 3
seconds. This turns the unit off, but does not
turn off the CONTROL-LOCK function.

Starting with the DAC3 off, press and hold
the POWER button for 3 seconds.

If AUTO-ON has been successfully enabled,
the unit cannot be turned off using the
POWER button or the OFF button on the
remote.

Disabling AUT O -ON

Starting with the DAC3 on, press and hold
the POWER button for 3 seconds. At the end
of 3 seconds the DAC3 will power down if the
AUTO-ON mode has been successfully
disabled.

Instruction Manual for DAC3 B with 1.X Firmware Page 13

Bi-directional 12V Trigger

Benchmark has
reinvented the 12
volt trigger by adding
bi-directional
signaling. The trigger
connection on the

DAC3 can be used as
an input, an output, or both. It is compatible
with any common 12 volt trigger input or
output. The 12V TRIGGER I/O can be used
to turn other audio components on when the
DAC3 turns on. The DAC3 can also turn on
and off in response to other connected
components. The Benchmark bi-directional
12V Trigger is compatible with virtually all
trigger systems.

The 12V TRIGGER I/O can be connected to
the trigger input or output ports on a
preamplifier, power amplifier, or both.

The DAC3 can send a 12 Volt DC trigger
signal to start other components in the
system, or it can wake up in response to an
externally generated trigger signal. The DAC3
automatically configures its trigger I/O port
as an input (slave) or output (master).

Trigger Output (DAC3 is Master)

When the DAC3 is turned on using the

POWER button (on the front panel), or the
ON button (on the remote), the DAC3

configures itself as a trigger master and will
drive the 12V TRIGGER I/O to 12 volts DC
and hold it there while the DAC3 is on. The
trigger output signal generated by the DAC3
is delayed so that the DAC3 can stabilize
before downstream devices (such as power
amplifiers) turn on. When powering down, the
DAC3 will mute before allowing the trigger
line to drop low. The DAC3 keeps the internal
power supplies running for 10 seconds after
dropping the trigger. This delay gives other
triggered components ample time to mute
and shut down.

If the AUTO-ON function is enabled, the
DAC3 will auto matically turn on when AC
power is applied, configure itself as a trigger

master, and ignore any external signaling on
the 12V TRIGGER I/O line. In AUTO-ON
mode, the DAC3 will always drive the 12V
TRIGGER I/O line to 12 V (after a short
start-up delay).

Trigger Input - (DAC3 is Slave)

If the DAC3 is off and an external device
pulls the trigger I/O to 12 volts, the DAC3
will configure itself as a trigger slave and will
follow the actions of the trigger input. The
DAC3 will then turn off when the external
device stops sending the 12 V trigger.

Typical Trigg e r Applications

In most systems, the 12V TRIGGER will be
used to connect the DAC3 to one other
device. The DAC3 can be connected to the
first trigger input at the beginning of a trigger
chain, or it can be connected to the last
trigger output at the end of the chain (less
common).

Typical trigger applications:

• DAC3 B → Preamplifier → Amplifier
o DAC3 B → LA4 → AHB2

• DAC3 B → Headphone Amplifier
o DAC3 B → HPA4

• DAC3 B → Amplifier
o DAC3 B → AHB2

The Benchmark bi-directional trigger system
also supports multiple trigger ports wired
together on a bus.

A group of Benchmark trigger ports can be
connected to a group of non-Benchmark
trigger input ports to form a single trigger
bus. A bus should never be connected to
more than one non-Benchmark trigger output
port. If an output port is connected to the
bus, this device should be used to start the
audio system.

A 3.5 mm (1/8") TRS "Y" cable can be used to
split the trigger output of the DAC3 to feed
more than one trigger input.

Instruction Manual for DAC3 B with 1.X Firmware Page 14

Benchmark AHB2 power amplifiers have two
trigger I/O ports that are wired in parallel.
This makes it easy to connect more than one
power amplifier to a trigger bus (without the
use of a "Y" cord). Connect a trigger cable
between the DAC3 and the first amplifier.
Use another trigger cable to connect this
amplifier to the next amplifier. Any number of
Benchmark amplifiers can be added to the
trigger bus. The DAC3 will turn on first, and
after a delay, all of the amplifiers will tu rn on
together.

Bi-Directional Trigger Applications

Benchmark products support bi-directional
communications over a trigger bus. Any
Benchmark product connected to the bus can
turn the entire system on or off. Be ca u s e of
the bi-directional design, any power button on
a Benchmark DAC3 or AHB2 can be used to
start or stop the system.

The Benchmark device that starts the system
will become the trigger master. If the trigger
master is turned off, all slave devices will
follow. If a slave device is turned off, all other
devices will stay on.

Trigger Specifications

The Benchmark 12V TRIGGER I/O has a
wide operating range to allow interfacing with
most other DC trigger systems. It should only
be used with trigger inputs that are designed
to tolerate 12 VDC.

• 12 VDC 200 mA current-limited output

• Input responds to 3.3 V logic and

higher

• Maximum input voltage = 30 VDC

• Maximum reverse input voltage = -0.3

VDC

• Input Impedance = 20 k Ohms

• 1/8" (3.5 mm) TRS jack

• Tip = 12 Volt Trigger I/O

• Ring = no connection

• Sleeve = chassis ground

If the DAC3 is used to turn the system on,
any connected AHB2 amplifiers will become
slave devices and they can be turned off
without shutting down the DAC3.

Slave devices can force the entire trigger bus
to shut down if the POWER button or OFF
button is pressed and held for 3 seconds.

Tip: Press and hold the POWER button on

any Benchmark device for 3 seconds to force
a shutdown of the entire trigger-connected
system.

Instruction Manual for DAC3 B with 1.X Firmware Page 15

HPA4, LA4 Compati b ility

High-Current Outputs

The DAC3 B is designed to work seamlessly
with Benchmark line amplifiers (such as the
HPA4 and LA4).

The line amplifier will control the system
volume and analog input switching. The
DAC3 B will be used to select the digital
inputs. Both are controlled from a single
Benchmark remote control.

USB MODE Selection

The DAC3 supports two USB MODES:

• USB Audio 1.1 mode - up to 24 bits
at 96 kHz

• USB Audio 2.0 mode - up to 24 bits
at 192 kHz plus DSD in DoP 1.1
format

Caution: Close all USB audio playback

applications before changing the USB MODE.
If an audio application is playing while the
USB MODE is changed, the audio application
may freeze. Avoid any unnecessary switching
between USB MODES. Rapid switching
between mode s can confuse some opera ting
systems.

The RCA and XLR outputs on the DAC3 B
are equipped with low-impedance high­current drivers. These robust outputs are well
equipped to drive a wide variety of input
impedances. Th e DA C3 B outputs remain
clean when driving inputs that present
difficult loads (high input capacitance a nd/or
low input impedance).

The XLR outputs on the DAC3 B are
equipped with jumper-configured passive low­impedance output pads. These pads can be
set to an attenuation of 0 dB (pad off), 10
dB, or 20 dB. The pads should be used to
match the output level of the DAC3 B to the
input sensitivity of the downstream device.

Tip: In most applications we recommend

placing a Benchmark HPA4 or LA4 line
amplifier between the DAC3 B and the power
amplifier. These Benchmark line amplifiers
will optimize the analog interface between the
DAC3 and the power amplifier while providing
a stepped relay gain control w ith exceedingly
low THD and noise. The HPA4 or LA4
provide a transparent path between the
DAC3 B and a power amplifier.

Driving Power Amplifiers

Note: The computer and DAC3 must be

connected and both must be on before the
USB MODE can be changed.

To change the USB MODE, press and hold
the USB button on the remote control for 3
seconds. If a remote contr ol is not available,
simultaneously press and hold both INPUT
buttons on the front panel for 3 seconds.

Tip: The 4X or 2X lamp will flash once every

time the USB input is selected. This flash
provides a convenient indication of the
current USB MODE. A flash of the 4X lamp
indicates that the unit is in USB Audio 2.0
mode. A flash of the 2X lamp indicates that
the unit is in USB Audio 1.1 mode.

If the system volume is being controlled
digitally by an upstream device, the DAC3 B
can be connected directly to an audio power
amplifier or a set of powered monitors. This
direct connection provides a clean path
between the DAC3 B and the amplifier, but it
is important to match the signal levels
between the DAC3 B and the power amplifier
in order to prevent excess ive use of the
upstream digital volume control.

The XLR outputs are equipped with adjustable
pads that can be used to optimize the system
gain structure in order to maximize the
system noise performance.

Most power amplifiers and powered monitors
will require the use of the 10 dB or 20 dB

Instruction Manual for DAC3 B with 1.X Firmware Page 16

pads. Use the 0 dB setting when driving a
Benchmark AHB2 power amplifier.

Tip: The Benchm ark AHB2 power amplifier

has a unique low-gain topology tha t a llows it
to accept full studio-level input signals. This
high-level interconnection provides a very
low-noise connection between the DAC3 and
the AHB2. Set the input SENSITIVITY
switch on the AHB2 to 22 dBu (all the way
down). This places the AHB2 full-power
output point at an input level of 2 2 dBu. This
level is exactly 2 dB lower than the calibrated
output level of the DAC3 B (when the pads
are set to 0 dB). This configuration optimizes
the gain-staging between the DAC3 and the
AHB2.

Tip: If you are using a direct connection

between a DAC3 B and a non-Benchmark
power amplifier, the XLR pads should be set
so that a normal listening level is reached
when the system volume control is near its
maximum setting. This w ill optimize the gain­staging between the DAC3 B and your power
amplifier.

Tip: Increase the pad setting if a comfortable

listening level is reached while the system
volume control is well below maximum.

Optical, coaxial, and USB inputs (U, D1, D2
and D3) can be passed through to the D4
connector. The signals are buffered but are
not processed in any way. For this reason,
any data format can be passed through to the
D4 connector, even when these formats
cannot be decoded by the DAC3. Surround
formats, such as DTS, Dolby Digital, cannot
be decoded by the DAC3, but they can be
passed to a surround system using the digital
pass-through function.

The digital pass-through can also be used to
provide the following digital signal
conversions:

• Optical to Coaxial

• USB to Coaxial

• Coaxial to Coaxial (buffering)

DoP encapsulated DSD can also be passed
through D4. DSD files on a computer can be
sent in DoP to the USB input on the DAC3.
The USB input can be routed to coaxial
output D4. This output can be recorded by
any 24-bit, 176.4 kHz digital recorder with a
coaxial input. The PCM digital recorder can
then be used to play the DSD recordings.

Tip: Decrease the pad setting if a comfortable

listening level cannot be reached when the
system volume control is at maximum.

Instructions for setting the XLR pad jumpers
are detailed in the Interna l Set ti ng s section
of this manual. The DAC3 B is shipped with
the XLR pads disabled (set to 0 dB). No
adjustments will be necessary if you will be
using a Benchmark AHB2 power amplifier or
Benchmark line amplifier.

Digital Pass-Through

The second coaxial input (D4) can be
reconfigured as a digital output. When
operating as an output, any selected digital
input is passed through to D4 without any
processing.

Instruction Manual for DAC3 B with 1.X Firmware Page 17

Firmware Version Identification

Digit 1

Digit 2

2

D1 D2

.4 1 U D3

.2

D4

.1

The firmware version is displayed during the
lamp test while the DAC3 B is turning on. At
least one lamp in the INPUT INDICATOR
will flash rapidly while the remaining lamps
will be on. The flashing lamps identify the
firmware version. The values of each lamp
are shown in this chart. Add the values of all
flashing lamps to determine the version
number. If no lamp flash es in the second
column, the second digit is a 0.

Example 1: The U lamp is the only lamp that

flashes. The firmware version is 1.0.

Example 2: The U and D4 lamps flash. The

firmware version is 1.1.

Example 3: The D1 lamp is the o nly lamp

that flashes. The firmware version is 2.0.

Instruction Manual for DAC3 B with 1.X Firmware Page 18

Rear Panel

Inputs

There are five stereo digital inputs on the
DAC3 B:

• USB - USB Audio 1.1 or 2.0 Input

• D1 - Optical Digital Input

• D2 - Optical Digital Input

• D3 - Coaxia l Digital Input

• D4 - Coaxial Digital Input or Output*

These inputs are selected using the INPUT
buttons on the front-panel or on the remote­control.

* D4 can be jumper-configured as a digital
PASS-THROUGH output. When enabled, the

selected digital input will be routed to the
internal D/A converter and to output D4. The
selected input will be buffered and sent to
output D4 even if the format cannot be
decoded by the DAC3 B.

The digital inputs support PCM stereo
AES/EBU and SPDIF digital formats. Maximum
word length is 24-bits. Maximum sample rate
is 192kHz.

The digital inputs also support DSD stereo at
a sample rate of 2.8224 MHz using DoP 1.1
encapsulation.

The USB input has two operating modes:

• USB Audio 1.1 - PCM up to 24-bits at
96 kHz

• USB Audio 2.0 - PCM up to 24-bits at
192 kHz and DSD (DoP 1.1 format)

Caution: The optical inputs (D1 and D2) are

not recommended for DSD or for sample
rates above 96 kHz. Optical connections may
be unreliable at sample rates above 96 kHz.

Tip: The DAC3 B will not decode

multichannel digital formats such as AC3, and
Dolby Digita l. The audio will mute and the
INPUT INDICATORS will flash whenever an
incompatible format is connected to the
selected digital input. If the PASS-THROUGH
mode is enabled, these multichannel formats
can be sent to a surround processor using
connector D4 as a digital output.

Caution: The 12V TRIGGER I/O is not an

audio connection! This is a 12V DC connection
for synchronizing the on and off sequencing of
an entire audio system.

Instruction Manual for DAC3 B with 1.X Firmware Page 19

Digital Inputs - Overview

All of the digital inputs on the DAC3 B use
Benchmark's UltraLock3™ system to remove
virtually al l of the interface jitter. The result is
that all digital inputs deliver identical audio
performance. The USB, optical, and coaxial
digital input s will all sound identica l if the y
receive identical data.

The USB Audio 2.0 mode was tested for
compatibility with Windows XP, Vista, 7, 8
and 10 (driver installation is required for all
Windows versions). It was also tested for
compatibility with Mac OS X starting with
version 10.6 (operation is driverless for all OS
X versions).

Optical Digital Inputs - D1 and D2

Computer Input – USB

The USB input accepts a Type-B male USB
connector. A Type-A to Type-B USB cable is
provided with the DAC3 B. The USB cable
connects the DAC3 B directly to a computer’s
USB output.

The USB input supports 44.1, 48, 88.2, 96,

176.4, and 192 kHz PCM sample rates at
word lengths up to 24-bits. The USB input
also accepts DSD in DoP 1.1 format.

The DAC3 B can be configured as a USB
Audio 1.1 or USB Audio 2.0 device. Press
and hold the USB button on the REMOTE for
three seconds to toggle the USB MODE. If a
remote is not available, s imultaneously press
and hold both input buttons on the front
panel for three seconds.

The USB AUDIO 1.1 mode does not require
the installation of a driver. It allows a quick
driverless connection to windows machines
when playing sample rates of 96 kHz or less.
In this mode, Windows machines can begin
streaming audio within seconds after the
DAC3 B is connected for the first time. No
software or hardware configuration is usually
required.

USB Audio 2.0 is required for DSD and for
all PCM sample rates exceeding 96 kHz.
Windows computers require a driver to
support the USB Audio 2.0 mode.

The USB Audio 1.1 mode was tested for
compatibility with Windows XP, Vista, 7, 8
and 10, Mac OS X, and iPads using the 30-pin
to USB Camera Kit. No driver installation is
required for any of these systems when
operating in USB Audio 1.1 mode.

The optical input connectors (D1 and D2) are
commonly known as TOSLINK connectors.
The TOSLINK optical connectors used on the
DAC3 B are designed to work well at sample
rates up to 96 kHz. Maximum word length is
24-bits. All sample rates between 28 and 96
kHz are supported. The optical inputs may be
unreliable at sample rates above 96 kHz. The
optical inputs will accept professional
AES/EBU data formats or consumer S/PDIF
data formats.

Tip: The optical inputs include dust caps.

Keep these in place if the input is not being
used.

Coaxial Digital Inputs - D3 and D4

The coaxial digital inputs (D3 and D4) use
female RCA connectors. The input impedance
is 75 Ohms. Maximum word length is 24-bits.
All sample rates between 28 and 195 kHz are
supported. The coaxial digital inputs will
accept professional AES/EBU data formats or
consumer S/PDIF data formats. The coaxial
inputs also accept DSD in DoP 1.1 format.

The coaxial digital inputs are D C isolated,
current limited, and diode protected. The RCA
body is bonded directly to the chassis to
prevent currents in the internal ground
system. This direct bonding also maximizes
RF shielding.

Caution: Use 75-Ohm coaxial cables for

digital audio connections D3 and D4. Digital
interfaces require the use of matched
impedances. Do not use 50-Ohm coaxial
cables, twisted pair cables, or any non-coaxial
cables for digital audio. The digital inputs may
not function, or may be unreliable if the
incorrect cable is used.

Instruction Manual for DAC3 B with 1.X Firmware Page 20

Tip: The RCA analog outputs have no

restrictions on cable type. But, to avoid
confusion, we recommend using 75-Ohm
coaxial cables for all RCA connections. 75­Ohm coaxial cables are compatible with digital
audio, analog audio, and video.

Note: The Coaxia l in p u ts (D3 and D4) accept

professional or consumer digital aud io
formats. The AES3-id and SMPTE 276M
standards speci fy a 75-Ohm, 1 Vpp,
professional format which is also known as
AES/EBU and is commonly used in video
production facilities. The IEC 609588-3
standard specifies a 75-Ohm, 0.5 Vpp,
consumer format which is also known as
S/PDIF, and is commo nly used in hi-fi
equipment. The coaxial inputs are designed to
accept either type of signal.

12V TRIGGER I/O

The Benchmark bi-directional 12V TRIGGER
is com patible with virtua lly all trigge r
systems. The 12V TRIGGER I/O connection
on the DAC3 can be used as an input, an
output, or both. It is compatible with most 12
volt trigger inputs and outputs. The 12V
TRIGGER can be used to turn other audio
components on when the DAC3 B turns on.
The DAC3 B can also turn on and off in
response to trigger signals sent from other
components.

The Benchmark 12V TRIGGER I/O has a
wide operating range to allow interfacing with
most other DC trigger systems. It should only
be used with trigger inputs that are designed
to tolerate 12 VDC.

• 12 VDC 200 mA current-limited output

• Input responds to 3.3 V logic and

higher

• Maximum input voltage = 30 VDC

• Maximum reverse input voltage = -0.3

VDC

• Input Impedance = 20 k Ohms

• 1/8" (3.5 mm) TRS jack

• Tip = 12 Volt Trigger I/O

• Ring = no connection

• Sleeve = chassis ground

Caution: The 12V TRIGGER I/O is not an

audio connection! This i s a 12V DC connection
for synchronizing the on and off sequencing of
an entire audio system.

The 12V TRIGGER I/O can be connected to
the trigger input or output ports on a
preamplifier, power amplifier, or both.

The DAC3 can send a 12 Volt trigger signal to
start other components in the system, or it
can wake up in response t o an externally
generated trigger signal. The DAC3
automatically configures the 12V TRIGGER
I/O port as an input (slave) or output
(master). See page 14 for more information.

Instruction Manual for DAC3 B with 1.X Firmware Page 21

Outputs

Analog Outputs

Industry-Stand ard XLR Wiring

XLR pin 2 = + Audio Out

•

XLR pin 3 = - Audio Out

•

XLR pin 1 = Cable Shield

•

Caution: If the balanced XLR outputs are

wired to an unbalanced input (using a special
adapter cable), pin 3 must be left floating.
Shorting pin 3 to ground will increase the
temperature of the output drivers, will
increase power consumption, and may cause
distortion.

The DAC3 B has one pair of balanced XLR
outputs and one pair of unbalanced RCA
outputs.

The DAC3 B features high-current output
drivers that are capable of driving 300-Ohm
loads without an increase in distortion. They
are also well suited for driving long cables or
high-capacitance loads.

Balanced XLR Analog Line Outputs

The Left and Right balanced outputs use
Neutrik™ gold-pin male XLR jacks. The XLR
shell and pin 1 (ground) are both directly
bonded to the chassis to prevent currents in
the internal ground system. This direct
bonding also maximizes RF shielding.

The XLR outputs have passive attenuators
that allow direct connections to a wide variety
of audio devices without a loss of dynamic
range. The 10 or 20 dB pads are usually
required for direct interfacing to power
amplifiers and powered speakers. The DAC3
B ships with the pads disabled (0 dB setting).

Unbalanced RCA Analog Outputs

The Left and Right unbalanced outputs use
female RCA jacks. The ground connections
are bonded to chassis ground. This prevents
ground loop currents in the internal analog
ground.

The RCA output impedance is very low (30
Ohms). This makes these outputs well suited
for driving high-capacitance loads and/or
high-capacitance cables.

Caution: Mono summing with an RCA ‘Y’

cable is not recommended as this can produce
distortion. Mono summing with a ‘Y’ cable can
be accomplished with the use of a modified
cable by implementing a 1k Ohm series
resistor in each leg of the ‘Y’.

Note: The XLR pads do not have any effect

on the level of the RCA outputs.

A full description of the output attenuators
and instructions for configuration is located in
the Internal Settings section of this manual.

TIP: Use the 0 dB pad setting when driving

Benchmark products and other professional
products with XLR inputs that support +24
dBu signal levels. Use the 10 dB pad when
driving consumer-gr a de XLR inputs.

Instruction Manual for DAC3 B with 1.X Firmware Page 22

AC Power-Entry and Fuse Module

Input Voltage Range

Note: The DAC3 B is equipped with a

universal power supply. There is no voltage
selection switch. AC voltage range is 88-264
VAC, 47-63 Hz.

Power Cord

Note: The AC power input uses a standard

IEC type connector. One USA-compatible
power cord is included with DAC3 B
converters. IEC style power cords in country­spec ific configur ations are av ailable in your
locality.

Fuses

Caution: For continued fire hazard

protection always replace the fuses with
the correct size and type (0.5A 250 V

®

Slo-Blo

5 x 20 mm – Littelfuse®
HXP218.500 or equivalent). The fuse
drawer includes two fuses. Always
replace both fuses at the same time.

Caution: Always use a grounded power

cord. The DAC3 B is equipped with a
standard IEC power entry module. Use
an IEC power cord that is equipped with
the appropriate connector for your
location. Cords are av ailable from you r
dealer.

Instruction Manual for DAC3 B with 1.X Firmware Page 23

Internal Settings

Jumper-Configured Options

The following functions are jumper
configured:

• XLR Output Pads

• Digital Pass-Through

Removing Top Cover

The DAC3 cover must be removed to gain
access to the jumpers. Do not attempt to
remove the faceplate or rear panel.

Caution: The DAC3 contains static sensitive

components. Static discharge may cause
component failures, may affect the long-term
reliability, or may degrade the audio
performance. Use a static control wrist strap
when changing jumper settings.

• Disconnect AC power by unplugging
the power cord at the back of the
DAC3.

• Remove the 8 screws holding the
cover (4 on each side).

• Do not remove any screws on the
front, rear, or bottom panels!

• Never remove the power entry safety
cover in the rear corner of the DAC3.

• Connect a static-control wrist strap to
the chassis before touching any
internal component.

• If a static-control wrist strap is not
available, keep one hand on the
chassis while moving the jumpers.
Avoid touching other components.

Instruction Manual for DAC3 B with 1.X Firmware Page 24

XLR Output Pads

Balanced Output Drive Capability:

Attenuator Output Maximum

Loss in dB

Setting (dB) Impedance Cable (ft) at 20 kHz

0 60

680 0.1

10 425 96 0.1

20 135 302 0.1

Unbalanced Output Drive Capability:

Output Maximum Loss in dB

Impedance Cable (ft) at 20 kHz

30 1360 0.1

XLR Output Pad Jumpers

The XLR outputs are equipped with low­impedance passive pads that may be used to
reduce the output levels while preserving the
full dynamic range of the DAC3. The DAC3
ships with the pads disabled (0 dB setting).

Tip: To set the XLR outputs are factory-

preset to deliver professional studio levels.
Most home installations will require the use of
the 10 dB or 20 dB pads.

Tip: Use the factory-default 0 dB setting

when driving Benchmark products such as the
HPA4, LA4 or AHB2. When directly driving
most other power amplifiers (or powered
speakers), start with the 10 dB pad setting.
If necessary, change the pads so that normal
listening levels are achieved when the system
volume control is near maximum.

When the output pads are enabled, the
output impedance changes slightly, and the
maximum recommended XLR cable length is
reduced as shown in Table 1. The table
assumes a cable capacitance of 32 pF/foot
and a maximum allowable loss of 0.1 dB at 20
kHz.

Four jumpers on four 6-pin headers (P8, P9,
P10, and P11) allow selection of the output
level at the XLR jacks. The jumpers are
properly configured if a normal playback level
is achieved when the VOLUME control is set
above the 11 o'clock position.

One pair of 6-pin headers control the
attenuation at each XLR jack as follows:

• 0 dB - (Attenuator disabled) – (Jumper
plug between pins 1 and 2 of each
header) - Factory Default

• -10 dB – (Jumper plug between pins 3
and 4 of each header)

• -20 dB – (Jumper plug between pins 5
and 6 of each header)

Table 1 - Cable Drive Capability

Figure 1 - Attenuators set to -10 dB

Instruction Manual for DAC3 B with 1.X Firmware Page 25

Digital PASS-THROUGH Function

The digital PASS-THROUGH function can be
enabled by moving two jumpers. When the
PASS-THROUGH function is enabled, D4
cannot be selected as an input . Any other
selected digital input will be routed to both
the internal D/A converter and to output D4.
The digital output at D4 is buffered, but is not
processed. Many digital audio formats ca n be
passed through to D4 (even when these
formats cannot be decoded by the DAC3).

Digital PASS-THROUGH Jumpers

To enable the PASS-THROUGH function,
move both P14 jumpers toward the faceplate
as shown in Figure 2. Once the jumpers are
moved into the positions shown in Figure 2,
D4 is configured as a digital audio output.

By default, D4 functions as a digital input and
the DAC3 is shipped with the jumpers set
according to Figure 3 (both jumpers toward
the rear panel).

Figure 3 - Digital PASS-THROUGH
Disabled (Factory Default)

Figure 2 – Digital PASS-THROUGH
Enabled

Instruction Manual for DAC3 B with 1.X Firmware Page 26

Rack Mounting

The DAC3 B is available with or without rack
mount ears. The chassis is one half the width
of a standard rack and occupies a one rack­unit height.

Units without rack-mount ears will require a
mounting tray. Units with rack-mount ears
will require a Rack-Mou nt Co up ler which
joins the DAC3 to another ½-wide
Benchmark product or to a Blank Plate.

The Rack-Mount Coupler, Rack-Mount
Tray and ½-Wide Blank Plate are available
from Benchmark.

Benchmark Rack-Mount Coupler

The Rack-Mount Coupler
joins two ½-wide 1-RU
products. Both products
must be equipped with rack
ears. Order with an optional
Blank Plate if only one unit
will be mounted in the rack.

Benchmark Rack Mount Tray

The Benchmark Rack Mount Tray mounts
up to two ½-wide Benchmark products in a
single race space. The tray accepts any
combination of ½-wide Benchmark products
(with or without rack-mount type faceplates).
A blank plate can be added when only one
unit is installed in the rack mount tray.

Benchmark ½-Wide Blank Plate

No tray is required when using the Rack­Mount Coupler.

The Benchmark ½-Wide Blank Plate is a
½-wide 1-RU anodized aluminum panel for
filling an unused ½-wide slot. It is available in
black or silver. The silver panel includes an
engraved Benchmark logo.

Visit BenchmarkMedia.com
selection of cable, accessories, and
replacement parts.

for a complete

Instruction Manual for DAC3 B with 1.X Firmware Page 27

DAC1, DAC2 and DAC3 Family
History

The pristine audio performance of the award­winning DAC1 made it the ‘Benchmark’ of
stand-alone D/A converters. The DAC1 USB,
DAC1 PRE , and DAC1 HDR added many
features to the basic DAC1 platform.
Benchmark converters are in use in many of
the world's top studios.

• Three coaxial digital inputs

• Three Headphone Gain Ranges

• LM4562/LME49860 opamps throughout

• Premium bulkhead-mounted RCA

connectors

In order to provide room for the analog inputs,
we removed the XLR dig it al input and replaced
it with tw o a d d it io n a l c o a x ia l d ig it al input s .

DAC1 HDR

The follo w in g is a brief overview of the various
Benchmark DAC1, DAC2 and DAC3 models:

DAC1 Series

DAC1

Benchmark's original DAC1 converter.

The DAC1 features included:

• Three digital inputs

• XLR outputs with passive pads

• RCA outputs

• Analog volume control

• HPA2™ headphone amplifier

• UltraLock™ jitter-attenuation system

DAC1 USB

The DAC1 USB introduced these
improvements:

• AdvancedUSB™ computer input

• Mute switch on the left headphone jack

• Two headphone gain ranges

• High-current LM4562/LME49860 output

stages - designed to driv e d if ficult lo a d s

• Lower output impedances

Benchmark's AdvancedUSB™ computer input
was the first USB audio interface to support 96
kHz audio without t h e ne e d to install special
drivers.

DAC1 PRE

The DAC1 PRE added th ese improvements:

The DAC1 HDR added:

• IR Remote Control

• HDR-VC™ (high dynamic range

volume control).

The HDR-VC™ features a custom-made,
motor-driven Alps potentiometer. The motor­driven control provides the audio performance
of a manual control while adding the
convenience of remote control.

DAC2 Series

DAC2 HGC

The DAC2 HGC maintains the familiar ½-wide
DAC1 form factor, but the entire product was

redesigned from the ground up.

The DAC2 HGC features:

• Four 32-bit converters per channel

• Native 24-bit/192kHz PCM conversion

• Native 64X DSD conversion

• High-headroom digital processing

• UltraLock2™ jitter attenuation

• Multi-mode asynchronous USB audio

input

• Sample rate and word length displays

• Polarity control

• Home theater bypass

• Digital p a ss-through

• Bi-directional 12V trigger

• Two stereo analog inputs

• Three stereo analog outputs

• Two optical in pu t s

• High-effic ie n c y low-noise power

supplies

Instruction Manual for DAC3 B with 1.X Firmware Page 28

DAC2 L

DAC3 vs. DAC2

The DAC2 L is identica l to t he DAC2 HGC
except that the DAC2 L has no headphone
amplifier.

DAC2 D

The DAC2 D is identical t o t he DAC2 HGC
except that the DAC2 D has no analog inputs
and no 12V trigger.

DAC2 DX

The DAC2 DX replaced the DAC2 D. The new
model added an XLR digital input and the 12V
trigger. It also added a second output bus so
that one set of outputs could be placed in
calibrated mode while the other was controlled
by the volume knob.

DAC3 Series

On the surface, the DAC3 series converters
look exactly like the DAC2 converters. They
have the same controls, the same connectors,
and even the similar-looking circuit boards.
The difference is that many critical
components and sys tems have been upgraded.
The new DAC3 delivers lower THD, improved
digital filter in g, and fa s ter PLL loc k t im es .

The DAC3 series adds the following
improvements over the DAC2 series:

• ESS SABRE-PRO D/A Conversion

• UltraLock3™ clock system

o Instantaneous lock
o Instantaneous input switching

• THD reduction system

o 2nd-harmonic compensation
o 3rd-harmonic compensation

• Improv e d d ig it al filte r s

o Lower passband ripple
o Flatter frequency response

• Higher maximum output level

• Increased Dynamic Range

The firmware, digital s ignal pr oc e ssing, and
UltraLock™ clock system have all been
upgraded in the new DAC3. Most notably, the
DAC3 series includes the new ES9028PRO D/A
converter. This groundbreaking D/A converter
IC offers several significant improvements over
the ES9018 converter used in the DAC2
series. Until the ES S P RO series wa s
introduced, the ES9018 was the highest
performance D/A converter IC available. The
ESS PRO series converters are now setting this
benchmark. The Benchmark DAC3 is one of
the first products to feature this new 32-bit
D/A converter.

Benchmark's ultra-clean analog stages, low­jitter UltraLock3™ clock system, and high­headro o m D SP lev e r a ge th e f ull capabi l ities of
the new ESS PRO series converters.

Instruction Manual for DAC3 B with 1.X Firmware Page 29

Benchmark Technologies

Native DSD Conversion

The digital coaxial inputs and the USB Audio

2.0 input on the DAC3 support native DSD

conversion. DoP 1.1 DSD encapsulation is
automatically detected on all digital inputs.
The system seamlessly switches to native
DSD conversion when DoP is detected. DoP

1.1 DSD encapsulation is supported by many
media players. DSD downloads are now
available from several sources.

Visit our website for an up-to-date list of DSD
and PCM high resolution download sites.

High Headroom DSP

All of the digital processing in the DAC3 is
designed with a headroom of 3.5 dB above 0
dBFS. A sinusoid that just reaches the
maximum positive and negative digital codes
has a level of 0 dBFS. If the peaks of the
sinusoid occur between samples, higher
signals can be captured without clipping. For
a pure tone, the maximum intersample peak
that can be represented by a PCM system is
+3.01 dBFS.

Benchmark's high-headroom DSP can handle
intersample peaks without overloading or
clipping. Intersample peaks are cleanly
rendered by the DAC3 and are delivered to
the analog outputs without clipping or
distortion. Very few D/A converters can
make this claim!

In most D/A conversion systems, intersample
peaks cause overloading of the upsampling
interpolators and digital filters that are found
in all sigma-delta converters. When overloads
occur, bursts of non-harmonic distortion are
produced. These bursts of high-frequency
distortion may occur many times per second
and may add a false brightness and
harshness to the sound. This defect impacts
PCM formats but does not impact 1-bit DSD
formats. The absence of intersample clipping
may explain some people's preference for
DSD. The DAC3 delivers clean PCM

conversion that meets or exceeds the clarity
of DSD.

Intersample Overs

(1 = Maximum Digital Code)

1.5

1

0.5

0

-0.5

-1

-1.5

Intersample overs are common in low sample
rate (44.1 kHz and 48 kHz) commercial
releases. Due to the mathematics and the
bandwidth of typical input signals,
intersample overs are less of a problem in
high sample rate recordings. The reason for
this is that the worst-case (+3.01 dB)
intersampl e ove rs occurs for pure tones that
are exactly 1/4 of the sample rate (as shown
in the figure above). At the 44.1 kHz CD
sample rate, the worst case occurs at 11.025
kHz. It turns out that many recordings have
substantial peaks near this frequency. I n
contrast, at a sample rate of 88.2 kHz, the
worst-case intersample overs occur at a
frequency of 22.1 kHz where most musical
sources have insufficient energy to produce
significant intersample overs. The 88.2 kHz
sample rate is still susceptible to intersample
overs, but the magnitude of the worst-case
overs tends to be much lower. For example,
at 1/8th of the sample rate (11.025 kHz), the
maximum intersample peak is about +0.66
dB instead of the 3.01 dB worst case at a
sample rate of 44.1 kHz.

The biggest advantage of higher sample rates
may be the immunity to intersample overs. If
higher sample rates sound better, this
difference may be entirely due to the absence
of DSP overloads cau se d by intersample
overs. Benchmark's high-headroom DSP
renders low sample rates with the clarity and
detail normally associated with high sample
rates.

Analog
Audio

Digital
Samples

Instruction Manual for DAC3 B with 1.X Firmware Page 30

1.5

0.5

-0.5

-1

-1.5

Conventional Interpolation

(Intersample Overs are Clipped)

1

Analog
Audio

0

Digital
Samples

32-bit SABRE-PRO D/A System

Four balanced 32-bit D/A converters deliver
audio to Benchmark's low-impedance current
to voltage converters. The 4:1 redundancy
reduces noise by 6 dB. The redundancy also
reduces the THD. The conversion system at
the core of the DAC3 is as good as it gets.
The analog circuits that follow the D/A
converter are carefully designed. Benchmark
has leveraged its long history of building
reference analog audio equipment to create
an outstanding output stage.

PCM systems can accurately capture peaks
that exceed 0 dBFS, but these peaks will
overload the oversampling interpolators in
most delta-sigma D/A converters. The
solution is not to eliminate the interpolation
process; the solution is to build interpolators
with more headroom.

High-Headroom Interpolation

(Intersample Overs are Not Clipped)

1.5

1

0.5

0

-0.5

-1

-1.5

The interpolation process is absolutely
necessary to achieve 24-bit state-of-the art
conversion performance. Unfortunately,
intersample overs cause clipping in most
interpolators. This clipping produces distortion
products that are non-harmonic and non­musical. We believe these broadband
distortion products often add a harshness or
false high-frequency brightness to digital
reproduction. The DAC3 avoids these
problems by maintaining at least 3.5 dB of
headroom in the entire conversion system.
We believe this added headroom is a
groundbreaking improvement.

Analog
Audio

Digital
Samples

Diagnostic Displays

Ever wonder why that 192 kHz 24-bit
download on your computer just doesn't
sound right? Your media player or comput er
may be downsampling to 44.1 kHz and/or
truncating to 16-bits. Many media players and
computer operating systems apply poor­quality sample rate conversion and/or
truncation. Fortunately these problems can be
eliminated w ith the selection of a good
frequency-agile media player.

Many disk players also downsample all
sources to 44.1/16. This processing can do
significant damage to the audio quality.

The sample-rate and word-length displays on
the DAC3 confirm the proper operation of
your disk player, media player, and computer.

Bi-Directional 12 Volt Trigger

Benchmark has re-invented the 12 volt
trigger. The trigger connection on the DAC3
can be used as an input or output or both,
and is compatible with any common 12 volt
trigger input or output. The trigger can be
used to turn a power amplifier on or off
automatically. The DAC3 will also respond to
a 12 volt trigger and follow the actions of
another audio component.

Benchmark component s can communicate bi­directionally on the trigger I/O ports. This
bidirectional communication provides greater
flexibility. In a given system, the power

Instruction Manual for DAC3 B with 1.X Firmware Page 31

button on any Benchmark device can be used
to start or stop the entire audio system in a
sequenced manner.

Distributed Power Regulation

3.5 dB, sample rate is 211 kHz, and jitter-

induced distortion and noise is at least 160 dB
below the level of the music - well below the
threshold of hearing. Benchmark's
UltraLock3™ system eli mi n at es all audible
jitter artifacts.

To achieve the lowest possible noise, the
DAC3 uses distributed power supply
regulation. Each critical subsystem has at
least one dedicated low-noise voltage
regulator.

We have created a discrete ultra low-noise
regulator for the ES9028PRO D/ A con v erter.
This Benchmark exclusive feature improves
the noise performance of the already­outstanding ES9028PRO.

Differential Amplifiers

Differential amplifiers remove common-mode
distortion components from the D/A converter
outputs. This feature is critical for achieving
low-distortion in down-stream devices.
Benchmark addresses common-mode
distortion so that it will not cause distortion in
power amplifiers and other connected
devices. Common-mode distortion can cause
audible distortion while escaping the scrutiny
of an audio analyzer. The balanced and
unbalanced outputs on the DAC3 deliver very
similar performance.

The Importance of Eliminating Jitter

Accurate 24-bit audio conversion requires a
very low-jitter conversion clock. J itter can
very easily turn a 24-bit converter into a 16­bit converter (or worse). There is no point in
buying a 24-bit converter if clock jitter has
not been adequately addressed.

Jitter is present on every digital audio
interface. This type of jitter is known as
‘interface jitter’ and it is present even in the
most carefully designed audio systems.
Interface jitter accumulates as digital signals
travel down a cable from one digital device to
the next. If we measure interface jitter in a
typical system we will find that it is 10 to
10,000 times higher than the maximum
allowable level for accurate 24-bit conversion.
Fortunately, interface jitter has absolutely no
effect on the audio unless it influences the
conversion clock in an analog-to-digital
converter (A/D), the conversion clock in a
digital-to-analog converter (D/A), or the rate
estimator in an asynchronous sample rate
converter (ASRC).

Many D/A converters omit the differential
amplifiers after the converters. Specifications
usually ignore common-mode distortion. A
balanced sign al with high common-mode
distortion can measure just fine when feeding
a precisely balanced input on a high-quality
audio analyzer. However, any imbalance in a
downstream device will expose the common­mode distortion.

Jitter-Immune UltraLock3™

UltraLock3™ is an improved version of the
UltraLock2™ clock system used in the
DAC2. The new UltraLock3™ system

provides faster lock times than the older
UltraLock2™ and UltraLock™ syst ems. The
DSP processing is 32-bits, DSP headroom is

Instruction Manual for DAC3 B with 1.X Firmware Page 32

Many converters use a single-stage Phase
Lock Loop (PLL) circuit to derive their
conversion clocks from AES/EBU, wordclock,
or superclock reference signals. Single-stage
PLL circuits provide some jitter attenuation
above 5 kHz but none below 5 kHz.
Unfortunately, digital audio signals often have
their strongest jitter components at 2 kHz.
Consequently, these converters can achieve
their rated performance only when driven
from very low jitter sources and through very
short cables. It is highly unlikely that any
converter with a single-stage PLL can achieve
better than 16 bits of performance in a typical
installation. Specified performance may be
severely degraded in most installations.

Better converters often use a two-stage PLL
circuit to filter out more of the interface jitter.
In theory, a two-stage PLL can remov e
enough of the jitter to achieve accurate 24-bit
conversion (and some do). However, not all
two-stage PLL circuits are created equal.
Many two-stage PLLs do not remove enough
of the low-frequency jitter. In addition, two­stage PLL circuits often require several
seconds to lock to an incoming signal. Two­stage PLL circuits may fail to lock when jitter
is too high, or when the reference sample
frequency has drifted.

UltraLock™ converters exceed the jitter
attenuation performance of two-stage PLL
converters while achieving near instantaneous
lock time. They are free from the slow-lock
and no-lock problems that can plague two­stage PLL designs. UltraLock™ converters
have extremely high immunity to interface
jitter under all operating conditions.

The UltraLock™ system is so effective that
no jitter-induced artifacts could be detected
using an Audio Precision System 2 Cascade
test set while the inputs to the DAC3 were
exposed to high levels of interface jitter. The
measurement limits includ ed the ability to
detect artifacts as low as –144 dBFS, but
none could be detected, even while applying
jitter amplitudes as high as 12.75 UI, over a
frequency range of 2 Hz to 200 kHz. Any
AES/EBU signal that can be decoded by the
AES/EBU receiver in the DAC3 will be
reproduced without the addition of any
measurable jitter artifacts.

Benchmark’s UltraLock™ technology
eliminates jitter-induced performance
problems. UltraLock™ technology isolates
the co nvers ion clock from the dig ital audio
interface cl ock. Jitter on a D/A digital audio
input, or an A/D reference input can never
have any measurable effect on the conversion
clock of an UltraLock™ converter. In an
UltraLock™ converter, the conversion clock
is never phase-locked to a reference clock.
Instead the converter oversampling-ratio is
varied with extremely high precision to
achieve the proper phase relationship to the
reference cl ock. The clock isolation of the

UltraLock™ system ensures that interface
jitter can never degrade the quality of the
audio conversion. Specified performance is
consistent and repeatable in any installation
with cables of any quality level!

How does conversion clock jitter degrade
converter performance?

Problem #1: Jitter phase-modulates the

audio signal. This modulation creates
sidebands (unwanted tones) above and below
every tone in the audio signal. Wors e y et,
these sidebands are often widely separated
from the tones in the original signal.

Jitter-induced sidebands are not musical in
nature because they are not harmonically
related to the original audio. Furthermore,
these sidebands are poorly masked (easy to
hear) because they can be widely separated
above and below the frequencies of the
original audio tones. In many ways, jitter
induced distortion resembles intermodulation
distortion (IMD). Like IMD, jitter induced
distortion is much more audible than
harmonic distortion, and more audible than
THD measurements would suggest.

Jitter creates ‘new audio’ that is not
harmonically related to the original audio
signal. This ‘new audio’ is unexpected and
unwanted. It can caus e a loss of imaging, and
can add a low and mid frequency ‘muddiness’
that was not in the origi nal audio.

Jitter-induced sidebands can be measured
using an FFT analyzer while the converter
plays a pure high-amplitude tone. We
typically use a full-scale 10 kHz test tone to
test for the presence of jitter-induced side
bands (see Graph 14
the DAC3 is free from any jitter-induced
sidebands to a measurement limit of about

-144 dB relative to the level of the test tone.

The graph plots the output spectrum of the
DAC3 when exposed to 31 different jitter
frequencies ranging from 100 Hz to 100 kHz.
All 31 output spectra are identical and are
free from any signs of jitter-induced
distortion.

). This FFT shows that

Instruction Manual for DAC3 B with 1.X Firmware Page 33

Problem #2: Jitter can severely degrade the
anti-alias filters in an oversampling converter.
This is a little known but easily measurable
effect. Most audio converters operate at high
oversampling ratios. This allows the use of
high-performance digital anti-alias filters in
place of the relatively poor performing analog
anti-alias filters. In theory, digital anti-alias
filters can have extremely sharp cutoff
characteristics, and very few negative effects
on the in-band audio signal. Digital ant i-alias
filters are usually designed to achieve at least
100 dB of stop-band attenuation. But, digital
filters are designed using the mathematical
assumption that the time interval between
samples is a constant. Unfortunately, sample
clock jitter in an A/D or D/A varies the
effective time interval between samples. This
variation alters the performance of these
carefully designed filters. Small amounts of
jitter can severely degrade stop-band
performance, and can render these filters
useless for preventing aliasing.

The obvious function of a digital anti-alias
filter is the removal of audio tones that are
too high in frequency to be represented at the
selected sample rate. The not-so-obvious
function is the removal of high-frequency
signals that originate inside the conver ter
box, or even originate inside the converter IC.
These high-frequency signals are a result of
crosstalk between digital and analog signals,
and may have high amplitudes in a poorly
designed system. Under ideal (low jitter)
conditions, the digital anti-alias filter may
remove most of this unwanted noise before it
can alias down into lower (audio) frequencies.
These crosstalk problems may not become
obvious until jitter is present.

is added to any digital input on an
UltraLock™ converter. Try the same tests on
any converter using conventional single or
two-stage PLL circuits. Tests should be
performed with varying levels of jitter and
with varying jitter frequencies. The results will
be very enlightening. Jitter related problems
have audible (and measurable) effects on A/D
and D/A devices. Pr actitioners of Digital Audio
need to understand these effects.

Is it possible to el iminate all of the
effects of jitter in an entire digital audio
system?

Interface jitter will accumulate throughout

even the most carefully designed digital audio
system. Fortunately, interface jitter can
only degrade digital audio if it affects the
sampling circuit in an a nalog-to-digital or
digital-to-analog converter. Any attempt to
cure jitter outside of an A/D or D/A will prove
expensive and, at best, will only partially
reduce jitter-induced artifacts. Dedicated
clock signals (word clock, and super clock,
etc.) are often distributed to A/D conver ters
and D/A converters in an attempt to reduce
jitter. Again, these are only partia l solutions
because jitter even accumulates in these
clock distribution systems. Furthermore, a
poor quality master clock generator can
degrade the performance of the entire system
(if converter performance is dependent upon
reference clock quality). Jitter-free A/D and
D/A converters are the only true insurance
against the ill effects of jitter. UltraLock™
converters are jitter-immune under all
operating conditions (they will never add
audible jitter-induced artifacts to an audio
signal).

Stop-band attenuation can be measured very
easily by sweeping a test tone between 24
kHz and at least 200 kHz while monitoring the
output of the converter.

Put UltraLock™ converters to the test:

We encourage our customers to perform the
above tests on UltraLock™ converters (or let
your ears be the judge). There will be
absolutely no change in performance as jitter

Instruction Manual for DAC3 B with 1.X Firmware Page 34

What UltraLock™ converters cannot do:

UltraLock™ converters cannot undo damage

that has already been done. If an A/D with a
jitter problem was used to create a digital
audio signal, then there is nothing that can be
done to remove the jitter-induced distortion
that happened inside the A/D converter.
Jitter-induced sidebands are extremely
complex and cannot be removed with any
existing audio device. Therefore, it is very

important to attack jitter at both ends of the
audio chain. The DAC3 is a great start, as it
will allow accurate assessment of various A/D
converters. It is impossi ble to audibly
evaluate A/D performance without a good
D/A. The consistent performance delivered by
the DAC3 eliminates one major variable ­jitter.

Multi-Mode Asynchronous USB
Audio

Plug it in and Start Listening…
Immediately

Benchmark's Advanced USB Audio system
supports the industry standard USB Audio

1.1 and USB Audio 2.0 protocols. These
audio protocols should not be confused with
USB port speeds. The USB Audio 1.1
protocol requires at least a USB 1.0 (Full
Speed) port. USB Audio 2.0 requires at least
a USB 2.0 (High Speed) port.

clock is generated inside the DAC3. The
asynchronous USB interface pulls data from
the computer without using computer­generated clocks. The D/A conversion in the
DAC3 is completely isolated by the
asynchronous USB interface and by the
UltraLock3™ jitter-attenuation sy stem.

The DAC3 has a low-jitter mast er cl ock w hich
controls the transfer of audio data from the
computer to the USB sub-system. The
computer asynchro nously transfers audio data
to a buffer in the DAC3. The contents of the
buffer are then asynchronously transferred to
the D/A conversion sub-system. This second
asynchronous tra nsfer eliminates any trace s
of jitter that accumulate as the data is
transferred between the USB and conversion
subsystems. No traces of jitter-induced
distortion are detectable at our measurement
limits (about -144 dBFS). This truly
represents the state-of-the art. Enjoy the
convenience of computer playback without
compromise.

Benchmark's USB Audio 1.1 and USB Audio

2.0 modes are frequency agile. This means
that the sample rate is controlled by the
computer. The DAC3 will fo llow sample r ate
changes initiated by the computer and/or the
media playback software.

Tip: The USB Audio 1.1 protocol will run on

any USB port, but if it is run on a USB 1.0
(Full Speed) port, it will require all of the
available bandwidth to support 96 kHz sample
rates. If a USB 1.0 port is the fastest port
available, make sure that there are no other
devices sharing the USB hub that services the
port. When possible, connect the DAC3 to a
port that supports USB 2.0 or higher.

Tip: The USB Audio 2.0 protocol is required

for sample rates above 96 kHz. This protocol
will not run on USB 1.0 ports. When possible,
connect the DAC3 to a port that supports
USB 2.0 or higher.

Asynchronous USB

In all modes the USB communications are
asynchronous. An ultr a low jitter conversion

The Asynchronous USB system supports USB
Audio 2.0 for high-resolution 192kHz, and
DSD playback. No drivers are required for
MAC operating systems. An easy-to-install
driver adds 192 kHz and DSD capabilities to
Windows operating systems.

The asynchronous driverless USB Audio 1.1
mode supports sample rates up to 96 kHz.
This USB mode can be selected from the front
panel or from the remote control. The
driverless USB Audio 1.1 mode allows quick
plug-and-play connections to Windows, MAC,
iOS, and Linux operating systems without
installing drivers. Just plug in the USB, and
the DAC3 becomes an available audio device.
In many cases, audio will automatically be
routed to the newly connected device. If not,
it can be selected as the current or default
playback device.

The industry-standard USB Audio Mode 2.0
mode is not yet natively supported by the
current Windows operating systems. For this
reason, a driver is required for Windows
operating systems. The driver supports
Windows XP, Vista, or 7, 8 and 10. This driver

Instruction Manual for DAC3 B with 1.X Firmware Page 35

is required for DSD and sample rates above
96 kHz when using Windows.

The USB subsystem is computer powered
(through the USB cord) and it remains active
when the DAC3 is powered down. This
feature prevents interruptions to the

computer playback operations and eliminates
the need to reconfigure the computer every
time the converter is turned on.

The Windows USB Audio 2.0 driver is
available at:

BenchmarkMedia.com/drivers

Instruction Manual for DAC3 B with 1.X Firmware Page 36

USB Driver Installation

Windows Operating Systems

Note: The DAC2/DAC3 driver is available for download at: BenchmarkMedia.com/drivers

Note: To provide full backward and forward compatibility, the DAC3 uses the DAC2 USB drivers.

This prevents the need to install two different sets of drivers. Please note that the DAC3 USB input
will be identified as "Benchmark DAC2" in your computer control panels. This is intentional.

Before you install the driver, make sure the USB cable is unplugged.

1. In the DAC2 Driver fold er, double click “setup.exe.”

Instruction Manual for DAC3 B with 1.X Firmware Page 37

2. A welcome scr een will pop-up. Click “Next.”

Instruction Manual for DAC3 B with 1.X Firmware Page 38

3. When you see the following sc reen, turn on the DAC3, plug in the USB cable, and select the
USB input on the DAC3. By default, the DAC3 is shipped in USB Audio 1.0 mode. Do not
proceed to the next step until the USB Audio 2.0 mode has been enabled. You can enable
the USB Audio 2.0 mode using one of the following two methods:

• METHOD 1 - REMOTE CONTROL: Using your remote control, press and hold USB
button for 3 seconds (the 4X light should flash on ce). If the 2X light flashes instead
of the 4X light, repeat this step.

• METHOD 2 - FRONT PANEL: From the front panel, simultaneously press and hold
both INPUT buttons for three seconds (the 4X light should flash once when selecting
the USB input). If the 2X light flashes instead of the 4X light, repeat this step.

Instruction Manual for DAC3 B with 1.X Firmware Page 39

4. You will now be prompted to select a location to install the driver. It will default to your
Program Files folde r. If you wish to install it another location, you can change the location.
We suggest keeping it in the default location. Click “Install”.

5. When the installation begins you will see the fo l lowing screen. Please be patient while the
driver installs. Installation may require several minutes.

Instruction Manual for DAC3 B with 1.X Firmware Page 40

6. When the installation finishes a message at the top will say “Installation Complete.” Click
“Next” to continue.

7. Click “Finish.” The Setup will close automatically. This completes the installation process.
You can now en j oy mu sic over the USB Audio 2.0 connection at sample rates up to 192
kHz. DSD can also be played in DoP 1.1 format.

Instruction Manual for DAC3 B with 1.X Firmware Page 41

Performance Graphs

Audio Precision

DAC3 - FFT Idle Ch ann el N oise a t Max Gain, 0 dB r = 0 dBFS = 27.5 dBu

DAC3 - FFT Idle Channel Noise.at27

Color

Sweep Trace Line Style

Thick Data Axis

Comment

1

1 Green

Solid 4 Fft.Ch.1 Ampl

Left

1 2 Red

Solid 4 Fft.Ch.2 Ampl

Right

-160

+0

-140

-120

-100

-80

-60

-40

-20

d

B

r

A

-160

+0

-140

-120

-100

-80

-60

-40

-20

d

B

r

A

0

32k

2k

4k 6k

8k 10k

12k

14k

16k

18k

20k 22k

24k

26k

28k

30k

Hz

Graph 1 – FFT Idle Channel Noise

The extraordinary performance of the DAC3 is demonstrated by the FFT plot shown above. There
is no sign of any AC hum, there are no idle tones, and there are no spurious tones detected at a
measurement limit of -160 dBFS.

The rise at 0 Hz is normal in an F FT analysis a nd is not an indication of noise. This 32k point FFT
analysis uses a Blackman-Harris window with 16x power averaging, and spans a frequency range
of DC to 32 kHz.

Instruction Manual for DAC3 B with 1.X Firmware Page 42

Graph 2 - Low Frequency FFT - AC Line-Related Hum

Audio Precision

DAC3 - FFT Idle Ch annel Noise - Low Frequency , 0 dBr = 0 dBFS = 27.5 dBu

DAC3 - FFT Idle Channel Noise - Low Fr equenc y.at27

Color

Sweep Trace Line Style

Thick Data Axis

Comment Cursor1 Cursor2

1 1 Green Solid 4 Fft.Ch.1 Ampl Left

Left Channel *-160.182 dB r *-158.092 dBr

1 2 Red Solid 4 Fft.Ch.2 Ampl Right Right Channel -159.850 dBr A -160.611 dBr A

-160

+0

-140

-120

-100

-80

-60

-40

-20

d

B

r

A

-160

+0

-140

-120

-100

-80

-60

-40

-20

-160.182

-158.092

d

B

r

A

25

400

50 75

100

125 150

175

200

225

250

275 300

325

350

375

59.4129

180.626

Hz

dx=121.213 Hz

dy=+2.090 dB

The DAC3 shows no evidence of AC line-related hum to a measurement limit of about -160 dBFS.
The cursors are placed at 60 Hz and 180 Hz (frequencies where we would expect to see
interference from the 60 Hz AC input. In the idle channel noise spectrum there is absolutely no sign
of any AC hum! At full output, these line-related frequencies still measure better than -133 dB (see

Graph 4

).

This graph demonstrates one of the advantages of switching power supplies. The switching power
supplies in the DAC3 operate at frequencies above the audio band and this eliminates the stro ng
line-frequency magnetic fields that would have been created by line-frequency power transformers.

Instruction Manual for DAC3 B with 1.X Firmware Page 43

Audio Pr ecision

DAC3 - FFT 10 kHz, 0 dBr = 0 dBFS = 24 dBu

DAC3 - F FT 10 kHz.at27

ColorSweep Trace

Line Style Thick

Data

Axis Comment

Source 2 Cursor1 Cursor2

1 2 Green Solid 4

Fft.Ch.1 Ampl Left : 1.00000 = S wr .Ch. A Input *-111.013 dBr *-124.989 dBr

2 2 Red Solid

4 Fft.Ch.1 Ampl

Left : 2.00000 =S wr .Ch. A Input

-111.241 dBr A

-127.362 dBr A

-160

+0

-140

-120

-100

-80

-60

-40

-20

-111.013

-124.989

d

B

r

A

0 32k 2k 4k 6k

8k

10k 12k 14k 16k 18k 20k 22k 24k

26k

28k

30k

20.0391k 30.0587k

Hz

dx=10.0196 kHz

dy=-13.975 dB

Graph 3 - FFT 10 kHz

The 10 kHz FFT analysis is an excellent test for detecting sample clock jitter. Jitter will create
sidebands (unwanted tones) above and below the 10 kHz test tone. For example, a jitter frequency
of 1 kHz would create two sideband tones; a lower sideband at 9 kH z, and an upper sideband at 11
kHz. Similarly, a jitter frequency of 2 kHz would produce sideband tones at 8 kHz and 12 kHz. The
above plot shows no evidence of jitter-induced sidebands to a measurement limit of about -149 dB
relative to the amplitude of the 10 kHz test tone.

Note the very low harmonic distortion; the 2nd harmonic (20 kHz) measured -111 dB, and the 3rd
harmonic (30 kHz) measured -125 to -127 dB.

This 32k point FFT analysis uses a Blackman-Harris window with 16x power averaging. The 10 kHz
fundamental has been removed by a notch filter in order to increase the resolution of the A/D
converter in the AP2722 test set.

Instruction Manual for DAC3 B with 1.X Firmware Page 44

Audio Pr ecision

DAC3 - FFT 1 kHz, 0 dBr = 0 dBFS = 24 dB u

DAC3 - F FT 1 kHz.at27

ColorSweep

Trace

Line Style Thick Data

Axis Comment Source 2 Cursor1 Cursor2

1

2 Green Solid 4 Fft.Ch.1 Ampl Left Left Channel : 1.00000 =Swr.Ch. A Input -125.680 dBr A -123.514 dBr A

2 2

Red

Solid 4 Fft.Ch.1 Ampl

Left Right Channel : 2.00000 = S wr .Ch. A Input *-133.647 dBr *-122.546 dB r

-160

+0

-140

-120

-100

-80

-60

-40

-20

-133.647

-122.546

d

B

r

A

0 3.4k 200 400

600

800 1k 1.2k 1.4k 1.6k 1.8k 2k 2.2k 2.4k 2.6k 2.8k

3k 3.2k

2k

3k

Hz

dx=1.00000 kHz

dy=+11.101 dB

Graph 4 - FFT 1 kHz

The 1 kHz FFT analysis demonstrates the very low harmonic distortion of the DAC3. The second
harmonic distortion (2 kHz) measured better than -126 dB, while the 3rd harmonic distortion
measured better than -122 dB relative to the amplitude of the 1 kHz test tone.

This 32k point FFT analysis uses a Blackman-Harris window with 16x power averaging. The 1 kHz
fundamental has been removed by a notch filter in order to increase the resolution of the A/D
converter in the AP2722 test set.

Note that under this full-output co ndition, the AC line-related hum frequencies (60 Hz, 180 Hz, and
240 Hz) measure better than - 133 dB.

Instruction Manual for DAC3 B with 1.X Firmware Page 45

Audio Precision

11/01/ 16 12:38:28

DAC3 - FREQUEN CY RESPONSE

Fs = 192 k Hz

DAC3 - Frequency Response.at27

ColorSweep

Trace Line Style Thick

Data Axis Comment Cursor1 Cursor2

1

1 Red Solid 4 Anlr.Lev el A Left *- 0.015 dBr *-0.031 dB r

-10

+1

-9.5

-9

-8.5

-8

-7.5

-7

-6.5

-6

-5.5

-5

-4.5

-4

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

-0

+0.5

-0.015

-0.031

d

B

r

A

10 90k 20

50

100 200 500 1k

2k 5k 10k 20k

50k

10.0021

40.8557k

Hz

dx=40.8457 kHz

dy=-0.016 dB

Graph 5 - Frequency Response

This plot demonstrates the ruler-flat frequency response of the DAC3. Note that the frequency
response measures - 0.015 dB at 10 Hz and -0.031 dB at 40 kHz. The extreme low-frequency
extension of the DAC3 virtually eliminates the phase shifts that often occur at low frequencies
(near 20 Hz). Bass is rendered in the proper timing relative to high-frequency content.

Instruction Manual for DAC3 B with 1.X Firmware Page 46

Audio Precision

DAC3 - Differential Phase

Fs = 96 k Hz

DAC3 - Differ ential Phase.at 27

ColorSweep Trace Line Style Thick

Data Axis Comment Cursor1 Cursor2

1 1

Green Solid 4

Anlr.Phase Left Left to Right *+0.24 deg *+0.42 deg

2

1 Red Solid 4 Anlr.Phase Left Right to Left

-0.25 deg -0.43 deg

-1

+1

-0.8

-0.6

-0.4

-0.2

+0

+0.2

+0.4

+0.6

+0.8

+0.24

+0.42

d
e
g

2.5k

45k 5k

7.5k

10k 12.5k 15k

17.5k 20k

22.5k

25k 27.5k

30k 32.5k 35k

37.5k

40k 42.5k

20.2555k

40.0511k

Hz

dx=19.7956 kHz

dy=+0.18 deg

Graph 6 - Differential P hase

This plot demonstrates the inter-channel phase accuracy of the DAC3. This is a highly expanded
scale, spanning only +/- 1 degree at 45 kHz. From this plot, the inter-channel phase accuracy is
calculated to be +/- 0.25 degrees at 20 kHz, and +/- 0.43 degrees at 40 kHz.

The phase accuracy of the DAC3 approaches the phase accuracy of the Audio Precision AP2722
test set. For this reason, the phase error in the AP must be subtracted from the measurement. The
green trace assigns the left channel to channel 1 of the AP, and the right channel to channel 2 of
the AP. The red trace reverses the inputs. The two traces must be averaged to remove the phase
errors of the AP test set.

DAC3 converters are phase-accurate between boxes. Three DAC3 converters can be used as a
group to form a phase-accurate 5.1 surround system. Four DAC3 converters can be combined to
form a 7.1 system. The phase accuracy between any two channels will match the typical phase
accuracy shown above.

Instruction Manual for DAC3 B with 1.X Firmware Page 47

Graph 7 - THD and THD+N vs. Amplitude (Balanced Outputs)

Audio Pr ecision

DAC3 - THD an d THD+N vs. Amplitude, 1 kH z, 0 dBFS = 24 dBu

DAC3 - THD and THD+N vs Amplitude. at27

ColorSweep Trace Line St yle

Thick Data

Axis Comment

1

1 Red Solid

4 Distortion. Ch. 1 Har m Sum1 Left THD

1 2 Black Solid 4

Anlr .THD+N Ampl Right

THD+N

-130

-90

-125

-120

-115

-110

-105

-100

-95

d

B

r

A

-130

-90

-125

-120

-115

-110

-105

-100

-95

d

B

r

A

-30 -0 -28 -26 -24

-22

-20 -18 -16 -14 -12 -10 -8 -6

-4

-2

dBFS

These plots demonstrate the very low harmonic distortion produced by the DAC3 with digital input
signal levels rang ing from -30 dBFS to 0 dBFS. These plots show that THD should never reach the
threshold of hearing in most listening environments. This is proof that the DAC3 is virtually
uncolored by any traces of harmonic distortion.

The black curve is a plot of THD+N, band limited to 22 kHz, and was acquired using the analog
analyzer in the AP2722 test set. The red curve is a plot of THD (harmonic distortion only) and was
acquired using the analog notch filter, A/D converter, and digital harmonic distor t io n analyzer in
the AP2722 test set. This THD curve includes a ll harmonics falling below 32 kHz. The steps near -3
dBFS and -9 dBFS are due to the auto ranging of the AP2722 tes t set and are an indication that the
THD performance of the DAC3 is very close to the measurement limits of the AP2722.

Instruction Manual for DAC3 B with 1.X Firmware Page 48

Graph 8 - THD and THD+N vs. Amplitude (Unbalanced Outputs)

Audio Pr ecision

DAC3 - THD an d THD+N vs. Amplitude, 1 kH z, 0 dBFS = 2Vrms

Unbalanced Outputs

DAC3 - THD and THD+N vs Amplitude Unbalanced.at27

ColorSweep Trace Line St yle

Thick Data

Axis Comment

1

1 Red Solid

4 Distortion. Ch. 1 Har m Sum1 Left THD Only

1 2 Black Solid 4

Anlr .THD+N Ampl Right

THD+N

-130

-90

-125

-120

-115

-110

-105

-100

-95

d

B

r

A

-130

-90

-125

-120

-115

-110

-105

-100

-95

d

B

r

A

-30 -0 -28 -26 -24

-22

-20 -18 -16 -14 -12 -10 -8 -6

-4

-2

dBFS

This plot shows the THD and THD+N performance of the unbalanced outputs.

Note that the THD performance of the unbalanced outputs a pproaches that of the balanced
outputs. The THD+N levels are slightly higher on the unbalanced outputs. This is due to the
relatively low (2 Vrms) signal levels used on unbalanced interfaces. This noise difference highlights
one advantage of professional-level balanced interconnects.

Instruction Manual for DAC3 B with 1.X Firmware Page 49

Graph 9 - THD vs. Amplitude - Balanced vs. Unbalanced Outputs

Audio Pr ecision

DAC3 - THD vs. Am plit ude, 1 kHz, 0 dBFS = 2V rms

Balanced vs. Unbalanced Outputs

DAC3 - T HD vs Amplitude Balanc ed vs Unbalanced.at27

ColorSweep

Trace Line Style Thick

Data Axi s Comment Source 2

1

3 Black

Solid 4 Distortion.Ch.1 Harm Sum1 Right THD Balanced Output : 2.00000 = S wr .Ch. A Input

2

2 Red Solid 4 Distortion.Ch.1 Harm Sum1 Left T HD Unbalanc ed Output

: 4.00000 = S wr .Ch. A Input

-140

-100

-135

-130

-125

-120

-115

-110

-105

d

B

r

B

-140

-100

-135

-130

-125

-120

-115

-110

-105

d

B

r

A

-30

-0

-28 -26

-24

-22 -20 -18 -16 -14 -12 -10 -8 -6 -4

-2

dBFS

This plot demonstrates that the balanced and unbalanced analog outputs on the DAC3 have very
similar THD performance. The unbalanced outputs (red curve) closely match the performance of
the balanced outputs (black curve) at high signal levels. T he sep a ration between the curves at
signal levels be low -10 dBFS is due to the improved SNR provided by the balanced interfaces. At 0
dBFS, the balanced interfaces were calibrated to +24 dBu (12.28 Vrms) while the unbalanced
interfaces were calibrated to +8.24 dBu (2 Vrms). The higher signal levels used with the balanced
interfaces make it easier to achieve high signal to noise ra tios. This is just one reason why
Benchmark recommends balanced interconnects.

The DAC3 includes differential am plifiers that remove com mon-mode THD from the balanced
outputs of the SABRE-PRO converters. These differential amplifiers give the unbalanced outputs the
ability to approach the THD performance of the balanced outputs. Please note that the differential
amplifiers also el iminate common-mode distortion on the balanced outputs.

Top-quality D/A conversion chips (such as the ES9028PRO) are equipped with balanced outputs.
These balanced outputs allow a significant reduction of THD if they are followed by precision
differential amplifiers. Conversion chips tend to produce significant common-mode distortion
products that should be removed by a differential amplifier. The DAC3 includes precision
differential amplifiers following the outputs of the ES9028PRO. Many competing products omit
these differential amplifiers. The omission of the differential a mplifiers would make the THD much
higher on the unbalanced outputs. The differential amplifiers also improve the system performance
when the balanced outputs are driving balanced inputs that are not precisely trimmed.

The THD measurements shown above confirm the effectiveness of the differential amplifiers in the
DAC3. Additional confirmation can be obtained by measuring the THD of either side of the
balanced outputs relative to ground.

Instruction Manual for DAC3 B with 1.X Firmware Page 50

Audio Precision

DAC3 - THD+N VS FRE Q AT 0 dBF S, 24 dBu (w/80 kH z LPF unweighted)

Balanced Outputs

DA C3 - THD+N vs FREQ UE NCY 80kHZ.at 27

ColorSweep Trace Line Style

Thick Data Axis Comment

1 1

Green Solid 4 Anlr.THD+N Ratio

Left Left Channel

1 2

Red Solid 4 Anlr.THD+N Ratio Left Right Channel

-130

-90

-125

-120

-115

-110

-105

-100

-95

d

B

20

20k

50 100

200 500

1k

2k 5k

10k

Hz

Graph 10 - THD+N vs. Frequency 80 kHz

The analog output stages on the DAC3 have high slew rates and are capable of main taining low
THD levels at high frequencies even when driven to 0 dBFS. Note that the THD+N remains very low
at 20 kHz, even when operating at maximum output levels.

Instruction Manual for DAC3 B with 1.X Firmware Page 51

Graph 11 - THD and THD+N vs. Frequency

Audio Pr ecision

DAC3 - THD an d THD+N vs. Frequen cy, 1 kH z, 0 dBFS , 24 dBu

Digital In to Balanced Analog Out

DAC3 - T HD and THD+N vs Frequency Digital t o Analog.at27

ColorSweep

Trace Line Style Thick

Data Axi s Comment Cursor1 Cursor2

1

1 Black

Solid 4 Anlr.THD+N Ampl Left THD+N, 80 kHz LPF-109.838 dBr A -107.584 dBr A

1

2 Red Solid 4 Distortion.Ch.1 Harm Sum1 Right THD, 48 kHz LPF

*-117.274 dBr *-111. 274 dB r

-140

-100

-135

-130

-125

-120

-115

-110

-105

-117.274

-111.274

d

B

r

A

-140

-100

-135

-130

-125

-120

-115

-110

-105

d

B

r

A

20

20k

50 100

200 500 1k 2k 5k 10k

1.00238k

10.0237k

Hz

TTT

These plots demonstrate that the harmonic distortion of the DAC3 is lower than the THD+N
numbers would suggest. This black curve is a plot of THD+N. The red curve is a plot of THD only.
Below about 10 kHz, the THD is so low that the THD+N measurement is dominated by noise.

Instruction Manual for DAC3 B with 1.X Firmware Page 52

Audio Precision

DAC3 - THD+N vs Sa m ple Ra te, 1 kH z at 0 dBFS ( w/20 kHz LPF unweigh ted)

DAC3 - THD+N vs Sample Rate.at27

ColorSweep Trace Line Style Thick

Data Axis Comment Cursor1 Cursor2

1

1 Green Solid

4 Anlr. THD+N Rat io Left Left Channel

-113.043 dB -113.041 dB

1 2

Red Solid 4 Anlr.THD+N Ratio Left Right Channel *-113.209 dB *-113.208 dB

-130

-90

-125

-120

-115

-110

-105

-100

-95

-113.209

-113.208

d

B

40k

200k 60k

80k

100k 120k

140k 160k 180k

28k

210k

Hz

dy=+0.001 dB

Graph 12 - THD+N versus Sample Rate

The THD+N performance of the DAC3 is identical at all Sample Rates.

Instruction Manual for DAC3 B with 1.X Firmware Page 53

Graph 13 - Jitter Tolerance

Audio Precision

DAC3 - INTERFACE JITTER TOLERANCE - Di st orti on vs Jitter

3.456 kH z Test Tone a t 0 dBFS, THD+N 22 t o 22 kHz BW

DAC3 - J ITTER TO L E RANCE.at27

ColorSweep Trace Line Sty le Thick Data Axis Comment

1 1 Red Solid 4 Anlr.THD+N Rat io Left
1 2 Black Solid 4 Dio.Interface Jitter Right

10m

20

20m

50m

100m

200m

500m

1

2

5

10

U

I

-120

+0

-110

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

d

B

100 90k 200 500 1k 2k 5k 10k 20k 50k

Hz

The Audio Engineering Society (AES) has created a jitter tolerance template for testing digital audio
devices. The black curve shows the AES jitter tolerance template (see ri g h t -hand vertical axis).
Induced jitter approaches 5 UI at 200 Hz, and is reduced to 0.125 UI above 8 kHz. The red trace
shows the THD+N of the DAC3 (left-hand vertical axis) while being driven with the jitter shown on
the black curve. Over the entire range of the AES jitter tolerance test, the THD+N performance of
the DAC3 is unchanged. The DAC3 easily passes the AES jitter tolerance test, and it does so
without any performance degradation.

Instruction Manual for DAC3 B with 1.X Firmware Page 54

Audio Precision

DAC3 - INTERFACE JITTER TOLERAN CE FFT

10 kHz Test Ton e at 0 dBFS, AES Ji tter Tolera nce Sweep

DAC3 - JITTER TOLERANCE FFT.at27

Color

Sweep Trace

Line Style

Thick Data Axis Comment Source 2

1 2 Blue Solid 1

Fft.Ch.1 Ampl

Left : 100.000 Hz=Dio.J itter Freq

2

2 Cyan

Solid 1 Fft.Ch.1 Ampl Left : 125.893 Hz=Dio. J it ter F r eq

3

2 Green Solid 1 Fft.Ch.1 Ampl Left

: 158.489 Hz=Dio.Jitter F r eq

4 2 Yellow Solid 1 Fft.Ch.1 Ampl

Left : 199.526 Hz=Dio.J itter Freq

5 2 Red

Solid 1 Fft.Ch.1 Ampl Left : 251.189 Hz=Dio. J it ter F r eq

6 2

Magenta Solid 1

Fft.Ch.1 Ampl Left : 316. 228 Hz=Dio.Jitter F r eq
7 2 Blue Solid 1 Fft.Ch.1 Ampl Left : 398.107 Hz=Dio.Jitter F r eq
8 2 Cyan Solid

1 Fft.Ch.1 Ampl Left : 501.187 Hz=Dio.Jitt er Freq
9 2 Green Solid 1 Fft.Ch.1 Ampl Left : 630.957 Hz=Dio.Jitter Fr eq
10 2 Yellow Solid 1

Fft.Ch.1 Ampl Left : 794. 328 Hz=Dio.Jitter F r eq

11 2 Red Solid

1 Fft.Ch.1 Ampl Left : 1.00000 kHz=Dio.Jitter Fr eq
12 2 Magenta Solid 1 Fft.Ch.1 Ampl

Left : 1.25893 kHz=Dio.Jitter Freq

13 2 Blue Solid

1 Fft.Ch.1 Ampl Left : 1.58489 kHz=Dio.Jitter Fr eq
14 2 Cya n Solid

1 Fft.Ch.1 Ampl Left

: 1.99526 k Hz=Dio.Jitter F r eq
15 2 Green Solid 1 Fft.Ch.1 Ampl Left : 2.51189 kHz=Dio. J itter Freq
16 2 Yellow Solid 1 Fft.Ch.1 Ampl

Left : 3.16228 kHz=Dio.Jitter Freq
17 2 Red Solid 1 Fft.Ch.1 Ampl Left : 3.98107 kHz=Dio. J itter Freq
18 2 Magenta Solid 1 Fft.Ch.1 Ampl

Left : 5.01187 kHz=Dio.Jitter Freq
19 2 Blue Solid 1

Fft.Ch.1 Ampl Left : 6. 30957 k Hz=Dio.Jitter F r eq
20 2 Cya n Solid 1 Fft.Ch.1 Ampl Left : 7.94328 kHz=Dio.Jitt er Freq
21 2 Green Solid 1

Fft.Ch.1 Ampl Left : 10. 0000 k Hz=Dio.Jitter F r eq
22 2 Yellow Solid 1 Fft.Ch.1 Ampl Left : 12.5893 kHz=Dio.Jitt er Freq
23 2 Red Solid 1 Fft.Ch.1 Ampl Left : 15.8489 kHz=Dio. J itter Freq
24 2 Magenta Solid 1 Fft.Ch.1 Ampl Left : 19.9526 k Hz=Dio.Jitter Fr eq
25

2 Blue Solid 1 Fft.Ch.1 Ampl Left : 25.1189 k Hz=Dio.Jitter Fr eq

26 2 Cya n Solid 1 Fft.Ch.1 Ampl

Left : 31.6228 kHz=Dio.Jitter Freq

27 2 Green Solid

1 Fft.Ch.1 Ampl Left : 39.8107 kHz=Dio.Jitter Fr eq
28 2 Yellow Solid 1 Fft.Ch.1 Ampl Left : 50.1187 kHz=Dio.Jitt er Freq
29 2 Red Solid 1 Fft.Ch.1 Ampl Left : 63.0957 kHz=Dio. J itter Freq
30

2 Magenta Solid 1 Fft.Ch.1 Ampl Left

: 79.4328 k Hz=Dio.Jitter F r eq

31 2 Blue Solid 1 Fft.Ch.1 Ampl Left : 100.000 k Hz=Dio.Jitter F r eq

-160

+0

-140

-120

-100

-80

-60

-40

-20

d

B

r

A

0

32k

2k 4k

6k

8k

10k

12k

14k

16k

18k

20k

22k

24k

26k

28k

30k

Hz

Graph 14 - Jitter Tolerance FFT

This figure shows a series of FFTs that were acquired while running the AES jitter tolerance test.
This is the ultimate jitter-immunity test.

Note that none of the 31 FFTs show any signs of jitter-induced sidebands. Note that the plots are
identical to the plots shown in Graph 3.

The DAC3 shows no change in performance when the AES jitter tolerance test is applied to the
digital inputs. No jitter-induced sidebands are visible anywhere in this measurement.

Please note that the 10 kHz fundamental needed to be notc hed out in order to make this very high­resolution measur ement. If the fundamental was not notched out, the spur iou s tones, produced by
the A/D converter in the AP2722 test set, would have obscured the virtually-perfect results.

Instruction Manual for DAC3 B with 1.X Firmware Page 55

Audio Precision

11/02/ 16 09:51:21

DAC3 - 11K 12K IMD

DAC3 - IMD 11K 12K.at27

Color

Sweep Trace Line Style Thick Data

Axis Comment Cursor1 Cursor2

1 1 Green Solid

4 Fft.Ch.1 Ampl Left

Left Channel -131.652 dB r A -125.861 dBr A

1 2 Red Solid

4 Fft.Ch.2 Ampl Right

Right Channel *-131. 548 dB r *-124.799 dBr

-160

+0

-150

-140

-130

-120

-110

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

-131.548

-124.799

d

B

r

A

-160

+0

-150

-140

-130

-120

-110

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

d

B

r

A

0

20k 2k

4k

6k 8k

10k 12k

14k

16k

18k

1.01761k

10.0196k

Hz

dy=+6.749 dB

Graph 15 - IMD 11k 12K

This plot demonstrates that the DAC3 has very low IMD distortion. The 1 kHz difference frequency
measures -131 dB, and the 10 kHz and 13 kHz products measure about -125 dB. The actual IMD
may be better. The results shown are partially limited by the performance of the AP2722 test set.

All IMD distortion products should be well belo w audib le lev els.

Instruction Manual for DAC3 B with 1.X Firmware Page 56

Specifications

Audio Performance

Fs = 44.1 to 96 kHz, 20 to 20 kHz BW, 1 kHz test tone, 0 dBFS = +24 dBu (unless noted)

SNR – A-Weighted, 0 dBFS = +24 dBu

124.5 dB, 128 dB relative to dig. clip

SNR – Unweighted, 0 dBFS = +24 dBu

122.5 dB, 126 dB relative to dig. clip

Dynamic Range - A-Weighted, 0 dBFS = +24 dBu

124.5 dB, 128 dB relative to dig. clip

Dynamic Range - Unweighted, 0 dBFS = +24 dBu

122.5 dB, 126 dB relative to dig. clip

THD+N, 1 kHz at 0 dBFS

-113 dBFS, -113 dB, 0.00022%

THD+N, 1 kHz at -1 dBFS

-114 dBFS, -113 dB, 0.00022%

THD+N, 1 kHz at –3 dBFS

-119 dBFS, -116 dB, 0.00016%

THD+N, 20 to 20 kHz sweep at –3 dBFS

-113 dBFS, -110 dB, 0.00032%

Frequency Response at Fs=192 kHz

+0 dB, -0.015 dB (20 to 20 kHz)

-0.15 dB at 80 kHz

Frequency Response at Fs=48 kHz

+0 dB, -0.015 dB (20 to 20 kHz)

-0.005 dB at 20 kHz

Crosstalk

-116 dB at 20 kHz

-137 dB at 20 Hz

Maximum Amplitude of Jitter Induced Sidebands (10
kHz)

< -144 dB
Maximum Amplitude of Spurious Tones with 0 dBFS test
signal

< -138 dB
Maximum Amplitude of Idle Tones

< -147 dB

Maximum Amplitude of AC line related Hum & Noise

< -133 dB

Inter-channel Differential Phase (Stereo Pair – any
sample rate)

+/- 0.25 degrees at 20 kHz

Inter-channel Differential Phase (Between DAC3 Units
Fs<110 kHz) Any sample rate.

+/- 0.25 degrees at 20 kHz
Maximum Lock Time after Fs change

6 ms

Soft Mute Ramp Up/Down Time

9.6 ms

Mute on Receive Error

Yes

Mute on Lock Error

Yes

Mute on Idle Channel

No

50/15 us De-Emphasis En a b le

Automatic in Consumer Mode

De-Emphasis Method

Digital IIR

De-Emphasis Supported at

Fs = 32, 44.1, 48 kHz

-0.015 dB at 10 Hz

-0.005 dB at 20 kHz

-0.031 dB at 40 kHz

-0.015 dB at 10 Hz

-130 dB at 1 kHz

kHz 0 dBFS test tone, 12.75 UI sinusoidal jitter at 1

Instruction Manual for DAC3 B with 1.X Firmware Page 57

Group Delay (Latency)

Delay – Digital Input to Analog Output (function of

sample rate)

1.36 ms at 44.1 kHz

0.47 ms at 192 kHz

Digital Audio Inputs

Number of Digital Inputs (switch selected)

5 (1 USB, 2 Optical, 2 Coaxial)

Number of Channels

2

Input Sample Frequency Range

28 to 210 kHz (Coaxial Inputs)

(USB Input)

Maximum Input Word Length

24 bits

Digital Input Impedance

75 Ohms (Coaxial Inputs)

DC Blocking Capacitors on Digital Inputs

Yes (Coaxial Inputs)

Transient and Over-Voltage Protection on Digital Inputs

Yes (Coaxial Inputs)

Minimum Digital Input Level

250 mVpp (Coaxial Inputs)

Jitter Tolerance

(With no Measurable Change in Performance)

>12.75 UI sine, 100 Hz to 3 kHz

>0.25 UI sine above 160 kHz

Jitter Attenuation Method

Benchmark UltraLock3™ - all inputs

1.27 ms at 48 kHz

0.90 ms at 88.2 kHz

0.82 ms at 96 kHz

0.51 ms at 176.4 kHz

28 to 96 kHz (Optical Inputs)

44.1, 48, 88.2, 96, 176.4, 192 kHz

Instruction Manual for DAC3 B with 1.X Firmware Page 58

>1.5 UI sine at 20 kHz

>1.5 UI sine at 40 kHz

>1.5 UI sine at 80 kHz

>1.5 UI sine at 90 kHz

Balanced Analog Outputs

Number of Balanced Analog Outputs

2

Output Connector

Gold-Pin Neutrik™ male XLR

Output Impedance

60 Ohms (Attenuator off)

135 Ohms (Attenuator = 20 dB)

Analog Output Clip Point

+29 dBu

Factory Calibration (with 0 dBFS digital inpu t )

+24 dBu (Attenuator = 0 dB)

Maximum Amplitude of Intersample Peaks

+27.5 dBu (Attenuator = 0 dB)

Output Level Variation with Sample Rate

< +/- 0.006 dB

Unbalanced Analog Outputs

Number of Unbalanced Analog Outputs

2

Output Connector

RCA

Output Impedance

30 Ohms

Analog Output Clip Point

+13.5 dBu (3.7 Vrms)

Factory Calibration (with 0 dBFS digital input)

+8.2 dBu (2 Vrms)

Maximum Amplitude of Intersample Peaks

+11.7 dBu (3 Vrms)

Output Level Variation with Sample Rate

< +/- 0.006 dB

Status Display

Indicators - Type and Location

12 LEDs on Front Panel

Selection/Status Indication

1 – Control Lock

4 – Sample Rate

425 Ohms (Attenuator = 10 dB)

+17.5 dBu (Attenuator = 10 dB)

+7.5 dBu (Attenuator = 20 dB)

Instruction Manual for DAC3 B with 1.X Firmware Page 59

5 – Input
2 – Word length

AC Power Requirements

Nominal Operating Range

100 – 240 VAC, 50 - 60 Hz

Min/Max Operating range

88 – 264 VAC, 47 - 63 Hz

Power

< 0.5 Watts Standby

12 Watts Typical Program

15 Watts Maximum

Fuses (2 required)

5x20 mm, 0.5 A 250 V Slo-Blo® Type

Dimensions

Form Factor

½ Rack Wide, 1 RU High

Depth behind front panel

8.5” (216 mm)

Overall depth including connectors

9.33” (237 mm)

Width

9.5” (249 mm)

Height

1.725” (44.5 mm)

Weight

DAC3 B only

3 lb.

DAC3 B with accessories and manual

4 lb.

Shipp ing weight

7 lb.

Instruction Manual for DAC3 B with 1.X Firmware Page 60

Regulatory Compliance

of any homogeneous Lead (Pb), Mercury (Hg), Hexavalent Chromium (Cr VI), and flame
compliance could void the user's authority to operate the equipment.

FCC and RoHS Compliance Statements

FCC Notice (U.S. Only)

NOTICE: This equipment has been tested and found to comply with the limits for a Class B
digital device, pursuant to Part 15 of the FCC Rules. T hese limits are designed to provide
reasonable protection against harmful interference in a residential insta llation. This equipment
generates, uses, and can radiate radio frequency energy and, if not installed and used in
accordance with the instructions, may cause harmful interference to radio communications.
However, there is no guarantee that interference will not occur in a particular installation. If
this equipment does cause harmful interference to radio or television reception, which can be
determined by turning the equipment off and on, the user is encouraged to try to correct the
interference by one or more of the following measures:

• Reorient or relocate receiving antenna.

• Increase the separation between the equipment and receiver.

• Connect the equipment into an outlet on a circuit differ ent from that to which the receiver is

connected.

• Consult the dealer or an experienced radio/TV technician for help.

This device complies with Part 15 of the FCC rules. Opera tion is subject to the following two
conditions:

1. This device may not cause harmful interference.

2. This device must accept any interference received including interference that may cause
undesired operation.

Instructions to Users: This equipment complies with the requirements of FCC (Federal
Communication Commission) equipment provided that following conditions are met:

• RCA Digital Connection s: Shielded 75-Ohm coaxial cable must be used.

NOTICE: Changes or modifications not expressly approved by the party responsible for

RoHS Compliant Information

This statement clarifies Benchmark Media Systems, Inc. product compliance with the EU’s
(European Union) directive 200 2/95/EC, or, RoHS (Restrictions of Hazardous Substances).

As of July 01, 2006, All Benchmark Media Systems, Inc. products placed on the European Union
market are compliant (containing quantity limit weight less than or equal to 0.1% (1000 ppm)

retardant Polybrominated Biphenyls (PBB) or Polybrominated Diphenyl Ethers (PBDE)).

Instruction Manual for DAC3 B with 1.X Firmware Page 61

CE Certificate of Conformity

Instruction Manual for DAC3 B with 1.X Firmware Page 62

Warranty Information

Benchmark 1-Year Warranty

The Benchmark 1-Year Warranty

Benchmark Media Systems, Inc. warrants its products to be free from defects in material and
workmanship under normal use and service for a period of one year from t he date of
delivery.

This warranty extends only to the original purchaser. This warranty does not apply to fuses,
lamps, batteries, or any products or parts that have been subjected to misuse, neglect,
accident, modification, or ab normal operating conditions.

In the event of failure of a product under this warranty, Benchmark Media Systems, Inc. will
repair, at no charge, the product returned to its factory. Benchmark Media Systems, Inc. may,
at its option, replace the product in lieu of repair. If the failure has been caused by misuse,
neglect, accident, or, abnormal operating conditions, repairs will be billed at the normal shop
rate. In such cas es , an est imate will be submitted before work is s ta rted, if requested by the
customer.

Attempts to deliberately deface, mutilate, or remove the product's label will render this
warranty void. Benchmark will not honor warranties for any products disingenuously purchased
on the US or Canadian markets for export.

The foregoing warranty is in lieu of all other warranties, expressed or implied, including but not
limited to any implied warranty of merchantability, fitness or adequacy for any particular
purpose or use. Benchmark Media Systems, Inc. shall not be liable for any s pecial, incidental,
or consequential damages, and reserves the right to change this information without notice.
This limited warranty gives the consumer-owner specific legal rights, and there may also be
other rights that vary from state to state.

Instruction Manual for DAC3 B with 1.X Firmware Page 63

Benchmark Extended Warranty Options

The Benchmark Extended 5-Year Warranty *

Benchmark Media Systems, Inc. optionally extends the standard 1-year warranty to a period of
five years from the date of delivery.

*For the extended warranty to become effective, the original purchaser must register the
product at the time of purchase either by way of the enclosed registration card or through the
product registration section of the Benchmark Me dia Systems, Inc. website. This optional
warranty applies only to products purchased within the US and Ca na da and is extended only to
the original purchaser.

Attempts to deliberately deface, mutilate, or remove the product's label will render this
warranty void. Benchmark will not honor warrant ie s for any products disinge nuously purchased
on the US or Canadian markets for export. The terms of the extended warranty are subject to
change without notice. For products purchased outside the US and Canada, please refer to the
Extended Two 2-Year International Warranty.

The Benchmark Extended 2-Year International Warranty **

Benchmark Media Systems, Inc. optionally ex tends the standard 1-year warranty to a period of
two years from the date of delivery.

**For the extended warranty to become effective, the original purchaser must register the
product at the time of purchase either by way of the enclosed registration card or through the
product registration section of the Benchmark Me dia Systems, Inc. website. This optional
warranty applies only to products purchased o utside the US a nd Canada and is extended only
to the original purchaser.

Attempts to deliberately deface, mutilate, or remove the product's label will render this
warranty void. Benchmark will not honor warrant ie s for any products disinge nuously purchased
on the US or Canadian markets for export. The terms of the extended warranty are subject to
change without notice. For products purchased in within the US and Canada, please refer to the
Extended Five 5-Year Warranty.

Notes on Warranty Repairs

An RMA (return merchandise authorization) number, issued by our Customer Service
Department, is required when sending products for repair.

They must be shipped to Benchmark Media Systems prepaid and prefe rably in their original
shipping carton with the RMA number clearly visible on the exterior of the packaging. A letter
should be included giving full details of the difficulty.

Instruction Manual for DAC3 B with 1.X Firmware Page 64

Revision A - 10/22/2018

Copyright © 2007, 2008, 2009, 2012, 2013, 2014, 2015, 2016, 2017, 2018

Benchmark Media Systems, Inc .

All rights reserved.

Benchmark Media Systems, Inc.

Benchmark Media Systems, Inc.

203 East Hampton Place, STE 2

Syracuse, NY 13206

USA

PHONE: [phone]

FAX: [phone]

benchmarkmedia.com

Instruction Manual for DAC3 B with 1.X Firmware Page 65