Benchmark DAC2 L - Digital to Analog Audio Converter - Discontinued

The DAC2 L has been discontinued.

Overview

A New Reference - Going Beyond the Legendary DAC1

Benchmark's DAC1 family of D/A converters have been the reference to which other converters have been compared. It is rare to find a converter review that does not draw comparisons to the DAC1. The DAC1 has been the best-selling 2-channel reference-quality converter and is in daily use at many of the finest recording studios and mastering rooms. DAC1 converters are also enjoyed by thousands of audiophiles. Benchmark has raised the bar ... the DAC2 defines a new reference.

Reference Performance

The DAC2 is Benchmark's second-generation 2-channel D/A converter. The DAC2 converter has lower noise and lower distortion than Benchmark's DAC1 converter.The performance of the DAC2 exceeds the measurement limits of some of  today's best test equipment.

The DAC2  delivers outstanding musical detail and precise stereo imaging. It employs an advanced high-headroom digital filter design, and a new high-sample-rate Asynchronous USB Audio interface. All inputs are fully isolated from interface jitter by Benchmark's new UltraLock2™ jitter attenuation system.

Internal digital processing and conversion is 32-bits, and this processing includes 3.5 dB of headroom above 0 dBFS. This headroom prevents the DSP overloads that commonly occur in other D/A converters.

Four balanced 32-bit D/A converter are summed together to create each balanced analog output. This 4:1 summation provides a 6 dB noise reduction, and gives the DAC2 industry-leading performance.

Native DSD Conversion

All digital inputs on the DAC2 support native PCM or DSD conversion. From any input, DSD is transported with bit accuracy over DoP 1.1. DSD and PCM are both natively converted to analog. There are no DSD to PCM or PCM to DSD conversions to compromise the quality of the music. The DAC2 conversion system seamlessly switches between native PCM and native DSD conversion. DSD over DoP 1.1 is supported by many media players, and DSD downloads are now available from several sources.

Direct Connectivity to Power Amplifiers

Benchmark DAC1 and DAC2 converters are designed to directly drive power amplifiers and speakers. Benchmark converters feature adjustable low-impedance passive attenuators at the XLR outputs that can be used to optimize the interface to the power amplifier (or powered monitor). This unique Benchmark feature optimizes the gain staging between the DAC and the power amplifier. Proper gain staging cannot be overemphasised. When audio stages are properly matched, each component in the audio chain is able to operate at its optimum signal level, and the system performance is significantly improved.

Sonically-Neutral Studio Monitoring

All Benchmark converters are designed for maximum transparency. This transparency is absolutely essential in the studio monitoring chain. For this reason, DAC2 converters are ideal for critical reference-quality professional systems. Unlike many competing products, the DAC2 is not designed to add "euphonic" coloration to the audio. Instead it is designed to be as uncolored and natural as possible.

Step Into the Studio

When Benchmark's professional converters are used in hi-fi applications, studio-quality sound can be enjoyed in a home environment. Enjoy pure music without any coloration from the electronics. Hear the music exactly the way it was heard in the studio, and exactly the way the artists intended.

Discover the natural, uncolored, analog sound of the DAC2.

Sit in the Performance Space

Transparent sound can go beyond replicating the studio experience. Recordings that have been produced with a natural and unprocessed sound can transport you to the performance space. But, this can only happen when the entire playback chain is selected for maximum transparency.

This experience of "being there" cannot be created by systems that are designed to add "warmth" or "euphonic color" to the music. 

Technology

New Technologies

• Hybrid Gain Control
• UltraLock2™ Jitter Attenuation System
• High-Headroom DSP
• Multi-Mode Asynchronous USB Audio System
• Quad 32-bit balanced D/A Conversion System
• Distributed Power Regulation

Hybrid Gain Control

The DAC2 L includes Benchmark's unique Hybrid Gain Control (HGC) system. The DAC2 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 DAC2 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 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 will make full use of your power amplifier's dynamic range. Experience new details in your favorite recordings.

UltraLock2™ Jitter Attenuation System

UltraLock2™ is an improved version of the UltraLock™ system used in the DAC1 and ADC1 product families. DSP processing is 32-bits, DSP headroom is 3.5 dB, sample rate is 211 kHz, and jitter-induced distortion and noise is at least 140 dB below the level of the music - well below the threshold of hearing. Benchmark's UltraLock2™ system eliminates all audible jitter artifacts.

High Headroom DSP - with 3.5 dB "Excess" Digital Headroom

All of the digital processing in the DAC2 is designed to handle signals as high as +3.5 dBFS. Most digital systems clip signals that exceed 0 dBFS. The 0 dBFS limitation seems reasonable, as 0 dBFS is the highest sinusoidal signal level that can be represented in a digital system. However, a detailed investigation of the mathematics of PCM digital systems will reveal that inter-sample peaks may reach levels slightly higher than +3 dBFS while individual samples never exceed 0 dBFS. These inter-sample overs are common in commercial releases, and are of no consequence in a PCM system until they reach an interpolation process. But, for a variety of reasons, virtually all audio D/A converters use an interpolation process. The interpolation process is absolutely necessary to achieve 24-bit state-of-the art conversion performance. Unfortunately, inter-sample overs cause clipping in most interpolators. This clipping produces distortion products that are non-harmonic and non-musical . We believe these broadband distortion products often add a harshness or false high-frequency sparkle to digital reproduction. The DAC2 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.

Multi-Mode Asynchronous USB System

Benchmark's USB system supports USB Audio 2.0, DSD, and USB Audio 1.1. It is frequency agile, and will follow sample rate changes initiated by the computer and/or the media playback software. In all modes the USB communications are asynchronous in order to eliminate unnecessary sources of jitter.

The DAC2 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 DAC2. 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 measurable to our measurement limits (better than -150 dBFS). This truly represents the state-of-the art. Enjoy the convenience of computer playback without compromise. 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.

An 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 DAC2 becomes an available audio device.

The USB subsystem remains active when the DAC2 is powered down. This prevents interruptions to the computer playback operations and eliminates the need to reconfigure the computer every time the converter is turned on.

Quad 32-bit Balanced Conversion 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 and distortion to levels that set new benchmarks. The conversion system at the core of the DAC2 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 high-end analog audio equipment, in order to create an outstanding output stage.

Distributed Power Regulation

To achieve the lowest possible noise, the DAC2 HGC uses distributed power supply regulation. Each critical subsystem has at least one dedicated low-noise voltage regulator.

Diagnostic Tools - Sample-Rate and Word-Length Indicators

Ever wonder why that 192 kHz 24-bit download on your computer just doesn't sound right? Your media player may be down-sampling to 44.1 kHz and/or truncating to 16-bits. Many computers and media players apply poor-quality sample rate conversion and truncation. Fortunately these problems can be eliminated with the selection a good frequency-agile media player. The sample-rate and word-length displays on the DAC2 confirm the proper operation of your media player.

Polarity Switch

You may encounter recordings with inverted polarity. The DAC2 HGC and DAC2 L include a polarity switch to correct the problem.

Home Theater Bypass

The DAC2 can be integrated into a home theater system. Typically the DAC2 drives the left and right power amplifiers, and an analog feed from the home theater system is connected to either of the analog inputs on the DAC2. A programmable Home Theater Bypass function sets the pass-through gain to unity when the surround system is active. The DAC2 HGC and DAC2 L include an indicator light that is illuminated when bypass is active.

Digital Pass Through

The second coaxial input on the DAC2 can be reconfigured as a digital output. In output mode, any selected digital input (including USB) will pass through to the coaxial output. The digital pass through is bit-transparent and even supports DSD (DoP 1.1). Dolby digital and DTS formats can also be passed through to a surround processor.

Bi-Directional 12 Volt Trigger

Benchmark re-invents the 12 volt trigger. The trigger connection on the DAC2 can be used as an input, an output, or both. It 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 DAC2 will also respond to a 12 volt trigger to follow the actions of another audio component.

Power Switch

The power switch can place the DAC2 in standby, or full shut down. In full shut down, the unit will still respond to the trigger input and the IR remote control. Power consumption is less than 0.5 W in full shut down.

Low Power Consumption

The DAC2 uses high-efficiency low noise power supplies and may be operated from any standard international voltage without adjustment. Power consumption is 12 W typical.

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Specifications

The DAC2 L has the same features and performance as the DAC2 HGC, but without the headphone amplifier.

Audio Performance
Fs = 44.1 to 96 kHz, 20 to 20 kHz BW, 1 kHz test tone, 0 dBFS = +24 dBu (unless noted)
SNR – A-Weighted, 0 dBFS = +24 dBu	126 dB
SNR – Unweighted, 0 dBFS = +24 dBu	123 dB
THD+N, 1 kHz at 0 dBFS	-109 dBFS, -109 dB, 0.00035%
THD+N, 1 kHz at -1 dBFS	-110 dBFS, -109 dB, 0.00035%
THD+N, 1 kHz at –3 dBFS	-113 dBFS, -109 dB, 0.00035%
THD+N, 20 to 20 kHz test tone at –3 dBFS	-112 dBFS, -108 dB, 0.00040%
Frequency Response at Fs=96 kHz	+0 dB, -0.04 dB (20 to 20 kHz) -0.04 dB at 10 Hz -0.04 dB at 20 kHz -0.04 dB at 40 kHz -0.7 dB at 45 kHz
Frequency Response at Fs=48 kHz	+0 dB, -0.04 dB (20 to 20 kHz) -0.04 dB at 10 Hz -0.04 dB at 20 kHz
Crosstalk	-137 dB at 20 Hz -130 dB at 1 kHz -116 dB at 20 kHz
Maximum Amplitude of Jitter Induced Sidebands (10 kHz 0 dBFS test tone, 12.75 UI sinusoidal jitter at 1 kHz)	< -144 dB
Maximum Amplitude of Spurious Tones with 0 dBFS test signal	< -138 dB
Maximum Amplitude of Idle Tones	< -147 dB
Maximum Amplitude of AC line related Hum & Noise	< -140 dB
Inter-channel Differential Phase (Stereo Pair – any sample rate)	+/- 0.25 degrees at 20 kHz
Inter-channel Differential Phase (Between DAC2 Units Fs<110 kHz) Any sample rate.	+/- 0.25 degrees at 20 kHz
Maximum Lock Time after Fs change	400 ms
Soft Mute Ramp Up/Down Time	50 ms
Mute on Receive Error	Yes
Mute on Lock Error	Yes
Mute on Idle Channel	No
50/15 us De-Emphasis Enable	Automatic in Consumer Mode
De-Emphasis Method	Digital IIR
De-Emphasis Supported at	Fs = 32, 44.1, 48 kHz

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)	5 (1 USB, 2 Optical, 2 Coaxial)
Number of Channels	2
Input Sample Frequency Range	28 to 210 kHz (Coaxial Inputs) 28 to 96 kHz (Optical Inputs) 44.1, 48, 88.2, 96, 176.4, 192 kHz (USB Input)
Maximum Input Word Length	24 bits
Digital Input Impedance	75 Ohms (Coaxial Inputs)
DC Blocking Capacitors on Digital Inputs	Yes (Coaxial Inputs)
Transient and Over-Voltage Protection on Digital Inputs	Yes (Coaxial Inputs)
Minimum Digital Input Level	250 mVpp (Coaxial Inputs)
Jitter Tolerance (With no Measurable Change in Performance)	>12.75 UI sine, 100 Hz to 3 kHz >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
Jitter Attenuation Method	Benchmark UltraLock2™ - all inputs

Balanced Analog Outputs
Number of Balanced Analog Outputs	2
Output Connector	Gold-Pin Neutrik™ male XLR
Output Impedance	60 Ohms (Attenuator off) 425 Ohms (Attenuator = 10 dB) 135 Ohms (Attenuator = 20 dB)
Analog Output Clip Point	+30 dBu
Factory Set Bypass Level (at 0 dBFS)	+23 dBu (Attenuator = 0 dB)
Output Level Range (at 0 dBFS) In ‘Variable’ Mode	Off to +23 dBu (Attenuator off) Off to +13 dBu (Attenuator = 10 dB) Off to +3 dBu (Attenuator = 20 dB)
Output Level Variation with Sample Rate (44.1 kHz vs. 96 kHz)	< +/- 0.006 dB

Unbalanced Analog Outputs
Number of Unbalanced Analog Outputs	4
Output Connector	RCA
Output Impedance	30 Ohms
Analog Output Clip Point	+13.5 dBu
Factory Set Home Theater Bypass Output Level (at 0 dBFS)	+8.2 dBu (2 Vrms)
Output Level Range (at 0 dBFS)	Off to +8.2 dBu
Output Level Variation with Sample Rate (44.1 kHz vs. 96 kHz)	< +/- 0.006 dB

HPA2TM Headphone Outputs
Number of Headphone Outputs	0 The DAC2 L has the same features and performance as the DAC2 HGC, but without the headphone amplifier.
Output Connectors	N/A
Output Impedance	N/A
Output Level Control	N/A
Output Level Range (at 0 dBFS) into 60-Ohm Load	N/A
Maximum Output Current	N/A
Overload Protection (independent per channel)	N/A
Bandwidth	N/A
THD+N	N/A

Status Display
Indicators - Type and Location	16 LED’s on Front Panel
Selection/Status Indication	1 – Dim/Mute 1 - Polarity 6 – Input 2 – Bypass/Calibrated Output 2 – Word length 4 – Sample Rate

AC Power Requirements
Nominal Input Operating Voltage Range (VAC RMS)	100 – 240V
Frequency	50-60 Hz
Power	< 0.5 Watts Idle 12 Watts Typical Program 15 Watts Maximum
Fuses	5 x 20 mm (2 required) 0.5 A 250 V Slo-Blo® Type
Min/Max Operating range (VAC RMS)	90 – 260 47 – 63Hz

Dimensions
Form Factor	½ Rack Wide, 1 RU High
Depth behind front panel	8.5” (216 mm)
Overall depth including connectors but without power cord	9.33” (237 mm)
Width	9.5” (249 mm)
Height	1.725” (44.5 mm)

Weight
DAC2 only	3 lb.
DAC2 with remote control, power cord, extra fuses, and manual	4 lb.
Shipping weight	7 lb.

New Features

DAC1 customers requested many new features which have been integrated into the new DAC2 HGC:

• Sample Rate Display
• Word Length Display
• More Digital Inputs (5 total)
• More Analog Inputs (2 total)
• More Analog Outputs (3 total)
• Digital Pass Through
• Native DSD Conversion
• Polarity Switch
• Asynchronous USB 2.0
• Driverless Asynchronous USB 1.1
• Home Theater Bypass
• Bi-Directional 12 Volt Trigger
• Power Switch
• Low Power Consumption
• New Benchmark Technologies

Manual

Detailed specifications and performance plots are available in the downloadable manual.

DAC2 Series Manual

Accessories

View a list of recommended accessories for your DAC2 L here!

Downloads

Manual

DAC2 Series Manual

Driver

Windows operating systems require a driver when operating in USB 2.0 mode (required for 192 kHz operation).  No driver is required for Mac or Linux operating systems.  No driver is required for any operating system when operating in USB 1.1 mode (sample rates up to 96 kHz).

DAC2 Driver

DAC2 Application Notes

DAC2 App Notes

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DESIGNED, ASSEMBLED, AND TESTED IN THE USA

This Benchmark product was designed, assembled, and tested in the USA using USA and imported components. Most major components are made in USA.

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