Benchmark DAC3 B - Digital to Analog Audio Converter

DAC3 B - Reference Quality - Basic Features

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

To make system integration easy, the DAC3 B retains IR remote control (handset optional), 12 V trigger, and the programmable auto-on feature. The DAC3 B adds a control-lock feature that turns off the remote control and locks the keypad to prevent tampering and accidental changes. The optional 1/2-width rack-mount faceplate allows the mounting of two units in a single 1-RU rack space.

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.

Technology

DAC3 Technologies

• Harmonic Compensation
• UltraLock3™ Jitter Attenuation System
• High-Headroom DSP
• Multi-Mode Asynchronous USB Audio System
• Quad 32-bit balanced D/A Conversion System
• Distributed Power Regulation

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. To the best of our knowledge, no other D/A converter has lower THD than the Benchmark DAC3.

UltraLock3™ Jitter Attenuation System

UltraLock3™ is an improved version of the UltraLock2™ system used in the DAC2 product family. UltraLock3™ locks with precise phase accuracy in only 6 ms. In contrast, the UltraLock2™ system required 400 ms. Both UltraLock™ systems provide virtually perfect jitter attenuation, but the lightning-fast lock time of the new UltraLock3™ will be appreciated by many of our users.

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 UltraLock3™ system eliminates all audible jitter artifacts.

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

All of the digital processing in the DAC3 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 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.

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 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 subsystem. 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 DAC3 becomes an available audio device.

The USB subsystem remains active when the DAC3 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 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 high-end analog audio equipment, in order to create an outstanding output stage.

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 non-linearities are attenuated by 6 dB.

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 DAC3 confirm the proper operation of your media player.

Control Lock

The DAC3 B can be locked to avoid accidental changes that could cause a loss of audio in dedicated applications. This feature disables the IR remote control and the front panel buttons.

Digital Pass Through

The second coaxial input on the DAC3 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 DAC3 will also respond to a 12 volt trigger to follow the actions of another audio component.

Power Switch

The power switch can place the DAC3 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 DAC3 uses high-efficiency low noise power supplies and may be operated from any standard international voltage without adjustment. Power consumption is 12 W typical.

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.

Specifications

Important Features

• Sample Rate Display
• Word Length Display
• 5 Digital Inputs
• 2 Stereo Analog Outputs (1 RCA, 1 XLR)
• Digital Pass Through
• Native DSD Conversion
• Control-lock Switch
• Asynchronous USB 2.0
• Driverless Asynchronous USB 1.1
• Bi-Directional 12 Volt Trigger
• Power Switch
• Low Power Consumption
• ES9028PRO Converter

Downloads

Manual

DAC3 B Manual

Driver

Windows operating systems prior to Windows 10 require a driver when operating in USB Audio 2.0 mode. USB Audio 2.0 mode is required for sample rates over 96 kHz. No driver is required for Windows operating systems when operating in USB Audio 1.1 mode (sample rates up to 96 kHz). No driver is required for Mac or Linux operating systems.

DAC2 and DAC3 Driver