Barry: Hey John – another day, another digital audio review, right?
John: Yes indeed, Barry.
B: What’s up for consideration today?
J: The Antipodes DX music server (US$6500 and up) from New Zealand. It’s the gloss-fronted silver one over there, sat atop another Antipodes Audio music server – the (matte black) DXe.
B: You have two? WTF!
J: Yes, but only temporarily. After upgrading from the DS Reference to the DXe, Antipodes Audio’s founder Mark Jenkins sent me a DX for formal consideration.
B: Sounds like Antipodes offer a LOT of models?
J: Antipodes Audio consolidated their range last year before announcing proper representation in North America. The DXe that you see beneath the still top-of-the-range DX has been discontinued. It’s been replaced by the mid-range DV which can be optioned with or without HDD – sans local storage it runs as a streamer only. The half-width DS is their entry-level model. It doesn’t internalise AC/DC conversion like the forerunning DS Reference. Instead, a switch mode power supply does the deal.
B: Aren’t linear power supplies superior to switch-mode bricks?
J: Not always, Barry. It largely depends on their noise profile and to what extent that noise pollutes the server’s internals. A good quality SMPS will best a poor quality linear PSU.
B: Noise profile?
J: Electrical noise. Not to be confused with mechanical noise, vibrations.
J: Simplifying, there are essentially two types of electrical noise: 1) EMI can travel down your home’s mains power line, out of the wall socket and then into noise-sensitive equipment like music servers; and 2) RFI – the airborne version of EMI – that enters your equipment over the air, often with the power cable acting as an aerial.
B: Got it – but haven’t we drifted off topic?
J: Not really. Not only is an audio system vulnerable to externally sourced noise pollution but also each component generates its own level and spectrum of electrical noise. The average Mac or PC hasn’t been designed with noise minimisation in mind. Jenkins’ servers have.
B: I see. But aren’t all computers alike? It’s just ones and zeroes, isn’t it?
J: I wish it were that simple, Barry, but it just isn’t. The electrical noise that finds its way into a sensitive component like a digital audio server or DAC can cause jitter. Jitter eviscerates sounds quality.
J: Even with a Resonessence Labs Concero HD deployed as USB-S/PDIF converter and iFi iUSBPower supply supplying the 5V to the DAC, a MacMini can’t get close to any of the Antipodes servers’ audible avidity and clarity.
J: Yes. The DS Reference that I had early last year usurped the Mac Mini in nearly every respect: less treble glare, more cleanly defined player outlines, more vibrant tone colours and fresher dynamics.
B: What about the AURALiC Aries?
J: It’s great – I’d peg it as a better sonic performer than the aforementioned tricked-out Mac Mini, but it falls short of the Antipodes units.
B: Understood. What is it about the Antipodes Audio gear that makes it (sound) different? Looks like a fairly ordinary PC to me.
J: Like its less expensive siblings, the DX is essentially a headless Linux PC…and I’m with you on its plain Jane looks. I prefer the more stylised aesthetics of both the AURALiC streamer and the Aurender X100L to the Antipodes’ austere physical appearance.
B: So the magic happens on the inside?
J: Precisely. At the core of main man Mark Jenkins’ approach to music server design is keeping electrical noise as low as possible during every step in the server’s digital audio chain, as opposed to letting it run wild and then re-clocking or power filtering after that fact.
J: Yup. Both are highly effective in their own right but Jenkins would call them band-aid fixes. He believes in getting everything correct first time.
B: That makes intuitive sense.
J: Jenkins is therefore keen to keep his server designs as simple as possible. Every chip or process contributes to the server’s electrical noise. Let me read you what Jenkins wrote me in a recent email: “In our view, it is better to do only what is required, and then optimise each step. By contrast, we see some commercial servers being made without much attention to minimising the noise generated, and then using noise filtering to deal with it. When we experimented with that approach the music simply sounded boring and lacked life. So we have gone in the other direction, to avoid all noise filtering, keep the technology to a minimum and focus on minimising the noise generated by each step. The widely used digital theory suggests this is irrelevant as the signal can be regenerated in the DAC, making earlier steps irrelevant. The reality strongly suggests otherwise. You only have to listen to a couple of different digital sources to hear it. So we have gone in the other direction, to avoid all noise filtering, keep the technology to a minimum and focus on minimising the noise generated by each step. We believe this way delivers much more musically engaging sound.”
J: Minimalism. Let’s pop the lid on the DX and look at the specifics.
J. First up, the hard drive. The DX runs with a 3D V-NAND 2.5” SSD from Samsung – that’s its fundamental advantage over the DV and DS’s HDD that run custom firmware; as such, they can’t be bought in the shops. Storage capacity in this unit is 2TB – it sells for US$7500 – but the DX can be also be specc’d with either 1TB or 3TB drives for US$6500 and US$8500 respectively. The SSD’s cage is located so that its SATA connections to the motherboard are as short as possible, for which silver-screened, silver wired cables are used.
Jenkins adds, “The SSDs in your review sample are technology from Samsung (we also use Samsung RAM). The technology advances here and new products coming onto the market mean we may change this part from time to time. There is one aspect of the design of nearly all SSDs that we would like changed and we are currently making progress with one manufacturer willing to work with us on this. We audition new SSDs as they come on the market and, frankly, most sound very much like the others, but we will keep listening.”
B: Sounds like Mr Jenkins likes to play it by ear as well as play the engineer?
J: Indeed. There are strong similarities between his and Rob Watts’ (of Chord Electronics) approach to product development, refinement. Listening tests often give rise to conclusions not readily apparent from a components’ spec sheet.
B: Sounds like a time-intensive process?
J: That’s how Jenkins reportedly selected the DX’s motherboard, derived from an off-the-shelf model. “The trick for us was discovering what chip-sets we liked (lots of listening and triangulation), finding the reference design that delivered that, then finding a motherboard manufacturer implementing this reference design that was prepared to work closely with us on bringing it to fruition the way we wanted it”, says Jenkins. “It worked out much better than we expected with the manufacturer opening up their resources to measure noise in a way we could see it, and tune it on the fly while keeping the board utterly stable. Tuning the noise of the whole server at the same time enabled us to not only clock the individual chips for reduced noise but also shift the noise of each chip-set away from others. The new board meant the DS Reference was replaced with this new range.”
B: Aha – that’s interesting what Jenkins says about tuning the noise out of the server.
J: In listening tests, the DX motherboard reportedly sounded noticeably better than that previously used in the DS Reference.
B. I assume that the motherboard uses PCIe expansion sockets?
J. Nope. It’s no secret that Jenkins prefers SoTM’s tX PCI USB audio card to the PCIe version. The SoTM card gets its own dedicated rail from the custom power supply board that, in spite of SoTM’s thorough on-board regulation, has a significant influence on the card’s sound. Again echoing Rob Watts post Hugo TT discoveries, Jenkins has found a way to optimise the USB card’s sonic performance without resorting to batteries, which he claims don’t sound as good. THAT’s interesting.
B: So what’s the deal with the Antipodes power supply? It sounds to me like it’s is fundamental to the DX’s sonic success.
J: You know it. I’ll let Jenkins explain: “Power supplies, done right, are very expensive. The power supply on the right is made up of our custom-wound transformer, high current rectifier bridge and the regulator board. Small design differences here make huge differences to the end sound quality, and the needs are quite different from say a pre-amp or DAC output stage. One of the challenges with the server design we have developed is that it has very high in-rush current requirements, and so the power supply has to be hefty just to start the server. Once the server is running, its power needs are low and the supply is in idle. You may spot the two large transistors poking out from under the power supply circuit board and connected to the thick power supply plate. These are discrete devices that carry all the current, and the circuit board components are all about setting a very tight reference voltage. The result is a hybrid of tight IC regulation and low-noise discrete regulation, that sounds better than if we went one way (IC-based) or the other (all-discrete).One key area is the transformer. One of the main reasons for an external power supply is you keep the transformer noise (electronic, not acoustic) away from the signal (and you can use a standard and low-cost transformer). But an external power supply means carrying a DC signal a long way, and that is not a good thing either. The solution we decided on was to build a transformer we could put inside the server. This was no mean feat, given the size needed, the electrical flux and magnetic field issues, and how they affect the digital signal. Using off-the-shelf transformers inside the server sounded utterly awful. It took us a while to understand how to solve this and I remember telling my guys I had given up, but they asked for one more try and that one did it – totally blew me away. The transformer may not look much but it is special.”
B: You know what else I see inside that case? Air.
J: Ha! Buyers looking to maximise component count per each dollar will likely be suspicious. That said, vacant internal volume assists with cooling and so the move to a full width case apparently obviated the need for mechanically and electrically noisy internal fans.
B: I see there’s a CD drive present too.
J: You spy correctly, Barry. You don’t get a CD ripper with an Aurender or AURALiC solution. This gives the Antipodes boxes a competitive edge with those who have yet to rip their collections or want a more direct method than ripping to a separate computer and then drag-dropping the files onto the DX’s network folder share. The Vortexbox operating system is configured to rip in paranoid mode to uncompressed FLAC.
J: It’s a fork of the Fedora Linux operating system that turns any PC into a music server. Jenkins applies tweaks in collaboration with Vortexboxer’s overseer Andrew Gillis. Guess what? The software tweaks help to minimise the impact of electrical noise. The data is gently nursed through every step: from hard drive to RAM (where approximately 1GB is buffered) before it is dispatched to the output card where it is buffered once more and then high-precision clocked out to the connected DAC via the SoTM USB card. There are two USB ports: one with 5V output and one without. The latter would be of interested to self-powered USB receivers like that found in the Metrum Hex.
B: Is the DX compatible with any USB DAC?
J: I’m not sure about EVERY DAC on the market but I’ve yet to encounter one that doesn’t play ball. Sometimes the DX requires a reboot to register a hot-swapped DAC but mostly the DAC is registered instantly. And yes, Antipodes support m2Tech’s first generation hiFace (and its OEM derivatives) and the Mytek units.
B: I meant to ask earlier: if the DX runs headless (ie. no monitor), how do you control it?
J: The entire Antipodes server range run Squeezebox Server as part of the Vortebox install. That means you get to choose from a range of control methods: iPeng would be my pick for iOS and OrangeSqueeze for Android – but there are many others. Or you can use a web browser on any device. Direct wire a PC or Mac into the network for a completely wi-fi-free setup — the DX only connects to the host network via Ethernet.
B: Does it do DSD? Haha.
J: Jenkins moved from MPD to Squeezelite this time last year so yes, the DX is fully buzzword compliant. That means up to 2xDSD and DXD are covered here, assuming you even have software in those formats, Barry?
B: Not really, but I keep hearing that DSD is set to be the next big thing.
J: Hmmmmm….moving on….
B: Can we talk about sound quality? I see you’ve got Vinnie Rossi’s LIO working amplifier duties on both the Zu Audio Soul MKII and the KEF LS50 as well the Andrew Jones designed standmounts from Pioneer.
J: Yes, I’ve been alternating between those three loudspeakers recently.
B: Three separate data points from which to draw conclusions – nice.
J: Having spent extended time with three different Antipodes servers, I can say with confidence that each step up the range 1) removes a layer of greyness that has tonal colours sounding more vibrant, glossier and 2) kicks dynamics harder in the pants. I’m not gonna crap on about black backgrounds. The DX pushes illumination deeper into the mix than both the DXe and DS Reference, which in turn both easily and gracefully best a fully tricked out MacMini.
B: How does the DX compare to the Aurender X100L (US$3499) that you have over there?
J: Good question. I seriously dig Aurender’s industrial design and the work they’ve put into their iOS app really pays dividends when it comes to the end user experience. However, I still hear shades of upper-lip and cymbal glare with the Aurender that I just don’t hear via the DX. You have to hear it gone to notice it was there in the first place. Glare pulls your attention upward, as if the music is constantly saying, “Chin up!”. The DX sounds fuller with tonal body and more muscular whilst simultaneously sounding more relaxed. Of course, like many digital deltas, the differences between these two servers aren’t huge. You might not pick them during the quick-fire nature of an A/B comparison. They reveal themselves over time. Had I not heard the DX, it’s unlikely I would’ve picked the Aurender’s comparatively more chromed cymbal shimmer and ambient decay. The DX doesn’t colour music as much its more affordable competitors – it sounds organic, natural, big, bold and – best of all – more detailed in a way that’s not artificially led by keener transients.
B: You get what you pay for!
J: You most certainly do. I’m not pretending that the DX is cheap – it isn’t – but it offers the most refined, detailed, immersive and organic presentation I’ve heard to date.
B: Oh, I forgot to ask: does the DX run Tidal?
J: Yes. The Squeezebox Server’s Tidal implementation relies on the ICKStream gateway. It’s not as slick as AURALiC’s or Aurender’s API-direct connection but it works 95% of the time. Here though things get interesting. Play the same song from the internal 2TB drive and then the same song from Tidal and you’ll notice the Tidal take returns a little glare to the uppermost frequencies and rigidity to the most subtle of micro-dynamics. I note similar qualitative differences when comparing locally stored music to sourcing files from the NFS-mounted DXe. It would seem that the DX’s SSD sounds slightly better than any streamed digital audio feed.
B: Perhaps a busier Ethernet interface adds more electrical noise?
J: You’re catching on, Barry. This puts me in a bit of a quandary though. My digital audio library runs to 4TB and the DX’s internal SSD tops out at 2TB. One possible solution would be to cleave my library in two, drop the ‘inferior’ half onto an external hard drive and plug it into the ‘backup’ USB port of the DX; the server will automount the USB drive and playback music from it. Again though, it doesn’t quite have that last soupcon of richness heard when playing files direct from the internal SSD.
B: Do all DACs benefit from the DX?
J: Yes, but it’s the less luxurious units that reap the biggest rewards. Experimentation gave rise to some interesting results. The DAC most seduced by the DX’s charms was that the ESS 9023 implementation found in the Peachtree Audio Nova220SE, thus eroding the need to retire the Nova’s internal D/A conversion in favour of a superior off-board solution. Things got spicier still when considering the Resonessence Labs’ INVICTA (US$4999) and CONCERO HD (US$850). I preferred the sound of the latter fed by the Antipodes server to the former fed direct USB from a MacBook Air.
J: Right?! Not being an engineer, I’ll assume that the INVICTA’s ability to deflect incoming electrical noise isn’t as great as the Antipodes’ talents in taming it from the very outset. The AURALiC Vega also surrenders to the DX’s low noise magic, showing wider and (especially) deeper soundstaging across all genres of music but especially noticeable with the more lit-up garage rock sounds of Built to Spill and the post-punk intensity of McLusky.
B: Altright, I gotta run shortly – concluding remarks, Señor Darko?
J: What we have here is a box that bucks conventional thinking that one should spend proportionately more on a DAC than the transport that feeds it. Those who juice more humble loudspeakers from amplifiers that demanded longer green will know where I’m coming from when I say that the Antipodes Audio DX firing into something as humble as the Schiit Bifrost Uber is fundamentally more aurally nourishing than the AURALiC Vega or Resonessence Labs INVICTA sourcing binary from an Apple MacBook Air. A DAR-KO award is applied here not only for the DX’s performance but because even if you don’t drop cash on an Antipodes server, Mark Jenkins’ DX clearly demonstrates without any shadow of a doubt that not all computers sound alike, that it’s not all ones and zeroes and that electrical noise is a digital audio issue not to be sniffed or sneered at.
Me? I’ll be upgrading again.
Further information: Antipodes Audio