ANTIPODES K50 Music Server - high power dual-computer USB SPDIF AES3 12S Ethern

AT 11 MS K50
NZ$ 20,000.00 pr (incl. GST)

Exceptional Musicality with Exceptional Transparency for Ultimate Sound Quality

The full-width Antipodes K50 is our latest advance of the state of the art in digital audio, and fully implements the new technologies delivered by the Antipodes OLADRA Project. Refinement, dimensionality, dynamics, timbre and resolution are exceptional. The Antipodes K50 gets out of the way to let you fully experience the emotional impact of the original recording.
The Antipodes K50 integrates three separately powered and isolated computation engines:
A high power engine to enable Server Apps to effortlessly handle a huge music library, re-assemble internet streams to recover the original file's sound quality, handle DSP features without loss of quality, and to serve the cleanest possible stream to the Player App.
An advanced player engine to run the selected Player App to provide exceptional USB Audio output and to feed the Reclocker.
An all-new fully-isolated reclocking engine to provide exceptional S/PDIF, AES3 and I2S digital outputs.
Insert your own SSDs or have your provider install them for you - up to 24TB. Add USB drives. Include music files located elsewhere on your network. Upload music files from anywhere on your network. Add internet streaming services. Attach an Antipodes K10 Ripper to import music from your CDs. All easily user-configurable to form a single integrated music library that is available to all playback solutions selected.
Easily select the playback solutions you wish to use, from the world's best high-end digital audio software providers. Stream by Direct Ethernet connection, USB Audio, S/PDIF, AES3 or I2S to your main stereo system, and at the same time stream over your network to streaming devices.
Setup and control everything from your desktop, laptop, tablet or smartphone.





K50 Connections
Insert up to three 2.5" Sata SSDs. They will click securely in place.
USB Audio 2.0 Output
Femto Word Clock Master Output on BNC
AES3 Digital Audio Output on 3-pin XLR
S/PDIF Digital Output on BNC
S/PDIF Digital Output on RCA
I2S Digital Output on HDMI
Dual USB Ports For External CD Ripper (eg. Antipodes K10)
Two Servicing Ports
Ethernet Connection to Network on RJ45
Ethernet Connection for Direct Streaming to Streamer on RJ45
Two USB Ports for USB Disks
Mains Power IEC Inlet - User Switchable 110-120vac to 220-240vac


Cooling - Passive Fanless Silent
Case - CNC Machined From Solid Alloy
Direct Stream Ethernet Output - YES
USB Audio 2.0 Output - PCM to 32bit/768kHz / DoP to DSD512 / Native DSD to DSD512
S/PDIF Output On RCA and BNC - PCM to 24bit/192kHz / DoP to DSD64 / 
AES3 Ouput On XLR - PCM to 24bit/192kHz / DoP to DSD64 
I2S Output On HDMI - PCM to 32bit/384kHz / DoP to DSD256 / Native to DSD512
Optional Music Storage - Easy Self-Unstallable Without Tools / 3 Bay Slide-In / Up To 24TB
Hardware Modules - V5.6H For Server Apps / V5X For Player Apps / R1I Reclocker
Power Supply Internal - 3x HSL80
AC Power Switchable - 110-120VAC 60Hz / 220-240VAC 50Hz
Size - 445W x 370D x 120H mm
Shipping size: 600W x 550D x 250H mm 
Weight - 16kg
Warranty - Back to base (Return To Seller) - 3 Years


The K50 is about more than ticking audiophile boxes. It is a Music Server that faithfully reproduces all the intricate elements of the music, and nothing but the music.

CONCLUSION: The K50 is an Absolute Game Changer. While the CX and EX remain fantastic products and I can still see why I elected them as my references 3 years ago, the K50 does everything that the older combo does and improves on this with more fluid and more highly resolving treble, more accurate focus and increased transparency. More importantly, the K50 adds an overwhelming sense of natural flow and stunningly deep soundstaging, making other server/streamer sources sound relatively flat and mechanical in comparison. What’s especially unique about the K50 is that it not only produces music in a natural, organic and free-flowing manner, it also has great PRaT and sounds lively and upbeat. But the K50 is about more than ticking audiophile boxes. It is a Music Server that faithfully reproduces all the intricate elements of the music, and nothing but the music.

   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.

Project OLADRA

As I explained in the original DX review in 2017 and in the successive DS BaseEX and EX+CX reviews, Mark Jenkins of Antipodes Audio takes a unique approach to the concept of Music Servers.

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 suport 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.

System Context

The K50 will be used in the context of basically two systems: the CH Presision C1 DAC with the CHP AI.5 power amp driving Martin Logan ESL15A speakers, the AUQA Formula XHD DAC with V2 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 JormaAES/EUS cable.

Running In

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.

First Listening

My first impressions of the K50 were formed during the reviewing of the Aequo Stilla loudspeakers. As a result, I was using the Aqua Formula xHD DAC with the Audio-GD preamp and neither the Logans nor the Magicos were set up for use. But the relatively unfamiliar setup did not stop me from noticing right away how much of a Milestone product the K50 is.

All of the K50’s three main sections are built with the highest quality in mind, and thus, the K50 works equally well as a Server only or a Player only. However, I soon found that the full extent of the K50’s magic happens when it is used as an integrated system.

K50 as a player

When using the K50 as a Roon player, fed from CX in the capacity of a Roon Server, the K50’s very interesting Reclocking Digital Output section becomes available. For the comparison with the EX as a Player, though, I necessarily stuck to USB using the Final Touch Audio Callisto cable. Even so, the differences with the EX as a player were immediately obvious. The K50 has a sweeter and more refined treble, sounds rounder and more relaxed and has more spacious, deeper soundstaging. Most noteworthy, though, the K50 sounds much more organic.

Although this combination possesses a refreshing lack of stridency that is otherwise so common in digital replay, I did feel that the sound could do with a little bit more tightness and sparkle. Adding the Bryston BDP3 as a Player also connected to the DAC via USB, and fed by the CX, substantiated this feeling by providing faster pacing and more immediate transient behavior albeit at the cost of sounding more mechanical, less colorful and flatter in terms of soundstaging.

Somehow, I think the CX was undermining the K50’s performance. Somewhat puzzled by this mixed result, I decided that the next step would be to use the K50 integrally as a Server + Player and with its AES/EBU output.

K50 as a Server + Player

Switching to the complete K50 package as a Roon Server and Roon Player with its Reclocking Digital Output section and using the Jorma AES/EBU cable, still with the Aqua/Audio-GD/Aequo setup, the leap in performance was absolutely stunning.

This was definitely something else!

All of the aforementioned organic naturalness remains but with increased transparency, presence, speed and impact. While the BDP-3 remains the King of tightness, all other aspects of the K50’s performance are just so much more involving. Most remarkably, the soundstage has a depth of imaging that reminds me of what the Wadia 861 CD player could do. At that time, I compared the player’s output and input independently and established that the player’s Clocklink function was crucial to it producing a deep soundstage. Since then, I have used countless servers and streamers with various connection methods but not a single unit has come close to reproducing that kind of depth without introducing unwanted side effects. Until now, that is.

One of the K50’s unique strengths is that it not only produces music in a natural and free-flowing manner, it also has great PRaT and the uncanny ability to reproduce everything in a most realistic manner, making all the instruments sound utterly authentic and convincing.

At this point, I was already smitten. Then, it hit me that it was only just Roon that I had been listening to. And not only that, so far, I had only heard one output and there were many more to assess!

Other player Apps

Regular readers will know that I recently noticed that Roon did not sound quite as crispy and articulate as UPnP. As a result, I re-assessed all of my playback options and found that there are subtle differences from method to method (MPD, UPnP, Squeezelite) but Roon was the one standing out negatively for appearing somewhat thickened and crushed dynamically. This is really rather unfortunate because the Roon interface is so great. Fortunately, if you don’t want to switch to UPnP or MPD, there is a very easy solution. Ever since its inception, Roon has been working hard to be compatible with just about every hardware device and streaming format out there and that includes Squeezelite. As can be read in the K50 instructions, many users opt to combine the Roon server with the Squeezelite Player to achieve the best of both worlds.

To use Squeezelite with Roon, don’t forget to enable Squeezebox support in the Roon – Setup settings and to disable the Squeeze Server in the Antipodes interface.

At this point, the Aequo speakers had been relegated to the other room and the Logans were back in their old positions and used for the remainder of this review.

When comparing Roon Server + Roon Player to Roon Server + Squeezelite, the aforementioned Roon effect is not fully gone but the bass tightens up, transients become faster and the entire presentation just becomes a little bit directer and clearer – importantly, while retaining 100% of the organic naturalness.

If you want the absolute maximum in tightness, articulation, transparency and purity then MPD is the way to go. But that does mean that Roon cannot be used.

Note that the player zone name in Roon remains “Antipodes D2”, whether you select Digital Audio or Roon.

I do need to mention that the remaining difference between Roon+Squeeze and UPnP or MPD, while important to me, seems not to affect many other users quite as much. When asked about it, most admit to not having made comparisons but also not to be missing anything. Whenever I did do the comparison with someone else either at my place or theirs, however, the difference was there for both of us to hear. It’s not day and night, perhaps, but certainly sunny day versus cloudy day. Either way, I also recall that only two paragraphs back I already admitted to being smitten with the K50’s performance and that was with Roon Server and Roon Player. So, as always, it’s relative, just like pretty much everything else in the wonderful world of high-end audio.

Outputs compared using the C1 DAC

The K50 offers all the digital outputs that one could possibly want. Direct Ethernet, USB, AES/EBU, S/PDIF on RCA, S/PDIF on BNC and I2S. So, how do they compare? Curious minds want to know how! I listened to the first three using the CH Precision C1 DAC and noticed, first and foremost, that they all sound very good. The best output, by far, was the AES/EBU but I’ll be the first to admit that this has a lot to do with the excellent Jorma cable. However, also when comparing for instance AES/EBU with S/PDIF using Magami 3080 and Belden RG59 respectively, I would say that the AES/EBU output is still the most precise while the cinch output adds some heft and color in the bass that some listeners might prefer and others may call coloration. I’m not judging here. Not too long ago and for the longest time, I preferred S/PDIF over Belden RG59 for that very reason in my then setup.

I also listened to the I2S output using the only DAC that I have with such an input: the Jays Audio DAC-2 Signature. When toggling blindly (which is easy as I can’t read the display from the listening position) between AES via Jorma and I2S via a good quality Sony HDMI cable I had a repeated preference for the input that sounded most articulate and most upbeat. I’m afraid it was the Jorma. Perhaps, if I also had a Jorma or other very high-end HDMI cable, the outcome would have been reversed, but for now, it seems that the quality of the cable is more important than the (supposed) superiority of the connection method.

By the way, since there is no universally agreed standard for the I2S pinout some products will simply not work with another I2S product while others provide dip-switches inside to change the connection scheme. Very smartly, the K50 offers DIP switches at the bottom of the unit for easy access to allow for any required combination. Jay’s Audio adheres to the PS Audio standard which is set on the K50 by having all dips in the off position with the exception of 9 and 10 which should be in the on position.

My early review sample was set with all DIPs in the OFF position but Mark later confirmed that all K50 and K20 units will be shipped with the DIPS according to the PS Audio standard.

The more I work with traditional connections again, it seems, the more I become detached from USB. While the K50 sounds absolutely great via its USB output, open, focused, transparent and articulate, there’s a now inescapable kind of mechanical sense of the music being slightly in minor, slightly less sunny and positive, than via AES/EBU. And this is not only the case with the Jorma cable, I also feel that the music comes across as more organic than with the Callisto USB cable even when using the Mogami AES/EBU cable. For some reason, this traditional output gives me most of that super-natural, non-technical, utterly free-flowing feeling.

Just like I found with the earlier Antipodes servers, Direct Stream Ethernet from the K50 puts in a superb performance with the C1, very well-balanced, upbeat and lively yet with a relaxed touch and great finesse. It’s markedly less technical than USB and I’d pronounce it the very best output if it wasn’t for AES/EBU with the Jorma cable, which adds transparency and makes it all sound even more free-flowing and more organic. You can hear this very clearly in vocal parts that come across more freely, more human and just more realistic. Compared to the AES/EBU connection, the otherwise clean and very pure sounding Ethernet connection is comparatively flatter and more stilted. On the other hand, the technically perfect Ethernet connection does have slightly tighter bass which can be really nice with certain music. Thus, between AES/EBU and Direct Stream Ethernet, it is mostly a matter of personal preference: maximum organic flow and 3D-imaging (but a little rounder) or maximum precision (and a little flatter).

Going from the K50 to the CX using Direct Stream Ethernet to the C1 reminds me why I raved about this connection at the time. It sure puts in a very engaging and musical performance but the comparison does make it impossible not to note that little nags that I started to have with its performance over the years turn out to have been addressed by the K50. For instance, the CX’s delivery is less airy and refined, more rounded (less crisp and detailed), dynamically less expressive, less well-focused and less spacious. Ouch, reading that out loud does seem like a bit of a leap in performance and to be honest, I really do indeed feel that this is the case.

Outputs compared using the Aqua Formula xHD DAC

Just to avoid an accidental ideal or perhaps not so ideal marriage of output and input interfaces (USB receivers in particular, are not all created equal) I switched from the C1 to the Aqua Formula xHD DAC and Audio-GD Master 1 preamp while retaining the A1.5 amp and ESL15A speakers. But here I can be very brief because, with the exception of USB, the differences between the various outputs work out similarly as with the C1 DAC.

In a deviation from the results with the C1 DAC, USB with the Final Touch Audio Callisto cable connected to the Aqua DAC has a nice and gentle, slightly sweet and free-flowing quality to it which, with this DAC, may make it a preferred connection for some ears. Interestingly, with the Aqua DAC, I don’t really feel very strongly that USB is more stilted or mechanical than AES/EBU. Still, to my ears, also with the Aqua, the Jorma AES connection remains technically superior with the tightest, most articulate and purest sound even if some of the aforementioned ears may find it a little too controlled with this DAC.

Just why would the results with USB be different between the Aqua and the CH? Maybe it’s because the Aqua has a tighter overall sound or, more likely, it’s because it has a different USB implementation. Now that I am already splitting hairs, let’s complete the exercise by including some more of my reference USB cables.

USB Cable Comparison

The original Curios Cable delivers a solid performance, literally, with great bass and timing. But compared to the Callisto, it’s a little rough and unrefined. The urios Evolved works surprisingly well, restoring the tonal balance to the best approach to neutrality that I’ve heard the K50 do yet with a USB cable. The slight sense of reduced dynamic impact that I noted in its original review is not very evident now. However, it doesn’t take more than 2 seconds to hear that the AES/EBU connection still sounds more focused and more energetic. The CAD USB cable, as always, provides really powerful bass and remarkably sonorous tonality but with less apparent energy on top to make for a slightly dark sound. The AudioQuest Diamond, finally, turns in a very neutral sound but it’s also the least propulsive, dimensional and energetic. Switching back to the AES/EBU connection reaffirms its prime position and strengthens my growing belief that the good old traditional digital connections that we (yes, me, too) were all so quick to discard when USB became popular, actually provide better and more predictable results.

K50 compared to EX+CX via USB using the CH C1 DAC

As a final comparison, I returned to the CH C1 DAC and the Callisto USB cable to compare the K50 as an integrated Server + Player up with the CX + EX combo, the latter two interconnected via Direct Stream Ethernet.

Listening again to the EX and CX this way it was easy to see why I fell for the combination. The added spaciousness and flow and deeper soundstage that the EX brings to the table still combines with the CX’s propulsive and powerful delivery to make for an engaging performance. But switch to the K50 and all bets are off. The newcomer simply does everything that the older combo does and improves on this with more fluid and more highly resolving treble, more accurate focus and increased transparency. And last but not least, the K50 adds an overwhelming sense of natural flow and deep soundstaging, making other server/streamer sources sound flat and relatively technical in comparison. And I’m afraid that includes the CX and EX. It can be painful when a new product declassifies the one before it but otherwise there would be no real progress.

Technically, the CX+EX and K50 can easily be distinguished by all the above but arguably its biggest achievement is heard when going back to the combo. This is when you fully realize the strides that have been made. It’s not so much the areas in which the K50 outshines the older combo that is most impressive, it’s actually what the server does not do, which is, sounding like a music server. Rather, it sounds like music.

This aspect of its performance is observed best when not focusing on anything and just enjoying the music with the K50. Every time I do, I notice that I soon slip out of the critical reviewer-mode and enter the more relaxed music listener-mode. But as soon as I switch to the older combo, I’m back into critical reviewer mode. This, I feel, is the biggest compliment that I can give a music server.

Wrapping it up

At this point, still, I’ve touched only upon a small fraction of the K50’s possibilities. Apart from several more Player options, there are various diagnostics sections and many other tools. But if I were to discuss all of this in detail then the review could end up thrice as long and, as it stands, it’s already plenty lengthy. Also, the main point of any audio component is its sound quality and I think I’ve driven that point all the way home.

In order to discover the full extent of the K50’s functionality, I encourage the reader to head to the Antipodes website or contact the nearest dealer (Audio Reference in Auckland) to request a demo.


The K50 is an Absolute Game Changer. While the CX and EX remain fantastic products and I can still see why I elected them as my references 3 years ago, the K50 does everything that the older combo does and improves on this with more fluid and more highly resolving treble, more accurate focus and increased transparency. More importantly, the K50 adds an overwhelming sense of natural flow and stunningly deep soundstaging, making other server/streamer sources sound relatively flat and mechanical in comparison. What’s especially unique about the K50 is that it not only produces music in a natural, organic and free-flowing manner, it also has great PRaT and sounds lively and upbeat. But the K50 is about more than ticking audiophile boxes. It is a Music Server that faithfully reproduces all the intricate elements of the music, and nothing but the music.