Antipodes K50 Music Server
Review sample supplied by Ohm Audio
Retail prices in the Netherlands incl 21% VAT:
No internal storage: €15.995
Available SSD storage: 1 TB (€120) / 2 TB (€270) / 4 TB (€630) / 8 TB (€1260)
Available in black or Silver
Having reviewed several Antipodes Music Servers and having owned the CX and EX for close to two years as my references, I was excited to hear of the OLADRA project and even more so the arrival of an all-new range with the K50 as the King of the Hill.
The approach that led to the EX and CX products comes down to two major factors: We all appreciate that the digital clock is important, but Noise and Bandwidth constraints prevent the accurate transmission of the clock data to your DAC. Noise is not a one-dimensional problem, because changing the frequency at which the noise occurs not only affects its impact on sound quality but can also be used to minimize the creation of noise nodes that are caused by overlapping noise peaks from multiple noise sources. But the project findings emphasized that bandwidth was equally important because a digital signal is a square wave that requires massive bandwidth in order to precisely define the timing of a change between a one and a zero. Antipodes addressed these matters by carefully tuning the motherboards in the relevant areas, eschewing the use of PCI- or USB extension boards and developing their own ultra-fast and low-noise power supplies.
Project OLADRA started well before the CX and EX were released, and those models came about to embody the early findings of the project. The project focused on developing music server technology to jointly optimize noise reduction and bandwidth expansion, and discover how to optimally manage the trade-offs between these objectives, confirmed by exhaustive listening tests. For instance, when filtering out noise from a signal you limit that signal’s bandwidth. That led to the quest to avoid the generation of noise in the first place rather than filtering it out later. The new K Series and S Series include the first full implementation of the OLADRA design, and they were designed using two key technologies: Interference Spectrum Management (using new insights into how to address noise generated by all active parts on the motherboard, while preserving bandwidth) and Hybrid Switched Linear power supplies.
As can be seen in the picture above, a large section of the K50’s internal space is occupied by the power supply section.
The new power supplies are neither switched nor linear and instead use elements of these two types of power supply in a novel way (achieving the speed of the best switched-mode power supplies and the low noise of the best linear power supplies) which has several large benefits, particularly in the context of digital circuits, where low noise and ultra-high bandwidth are required.
As Mark explains: “With noise, the quantum is very important, but you can do two things by shifting the frequency at which the noise occurs. First, changing the frequency changes the impact on tone and timbre. For example, noise at one frequency may result in super-tight bass, but of the sort that does not breathe and flow like the real thing. At a different frequency, it will emphasize high-frequency detail. At other frequencies, the sound can become too forward or too recessed. But second, if you have two (or more) active components on a PCB then they independently generate a spectrum of noise. The impact is dramatically worse if you allow their noise peaks to coincide – ie. you create nodes. So by shifting them so that the ‘hills’ of one coincide with the ‘valleys’ of the other, the noise floor is reduced. So the ISM technology is about how to manage the noise of multiple noise sources (active components of the circuit) for the best result and is an incredibly complex process”.
Although this still describes the OLADRA project quite superficially, I feel that it perfectly illustrates the kind of out-of-the-box thinking that makes all the difference in the seemingly simple yet treacherously complicated world of Digital Audio.
More details of the OLADRA project, a thorough explanation of how noise affects the signal and lots of other topics are detailed in the support section of the fully overhauled Antipodes website. I really urge those who are technically inclined to check it out for it makes absolutely fascinating reading.
AMS v3.0 interface
In addition to the new OLADRA platform, Antipodes has also been working on a fresh new look for their Operating System, now called AMS V3.0. With a beautiful, classy and easy to navigate “Dark-Theme” look, the local user interface is now seamlessly integrated with the external Antipodes website to make for easy switching. You could start on the Antipodes website in any browser to check out your new purchase and switch immediately to your local “My Antipodes” environment or vice versa. Alternatively, you can still reach the Web Interface by typing “myantipodes” in the search bar.
The K50 is the Antipodes range-topper Music Server, containing three individual, separately powered and isolated computing devices, one computer optimized for the server part, one computer optimized for the player part, and a proprietary Antipodes board dedicated to the reclocker and digital output section. With Direct Ethernet, USB, Femto Word Clock, AES2, S/PDIF on RCA, S/PDIF on BNC and I2S on HDMI, the unit is fully equipped. The K50 is passively cooled using a big internal heatsink, although, the word “heat” is not something I would use in relation to this server because it remains absolutely cold to the touch. When asked about this, Mark confirmed that this has nothing to do with processor throttling or any such measures but is the result of using very efficient power supplies.
Stepping down the model numbers there are the single-computer K40 “server apps only” version of the K50 that includes the range topper’s high power computation engine but no player section or digital outputs and is optimized to function as an ideal server to output isolated streams to an Ethernet DAC. Then, there’s the dual-computer K30 that contains two separately powered and isolated computation engines for server- and player functions to output via Direct Ethernet or USB and is designed to deliver a large chunk of the K50’s performance at a more affordable price.
Apart from these Big Boy Music Servers, there is also a K10 CD ripper and the four-unit modular S-series consisting of the Server+Player S40 and S30, the S60 Power Supply and the S20 Reclocker. The powerful S40 can be used equally well as a Server and Player while the S30 is great as a cost-effective Server + Player and ideal as a Player.
For this review, though, I will focus only on the K50.
The K50 will be used in the context of basically two systems: the CH Precision C1 DAC with the CH Precision A1.5 power amp driving Martin Logan ESL15A speakers, the Aqua Formula xHD DAC with V2 output board, the Audio-GD Master 1 preamp also driving the same amp and speakers and, as a special guest, the Aequo Stilla loudspeakers (review forthcoming). Interlinks used are the CH Precision Balanced Link between C1 and A1.5 and Siltech Paris between Aqua, Audio-GD, and A1.5. Speaker cables are the Jorma Trinity and Driade Flow 405. For comparison, I used the Antipodes CX and EX as well as the Bryston BDP-3 network player. The preferred digital connection to the DACs in all cases was the Jorma AES/EBU cable.
I was forewarned that the power supply needs copious amounts of running in, but regardless, the K50 blew me away right from its first notes. What happens with prolonged use after about 3 weeks in is that the sound gradually becomes a little sweeter and more relaxed. Even so, one of the most overwhelming aspects that I noticed right at the beginning was just how organic the K50 sounds.