Review: Antipodes Audio K50 Music Server- An absolute game changer

Having reviewed various Antipodes Music Servers and having owned the CX and EX for almost two years as my references, I was excited to hear about the OLADRA project and even more the arrival of a completely new range with the Antipodes Audio K50 Music Server as the king of the hill. .

OLADRA project

As I explained in the original DX review in 2017 and successive DS Base, EX, and EX + CX reviews, Antipodes Audio’s Mark Jenkins takes a unique approach to the concept of music servers.

The focus you brought to the EX and CX products comes down to two main factors: We all appreciate that the digital clock is important, but noise and bandwidth restrictions prevent accurate transmission of clock data to your DAC. Noise is not a one-dimensional problem, because changing the frequency at which noise occurs not only affects its impact on sound quality, but can also be used to minimize the creation of noise nodes caused by noise peaks. overlapping multiple noise sources. But the project’s findings emphasized that bandwidth was equally important because a digital signal is a square wave that requires massive bandwidth to precisely define the timing of a change between a one and a zero.

The OLADRA project began long before the CX and EX models were released, and those models emerged to incorporate the early findings of the project. The project focused on developing music server technology to jointly optimize noise reduction and bandwidth expansion, and discovering how to best manage trade-offs between these targets, confirmed by extensive listening tests. For example, by filtering noise from a signal, you limit the bandwidth of that signal. That led to the quest to avoid generating noise in the first place rather than filtering it later. The new K and S Series include the first full implementation of the OLADRA design, and were designed using two key technologies:

As can be seen in the image above, a large part of the internal space of the K50 is taken up by the power supply section.

The newer power supplies are neither switching nor linear, and instead use elements of these two types of power supplies in a novel way (achieving the speed of the best switching power supplies and the low noise level of the best sources Linear Power Supply) which has several great benefits, particularly in the context of digital circuits, where low noise and ultra-high bandwidth are required.

As Mark explains: “With noise, quantum is very important, but you can do two things by changing the frequency at which noise occurs. First, changing the frequency changes the impact on pitch and timbre. For example, noise at one frequency can result in super-tight bass, but the kind that doesn’t breathe or flow like the real thing. At a different frequency, it will emphasize the high-frequency details. At other frequencies, the sound may become too direct or too deep. But secondly, if you have two (or more) active components on a PCB, they independently generate a noise spectrum. The impact is dramatically worse if you allow your noise peaks to match, that is, you create nodes. Then, by changing them so that the “hills” of one coincide with the “valleys” of the other, background noise is reduced. So ISM technology is about managing noise from multiple noise sources (active circuit components) to get the best result and it’s an incredibly complex process. “

Although this still describes the OLADRA project quite superficially, I think it perfectly illustrates the kind of innovative thinking that makes a difference in the seemingly simple but treacherously complicated world of digital audio.

More details of the OLADRA project, a detailed explanation of how noise affects the signal and many other topics are detailed in the support section of the completely revised Antipodes website. I really urge those who are technically inclined to check it out because it is an absolutely fascinating read.

AMS v3.0 interface

In addition to the new OLADRA platform, Antipodes has also been working on a fresh new look for its operating system, now called AMS V3.0. Nice looking, elegant and easy to navigate in dark tones, the local user interface is now seamlessly integrated with the Antipodes external website for easy change. You can start on the Antipodes website in any browser to verify your new purchase and immediately switch to your local “My Antipodes” environment or vice versa. Alternatively, you can still access the Web Interface by typing “myantipodes” in the search bar.

K50

The K50 is Antipodes’ high-end music server, containing three separate, isolated, powered individual computing devices, a server-side optimized computer, a player-side optimized computer, and a dedicated Antipodes board dedicated to the reclocker and the 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 by a large internal heat sink, although the word “heat” is not something I would use in relation to this server because it remains absolutely cool to the touch. When asked about this, Mark confirmed that this has nothing to do with processor throttle or any such measure,

Narrowing down the model numbers, there is the K40 “server applications only” single-computer version of the K50 that includes the top-of-the-range high-powered calculation engine, but no player section or digital outputs and is optimized to function as a Ideal server for generating isolated streams to an Ethernet DAC. Then there’s the dual-computer K30 that contains two separately powered and isolated compute engines for server and player functions to output via Direct Ethernet or USB and is designed to deliver a large portion of the K50’s performance to a more affordable price.

In addition to these Big Boy music servers, there is also a K10 CD ripper and the modular S-series of four units 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 excellent for its cost as a server + player and ideal as a player. However, for this review, I will focus only on the K50.

System context

The K50 will be used in the context of basically two systems: the CH Precision C1 DAC with the CH Precision A1.5 power amplifier driving Martin Logan ESL15A loudspeakers, the Aqua Formula xHD DAC with V2 output board, the Audio- GD Master 1 also driving the same amp and speakers and, as a special guest, the Aequo Stilla speakers (review coming soon). The interconnection cables used are the balanced CH Precision between C1 and A1.5 and Siltech Paris between Aqua, Audio-GD and A1.5. The speaker cables are Jorma Trinity and Driade Flow 405. For comparison, I used Antipodes CX and EX, as well as Bryston BDP-3 network player. The preferred digital connection to the DACs in all cases was the Jorma AES / EBU cable.

Filming

I was warned that the PSU needs a lot of work, but regardless, the K50 surprised me from its first notes. What happens with prolonged use after about 3 weeks is that the sound gradually becomes a little sweeter and more relaxed. Still, one of the most overwhelming aspects that I noticed early on was how organic the K50 sounds.

First listen

My first impressions of the K50 were formed during the review of the Aequo Stilla speakers. As a result, I was using the Aqua Formula xHD DAC with the Audio-GD preamp and neither the Logans nor Magicos were configured for use. But the relatively unknown setup didn’t stop me from immediately realizing how important a monolithic product like the K50 is.

The three main sections of the K50 are built with the highest quality in mind and therefore the K50 performs just as well as a server only or as a player only. However, I soon discovered that all the magic of the K50 happens when it is used as an embedded system.

K50 as a player

When using the K50 as a Roon player, powered from the CX as a Roon server, the very interesting Reclocking Digital Output section of the K50 is available. However, for comparison to the EX as a player, I necessarily stuck with the USB using the Final Touch Audio Callisto cable. Still, the differences to the EX as a player were immediately obvious. The K50 has sweeter, more refined highs, sounds rounder and more relaxed, and has a more spacious and deeper soundstage. Most notably, though, the K50 sounds a lot more organic.

Although this combination has a refreshing lack of shrillness, which is otherwise so common in digital playback, I felt that the sound could work with a little more tension and brightness. Adding the Bryston BDP-3 as a player also connected to the DAC via USB, and powered by the CX, confirmed this feeling by providing a faster beat and more immediate transient behavior, albeit at the cost of sounding more mechanical, less colorful and flatter in terms of sound staging.

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 server + player

When switching to the full Antipodes Audio K50 package as a Roon server and Roon player with its Reclocking Digital Output section and using the Jorma AES / EBU cable, even with the Aqua / Audio-GD / Aequo setup, the jump in performance was absolutely impressive.

It was definitely something else!

All the aforementioned organic naturalness is maintained but with greater transparency, presence, speed and impact. While the BDP-3 remains the firmness king, all other aspects of the K50’s performance are much more complex. Most notably, the soundstage has a picture depth that reminds me of what the Wadia 861 CD player could do. At that point, I compared the player’s input and output independently and set the player’s Clocklink function to it was crucial to producing a deep soundstage. Since then, I’ve used countless servers and transmitters with various connection methods, but not a single unit has come close to reproducing that kind of depth without introducing unwanted side effects. So far, that is.

One of the unique strengths of the K50 is that it not only produces music in a natural and fluid way, it also has great PRaT and the amazing ability to reproduce everything in the most realistic way, making all instruments sound absolutely authentic and convincing. .

At this point, he was already in love. Then, I realized that I had only been listening to Roon. And not only that, until now, I had only heard one output and there were many more to evaluate!

Other player apps

Regular readers will know that I recently noticed that Roon didn’t sound as crisp and articulate as UPnP. As a result, I re-evaluated all my playback options and found that there are subtle differences from method to method (MPD, UPnP, Squeezelite), but Roon was the one that stood out negatively for appearing somewhat dynamically thickened and squashed. This is actually quite unfortunate because Roon’s interface is great. Fortunately, if you don’t want to switch to UPnP or MPD, there is a very simple solution. Since its inception, Roon has worked hard to be compatible with almost every hardware device and streaming format out there and that includes Squeezelite. As you can read in the K50 instructions,

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

When comparing Roon Server + Roon Player to Roon Server + Squeezelite, the aforementioned Roon effect does not completely disappear, but the bass hardens, the transients become faster, and the whole presentation becomes a little more direct and clear, which more importantly, while retaining 100% organic naturalness.

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

should mention that the remaining difference between Roon + Squeeze and UPnP or MPD, while important to me, does not seem to affect many other users as much. When asked about it, most admit to not having made comparisons but not missing anything either. However, every time I made the comparison with someone else in my house or theirs, the difference was there for both of us to hear. It may not be day and night, but it is sunny versus cloudy. Either way, I also remember just two paragraphs ago I already admitted that I was in love with the performance of the K50 and that was with Roon Server and Roon Player. So, as always, it is relative, like almost everything else in the wonderful world of high-end audio.

Comparison of outputs with the C1 DAC

The K50 offers all the digital outputs one could wish for. Direct Ethernet, USB, AES / EBU, S / PDIF on RCA, S / PDIF on BNC and I2S. So how do they compare? Inquiring 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 great. The best result by far was 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 example, AES / EBU with S / PDIF using Mogami 3080 and Belden RG59 respectively, I would say that the AES / EBU output is still the most accurate, while the RCA output adds some weight and color in the bass that some listeners may prefer and others may call coloration. I am not judging here. Not long ago and for a long time,

I also listened to the I2S output using the only DAC I have with such an input: the Jay’s Audio DAC-2 Signature. By blindly switching (which is easy because I can’t read the screen from the listening position) between AES via the Jorma and I2S via a good quality Sony HDMI cable, I had a repeated preference for the input that sounded more articulate and optimistic. I’m afraid it was the Jorma. Perhaps, if I also had a Jorma or other very high-end HDMI cable, the result 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 I2S pinout, some products just won’t work with another I2S product while others provide DIP switches inside to change the connection scheme. Very cleverly, the K50 offers DIP switches on the bottom of the unit for easy access to allow for any required combination. Jay’s Audio adheres to the PS Audio standard that is set in the K50 by having all dips in the off position with the exception of 9 and 10 which must be in the on position.

It seems that the more I work with traditional connections, the more I detach myself from USB. While the Antipodes Audio K50 sounds absolutely great through its open, focused, transparent and articulate USB output, there is now a kind of inescapable mechanical feeling that the music is slightly less, slightly less sunny and positive than through the AES. / EBU. And this is not only the case with the Jorma cable, I also feel that the music seems more organic than with the Callisto USB cable, even when using the Mogami AES / EBU cable. For whatever reason, this traditional outing gives me most of that supernatural, non-technical, completely fluid feel.

Like I found with previous Antipodes servers, the K50’s Direct Stream Ethernet offers excellent performance with the C1, very well balanced, lively and lively, but with a laid-back touch and great finesse. It’s noticeably less technical than USB and I’d rate it a better output if it weren’t for the AES / EBU with the Jorma cable, which adds transparency and makes everything sound even smoother and more organic. You can hear this very clearly in the vocal parts that are perceived more freely, more human and simply more realistic. Compared to the AES / EBU connection, the otherwise clean and very pure sounding Ethernet connection is comparatively flatter and more forced. On the other hand, the technically perfect Ethernet connection has slightly tighter bass that can be very pleasant with certain music. So between AES / EBU and Direct Stream Ethernet, it’s mostly a matter of personal preference: maximum organic stream and 3D images (but a little more rounded) 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 was excited about this connection at the time. It sure delivers a very engaging and musical performance, but the comparison makes it impossible not to notice that the little annoyances I started having with its performance over the years turned out to have been addressed by the K50. For example, the CX’s delivery is less airy and refined, more rounded (less sharp and detailed), dynamically less expressive, less focused and less spacious. Alas, reading that out loud seems like a small jump in performance and to be honest I really feel like this is the case.

Results compared to the Aqua Formula xHD DAC

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

In a departure from the results with the C1 DAC, the USB output with the Callisto Final Touch Audio cable connected to the Aqua DAC has a nice, smooth, slightly sweet and flowing quality that, with this DAC, may make it the preferred connection for some. ears. Interestingly, with the Aqua DAC, I don’t really think that USB is more rigid or mechanical than AES / EBU. Still, to my ears, also with the Aqua, the Jorma AES connection is still technically superior with the tighter, more articulate and purer sound, even if some of the aforementioned ears may find it a bit too controlled with this DAC.

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

USB cable comparison

The original Curious Cable offers a solid performance, literally, with excellent bass and sync. But compared to the Callisto, it is a bit rough and unrefined. The Curious Evolved works surprisingly well, restoring tonal balance to the best neutral approach I’ve heard the Antipodes Audio K50 do with a USB cable. The slight feeling of reduced dynamic impact that I noticed in its original review is not very apparent now. However, it doesn’t take more than 2 seconds to hear that the AES / EBU connection still sounds more focused and energetic. The CAD USB cable, as always, provides really powerful bass and remarkably sonorous tonality, but with less apparent energy at the top creating a slightly dark sound. The AudioQuest Diamond, finally, it generates a very neutral sound but is also the least propellant, dimensional and energetic. Returning to the AES / EBU connection reaffirms its privileged position and strengthens my growing belief that the good old traditional digital connections that we (yes, me too) quickly scrapped when USB became popular actually deliver better and more predictable results.

K50 vs. EX + CX via USB using the CH C1 DAC

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

Hearing the EX and CX again in this way, it was easy to see why I fell in love with the combination. The added spaciousness and flow and deeper soundstage that the EX brings to the table are still combined with the powerful, propelling delivery of the CX for an engaging performance. But switch to K50 and all bets are off. The newcomer simply does everything the combo above does and enhances it with smoother, higher resolution highs, more precise focus, and greater transparency. And last but not least, the K50 adds an overwhelming sense of natural flow and a deep sound scene, making other server / player sources sound flat and relatively technical in comparison. And I’m afraid that includes the CX and EX.

Technically, the CX + EX and Antipodes Audio K50 can be easily distinguished by all of the above, but arguably their greatest achievement is heard coming back to the combo. This is when you realize the progress that has been made. It’s not so much the areas in which the K50 outshines the old combo that is most impressive, but what the server doesn’t do, that is, sound like a music server. Rather it sounds like music.

This aspect of your performance is best seen when you are concentrating on nothing and simply enjoying music with the K50. Every time I do, I notice that I soon get out of critical reviewer mode and into more relaxed music listening mode. But as soon as I switch to the previous combo, I go back to critical reviewer mode. This, I think, is the highest compliment I can give a music server.

Wrapping it up

At this point, still, I have mentioned only a small fraction of the Antipodes Audio K50’s capabilities. Apart from several more player options, there are several diagnostic sections and many other tools. But if you were to discuss all of this in detail, then the review could end up being three times as long, and as it stands, it’s already pretty long. Also, the main point of any audio component is its sound quality and I think I have carried that point to the end.

To discover the full scope of the K50’s functionality, I encourage the reader to visit the Antipodes website or contact the nearest dealer to request a demo.

Antipodes Audio K50 Music Server- Conclusion

The Antipodes Audio K50 Music Server is an absolute change. While the CX and EX are still fantastic products and I can still see why I chose them as my references 3 years ago, the Antipodes Audio K50 does everything the combo above does and enhances this with smoother, higher resolution highs, a more focused approach. accurate and greater transparency. More importantly, the Antipodes Audio K50 adds an overwhelming sense of natural flow and an incredibly deep soundstage, making other server / streamer sources sound relatively flat and mechanical in comparison. What’s especially unique about the Antipodes Audio K50 is that it not only produces music in a natural, organic and fluid way, it also has great PRaT and sounds upbeat and like live music. But the Antipodes Audio K50 is more than just checking audiophile boxes.