Chord Electronics Qutest DAC

Funny Name, Serious Tech

Equipment report
Categories:
Digital-to-analog converters
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Products:
Chord Electronics Qutest
Chord Electronics Qutest DAC

If we were to rate audiophile firms on the basis of the strength of their brand identities, Chord would be near the top of the list. The letter Q has figured prominently in the nomenclature of many of their creations; this notion is either clever or quaint, depending on your mood. The company’s latest, the Qutest, which replaces the 2Qute and, priced right at $1895, is the middle child of Chord’s DAC lineup. It also arguably offers Chord’s best value, as it includes almost all of the digital “special sauce” found in the maker’s Hugo and Dave models, but in a much smaller, more pocketbook-friendly package.

DAC Types and Technical Details
DACs come in several basic types. First, there are “chip DACs” that use a modern digital chip made by AKM or Burr-Brown as the heart of their designs. Second are “ladder DACs” which use a resistor array to decode a digital signal. These are usually expensive due to the high number of critically-matched parts needed to make the design successful. MSB and dCS are two manufacturers who make ladder-based DACs. The third kind of DAC is an NOS (short for “non-over-sampling” but this could also stand for “new old stock”) DAC. These use older DAC chips with “simpler” internal designs and filters that some audiophiles prefer due to their relative simplicity. Finally, we have FPGA DACs, which use a field-programmable gate array chip as their heart. The FPGA can be thought of as a blank slate that can be programmed to perform any function. PS Audio’s DSD and DSD Jr. and all Chord DACs use this last methodology.

Compared with other DAC designs an FPGA-based DAC has several unique characteristics, the most important being the amount of custom programming and proprietary algorithms that can be applied to a design. Over-sampling, digital filters, and the way the DAC works on a very basic level all can be dictated by the firmware in the FPGA. Also, an FPGA DAC can be updated incrementally, or have its operating system completely changed by a firmware update.

But just because a DAC is of one type or another does not mean that it will be inherently better or worse than another kind of DAC design. Implementation still remains the critical element in a DAC’s success or failure. I’ve seen inexpensive ladder DACs that performed worse than NOS DACs. I’ve also heard two DACs that use the same, standard “off-the-shelf” DAC chip sound quite different from each other because they had different analog circuitry in their analog sections. Even NOS DACs, which almost universally measure poorly when compared to oversampling DACs, have adherents among audiophiles who yearn for an “analog-like” DAC presentation.

In short, audiophiles have many choices in both design and execution when it comes to DACs. And while Chord’s approach is not unique, it is among the roads less traveled. And Chord’s path requires far more programming and digital design savvy than one that merely inserts a digital chip into a standard layout. Also, because its designs are proprietary, Chord doesn’t hand out circuit diagrams to anyone who asks—hence the reason it’s called “secret sauce.” Actually, Chord has a very particular name for its secret sauce: Chord Electronics custom-coded Xilinx Artix 7 (XC7A15T) FPGA.

The Qutest supports PCM files from 44.1kHz/16-bit all the way up to 768kHz/32-bit as well as natively supporting DSD to DSD512. With a standard SPDIF signal via one of its two BNC connections the Qutest maxes out at 384/32, but the Qutest has provisions for a “dual data mode” connection that offers up to 768/32 resolution. Even Qutest’s TosLink optical input will accept up to 192/24 although most devices’ TosLink outputs are limited to a 96/24 maximum.

Design, Ergonomics, and Setup
If you like your components big and beefy, you’ll be disappointed by the Qutest’s diminutive dimensions—1 1/12" (41mm) tall by 6 1/4" (160mm) wide by 2 7/8" deep. It does weigh almost 1.7 pounds (770 grams) due in part to its machined-aluminum casing that gives it some heft—like a very smart brick. The front panel has two translucent polycarbonate buttons while the top has a larger spherical transparent glass window; different colors are used as display indicators. The rear panel accommodates one USB-B, one 5.2V micro-USB power input, two BNC coaxial, and one TosLink optical input in addition to one pair of RCA single-ended outputs.

The Qutest is a basic DAC. By that I mean there are no variable output adjustments or volume controls. It does have three output levels of 1, 2, and 3 volts that can be set upon startup. While 2 volts is the de facto standard for full output from a line-level device, having the other voltage options vastly increases the chances that the Qutest will allow whatever preamp or line-level volume control you mate it with will operate within its optimal range. I used the 1-volt setting with a Channel Islands Audio PC4 MKII passive volume control so that I could turn the Channel Island’s volume control knob up to slightly above 2/3 full to reach satisfying levels during desktop listening.

Nowadays, it’s important to know what input sources a DAC does and does not support. The Qutest supports USB—driverless with a Mac/Unix system, driver-required for Windows—but the Qutest does not have an input for Ethernet or WiFi and is not a UPnP-discoverable device. If you want to use the Qutest DAC for streaming sources, it will need an additional network-aware component in front of it to pass the digital signal to one of Qutest’s inputs.

The Qutest’s control surfaces share a Chord family trait of using colored buttons whose hues can change depending on the digital filter settings, inputs, and bit resolution. Like most semi-complex systems, the Qutest’s color system is simple once you get it. I spent the first several weeks with the trifold Qutest user manual nearby for reference. The range of colors needed to cover the entire sample frequency spectrum was impressive. As an ex-photographer, I have a highly developed sense of color and an ability to differentiate among variances in hue, but the differences between the colors indicating 384kHz and 706kHz glowing from the Qutest’s circular module were too subtle to be able to tell, consistently, which sample frequency was being employed.

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