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Chord Electronics QBD 76 Bluetooth DAC

QBD76 the World's Most Technically Advanced DAC

Next generation DAC resolves more musical information than any DAC using conventional
chips and includes USB and Bluetooth inputs.

Chord Electronics has once again produced the world's most technically advanced DAC. Building on the huge success of the award winning DAC64, the QBD76 now takes D/A conversion to a new level of performance not available in any other product. In addition USB and digital Bluetooth inputs allow you to enjoy very high quality audio playback from anywhere your music happens to be stored.

Instead of simply using the best off the shelf DAC chips, Chord actually designed their own using the newest Xilinx field programmable gate arrays. This state-of-the-art development platform provides Chord engineers with a staggering 1,250,000 logic gates with which to design their DAC.

This level of capability was undreamt of only a few years ago. By comparison the best DAC chips available today use only 30,000 logic gates. Thus, with over 40 times the development power, Chord engineers were able to control every aspect of their DACís design and performance. As a result, the QBD76 is capable of resolving 40dB more data than DACs using the best off the shelf chips.

This means the QBD76 can resolve more musical information than any DAC using even the best chips can. This remarkable innovation takes the QBD76 very near the theoretical limit for CD audio, and once again Chord emerges with technology literally years ahead of the competition.

" This is the very best DAC I've heard to date...

it's obvious that Chord's new QBD76 is in a gang of one. Dramatically musical yet devastatingly revealing sound makes this unique product the definitive digital to analogue converter right now."  - Hi-Fi World, Sept. 2008
Click here to open a PDF copy of the full review.
"Remember, although the DAC64 was Stereophile's 2007 Product of the Year, and awarded A+ Recommended Component in 2007, it is actually eight year old technology! Imagine the improvements in digital technology over the past eight years. Better yet, don't imagine, go hear one today!
With itís new design and updated WTA algorithm, the QBD76 achieves a signal to noise ratio greater than 120 dB, a dynamic range of 122dB, and, remarkably, less than 3pS clock jitter cycle to cycle! The QBD76 has astounding resolving power and is better able to reconstruct transient edges than the DAC64. This results in substantial improvements in: timing, imaging, soundstage depth, pitch reproduction and bass definition.

Usability has been improved with the addition of a display and control via a microcontroller circuit. Input selection, phase and RAM buffer settings can all be changed using three buttons on the top panel. Configuration is clearly visible via the magnified display. There are two coax, two AES, two optical, one USB and one Bluetooth A2DP input.



World's first high quality Bluetooth DAC

The most noteworthy advance may be the Bluetooth audio input. Imagine your cell phone, PC or PDA transformed into a CD quality music player connected wirelessly to your stereo or home theater! Now you can because the QDB76 is the world's first DAC to use the superior digital output from Bluetooth.

Modern phones, personal digital assistants and personal computers now have the ability to transmit high quality audio using the Bluetooth Advanced Audio Distribution Profile or A2DP for short. Chord engineers worked with the originators of Bluetooth in Finland to design a custom Bluetooth receiver which is able to extract and decrypt the much higher quality digital audio output from the Bluetooth A2DP signal.

By using this digital signal the QBD76 can reproduce music transmitted wirelessly at literally CD quality. Chord's DAC is the world's first to utilize this digital signal. Therefore the QBD76 will sound substantially better than virtually all other devices which can only access the analog audio output of Bluetooth.

With true ground breaking sonic performance and features the QBD76 defines the future of high quality digital music playback. US retail price is $6,295. The QBD76 is in stock at Bluebird now in both silver and black finishes.

Technical Background

The QBD76, from digital input to the DAC outputs, was designed using the latest generation of field programmable gate array devices, (FPGA), now with 1.25 million gates. The FPGA handles the switching of the SPDIF inputs, all digital SPDIF decoding, digital PLL, RAM buffer controller, WTA filtering, and the 5th generation Pulse Array DAC. All of these functional blocks are designed at the gate level, for maximum performance.

The QBD76 features state of the art improvements to the Pulse Array DAC, in particular the noise shaper architecture. Considerable work was done to improve this aspect of Pulse Array with the specific aim of reducing noise. Amongst other improvements the 5th generation Pulse Array now has 8th order noise shaping, (the highest order of noise shaping of any known DAC), and 2608 times oversampling and digital filtering. A new digital PLL was developed using a highly accurate 115MHz clock. Data related jitter is completely removed from the source, and all that remains is random master clock jitter of less than 3pS cycle to cycle.