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Ayre Acoustics QX-8 Digital Hub review

  • With the recent release of the QX-8 Digital Hub (US$5950), Ayre Acoustics has filled a major gap in its DAC product line-up, one that previously comprised the Codex (US$1795) and the top-of-the-line QX-5 Twenty (US$9950) to leave a gaping hole in between. On a personal level, I have been awaiting the release of the QX-8 to see how close it comes sonically to my QX-5; a DAC that has served as one of my review references over the last 2 years.

    Like its big brother, the QX-8 offers users multiple input formats including an asynchronous USB input, 2 x asynchronous S/PDIF, 3 x optical inputs and – a surprise – Ethernet. Given the modular design of the QX-8, users can select either USB, Ethernet (or both) at time of order. Pay for what you need only. Ayre allows the owner to add an input module at a future time as and when desired. Pricing on the QX-8 comes in as follows:

    • Digital Base (S/PDIF inputs only) US$4,950
    • USB (Asynchronous USB added to digital base) US$5450 (US$500 Upgrade)
    • Net (Ethernet input added to digital base) US$5650 (US$700 Upgrade)
    • Full (Both USB and Ethernet inputs added to digital base) US$5950.00 (US$1000 Upgrade)

    The QX-8 shares its understated aluminum chassis design with the rest of the new 8 series products. As with the QX-5, there are two front panel buttons that allow one to place the DAC in standby mode or enter/select different setup functions. The large round volume control ring on the front panel also serves as a navigation tool when the DAC is in setup mode. The small panel display not only allows the user to see the input selected and the sample rate of the file being played but can show file metadata when the Ethernet input is engaged. The display can be set to turn off automatically at a predetermined interval to reduce “noise” or if one is worried about the display’s lifespan. Headphone outputs – balanced and single-ended – are also located on the front panel.

    Ayre includes a black plastic multi-function remote control with the QX-8 that also serves as a control handset for other 8 series products.

    The QX-8 uses an ESS ES9038Q2M DAC chip and offers the general design features found in Ayre products: zero-feedback with fully-balanced, fully-discrete circuitry, Ayre’s Double Diamond output stage as well as Ayre’s Equilock gain stage. The well-known Ayre Minimum Phase digital filter is used in the QX-8 along with single-pass 16X oversampling. Other features found in the QX-8 include a linear analog power supply, high-speed circuit board material and digital volume control.

    The Ethernet (or WiFi) input turns the DAC into a Roon Ready Endpoint. It also supports Spotify, mConnect Control and generic UPnP apps that support the DLNA standard. The network input supports PCM sample rates up to 192kHz and DSD64 as DoP. The USB input goes higher still: PCM 384kHz, DSD64 and DSD128 as DoP.

    For wi-fi connectivity, we look to the back panel’s pair of additional USB ports that interface with the (supplied) wi-fi adaptors. These same USB ports can also be used to directly access files from a USB flash drive. There is a firmware update port on the back panel and a choice of balanced and single-ended outputs. Two AyreLink connectors are available for control linking to other Ayre components. A master AC switch is located under the back-panel IEC power inlet.

    Design choices

    I asked Ariel Brown, Chief Technology Officer and Vice President, several questions concerning the design of the QX-8:

    What do you feel are the design highlights of the QX-8?

    “The QX-8 employs the latest evolution of our complementary JFET voltage gain stage and Diamond output buffers, continuing the core Ayre philosophies of balanced, discrete, zero-feedback analog circuit design.

    What can you tell us about the power supply design of the QX-8?

    “As all Ayre products have been, the power supply is a linear (non-switching) design. A custom E-I transformer is employed for best AC mains isolation and is electrically and mechanically isolated from the chassis. Low ESR Rubycon electrolytic aluminum capacitors provide smoothing after full-wave bridge rectification. Voltage domains are extensively separated with their own regulators. All analog stages, DAC, and crystal oscillators are fed by their own discrete zero-feedback low-noise “AyreLock” regulators. All power supplies are distributed via ultra-low impedance internal planes in the 6-layer circuit board.

”

    How does the QX-8 differ from the QX-5?

    “The basic functionalities and topologies are the same between the 5 and 8. The difference is in the level of implementation. The QX-5 uses higher quality (more expensive) components, particularly resistors and capacitors. The 5 uses the biggest ESS DAC available (ES9038PRO) where the 8 uses the ES9038Q2M. The QX-5 uses four separate transformers for even further separation of the power supply domains compared to the QX-8s single transformer. The QX-8 uses a more graphic capable display while the QX-5’s simpler display will generate zero noise when on. The QX-5 uses a no-compromise 8-layer PCB stackup for the Main and digital circuit boards.
”

    Sound

    The QX-8 was connected with balanced cables to an Ayre KX-R Twenty pre-amplifier and MX-R Twenty amplifiers. As good as I found the direct connection of the QX-8 to the MX-R Twenty amps, my sonic preference was to use the QX-8 with the Ayre KX-R Twenty pre-amplier in the chain: a richer but also more relaxed sound when compared to the QX-8 playing solo and directly into the MX-R Twenty amps.

    After an extensive burn-in (Ayre recommends 100 to 500 hours), I listened via the Ethernet input. The QX-8 was immediately identified by Roon running on my Roon Nucleus+ server. For those of you that haven’t had the opportunity to work with Roon, the simplicity of setup and rock-solid operation across a network has to be experienced to be fully appreciated.

    My initial sonic impressions included descriptive terms as big, bold, and detailed with an excellent transient response. The QX-8 delivers the characteristic “Ayre Acoustics Sound”: extremely neutral, dynamic with very well controlled bass and an overall lack of hardness. If you are looking for warmth or midbass fullness, you might be disappointed by the QX-8. What the QX-8 delivers is absolute tonal accuracy in its overall presentation.

    The recent Sara Bareilles release Amidst the Chaos (24/96) was delivered by the Ayre with a bold sound signature. The bass was solid with a clear percussion background that didn’t swamp Bareilles’ voice. The rhythmic drive of this recording was clearly revealed by the QX-8. Dynamic life and detail emerged with no image smearing or unnatural spotlighting of instrumental details.

    I found the QX-8 to be capable of reproducing well-recorded orchestral music with a natural bloom and dimensionality that was a pleasure to experience. The relaxed presentation of the QX-8 allowed me to listen for hours without fatigue or distraction. Bach: Double & Triple Concertos performed by Rachel Podger with the Brecon Baroque (DSD64) provided a fine example of what the QX-8 was capable in terms of delivering a harmonically rich presentation with purity and liquidity. The QX-8 was able to reproduce a richly layered soundstage with an ultra-quiet background. Resolution of low-level information was very good with an overall presentation that was delicate and nuanced.

    I find tonal naturalness to be a hallmark of the QX-8’s delivery. As I listened to the deceased Canadian folksinger Stan Rogers’ Turnaround (24/96) that was recorded in 1977-1978, I took delight in the beautiful richness of Stan’s baritone voice backed by acoustic stringed instruments. The dynamic life and detail of this recording emerged from the QX-8 that simply let the music flow effortlessly with timbral fidelity. I found the QX-8 to have a wonderful immediacy.

    How’s the headphone amplifier?

    Ayre has included an analog linear power supply that can juice both balanced and unbalanced headphones. The headphone power supply also makes use of Ayre’s Diamond amplifier circuit; a circuit found on their most expensive preamps and power amps. I listened to the QX-8 with AudioQuest NightHawk headphones using the 3.5mm balanced jacks. The sound I experienced was very similar to what I heard with the balanced outputs to my Ayre monoblocks. The combination of the AudioQuest NightHawk and QX-8 proved to be very satisfying and enjoyable to listen to. I believe that many headphone enthusiasts are going to love the QX-8.

    Network or USB?

    One question that I know many of you will have is which input delivers the best sound? I decided to try tweaking both the Ethernet and USB inputs to see if I could find a personal favorite for my system. I placed a TJM Electronics GigaFoilv4 inline “Fiber Optic Isolation Link” powered by an UpTone Audio JS-2 linear power supply in the Ethernet line. For USB, I employed my recently updated Sonore Signature Rendu SE converted to an opticalRendu with the new Turbo linear power supply. Both of these components allowed each input to function at an enhanced level of acoustic performance. I guess if I could only have one of these expensive tweaks, I would opt for the opticalRendu with its USB output. But you can be assured that one doesn’t have to make this extra investment to experience the exceptional sonic qualities of the QX-8.

    QX-8 Digital Hub or QX-5 Twenty?

    It should come as no surprise that the QX-8 and the QX-5 are cut from the same sonic cloth. Essentially, both DACs are tonally similar. But careful listening allows one to hear the sonic differences between these DACs. It’s all about refinement when discussing the QX-5. The QX-5 is the more revealing DAC and, without question, is more transparent than the QX-8. The low-level transients revealed by the QX-5 get somewhat smoothed over by the QX-8. Complex musical passages are rendered with greater precision in terms of focus and clarity. While the soundstage width of both DACs is similar, the QX-5 is superior in its ability to reproduce depth and acoustic spaces.

    Wrap

    Ayre Acoustics has successfully managed to deliver much of the sound quality of the top-of-the-line QX-5 Twenty in the QX-8’s significantly less expensive package. I found both the Ethernet and USB inputs to be excellent sounding and very musically satisfying. For those of you with a server running Roon, the Roon Ready Ethernet input will simplify installation and deliver unshakable performance. I found the QX-8 Digital Hub to be a serious contender in the high-end DAC marketplace that allowed me to fully enjoy my music library with exceptional tonal neutrality and impressive resolution.

    Further information: Ayre Acoustics


    Associated equipment:

    The Ayre Acoustics QX-8 Digital Hub was powered with a Shunyata Research Sigma NR AC cable, and Shunyata Triton V3 / Typhon QR power conditioners. Each Ayre Acoustics MX-R Twenty monoblocks were powered with their own Shunyata Research Typhon QR power conditioners.

    Ethernet Cables: AudioQuest Diamond, Blue Jeans Cable Cat 6a
    Server: Roon Labs Nucleus+
    External Hard Drives: G-Technology 24 TB G|RAID Thunderbolt 2 / USB 3
    Analog Cables: Shunyata Sigma SP Speaker cables, Shunyata Sigma XLR
    Preamplifier: Ayre Acoustics KX-R Twenty preamp
    Amplifiers: Ayre Acoustics MX-R Twenty monoblock amps
    Speakers: Wilson Alexia Series 2
    Other DACs on Hand: Ayre Acoustics QX-5 Twenty 
Power Conditioners: Shunyata Research Hydra Triton v3, Typhon QR, and DPC-6 v2
    Headphones: AudioQuest NightHawk
    Ethernet Filter: TJM Electronics GigaFoilv4 inline “Fiber Optic Isolation Link”
    Streaming USB Source: Sonore Signature Rendu SE updated to opticlRendu
    Linear Power Supply: UpTone Audio JS-2

    Editor’s note: This will be Steve Plaskin’s final review for Darko.Audio before he returns to Michael Lavorgna’s bosom at Twittering Machines. I’d like to thank Steve for the meticulous care and insight that he brings to the review process.

    Steven Plaskin

    Written by Steven Plaskin

    Steven Plaskin is a retired podiatrist living in Southern California. He reviewed for AudioStream for six years before joining Darko.Audio.

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