Country of Origin


Summus 4C + 2C

Reviewer: Srajan Ebaen
Financial interests: click here
Main system: Sources: Retina 5K 27" iMac (4GHz quad-core with Turbo, 32GB RAM, 3TB FusionDrive, OSX Yosemite. iTunes 14.4), PureMusic 3.02, Audirvana 3, Qobuz, Tidal, Singxer SU-6 USB bridge, Sonnet Pasithea DAC; Active filter: icOn 80Hz/4th-order hi/lo-pass; Power amplifiers: Kinki Studio EX-B7 monos, Enleum AMP-23R; Headamp: Kinki Studio THR-1, Cen.Grand Silver Fox; Phones: HifiMan Susvara; Loudspeakers: sound|kaos Vox 3awf + sound|kaos DSUB15 on Carbide Audio footers powered by Kinki Studio EX-M1 integrated, Audio Physic Codex, Cube Audio Nenuphar Cables: Complete loom of Allnic Audio ZL; Power delivery: Vibex Granada/Alhambra on all source components, Vibex One 11R on amps, Furutech DPS-4.1 between wall and conditioners; Equipment rack: Artesanía Audio Exoteryc double-wide 3-tier with optional glass shelves, Exoteryc Krion and glass amp stands; Sundry accessories: Acoustic System resonators, LessLoss Firewall for loudspeakers, Furutech NCF Signal Boosters; Room: 6 x 8m with open door behind listening seat
2nd system: Source: Soundaware D300Ref SD transport clock-slaved to Denafrips Terminator +; Preamp/filter: icOn 4Pro SE; Amplifier: Goldmund Job 225; Loudspeakers: MonAcoustic SuperMon Mini or Acelec Model One + Dynaudio S18 sub; Power delivery: Furutech GTO 2D NCF; Equipment rack: Hifistay Mythology Transform X-Frame [on extended loan]; Sundry accessories: Audioquest Fog Lifters; Furutech NFC Clear Lines; Room: ~3.5 x 8m
Desktop system: Source: HP Z230 work station Win10/64; USB bridge: Singxer SU-2; Headamp/DAC: iFi iDSD Pro Signature;  Headphones: Final D-8000; Active speakers: DMAX SC5
Upstairs headfi/speaker system: Source: smsl Dp5 transport; DAC: Auralic Vega; Integrated amplifier: Schiit Jotunheim R; Phones: Raal-Requisite SR1a; Active DSP speakers: Fram Midi 120
2-channel video system: Source: Oppo BDP-105; All-in-One: Gold Note IS-1000 Deluxe; Loudspeakers: Zu Soul VI; Subwoofer: Zu Submission; Power delivery: Furutech eTP-8, Room: ~6x4m
Headphones: Audeze LCD-2 & LCD-XC; Final D-8000, Sonorous III & X; HifiMan HE-1000 & Susvara; Meze 109 Pro [on review]; Raal-Requisite SR1a

Review component retail: €4'990 [€2'390 for 2C, €2'990 for 4C when purchased separately]

Winter already came. Bet on summer for a change. "Hi Srajan, although this is my first time addressing you, the product of the company I represent is well known to you. My name is Dalibor and the company I represent is HD info based in Zagreb, Croatia. Our Stylus audio player, pre-installed on Euphony OS, runs on Jord Groen's flagship music streamer and as you mentioned in the review, is an important contributor to the exceptional sound quality of the Pink Faun 2.16 ultra streamer. The latest version of our software which Jord announced to you during the review includes DSP features with a very sophisticated Mozzaik upsampling algorithm written by Marko Dvecko whose Mozzaik 1 amplifier you also reviewed some time ago. So, if you are still under the impression that Croatia is not only interesting for Game of Thrones tourists, let me introduce you to a product that we would like you to try and if it seems interesting, write a review."

"Our dual streamer setup, Summus 4C + 2C is, as we like to call it, synthesis. Maybe it's a little bold but not for those who really understand computer audio. We literally wrapped our operating system which is highly optimized for audio transmission into a hardware platform that allows it to flourish best. Unlike most streamer manufacturers, we turned the R&D process upside down. Knowing that only perfect audio software enables perfect audio file transfer, we first developed an operating system that is fully dedicated to audio transfer. Finding hardware that would click harmoniously with the already fine-tuned software was a much simpler task. By combining the main Summus 4C streamer for tasks which require CPU power and the Summus 2C end point now exclusively dedicated to perfect DAC streaming, we created a system that should be very interesting for music lovers who know the original sound of acoustic instruments. Let me know if we can count on your interest in another product from Croatia's 'small hifi boutique'. Best regards, Dalibor Kasac."

"Da." Hello headless audiophile streamer/server. Its browser-based log-in can decommission tablets for library navigation. That simply requires an Internet connection with live access to Euphony's server to play back even local files. Yet it's a boon if one suffers WiFi allergies like our household. Use a hardwired PC's monitor screen and keyboard for all your nav needs. As Dalibor reminded me, I'd indeed had good prior experience with their Stylus player software which came pre-installed in the Dutch review streamer. Bundling it now with hardware not priced through the roof like Pink Faun's best was extra relevant. To this day I've not seen/heard attractive reason to abandon my dedicated music iMac with Audirvana and a super-cap powered external Singxer SU-6 USB bridge. While 'audiophile' servers—yawn!—love to brag about caching music in RAM, PureMusic/Audirvana did all that at the very beginning of PCfi already. What's more potent then, slick server software or overly pricey server hardware? It's no trick question. Back in the day, an iTunes bypass with PureMusic sounded clearly superior. It proved how player software had a decisive impact on sound quality. Audirvana, HQPlayer and Roon don't sound alike. Etc. A lot of it seems down to how software allocates/manages computing resources; and how much it loads down those resources in the first place. Of course all that lives in the digital domain. Differences exist but not at a delta commensurate with analog i.e. DACs, amplifiers and speakers. Once servers cost upward of €10K, allocating just half those funds to analog will net far bigger audible returns. Also true is that any part of our system can always be improved. The percentages simply shrink. Today is about shining up our binary transporter; what in the days of physical media was a CD transport but in these days of cloud data goes by server, streamer or renderer. Eke out another percent or two of more persuasive sonics? Or could it be more?

As always, armchair beliefs are fundamentally argumentative. To know for ourselves—and whether we find any differences clear improvements and attractive versus a given expenditure; or instead far too marginal to bother with—requires that we listen for ourselves. It's still no guarantee that others would agree. But when the aim of a hifi is to please its owner/s, we're not swayed by mass consensus, just personal experience. So naturally I signed up to mint mine. "We studied the setup you intend to use and you can connect our endpoint via USB to your Singxer bridge. We will provide you our dual streamer setup. You'll also get instructions how to connect the machines and add your iMac library to the system." Here I corrected Dalibor. When I add €5K of hardware plus two more power cords and signal cabling to my existing streaming source, I expect it to outperform my stuff without still running into an external USB bridge. I expect it to already include the same buffering/reclocking functionality in one or both of its boxes. In short, Summum should output directly to my DAC via USB, I²S, AES/EBU or coax; whatever team Euphony considered the best-sounding format. Euphony would already run two boxes against my lone budget resident. Common sense had to prevail to make this a fair comparo, not cheat by starting out 3:1. If two boxes versus one plus lots of extra cashish couldn't book a win, why bother? And should Euphony's Stylus player sound better than Audirvana, why wouldn't I just install that for a small fee and forget about the extra hardware altogether? As I thought about it, I saw that this gig would need to unpack a number of things.

"We'd really like you to use our I²S output because we think it's the best. The problem is that your Sonnet Pasithea DAC doesn't support I²S over HDMI. You can of course connect the Sonnet to our Endpoint's coaxial output but for optimal performance a Denafrips Terminator Plus with I²S over HDMI input would be a much better choice for our dual-streamer setup. Using the Singxer bridge doesn't make sense, agreed." I explained that Pasithea is superior to the Terminator Plus which is why I use it in the main system. I'd reviewed the Pink Faun with I²S over RJ45. Couldn't Euphony fit a matching output? "All hardware manufacturers make their own decisions. Sonnet's use of RJ45 for I²S is based on fine-tuning their DAC with their Linux-based Roon endpoint that outputs the older non-differential I²S via RJ45. Our streamers use a more advanced differential I²S protocol to overcome all non-differential I²S limitations of high noise, 192kHz PCM limit and no DSD. The advantages of differential I²S are very similar to those of differential AES/EBU over non-differential coaxial S/PDIF transmission." Could I then at least use AES/EBU as I did now between bridge and DAC? "We don't have sufficient PCB space for an XLR connector. And, we're finalizing the latest Stylus software version for your review samples so just a few more days, please." I confess to a bit of confusion. Euphony call AES/EBU superior to coax then design their hardware to not support it. And by excluding customers with I²S via RJ45 DACs, those are forced to use coax which is inferior to non-differential I²S. Didn't those decisions seem a bit restrictive and contradictive for €5K specialty hardware? As Dalibor put it, it's simply down to decisions each manufacturer makes for themselves. These are Euphony's so coaxial S/PDIF would be my default transmission protocol.

… to be continued…