Benchmark DAC3 HGC, L Digital to Analog Converter Instruction Manual
Below you will find brief information for DAC3 HGC, DAC3 L. Both of these models are reference-grade stereo preamplifiers with built-in digital to analog converter for PCM and DSD audio formats. They offer high-resolution audio playback up to 192kHz, with dedicated headphone amplifiers for critical listening and high-fidelity. The manual covers details about installation, operation, and available features.
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Benchmark DAC3 HGC and DAC3 L
Instruction Manual
Reference Stereo Preamplifier
PCM and DSD D/A Converter
Asynchronous USB
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
®
5 X 20
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, 50-60
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.
Modifications
CAUTION: DO NOT SUBSTITUTE PARTS
OR MAKE ANY MODIFICATIONS
WITHOUT THE WRITTEN APPROVAL OF
BENCHMARK MEDIA SYSTEMS, INC.
MODIFICATION MAY CREATE SAFETY
HAZARDS AND VOID 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 HGC and DAC3 L with 1.X Firmware Page 2
Contents
Safety Information
Fuses
AC Input Voltage Range
Power Cord
Modifications
Repairs
Features
Introduction
Applications
DAC3 vs. DAC2
DAC3 vs. DAC1
DAC3 Technologies
Front Panel
Rear Panel
Quick Start Guide
Audio Inputs
Remote Control
Front Panel Controls
Front Panel Displays
Headphone Jacks
Operational Details
DIM and MUTE Functions
Auto-On Function
Bi-directional 12V Trigger
HT Mode
USB MODE Selection
Driving Power Amplifiers
HPA2™ Headphone Amplifier
Digital Pass-Through
Firmware Version Identification
Rear Panel
Inputs
Outputs
AC Power-Entry and Fuse Module
Internal Settings
Jumper-Configured Options
Removing Top Cover
XLR Output Pads
Headphone Switch Configuration
Headphone Amplifier Gain
Digital PASS-THROUGH Function
5
5
5
5
5
8
8
9
9
9
10
11
13
2
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2
4
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18
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19
20
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26
26
26
26
27
28
29
Rack Mounting
Benchmark Rack Mount Tray
Benchmark ½-Wide Blank Plate
30
30
30
DAC1, DAC2 and DAC3 Family History 31
DAC1 Series
DAC2 Series
DAC3 Series
31
31
32
Benchmark Technologies 33
Hybrid Gain Control™
Native DSD Conversion
High Headroom DSP
32-bit SABRE-PRO D/A System
Diagnostic Displays
Bi-Directional 12 Volt Trigger
Distributed Power Regulation
HPA2™ Headphone Amplifier
Differential Amplifiers
Jitter-Immune UltraLock3™
36
36
Multi-Mode Asynchronous USB Audio 39
33
33
33
35
35
35
35
35
USB Driver Installation
Performance Graphs
41
46
Specifications
Audio Performance
Group Delay (Latency)
Digital Audio Inputs
Jitter Tolerance
Balanced Analog Outputs
Unbalanced Analog Outputs
HPA2
TM
Headphone Outputs
Unbalanced Analog Inputs
Status Display
AC Power Requirements
Dimensions
Weight
Regulatory Compliance 67
FCC and RoHS Compliance Statements 67
FCC Notice (U.S. Only)
RoHS Compliant Information
CE Certificate of Conformity
67
67
68
63
63
64
64
64
65
65
65
66
66
66
66
66
Warranty Information 69
Benchmark 1-Year Warranty 69
Benchmark Extended Warranty Options 70
Notes on Warranty Repairs 70
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 3
Features
HGC™ (Hybrid Gain Control) – combines motor-driven active analog potentiometers, 32-bit digital attenuators, and passive analog attenuators, to achieve state-of-the-art performance
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 27 )
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 UltraLock3™ 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
HPA2™ reference-grade "0-Ohm" headphone power amplifier with dual high-current outputs (DAC3 HGC only)
HPA2™ gain jumpers for customizing headphone output gain for headphone sensitivities
2 Headphone Output Jacks – one jack automatically mutes the main outputs (DAC3 HGC
only), mute feature can be disabled (Page 27 )
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 29 )
2 Stereo Analog Inputs – 2 pairs unbalanced (RCA)
3 Stereo Analog Outputs – 1 pair balanced (XLR), plus 2 pairs unbalanced (RCA)
IR Remote with metal housing provides control of all functions (optional on some models)
HT Bypass – places analog inputs in a unity-gain pass-through mode, sets digital inputs to a
calibrated output level - all inputs can be individually programmed (Page 17 )
Polarity Switch – inverts the polarity of selected digital inputs
Mute – accessible from remote or front panel
Dim – Reduces output level by 20 dB, accessible from remote or front panel
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
AUTO-ON Function - can be programmed to turn on when AC is applied (Page
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, 50-60 Hz
Meets FCC Class B and CE emissions requirements
Tested for immunity to radiated and conducted RF interference
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 4
Introduction
Applications
The DAC3 is a professional reference-grade audio digital to analog converter with
Benchmark's HPA2™ headphone amplifier.
The DAC3 supports 24-bit D/A conversion of
PCM at sample rates up to 192 kHz. It also supports direct conversion of 1-bit DSD at a
2.8224 MHz sample rate. It is designed to be very transparent and this makes it well-suited for critical monitoring in studio control rooms and mastering rooms.
The DAC3 is also well-suited for high-end hi-fi environments. It includes a generous collection of inputs and outputs and can serve as the central component in any stereo hi-fi system. The DAC3 provides D/A conversion, source selection, volume control, and headphone amplification. A remote control,
12V trigger, and home theater bypass function provide the features needed in a home environment.
The DAC3 is designed to directly drive a wide variety of power amplifiers and powered monitors. The balanced outputs include lowimpedance passive pads that can be adjusted to optimize the interface between the DAC3 and the power amplifier. This optimization can provide substantial improvements in the system-level SNR and THD+N performance.
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 frequency 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
Home Theater Bypass
Digital Pass-Through
High-Headroom DSP
Dual-Domain Hybrid Gain Control
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 averaged across the four 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 HGC and DAC3 L with 1.X Firmware Page 5
High-Headroom Digital and Analog
Processing
UltraLock3™ Clock System
The DAC3 has generous amounts of analog and digital headroom. The analog clip point is above 29 dBu. The digital clip point is 27.5 dBu. When operating at a typical -20 dB at
+4 dBu studio calibration, the DAC3 has 3.5 dB of digital headroom above 0 dBFS. This digital headroom prevents the clipping of intersample overs.
UltraLock3™ provides the outstanding jitter attenuation of Benchmark'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 recordings. When recordings 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.
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 intentional.
Asynchronous USB Audio 2.0
Low-Noise Power Supplies
The USB Audio 2.0 interface supports DSD and 192 kHz, 24-bit PCM. No drivers are required for Apple operating systems. Drivers are provided for Windows operating systems at: BenchmarkMedia.com/drivers
The DAC3 uses high-efficiency low-noise power supplies. Each critical subsystem also has at least one dedicated low-noise regulator. The high-efficiency supplies deliver the substantial power required by the lowimpedance circuits, the headphone amplifier, 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.
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.
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 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.
HGC™ Hybrid Gain Control
HGC™ is Benchmark’s unique hybrid gain control that combines analog and digital gain control into a single volume control knob.
The HGC™ system uses an active analog gain control for analog inputs and a 32-bit dithered volume control for digital inputs. Both types of inputs leverage the low-impedance passive
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 6
analog attenuation system at the XLR outputs. 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.
The dual-domain HGC™ system combines the high dynamic range of Benchmark’s HDR™ analog control (used in the DAC1 HDR) with the low distortion and accuracy of a digital control. HGC™ outperforms traditional analog or digital volume controls, including the twostage DAC1 HDR™ system. Musical details are preserved over a very wide range of output levels. Analog inputs are controlled in the analog domain. Digital inputs are controlled in both domains.
Polarity Control
Each digital input can be inverted, to correct polarity problems. Some listeners report that polarity is incorrect on some recordings, and that they enjoy an improved listening experience when this is corrected. To toggle, use the POLARITY button on the front panel or press and hold the ON button on the remote.
The volume control is a servo-driven analog potentiometer. This control rotates in response to commands from the remote control while providing the convenience of manual adjustments with a physical knob.
Low-Impedance Passive Attenuators
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 the power amplifier or powered monitors. This optimization places the volume control in its best operating range. This exclusive
Benchmark feature can provide substantial improvements in the performance of the playback signal chain.
HT Mode
The HT mode sets the volume control to a calibrated level that is near its maximum setting. In HT mode the analog gain is set to
0 dB (unity gain). Likewise the digital attenuation is set to 0 dB (maximum output).
The HT light is illuminated when the HT mode is active.
The HT mode is similar to the CALIBRATED switch setting on the DAC1 except that it is programmable per input. This flexibility allows seamless integration into home theater systems where the DAC3 handles the main left and right channels.
Bi-directional 12V Trigger
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 format. 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.
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.
Digital Pass-Through
Auto-On Function
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
The DAC3 can be programmed to automatically turn on when AC power is
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 7
Front Panel
DAC3 HGC
DAC3 L
Rear Panel
DAC3 HGC and DAC3 L
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 8
Quick Start Guide
Audio Inputs
The DAC3 features two stereo RCA analog inputs and 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.
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
The remote control is designed to have a long operating range. In most applications it is not necessary to point the remote directly at the
DAC3.
The chart at the right summarizes the functions of the IR remote control.
OFF
Turns the unit off. Any devices 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 acting as a
TRIGGER BUS MASTER).
ON
Turns the unit on. Any devices slaved to the 12V TRIGGER will also turn on in a controlled sequence.
Press and hold the ON button for
3 seconds to toggle the
POLARITY function.
VOLUME Turns the volume up or down.
DIM
Toggles the -20 dB DIM function.
MUTE
INPUT
Toggles the MUTE function.
Press and hold the MUTE button for 3 seconds to toggle the HT mode on the selected input.
Selects the inputs.
D1
D2
D3
Selects optical digital input D1.
Selects optical digital input D2.
Selects coaxial digital input D3.
D4
USB
Selects coaxial digital input D4.
Selects USB input.
Press and hold the USB button for
3 seconds to toggle between the
USB 1.1 and USB 2.0 modes.
Analog
Selects analog input A1 and then toggles between A1 and A2.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 9
Front Panel Controls
The front panel controls duplicate all of the functions that are available from the remote control.
One additional function, AUTO-ON, is only controllable from the front panel. The AUTO-
ON function keeps the DAC3 on whenever AC line voltage is supplied.
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.
The chart at the right summarizes the functions of the front-panel controls.
POWER
Turns the unit on or off. Any devices slaved to the 12V
TRIGGER will also turn on or off in a controlled sequence.
Press and hold the POWER button for 3 seconds to force the 12V TRIGGER off (only necessary when another device is acting as a TRIGGER BUS
MASTER).
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.
If AUTO-ON is set, the
POWER button will toggle
MUTE on and off (the unit will remain on).
DIM/MUTE Press once to toggle the -20 dB
DIM function.
Double tap to set the MUTE function.
INPUT
VOLUME
(knob)
Selects the inputs.
Press and hold both input buttons for 3 seconds to toggle between the USB 1.1 and USB
2.0 modes.
This motor-driven knob can be turned by hand at any time
(even when being driven by the motor).
If HT mode is off, the motor drive will release when the knob is held or turned by hand.
If HT mode is on, the motor drive will attempt to return the volume control to the HT setting.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 10
Front Panel Displays
There are sixteen 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.
The HT light shows that HT mode is active.
A1 A solid blue light indicates that analog input A1 is selected.
A2 A solid blue light indicates that analog input A2 is selected.
U
A solid blue light indicates that the USB input is selected and operating normally.
A blinking blue light indicates that the input is selected but a connection to a computer has not been established.
D1 A solid blue light indicates that optical input D1 is selected and operating normally. A blinking blue light indicates that the input is selected but audio data is not being received.
D2 A solid blue light indicates that optical input D2 is selected and operating normally. A blinking blue light indicates that the input is selected but audio data is not being received.
D3 A solid blue light indicates that coaxial input D3 is selected and operating normally. A blinking blue light indicates that the input is selected but audio data is not being received.
D4 A solid blue light indicates that coaxial input D4 is selected and operating normally. A blinking blue light indicates that the input is selected but audio data is not being received.
Note:
D4 cannot be selected if the Digital
Pass Through function is enabled.
Instructions for configuring this jumperselected function can be found in the
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:
Slow Flash
(2Hz)
Med. Flash
(7Hz)
Rapid flashes
(14Hz)
Intermittent flashes
No digital signal (output muted)
Data transmission errors or
Non-PCM (output muted)
Non-audio data is being received (output muted)
Some data corruption is occurring, converter may be interpolating to replace invalid samples, check the cable.
Tip:
Common causes of input errors:
Disconnected or faulty 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
HT Indicator
HT A solid light indicates that the HT mode is active on the selected input and the volume control is in the factory calibrated position (near full clockwise).
A blinking light indicates that the HT mode is active but the volume control has not yet reached its calibrated position. The HT light and DIM/MUTE light will blink together if the unit is muted while HT mode is active.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 11
DIM, MUTE, and POLARITY Indicators
DIM/MUTE A solid red light indicates that the unit is in DIM mode. A slow flashing red light indicates that the unit is in MUTE mode.
A rapidly flashing red light indicates that the remote control is sending commands.
POLARITY Yellow light indicates that the
POLARITY inversion function is active.
Digital Format Indicators
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 conversion, 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.
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:
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.
Format indicators
The 44, 48, 2X, 4X, and DSD lights indicate the sample rate and format of the selected digital input as follows:
44 Only
48 Only
44 and 2X
48 and 2X
44 and 4X
48 and 4X
DSD
(4x and 2X)
All Off
The input format is PCM at a sample rate of 44.1 kHz (CD sample rate).
The input format is PCM at a sample rate of 48 kHz (often used with video).
The input format is PCM at a sample rate of 88.2 kHz
(high-resolution audio format).
The input format is PCM at a sample rate of 96 kHz (highresolution audio format).
The input format is PCM at a sample rate of 176.4 kHz
(high-resolution audio format).
The input format is PCM at a sample rate of 192 kHz (highresolution audio format).
The input format is 1-bit DSD at a sample rate of 2.8224
MHz (high-resolution audio format). Note: DSD must be streamed in DoP format.
Digital signal is not present or is not in a supported format.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 12
Headphone Jacks
(DAC3 HGC only)
The left-hand jack mutes the XLR and
RCA outputs.
The right-hand jack keeps all outputs active.
Headphone Mute Switch
The left-hand headphone jack includes a switch that mutes the main analog outputs
(XLR and RCA) when a headphone plug is inserted. This feature allows the listener to switch from loudspeaker to headphone playback seamlessly. This Auto-Mute feature can be disabled with internal jumpers.
Note:
Instructions for setting the Auto-Mute
section of this manual (Page 27 ).
Tip:
Use the left-hand jack to mute your loudspeaker system. Use the right-hand jack to keep all outputs active.
Driving Two Sets of Headphones
The HPA2™ is specifically designed with enough power to drive two sets of headphones.
Tip:
The Volume Control simultaneously adjusts the level for both jacks. If two listeners will be simultaneously using the headphone outputs, we recommend using headphones with identical or similar voltage sensitivities.
HPA2
TM
Headphone Power Amplifier
The headphone jacks are driven by
Benchmark's HPA2™ headphone power amplifier. This small and very clean power amplifier can deliver the current and voltage required by some of the most demanding headphones. The output impedance of the
HPA2™ is very close to 0 Ohms. This low output impedance delivers a high damping factor so that the amplifier can maintain precise control over the headphone transducers.
Headphone voltage sensitivities vary substantially, so we have equipped the
HPA2™ with Gain-Range jumpers that can be used to customize the headphone amplifier to your favorite headphones. If you find that you have too much output (volume control set below 11 o'clock), there are internal jumpers that can be adjusted to decrease the output level by 10 dB or 20 dB relative to the factory default setting.
Note:
Instructions for setting the headphone
Gain-Range jumpers can be found in the
Internal Settings section of this manual.
Tip:
For optimal performance, the headphone
Gain-Range jumpers should be set so that comfortable listening levels occur when the volume control is set above the 11 o'clock position.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 13
Operational Details
DIM and MUTE Functions
activated, the DIM mode will automatically deactivate, the DIM light will turn off, and the saved NORMAL setting will be replaced by the current volume setting.
Definition:
If the DIM, MUTE, and HT modes are all off, the DAC3 is in NORMAL mode.
DIM cannot be activated when HT mode is enabled.
Definition:
The NORMAL volume setting is the last volume setting that was in use before the DIM, MUTE, or HT modes were activated.
With digital inputs, DIM will reduce the output level by exactly 20 dB. With analog inputs, DIM will reduce the output level 20 dB +/- 0.5 dB.
MUTE Function
DIM Function
The DIM function reduces the output level by
20 dB. To toggle between NORMAL and DIM volume, press the DIM button on the remote or the DIM/MUTE button on the front panel.
The MUTE function immediately mutes all outputs. To toggle this function, press the
MUTE button on the remote or double-tap the DIM/MUTE button on the front panel.
The red DIM/MUTE light will turn on whenever DIM is active.
The red DIM/MUTE light will flash at a 1 Hz rate whenever MUTE is active.
When DIM is activated, the NORMAL volume setting is stored in memory while the volume control ramps down by 20 dB. When DIM is deactivated, the volume control ramps back to the NORMAL volume setting that was stored in memory.
The DIM function makes it convenient to fade back and forth between normal and background playback volume levels.
When MUTE is activated from a NORMAL listening mode, the audio will immediately mute while the motor-driven volume control ramps down to the -20 dB DIM position.
When MUTE is released, the output will unmute at the DIM volume position and then ramp back up to the previous setting. This movement of the motor-driven volume control provides a soft unmute when MUTE is released. It also allows immediate transitions between MUTE and DIM.
TIP:
In the studio, the DIM function allows a temporary reduction in level without losing the volume setting that was being used for monitoring.
Tip:
If the unit is in MUTE, press the DIM key to immediately enter the DIM mode.
Tip:
In home applications the DIM function allows temporary reductions in volume during
TV commercial breaks, phone calls, or other interruptions, without losing the volume setting that was being used for normal listening.
Tip:
If the unit is in MUTE, press the ON key to enter the NORMAL mode.
Tip:
if the unit is in DIM, press the MUTE key to toggle between DIM and MUTE.
Auto-On Function
If the volume is adjusted while DIM is active, it will not change the NORMAL setting unless the DIM volume is turned up above the last
NORMAL setting. If the volume control is turned up by more than 20 dB after DIM is
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
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 14
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. It is the only function that cannot be programmed from the remote control. This limitation prevents accidental access to this special feature.
Enabling AUTO-ON
Starting with the DAC3 off, press and hold the POWER button for 3 seconds.
If AUTO-ON has been successfully enabled, the POWER button will now function as a
MUTE button. The OFF button on the remote will also function as a MUTE button when
AUTO-ON is enabled.
Disabling AUTO-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.
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. 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 automatically 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 Trigger 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).
The DAC3 can send a 12 Volt DC trigger signal to start other components in the
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 15
Typical trigger applications:
DAC3 → Amplifier
DAC3 → Amplifier → Amplifier
DAC3 → Preamplifier → Amplifier
AVR → DAC3, and AVR → Amplifier
(AVR with 2 trigger outputs controls
DAC3 and power amplifier)
Trigger Bus Applications
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.
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 turn 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. Because 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.
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. This feature makes it easy to turn the AHB2 amplifier(s) off when listening to headphones.
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.
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
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 16
HT Mode
The HT mode sets the volume control to a calibrated level that is near its maximum setting.
The HT mode has three distinct applications:
Volume Control Bypass - useful when the system has an upstream digital volume control or a downstream analog volume control
Home Theater Bypass - allows highquality stereo playback on a system that is also used for surround applications
Calibrated Output - useful in studio applications where calibrated levels are needed
In HT mode the analog gain is set to 0 dB
(unity gain, RCA to RCA). Digital inputs are calibrated to +24 dBu at 0 dBFS (+4 dBu at
-20 dBFS) measured at the XLR outputs, and
2 Vrms measured at the RCA outputs. The HT light is illuminated when the HT mode is active.
Each input channel can be programmed individually by pressing and holding the mute button for three seconds. The HT mode is similar to the CALIBRATED switch setting on the DAC1 except that the HT mode can be programmable separately for each input. This flexibility allows seamless integration into home theater systems where the DAC3 handles the main left and right channels.
HT Mode - Volume Control Bypass
The HT mode is useful whenever the system volume will be controlled before or after the
DAC3. It is usually best to avoid having two cascaded volume controls in a playback system. Dual controls will usually degrade the noise performance of the system and they can lead to confusion.
If the DAC3 feeds a preamplifier, the preamplifier will provide a downstream analog volume control for the system and the DAC3 should be placed in HT mode for all inputs.
If the DAC3 is directly feeding an amplifier, but one or more sources have volume controls, the sources with volume controls can be set to HT mode.
Example 1: The USB input is fed from a computer that has an internal digital volume control. If you wish to use the volume control in the computer exclusively, you will want to program the USB input with the HT mode on.
All other inputs will have the HT mode turned off. If you do not wish to use the computer volume control, leave the HT mode off and disable the computer volume control (or set it to maximum).
Example 2: One of the analog inputs on the
DAC3 is fed from a preamplifier and the preamplifier is being used to control the system playback. Set this analog input to HT mode on.
HT Mode - Home Theater Bypass
The home theater bypass is useful when you have a home theater system that will also be used for playing stereo recordings. The DAC3 will directly drive the left and right power amplifiers while the AVR drives all other speakers. The analog left and right line-level outputs of the AVR will be connected to one set of analog inputs on the DAC3 (usually
A1). Stereo sources will be connected directly to the digital inputs on the DAC3. Surround sources will be connected directly to the inputs on the AVR.
When playing stereo recordings, digital feeds are sent directly to the DAC3 and the volume control on the DAC3 is used to control the playback level (HT mode must be off on all digital inputs). This configuration gives the best-possible performance for stereo applications because it eliminates the AVR from the stereo playback chain. If the stereo system includes a turntable and an outboard phono preamplifier, the outputs of the phono preamplifier can be connected directly to the
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 17
second set of analog inputs on the DAC3 (HT mode off, analog input A2).
When playing movies and other surround sources, analog signals from the AVR would pass through the DAC3 at unity gain (HT mode on, analog input A1).
After holding the button(s) for 3 seconds, either the 4X lamp or the 2X lamp will flash once indicating the new USB MODE. A flash of the 4X lamp indicates that the unit is now in USB Audio 2.0 mode. A flash of the 2X lamp indicates that the unit is now in USB
Audio 1.1 mode.
For stereo applications, digital sources would feed the DAC3 and the volume control on the
DAC3 would control the playback level (HT mode off, digital inputs).
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.
HT Mode – Calibrated Output
Any digital input can be set to the factorycalibrated fixed-gain by turning the HT mode on. In HT mode, the analog audio outputs are set to factory calibrated levels. This mode is useful in studio applications where calibrated interface levels are used between various pieces of equipment. (Note: This function is similar to the calibrated mode on the DAC1.)
Tip:
Avoid any unnecessary switching between USB MODES. Rapid switching between modes can confuse some operating systems.
Driving Power Amplifiers
The DAC3 is designed to directly drive virtually any audio power amplifier or powered monitor. This direct connection provides the cleanest and shortest path from the digital source to the monitor output.
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
Tip:
Benchmark does not recommend placing audio devices between the DAC3 and the power amplifier unless these devices are providing an indispensible system function. A direct connection between the DAC3 and the power amplifier will always provide the best system-level performance (SNR and THD+N).
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.
The RCA and XLR outputs on the DAC3 are equipped with low-impedance high-current drivers. These robust outputs are well equipped to drive a wide variety of input impedances. The DAC3 outputs remain clean when driving amplifiers that present difficult loads (high input capacitance and/or low input impedance).
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, select the USB
(U) input on DAC3 and then press and hold the USB button on the remote control for 3 seconds. If a remote control is not available, simultaneously press and hold both INPUT buttons on the front panel for 3 seconds.
The XLR outputs on the DAC3 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 to the input sensitivity of the power amplifier. Most power amplifiers and powered monitors will require the use of the 10 dB or 20 dB pads.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 18
Use the 0 dB setting when driving a
Benchmark AHB2 power amplifier. by Benchmark's HPA2™ headphone power amplifier.
Tip:
The Benchmark AHB2 power amplifier has a unique low-gain topology that allows 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 22 dBu. This level is exactly 2 dB lower than the calibrated
HT output level of the DAC3 (when the pads are set to 0 dB). This configuration optimizes the gain-staging between the DAC3 and the
AHB2 while placing the DAC3 volume control in the proper range.
Tip:
If you are using a DAC3 with non-
Benchmark power amplifiers, the XLR pads should be set so that comfortable listening levels occur when the VOLUME control is set above 11 o’clock. This will optimize the gainstaging between the DAC3 and your power amplifier.
The HPA2™ is one of the most transparent headphone amplifiers available. It also is able to deliver high current and/or high signal levels making it well suited for a wide variety of headphones. The near 0-Ohm output impedance provides outstanding damping of headphone drivers. This damping reduces distortion while maintaining precise control of the frequency response at the output of the amplifier.
The HPA2™ has a set of 3-position gainrange jumpers that can be used to increase or decrease the gain by 10 dB relative to the factory calibrated setting.
Tip:
Increase the pad setting if a comfortable listening level is reached at a VOLUME control setting below the 11 o'clock position.
Tip:
Decrease the pad setting if a comfortable listening level cannot be reached when the
VOLUME control is fully clockwise.
Instructions for setting the XLR pad jumpers
are detailed in the Internal Settings section
of this manual. The DAC3 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.
The jumpers change the gain of the HPA2™ headphone amplifier without changing the output impedance. This keeps the output impedance of the HPA2™ constant and very near 0 Ohms. External attenuators should never be inserted after a headphone amplifier as this would change the output impedance and alter the frequency response of the headphones.
Proper gain settings are important for maximizing the SNR of the headphone monitoring system. With proper settings, the full performance of the DAC3 can be delivered to the headphones for critical monitoring tasks and for maximum musical enjoyment.
Tip:
When the headphone gain jumpers are set properly, a normal listening level will be achieved at a VOLUME control setting above the 11 o'clock position.
HPA2™ Headphone Amplifier
(DAC3 HGC model only)
Tip:
If a normal listening level is achieved below an 11 o’clock VOLUME setting, the headphone gain is too high, and the gain should be decreased.
The left headphone jack has a mute switch that mutes all of the analog outputs on the back of the DAC3. The right headphone jack does not have a mute switch. The audio output on both jacks is wired in parallel and is driven
Tip:
If the level is too low at the maximum
VOLUME setting, the headphone gain is too low, and the gain should be increased.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 19
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.
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.
Firmware Version Identification
The firmware version is displayed during the lamp test while the DAC3 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
Digit 1 Digit 2
8 D1 D2 .8 are shown in this chart. Add the values
4
U
D3 .4
2 A2 D4 .2
1 A1 HT .1 of all flashing lamps to determine the version number. If no lamp flashes in the second column, the second digit is a 0.
Example 1:
The A1 lamp is the only lamp that flashes. The firmware version is 1.0.
Example 2:
The A1 and HT lamps flash. The firmware version is 1.1.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 20
Rear Panel
DAC3 HGC and DAC3 L
Inputs
There are seven stereo inputs on the DAC3:
A1 - RCA L & R Analog Inputs
A2 - RCA L & R Analog Inputs
USB - USB Audio 1.1 or 2.0 Input
D1 - Optical Digital Input
D2 - Optical Digital Input
D3 - Coaxial 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.
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 will not decode multichannel digital formats such as AC3, and Dolby
Digital. 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 HGC and DAC3 L with 1.X Firmware Page 21
Analog Inputs – RCA Unbalanced
The DAC3 has two sets of unbalanced stereo analog inputs with female RCA connectors.
The analog inputs can be used for devices such as:
Phono preamplifiers
FM Tuners
Tape Transports
Analog VCR outputs
iPod and MP3 devices
Outputs from analog mixing consoles
Digital Inputs - Overview
All of the digital inputs on the DAC3 use
Benchmark's UltraLock3™ system to remove virtually all of the interface jitter. The result is that all digital inputs deliver identical audio performance. The USB, optical, and coaxial digital inputs will all sound identical if they receive identical data.
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. The USB cable connects the DAC3 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 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, simultaneously 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 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 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
The optical input connectors (D1 and D2) are commonly known as TOSLINK connectors.
The TOSLINK optical connectors used on the
DAC3 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
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 22
consumer S/PDIF data formats. The coaxial inputs also accept DSD in DoP 1.1 format.
The coaxial digital inputs are DC 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.
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 to an externally generated trigger signal. The DAC3 automatically configures the 12V TRIGGER
I/O port as an input (slave) or output
(master). See the Bi-directional 12V
Trigger section for more information.
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.
Tip:
The RCA analog inputs and outputs have no restrictions on cable type. To avoid confusion, we recommend using 75-Ohm coaxial cables for all RCA connections. 75-
Ohm coaxial cables are compatible with digital audio, analog audio, and video.
Note:
The Coaxial inputs (D3 and D4) accept professional or consumer digital audio formats. The AES3-id and SMPTE 276M standards specify 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 commonly used in hi-fi equipment. The coaxial inputs are designed to accept either type of signal.
12V TRIGGER I/O
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 is a 12V DC connection for synchronizing the on and off sequencing of an entire audio system.
The Benchmark bi-directional 12V TRIGGER is compatible with virtually all trigger 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 turns on.
The DAC3 can also turn on and off in response to trigger signals sent from other components.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 23
Outputs
Analog Outputs
The DAC3 has one pair of balanced XLR outputs and two pairs of unbalanced RCA outputs.
The DAC3 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
configuration is located in the Internal
Settings section of this manual.
Industry-Standard 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.
Unbalanced RCA Analog 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 ships with the pads disabled (0 dB setting).
Use the 0 dB setting with the Benchmark
AHB2 power amplifier. A full description of the output attenuators and instructions for
The Left and Right unbalanced outputs use female RCA jacks. The ground connections are bonded to chassis ground at the location where analog ground is bonded to the chassis. This minimizes the effects of ground loops caused by AC currents in the cable shield. 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 will cause high amounts of 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.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 24
AC Power-Entry and Fuse Module
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.
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, 50-
60 Hz.
Power Cord
Note:
The AC power input uses a standard
IEC type connector. One USA-compatible power cord is included with DAC3 converters.
IEC style power cords in country-specific configurations are available in your locality.
Caution: Always use a grounded power cord. The DAC3 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.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 25
Internal Settings
Jumper-Configured Options
The following functions are jumper configured:
XLR Output Pads
Headphone Mute Switches
Headphone Gain
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.
Always connect a static-control wrist strap to the chassis before touching any internal component.
XLR Output Pads
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 factorypreset 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 with
Benchmark's AHB2 power amplifier. 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 VOLUME control is between the 11 o’clock and 3 o'clock positions.
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.
Table 1 - Cable Drive Capability
Balanced Output Drive Capability:
Attenuator Output Maximum Loss in dB
Setting (dB) Impedance Cable (ft) at 20 kHz
0
10
20
60
425
135
680
96
302
0.1
0.1
0.1
Unbalanced Output Drive Capability:
Output Maximum Loss in dB
Impedance Cable (ft) at 20 kHz
30 1360 0.1
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 26
XLR Output Pad Jumpers
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) requirements are different the HEADPHONE
SWITCH can be defeated.
Headphone Switch Disable
The HEADPHONE SWITCH on the left-hand headphone jack can be defeated by adding jumpers at JP1 and JP2.
HEADPHONE SWITCH enabled (no jumpers at JP1 or JP2) - Factory Default
HEADPHONE SWITCH disabled (jumpers installed at JP1 and JP2)
Figure 2 - Headphone Switch Enabled
(Factory Default)
Figure 1 - Attenuators set to -10 dB
Headphone Switch Configuration
(DAC3 HGC only)
The left-hand headphone jack is equipped with a switch that will mute the analog outputs when a headphone plug is inserted.
The right-hand headphone jack does not have a mute switch. In most cases it is convenient to have one jack that mutes the outputs and one that does not mute the outputs. If your
Figure 3 - Headphone Switch Disabled
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 27
Headphone Amplifier Gain
(DAC3 HGC only)
The gain range of the HPA2™ can be set using jumpers JP3 and JP4:
Gain = - 10 dB - see Figure 5
(Factory Default)
Gain = - 20 dB - see Figure 6
The jumpers change the gain of the HPA2™ headphone amplifier without changing the output impedance. This keeps the output impedance of the HPA2™ constant and very near 0 Ohms. External attenuators should never be inserted after a headphone amplifier as this would change the output impedance and alter the frequency response of the headphones.
Proper gain settings are important for maximizing the SNR of the headphone monitoring system. With proper settings, the full performance of the DAC3 can be delivered to the headphones for critical monitoring tasks and for maximum musical enjoyment.
Tip:
When the headphone gain jumpers are set properly, a normal listening level will be achieved at a VOLUME control setting above the 11 o'clock position.
Tip:
If a normal listening level is achieved below an 11 o’clock VOLUME setting, the headphone gain is too high, and the gain should be decreased.
Tip:
If the level is too low at the maximum
VOLUME setting, the headphone gain is too low, and the gain should be increased.
Figure 4 - HPA2™ Gain is 0 dB
Figure 5 - HPA2™ Gain is - 10 dB
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 28
Figure 6 - HPA2™ Gain is - 20 dB
Digital PASS-THROUGH Function
The digital PASS-THROUGH function can be enabled by moving both P14 jumpers toward the faceplate shown in Figure 7. Once the jumpers are moved into the position shown in
Figure 7, D4 is configured as a digital audio output. 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 can be passed through to D4
(even when these formats cannot be decoded by the DAC3).
By default, D4 functions as a digital input and the jumpers are set according to Figure 8.
Figure 7 – Digital PASS-THROUGH
Enabled
Figure 8 - Digital PASS-THROUGH
Disabled (Factory Default)
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 29
Rack Mounting
An optional rack mount tray allows the mounting of any two ½-wide Benchmark products in a single rack space. A blank plate can be added when only one unit is installed in the rack mount tray.
The Benchmark Rack Mount Tray and
Benchmark ½-Wide Blank Plate are available from Benchmark.
Benchmark Rack Mount Tray
Benchmark ½-Wide Blank Plate
The Benchmark ½-Wide Blank Plate is a
½-wide 1-RU anodized aluminum panel for covering an unused slot in the Benchmark
Rack Mount Tray. It is available in black or silver. The silver panel includes an engraved
Benchmark logo.
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).
Visit BenchmarkMedia.com
for a complete selection of cable, accessories, and replacement parts.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 30
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.
The following 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 drive difficult loads
Lower output impedances
Benchmark's AdvancedUSB™ computer input was the first USB audio interface to support 96 kHz audio without the need to install special drivers.
DAC1 PRE
The DAC1 PRE added these improvements:
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 digital input and replaced it with two additional coaxial digital inputs.
DAC1 HDR
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 pass-through
Bi-directional 12V trigger
Two stereo analog inputs
Three stereo analog outputs
Two optical inputs
High-efficiency low-noise power supplies
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 31
DAC2 L
The DAC2 L is identical to the DAC2 HGC except that the DAC2 L has no headphone amplifier.
DAC2 D
The DAC2 D is identical to the 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 systems have been upgraded.
The new DAC3 delivers lower THD, improved digital filtering, and faster PLL lock times.
The firmware, digital signal processing, 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 ESS PRO series was 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 highheadroom DSP leverage the full capabilities of the new ESS PRO series converters.
DAC3 vs. DAC2
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
Improved digital filters o
Lower passband ripple o
Flatter frequency response
Higher maximum output level
Increased Dynamic Range
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 32
Benchmark Technologies
Hybrid Gain Control™
HGC™ is Benchmark's unique Hybrid Gain
Control™ system. The DAC3 combines active analog gain control, passive low-impedance attenuators, a 32-bit digital gain control, and a servo-driven volume control.
All inputs are controlled by the rotary volume control. This volume control moves in response to commands from the remote control. Analog inputs are never converted to digital, and digital inputs never pass through an analog potentiometer. Digital inputs are precisely controlled in the 32-bit DSP system.
The DSP system preserves precise L/R balance, and precise stereo imaging, while avoiding any source of noise and distortion.
Benchmark's unique passive output attenuators provide distortion-free gain reduction without reducing the dynamic range of the converter. The attenuators optimize the gain staging between the DAC3 and the power amplifier. This optimization is absolutely essential for maximizing the dynamic range of the entire playback system.
Much of the success of the DAC1 and DAC2 converters can be attributed to the passive output attenuators. Musical details can be obscured by system noise whenever a preamplifier and power amplifier are improperly matched. The HGC™ system in your DAC3 will make full use of your power amplifier's dynamic range. Experience newly revealed details in your favorite recordings.
The front-panel volume control is a servodriven gain control built around a custommade Alps potentiometer. The custom Alps pot is equipped with a remote-controllable motor drive.
This potentiometer is equipped with a clutch which prevents damage from overriding the motor drive. If the pot is driven beyond the end of its range, it will not damage the motor.
Also, if the pot is manually overridden, it will not damage the motor.
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.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 33
Intersample Overs
(1 = Maximum Digital Code)
1.5
1
0.5
0
-0.5
-1
-1.5
Analog
Audio
Digital
Samples
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) intersample overs 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. In 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 caused by intersample overs. Benchmark's high-headroom DSP renders low sample rates with the clarity and detail normally associated with high sample rates.
1.5
1
0.5
0
-0.5
-1
-1.5
Conventional Interpolation
(Intersample Overs are Clipped)
Analog
Audio
Digital
Samples
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
Analog
Audio
Digital
Samples
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.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 34
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. button on any Benchmark device can be used to start or stop the entire audio system in a sequenced manner.
Distributed Power Regulation
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.
Diagnostic Displays
We have created a discrete ultra low-noise regulator for the ES9028PRO D/A converter.
This Benchmark exclusive feature improves the noise performance of the alreadyoutstanding ES9028PRO.
Ever wonder why that 192 kHz 24-bit download on your computer just doesn't sound right? Your media player or computer 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 with 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
HPA2™ Headphone Amplifier
The DAC3 headphone output is driven by
Benchmark’s signature HPA2™ headphone power amplifier. This high-current, highoutput amplifier has an output impedance that is nearly 0 Ohms. It is designed to drive loads as low as 30 Ohms without any increase in distortion. It also has sufficient amplitude to drive low-sensitivity 600-Ohm headphones.
The HPA2™ includes current-limiting circuits that fully protect against damage from short circuits. This is important because the right channel of a headphone amplifier will experience a short whenever a mono phone plug is inserted into the stereo headphone jack. Shorts may also occur when a plug is partially inserted.
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 components can communicate bidirectionally on the trigger I/O ports. This bidirectional communication provides greater flexibility. In a given system, the power
"0-Ohm" Output Impedance
Most headphone amplifiers use series resistors to maintain stability and protect against short-circuit conditions. These resistors are usually at least 30 Ohms, and have a negative impact on performance. A headphone amplifier with series resistors may measure very well on a test bench when driving resistive loads. However, the same amplifier will measure very poorly when driving a headphone load. Unfortunately, most manufacturers do not measure or specify headphone amplifier performance
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 35
when loaded with real headphones. The measurements use ideal resistive loads. Our measurements show that headphones do not behave like resistive loads.
Headphone Performance
In our tests we have measured substantial distortion across resistors that are wired in series with headphones. We have conducted measurements with a variety of headphones.
In general, distortion increases as headphone impedance decreases. This distortion can be eliminated with a properly designed "0-Ohm" headphone amplifier.
The performance of the HPA2™ does not change when headphones are driven. THD+N measurements for no-load, 30-Ohm resistive loads, 30-Ohm headphone loads, and 600-
Ohm headphone loads are virtually identical.
The HPA2™ will substantially improve the sound of 30 and 60-Ohm headphones. It will make very noticeable improvements with
600-Ohm headphones.
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™ systems. The
DSP processing is 32-bits, DSP headroom is
3.5 dB, sample rate is 211 kHz, and jitterinduced distortion and noise is at least 160 dB below the level of the music - well below the threshold of hearing. Benchmark's
UltraLock3™ system eliminates all audible jitter artifacts.
The Importance of Eliminating Jitter
Accurate 24-bit audio conversion requires a very low-jitter conversion clock. Jitter 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.
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.
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 signal 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.
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
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 36
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 remove 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 included 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 conversion clock from the digital audio interface clock. 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 clock. 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. Worse yet, 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 cause a loss of imaging, and can add a low and mid frequency ‘muddiness’ that was not in the original 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 16 Graph 16). This FFT
shows that the DAC3 is free from any jitterinduced sidebands to a measurement limit of about -144 dB relative to the level of the test
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 37
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.
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 anti-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 converter 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.
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 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. Practitioners of Digital Audio need to understand these effects.
Is it possible to eliminate 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 analog-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 converters and D/A converters in an attempt to reduce jitter. Again, these are only partial 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).
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
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 38
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 impossible to audibly evaluate A/D performance without a good
D/A. The consistent performance delivered by the DAC3 eliminates one major variable - jitter.
Asynchronous USB
In all modes the USB communications are asynchronous. An ultra low jitter conversion 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 system.
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.
The DAC3 has a low-jitter master clock which controls the transfer of audio data from the computer to the USB sub-system. The computer asynchronously 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 transfer eliminates any traces 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 follow sample rate 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.
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.
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.
The industry-standard USB Audio Mode 2.0 mode is not yet natively supported by the
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 39
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 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 HGC and DAC3 L with 1.X Firmware Page 40
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 folder, double click “setup.exe.”
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 41
2. A welcome screen will pop-up. Click “Next.”
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 42
3. When you see the following screen, 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 once). 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). If the 2X light flashes instead of the 4X light, repeat this step.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 43
4. You will now be prompted to select a location to install the driver. It will default to your
Program Files folder. 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 following screen. Please be patient while the driver installs. Installation may require several minutes.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 44
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 enjoy music 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 HGC and DAC3 L with 1.X Firmware Page 45
Performance Graphs
Audio Precision DAC3 - FFT Idle Channel Noise at Max Gain, 0 dBr = 0 dBFS = 27.5 dBu
r
d
B
A
+0
-20
-40
-60
-80
-100
-120
-140
-160
0 2k 4k 6k 8k 10k 12k 14k 16k
Hz
18k
Sweep Trace
1
1
1
2
Color Line Style Thick Data
Green Solid
Red Solid
4
4
Fft.Ch.1 Ampl
Fft.Ch.2 Ampl
Axis
Left
Right
Comment
DAC3 - FFT Idle Channel Noise.at27
20k 22k 24k 26k 28k 30k 32k
+0
-20
-40
-60
-80
-100
r
d
B
A
-120
-140
-160
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 FFT analysis and 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 HGC and DAC3 L with 1.X Firmware Page 46
Audio Precision DAC3 - FFT Idle Channel Noise - Low Frequency, 0 dBr = 0 dBFS = 27.5 dBu
A
r
d
B
-40
-60
-80
-100
-120
-140
+0
-20 dx=121.213 Hz dy=+2.090 dB
-160
25 75 100 125 150 200
Hz
225 250 275 300
Sweep Trace
1
1
1
2
Color Line Style Thick Data
Green Solid
Red Solid
4
4
Fft.Ch.1 Ampl
Axis
Left
Comment Cursor1 Cursor2
Left Channel *-160.182 dBr *-158.092 dBr
Fft.Ch.2 Ampl Right Right Channel -159.850 dBr A -160.611 dBr A
DAC3 - FFT Idle Channel Noise - Low Frequency.at27
325 350 375 400
Graph 2 - Low Frequency FFT - AC Line-Related Hum
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
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 strong line-frequency magnetic fields that would have been created by line-frequency power transformers.
+0
-20
-40
-60
-80
-100
r
d
B
A
-120
-140
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 47
Audio Precision DAC3 - FFT 10 kHz, 0 dBr = 0 dBFS = 24 dBu
-60
d
B
r
A
-80
-100
-111.013
-120
-124.989
-140
+0 dx=10.0196 kHz
-20
-40 dy=-13.975 dB
-160
0 2k 4k 6k 8k 10k 12k 14k 16k
Hz
18k 22k
Sweep Trace
1
2
2
2
Color
Green
Red
Line Style Thick Data
Solid
Solid
4
4
Fft.Ch.1 Ampl
Fft.Ch.1 Ampl
Axis
Left
Left
Comment Source 2
: 1.00000 =Swr.Ch. A Input
: 2.00000 =Swr.Ch. A Input
Cursor1
*-111.013 dBr
-111.241 dBr A
Cursor2
*-124.989 dBr
-127.362 dBr A
DAC3 - FFT 10 kHz.at27
24k 26k 28k 32k
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 kHz, 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 HGC and DAC3 L with 1.X Firmware Page 48
Audio Precision
+0
-20 dx=1.00000 kHz
-40
d
B
r
A
-60
-80
-100
-120
-122.546
dy=+11.101 dB
DAC3 - FFT 1 kHz, 0 dBr = 0 dBFS = 24 dBu
-160
0 200 400 600 800 1k 1.2k
1.4k
1.6k
1.8k
Hz
2.2k
2.4k
Sweep Trace
1
2
2
2
Color Line Style Thick Data
Green Solid
Red Solid
4
4
Fft.Ch.1 Ampl
Fft.Ch.1 Ampl
Axis
Left
Left
Comment Source 2
Left Channel : 1.00000 =Swr.Ch. A Input
Right Channel
Cursor1
-125.680 dBr A
*-133.647 dBr
Cursor2
-123.514 dBr A
*-122.546 dBr
DAC3 - FFT 1 kHz.at27
2.6k
2.8k
3.2k
3.4k
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 condition, the AC line-related hum frequencies (60 Hz, 180 Hz, and
240 Hz) measure better than - 133 dB.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 49
Audio Precision DAC3 - FREQUENCY RESPONSE
Fs = 192 kHz
11/01/16 12:38:28
+1
+0.5
dx=40.8457 kHz dy=-0.016 dB
r
d
B
A
-0.5
-1
-1.5
-2
-2.5
-3
-3.5
-4
-4.5
-5
-5.5
-6
-6.5
-7
-7.5
-8
-8.5
-9
-9.5
20 50 100 200 500 1k
Hz
2k
Sweep Trace
1 1
Color
Red
Line Style
Solid
Thick
4
Data Axis Comment
Anlr.Level A Left
Cursor1 Cursor2
*-0.015 dBr *-0.031 dBr
DAC3 - Frequency Response.at27
5k 10k 20k
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.
90k
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 50
Audio Precision
+1
+0.8
+0.6
dx=19.7956 kHz dy=+0.18 deg
DAC3 - Differential Phase
Fs = 96 kHz
d
e
g
+0
-0.2
-0.4
-0.6
-0.8
-1
2.5k
5k 7.5k
10k 12.5k
15k 17.5k
22.5k
Hz
25k 27.5k
30k
Sweep Trace
1
2
1
1
Color Line Style Thick Data
Green Solid
Red Solid
4
4
Anlr.Phase
Anlr.Phase
Axis
Left
Left
Comment
Left to Right
Right to Left
Cursor1 Cursor2
*+0.24 deg *+0.42 deg
-0.25 deg -0.43 deg
DAC3 - Differential Phase.at27
32.5k
35k 37.5k
42.5k
45k
Graph 6 - Differential Phase
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 HGC and DAC3 L with 1.X Firmware Page 51
Audio Precision DAC3 - THD and THD+N vs. Amplitude, 1 kHz, 0 dBFS = 24 dBu
d
B
r
A
-90
-95
-100
-105
-110
-115
-120
-125
-130
-30 -28 -26 -24 -22 -20 -18 -16
dBFS
-14 -12
Sweep Trace
1
1
1
2
Color Line Style Thick Data
Red Solid
Black Solid
4
4
Distortion.Ch.1 Harm Sum1
Anlr.THD+N Ampl
Axis
Left
Comment
THD
Right THD+N
DAC3 - THD and THD+N vs Amplitude.at27
-10 -8 -6 -4 -2
Graph 7 - THD and THD+N vs. Amplitude (Balanced Outputs)
These plots demonstrate the very low harmonic distortion produced by the DAC3 with digital input signal levels ranging 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 distortion analyzer in the AP2722 test set. This THD curve includes all harmonics falling below 32 kHz. The steps near -3 dBFS and -9 dBFS are due to the auto ranging of the AP2722 test set and are an indication that the
THD performance of the DAC3 is very close to the measurement limits of the AP2722.
-120
-125
-0
-130
-90
-95
-100
-105
-110
-115
d
B
r
A
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 52
Audio Precision DAC3 - THD and THD+N vs. Amplitude, 1 kHz, 0 dBFS = 2Vrms
Unbalanced Outputs
r
d
B
A
-105
-110
-115
-120
-125
-90
-95
-100
-130
-30 -28 -26 -24 -22 -20 -18 -16
dBFS
-14 -12
Sweep Trace
1
1
1
2
Color Line Style Thick Data
Red Solid
Black Solid
4
4
Distortion.Ch.1 Harm Sum1
Anlr.THD+N Ampl
Axis
Left
Comment
THD Only
Right THD+N
DAC3 - THD and THD+N vs Amplitude Unbalanced.at27
-10 -8 -6 -4 -2
Graph 8 - THD and THD+N vs. Amplitude (Unbalanced Outputs)
This plot shows the THD and THD+N performance of the unbalanced outputs.
Note that the THD performance of the unbalanced outputs approaches 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.
-90
-95
-100
-105
-110
-115
r
d
B
A
-120
-125
-0
-130
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 53
Audio Precision DAC3 - THD vs. Amplitude, 1 kHz, 0 dBFS = 2Vrms
Balanced vs. Unbalanced Outputs
-100
-105
-110
-115
d
B
r
A
-120
-125
-130
-135
-140
-30 -28 -26 -24 -22 -20 -18 -16
dBFS
-14 -12
Sweep Trace
1
2
3
2
Color Line Style Thick Data
Black Solid
Red Solid
4
4
Distortion.Ch.1 Harm Sum1
Distortion.Ch.1 Harm Sum1
Axis
Right
Left
Comment Source 2
THD Balanced Output
DAC3 - THD vs Amplitude Balanced vs Unbalanced.at27
-10 -8 -6 -4 -2
-100
-105
-110
-115
-120
-125
d
B
r
B
-130
-135
-0
-140
Graph 9 - THD vs. Amplitude - Balanced vs. Unbalanced Outputs
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. The separation between the curves at signal levels below -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 ratios. This is just one reason why
Benchmark recommends balanced interconnects.
The DAC3 includes differential amplifiers that remove common-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 eliminate 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 amplifiers 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 HGC and DAC3 L with 1.X Firmware Page 54
Audio Precision
d
B
-30
-40
-50
-60
+0
-10
-20
-70 dx=278.8 mW
DAC3 - Headphone Amplifier - THD+N vs Power at 1 KHZ (w/20 kHz LPF unweighted)
Headphone outputs into 300 Ohms, both channels driven dy=-21.278 dB
-90
-100
-102.254
-110
20u 50u 100u 200u 500u 1m
W
2m 5m 10m
Sweep Trace
1 1
Color
Red
Line Style
Solid
Thick
4
Data Axis Comment
Anlr.THD+N Ratio Left
Cursor1
*-80.976 dB
Cursor2
*-102.254 dB
DAC3 - HEADPHONE - THD+N vs Power - 300 Ohm Load.at27
20m 50m 100m
Graph 10 - Headphone Amplifier into 300 Ohms – THD+N versus Power
This plot shows the THD+N performance of the headphone outputs when driving a typical 300-Ohm load. Note that the THD+N performance of the headphone outputs approaches that of the balanced outputs (-110 dB at 20 mW). Benchmark's HPA2™ headphone amplifier can cleanly deliver 21.5 dBu (9.2 Vrms) into a 300-Ohm load.
This graph shows that the HPA2™ has the voltage required to drive high-impedance headphones.
The following graph shows that the HPA2™ has the power required to drive low-impedance headphones. In either case, the near 0-Ohm output impedance provides outstanding control and damping of the headphone drivers.
The HPA2™ includes 3 jumper-programmable gain ranges that can be configured to match the voltage sensitivity of your favorite headphones. The gain-range settings do not change the output impedance or the THD of the headphone amplifier.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 55
Audio Precision
d
B
-30
-40
-50
-60
+0
-10
-20
-70 dx=1.253 W
DAC3 - Headphone Amplifier - THD+N vs Power at 1 KHZ (w/20 kHz LPF unweighted)
Headphone outputs into 30 Ohms, both channels driven dy=-6.139 dB
-100
-110
-120
100u 200u 500u 1m 2m 5m 10m
W
20m 50m 100m
Sweep Trace
1 1
Color
Red
Line Style
Solid
Thick
4
Data Axis Comment
Anlr.THD+N Ratio Left
Cursor1 Cursor2
*-80.867 dB *-87.006 dB
DAC3 - HEADPHONE - THD+N vs Power - 30 Ohm Load.at27
200m 500m 1
1.253
2 3
Graph 11 - Headphone Amplifier into 30 Ohms – THD+N versus Power
This plot shows the THD+N performance of the headphone outputs under a very heavy load (30-
Ohms). Note that the THD+N performance of the headphone outputs still approaches that of the balanced outputs (-110 dB at 20 mW).
This graph demonstrate that Benchmark's HPA2™ headphone amplifier can cleanly deliver 1.25 W into 30 Ohms, both channels driven.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 56
Audio Precision DAC3 - THD+N VS FREQ AT 0 dBFS, 24 dBu (w/80 kHz LPF unweighted)
Balanced Outputs
d
B
-90
-95
-100
-105
-110
-115
-120
-125
-130
20 50 100 200 500
Hz
1k
Sweep Trace
1
1
1
2
Color Line Style Thick Data
Green Solid
Red Solid
4
4
Anlr.THD+N Ratio
Anlr.THD+N Ratio
Axis
Left
Left
Comment
Left Channel
Right Channel
DAC3 - THD+N vs FREQUENCY 80kHZ.at27
2k 5k 10k 20k
Graph 12 - THD+N vs. Frequency 80 kHz
The analog output stages on the DAC3 have high slew rates and are capable of maintaining 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 HGC and DAC3 L with 1.X Firmware Page 57
Audio Precision DAC3 - THD and THD+N vs. Frequency, 1 kHz, 0 dBFS, 24 dBu
Digital In to Balanced Analog Out
-100
T
dx=9.02137 kHz
T T
-105
-110
-115
d
B
r
A
-120
-125
-130
-135 dy=+6.001 dB
-140
20 50 100 200 500 2k
Hz
Sweep Trace
1
1
1
2
Color Line Style Thick Data
Black Solid
Red Solid
4
4
Anlr.THD+N Ampl
Axis
Left
Comment Cursor1 Cursor2
THD+N, 80 kHz LPF -107.584 dBr A
Distortion.Ch.1 Harm Sum1 Right THD, 48 kHz LPF *-111.274 dBr
DAC3 - THD and THD+N vs Frequency Digital to Analog.at27
5k
Graph 13 - THD and THD+N vs. Frequency
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.
-100
-105
-110
-111.274
-115
-117.274
-120
d
B
r
A
-125
-130
-135
20k
-140
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 58
Audio Precision
-90 dx=182.000 kHz
-95
-100
-105
d
B
-110
-113.208
-115
-120
-125
DAC3 - THD+N vs Sample Rate, 1 kHz at 0 dBFS (w/20 kHz LPF unweighted) dy=+0.001 dB
-130
28k
40k 60k 80k 100k 120k
Hz
140k
Sweep Trace
1
1
1
2
Color Line Style Thick Data
Green Solid
Red Solid
4
4
Anlr.THD+N Ratio
Axis
Left
Comment
Left Channel
Cursor1
-113.043 dB
Cursor2
-113.041 dB
Anlr.THD+N Ratio Left Right Channel *-113.209 dB *-113.208 dB
DAC3 - THD+N vs Sample Rate.at27
160k
Graph 14 - THD+N versus Sample Rate
The THD+N performance of the DAC3 is identical at all Sample Rates.
180k 200k
210k
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 59
Audio Precision
d
B
DAC3 - INTERFACE JITTER TOLERANCE - Distortion vs Jitter
3.456 kHz Test Tone at 0 dBFS, THD+N 22 to 22 kHz BW
+0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
100 200 500 1k 2k 5k
Hz
Sweep Trace
1
1
1
2
Color Line Style Thick Data
Red Solid
Black Solid
4
4
Anlr.THD+N Ratio
Dio.Interface Jitter
Axis
Left
Right
Comment
DAC3 - JITTER TOLERANCE.at27
10k 20k 50k
20
10
5
2
1
500m
U
I
200m
100m
50m
20m
90k
10m
Graph 15 - Jitter Tolerance
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 right-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 HGC and DAC3 L with 1.X Firmware Page 60
A
r
d
B
Audio Precision DAC3 - INTERFACE JITTER TOLERANCE FFT
10 kHz Test Tone at 0 dBFS, AES Jitter Tolerance Sweep
-80
-100
-120
-140
+0
-20
-40
-60
-160
0 2k 4k 6k 8k 10k 12k 14k 16k
Hz
18k 20k 22k
24
25
26
27
28
29
18
19
20
21
22
23
30
31
7
8
9
10
11
12
13
14
15
16
17
3
4
1
2
5
6
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Sweep Trace Color Line Style Thick Data
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Blue
Cyan
Green
Yellow
Solid
Solid
Solid
Solid
Red Solid
Magenta Solid
Blue
Cyan
Green
Yellow
Solid
Solid
Solid
Solid
Red Solid
Magenta Solid
Blue
Cyan
Green
Yellow
Red
Solid
Solid
Solid
Solid
Solid
Magenta Solid
Blue Solid
Cyan
Green
Solid
Solid
Yellow
Red
Solid
Solid
Magenta Solid
Blue Solid
Cyan
Green
Solid
Solid
Yellow
Red
Solid
Solid
Magenta Solid
Blue Solid
Axis
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Fft.Ch.1 Ampl Left
Comment Source 2
: 100.000 Hz=Dio.Jitter Freq
: 125.893 Hz=Dio.Jitter Freq
: 158.489 Hz=Dio.Jitter Freq
: 199.526 Hz=Dio.Jitter Freq
: 251.189 Hz=Dio.Jitter Freq
: 316.228 Hz=Dio.Jitter Freq
: 398.107 Hz=Dio.Jitter Freq
: 501.187 Hz=Dio.Jitter Freq
: 630.957 Hz=Dio.Jitter Freq
: 794.328 Hz=Dio.Jitter Freq
: 1.00000 kHz=Dio.Jitter Freq
: 1.25893 kHz=Dio.Jitter Freq
: 1.58489 kHz=Dio.Jitter Freq
: 1.99526 kHz=Dio.Jitter Freq
: 2.51189 kHz=Dio.Jitter Freq
: 3.16228 kHz=Dio.Jitter Freq
: 3.98107 kHz=Dio.Jitter Freq
: 5.01187 kHz=Dio.Jitter Freq
: 6.30957 kHz=Dio.Jitter Freq
: 7.94328 kHz=Dio.Jitter Freq
: 10.0000 kHz=Dio.Jitter Freq
: 12.5893 kHz=Dio.Jitter Freq
: 15.8489 kHz=Dio.Jitter Freq
: 19.9526 kHz=Dio.Jitter Freq
: 25.1189 kHz=Dio.Jitter Freq
: 31.6228 kHz=Dio.Jitter Freq
: 39.8107 kHz=Dio.Jitter Freq
: 50.1187 kHz=Dio.Jitter Freq
: 63.0957 kHz=Dio.Jitter Freq
: 79.4328 kHz=Dio.Jitter Freq
: 100.000 kHz=Dio.Jitter Freq
DAC3 - JITTER TOLERANCE FFT.at27
24k 26k 28k 30k 32k
Graph 16 - 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 notched out in order to make this very highresolution measurement. If the fundamental was not notched out, the spurious tones, produced by the A/D converter in the AP2722 test set, would have obscured the virtually-perfect results.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 61
d
B
r
A
Audio Precision
-60
-70
-80
-90
-100
-110
-120
-130
-140
-150
+0
-10
-20
-30
-40
-50
-160
0 dx=9.00196 kHz
1.01761k
2k dy=+6.749 dB
DAC3 - 11K 12K IMD
4k 6k 8k 12k 14k
Hz
Sweep Trace
1
1
1
2
Color Line Style Thick Data
Green Solid
Red Solid
4
4
Fft.Ch.1 Ampl
Axis
Left
Comment Cursor1 Cursor2
Left Channel -131.652 dBr A -125.861 dBr A
Fft.Ch.2 Ampl Right Right Channel *-131.548 dBr *-124.799 dBr
DAC3 - IMD 11K 12K.at27
16k 18k
11/02/16 09:51:21
20k
+0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
-124.799
-131.548
-140
-150
d
B
r
A
-160
Graph 17 - 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 below audible levels.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 62
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 = +27.5 dBu 128 dB
SNR – Unweighted, 0 dBFS = +27.5 dBu
Dynamic Range - A-Weighted at maximum volume
126 dB
128 dB
Dynamic Range - Unweighted at maximum volume
THD+N, 1 kHz at 0 dBFS
THD+N, 1 kHz at -1 dBFS
THD+N, 1 kHz at –3 dBFS
THD+N, 20 to 20 kHz sweep at –3 dBFS
Frequency Response at Fs=192 kHz
126 dB
-113 dBFS, -113 dB, 0.00022%
-114 dBFS, -113 dB, 0.00022%
-119 dBFS, -116 dB, 0.00016%
Frequency Response at Fs=48 kHz
Crosstalk
-113 dBFS, -110 dB, 0.00032%
+0 dB, -0.015 dB (20 to 20 kHz)
-0.015 dB at 10 Hz
-0.005 dB at 20 kHz
-0.031 dB at 40 kHz
-0.15 dB at 80 kHz
+0 dB, -0.015 dB (20 to 20 kHz)
-0.015 dB at 10 Hz
-0.005 dB at 20 kHz
-116 dB at 20 kHz
-130 dB at 1 kHz
-137 dB at 20 Hz
< -144 dB Maximum Amplitude of Jitter Induced Sidebands (10 kHz 0 dBFS test tone, 12.75 UI sinusoidal jitter at 1 kHz)
Maximum Amplitude of Spurious Tones with 0 dBFS test signal
< -138 dB
Maximum Amplitude of Idle Tones
Maximum Amplitude of AC line related Hum & Noise
Inter-channel Differential Phase (Stereo Pair – any sample rate)
Inter-channel Differential Phase (Between DAC3 Units
< -147 dB
< -133 dB
+/- 0.25 degrees at 20 kHz
+/- 0.25 degrees at 20 kHz
Fs<110 kHz) Any sample rate.
Maximum Lock Time after Fs change
Soft Mute Ramp Up/Down Time
Mute on Receive Error
Mute on Lock Error
Mute on Idle Channel
50/15 us De-Emphasis Enable
De-Emphasis Method
De-Emphasis Supported at
6 ms
9.6 ms
Yes
Yes
No
Automatic in Consumer Mode
Digital IIR
Fs = 32, 44.1, 48 kHz
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 63
Group Delay (Latency)
Delay – Digital Input to Analog Output (function of sample rate)
1.36 ms at 44.1 kHz
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
0.47 ms at 192 kHz
Digital Audio Inputs
Number of Digital Inputs (switch selected)
Number of Channels
Input Sample Frequency Range
5 (1 USB, 2 Optical, 2 Coaxial)
2
28 to 210 kHz (Coaxial Inputs)
28 to 96 kHz (Optical Inputs)
Maximum Input Word Length
Digital Input Impedance
44.1, 48, 88.2, 96, 176.4, 192 kHz
(USB Input)
24 bits
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)
Jitter Attenuation Method
>12.75 UI sine, 100 Hz to 3 kHz
>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
>0.25 UI sine above 160 kHz
Benchmark UltraLock3™ - all inputs
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 64
Balanced Analog Outputs
Number of Balanced Analog Outputs
Output Connector
Output Impedance
Analog Output Clip Point
Factory Set Bypass Level (with 0 dBFS digital input)
Volume Control Range (with 0 dBFS digital input)
2
Gold-Pin Neutrik™ male XLR
60 Ohms (Attenuator off)
425 Ohms (Attenuator = 10 dB)
135 Ohms (Attenuator = 20 dB)
+29 dBu
+24 dBu (Attenuator = 0 dB)
Off to +27.5 dBu (Attenuator off)
Off to +17.5 dBu (Attenuator = 10 dB)
Off to +7.5 dBu (Attenuator = 20 dB)
< +/- 0.006 dB Output Level Variation with Sample Rate
Unbalanced Analog Outputs
Number of Unbalanced Analog Outputs
Output Connector
Output Impedance
Analog Output Clip Point
Factory-Set Home Theater Bypass Output Level (with 0 dBFS digital input)
Output Level Range (with 0 dBFS digital input)
Output Level Variation with Sample Rate
4
RCA
30 Ohms
+13.5 dBu (3.7 Vrms)
+8.2 dBu (2 Vrms)
Off to +11.7 dBu (3 Vrms)
< +/- 0.006 dB
HPA2
TM
Headphone Outputs
Number of Headphone Outputs
Output Connectors
Output Impedance
Output Level Control
Output Level Range (with 0 dBFS digital input)
Output Power
Maximum Output Current
Overload Protection (independent per channel)
Bandwidth
THD+N at 20 mW
2
¼” TRS with switch on left-hand jack
< 0.11 Ohms
Stereo Control on Front Panel
Off to +21.5 dBu (9.2 Vrms)
1.25 W into 30 Ohms
250 mA
Current limited at 300 mA, Thermal
> 500 kHz, -0.35 dB at 200 kHz
-108 dB (0.0004%) into 300 Ohms,
-100 dB (0.0010%) into 30 Ohms
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 65
Unbalanced Analog Inputs
Number of Unbalanced Analog Inputs
Input Connector
Input Impedance
Analog Input Clip Point
Input Sensitivity
Bandwidth
THD+N (Analog to Analog, 2 Vrms in, +24 dBu out)
Status Display
Indicators - Type and Location
Selection/Status Indication
4
RCA
20 K Ohms
+18.5 dBu (6.5 Vrms)
+8.2 dBu (2 Vrms)
> 500 kHz, -0.6 dB at 200 kHz
-110 dB (0.00032%)
16 LEDs on Front Panel
1 – Dim/Mute
1 - Polarity
7 – Input
1 – Bypass/Calibrated Output
2 – Word length
4 – Sample Rate
AC Power Requirements
Nominal Operating Range
Min/Max Operating range
Power
Fuses (2 required)
100 – 240 VAC, 50 - 60 Hz
90 – 260 VAC, 47 - 63 Hz
< 0.5 Watts Standby
12 Watts Typical Program
15 Watts Maximum
5x20 mm, 0.5 A 250 V Slo-Blo
®
Type
Dimensions
Form Factor
Depth behind front panel
Overall depth including connectors
Width
Height
½ Rack Wide, 1 RU High
8.5” (216 mm)
9.33” (237 mm)
9.5” (249 mm)
1.725” (44.5 mm)
Weight
DAC3 only
DAC3 with accessories and manual
Shipping weight
3 lb.
4 lb.
7 lb.
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 66
Regulatory Compliance
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. These limits are designed to provide reasonable protection against harmful interference in a residential installation. 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 different 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. Operation 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 Connections: Shielded 75-Ohm coaxial cable must be used.
NOTICE: Changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to operate the equipment.
RoHS Compliant Information
This statement clarifies Benchmark Media Systems, Inc. product compliance with the EU’s
(European Union) directive 2002/95/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) of any homogeneous Lead (Pb), Mercury (Hg), Hexavalent Chromium (Cr VI), and flame retardant Polybrominated Biphenyls (PBB) or Polybrominated Diphenyl Ethers (PBDE)).
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 67
CE Certificate of Conformity
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 68
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 the 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 abnormal 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 cases, an estimate will be submitted before work is started, 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 special, 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 HGC and DAC3 L with 1.X Firmware Page 69
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 Media Systems, Inc. website. This optional warranty applies only to products purchased within the US and 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 warranties for any products disingenuously 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 extends 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 Media Systems, Inc. website. This optional warranty applies only to products purchased outside the US and 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 warranties for any products disingenuously 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 preferably 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 HGC and DAC3 L with 1.X Firmware Page 70
Revision B - 12/01/2016
Copyright © 2007, 2008, 2009, 2012, 2013, 2014, 2015, 2016
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: +1-315-437-6300
FAX: +1-315-437-8119 benchmarkmedia.com
Instruction Manual for DAC3 HGC and DAC3 L with 1.X Firmware Page 71

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Key features
- SABRE PRO 32-bit PCM and DSD conversion system
- Benchmark UltraLock3™ Jitter Attenuation System
- High Headroom DSP to eliminate clipping of intersample peaks
- Multi-Mode Asynchronous USB Audio 2.0
- HPA2™ reference-grade headphone amplifier (DAC3 HGC only)
- Low-Impedance Passive Output Pads for optimized SNR
- Bi-directional 12V Trigger for system control
- HT Bypass mode for seamless home theater integration
- Digital Pass-Through for digital audio signal routing
- Remote control with metal housing for full functional control