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June 2020
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World Premiere Review!
exaSound Delta Server For Streaming Music Online
A powerful Roon Core / Server implementation for audiophiles.
Review By Phil Gold


exaSound Delta Server For Streaming Music Online Review


  I've been late to a number of parties. I had such a great vinyl collection I was no early adopter of digital audio. When I did dip my toes in it was a Denon 3520 in around 1990, eight years after the launch of the CD, and I continued to favor my Linn Sondek LP12 until I reviewed and bought a very musical CD player, the Meridian G08 in 2004 (as reviewed here). I've progressed through a series of upgrades since then, culminating in the EMM Labs XDS1 which I use as a transport and the EMM Labs DV2, which is my DAC and volume control, eliminating the need for a preamp in my all-digital system. Now my walls hold two giant racks filled with CDs and SACDs and I have felt no great need to jump on the streaming or digital server bandwagons.

As a reviewer, I have dipped my toes into the streaming water a few times and I have built up quite a collection of digital music files on my computer. I even have a NAIM UnitiServe to feed a UnitiQute in a second system, but I haven't used it since I moved house a couple of years back, and now the unit seems to have expired. I have enjoyed using TIDAL through the remarkable KEF LSX active speakers but was not enamored of the user interface.

But the market has moved and out of a maze of competing standards, one service has come to dominate, and that is Roon. Roon is everywhere these days. My DV2 DAC supports it, your DAC likely supports it or will soon, and I'm pretty sure my toaster will get a Roon update next year. What Roon does is to wrap music from your TIDAL or Qobuz subscription, Internet Radio, your computer, your smartphone, and your music server into a consistent user interface across a wide range of interface devices including your computer, tablet or smartphone. And it automatically picks up (through the internet) all the required metadata on each recording so you can see the cover, the liner notes, the recording date, artist and composer names, and so on. It makes the job of cataloging and organizing your collection so much easier. The attraction of Roon is not in its particular capabilities, though they are awesome, or how well they are presented. It's Roon's success in the market that makes Roon so attractive to us.


About exaSound's Delta Server
But I'm not here to review Roon. I'm looking at a Music Server. There are many out there, but this one, the exaSound Delta Server, is rather special. In a confusing world, exaSound's George Klissarov is setting out to make things simple while offering top-notch audiophile quality. Those two things go together because the simpler the system, the more direct the path, and the fewer services there are to detract from the performance of the music server.

exaSound is conveniently based a few miles up the road from my apartment, and I have run into George at various shows and presentations. The last time was at the grand opening of the beautiful recording studio and listening rooms set up by Eli and Ofra Gershman. George was demoing the new Delta Server and explaining clearly what it did and why. Somehow some audience members took this as the ideal opportunity to explain that music is analog, and why shouldn't George expend his energies on making analog components instead. George was very diplomatic. I'm not sure I would have been in his place. George set up exaSound in 2010 to manufacture high-end DACs, networked music players and servers.

The company's mission is to empower audiophiles to enjoy studio master files the way they were recorded – at their original format, sampling rate, resolution, and number of channels. The company has developed proprietary asynchronous USB protocol, ASIO drivers and FPGA firmware to achieve a 32 bit, low-jitter, bit-perfect signal path. They were first to market with an 8 channel DXD DAC and the first DSD256 DAC (four times the SACD standard). exaSound sells direct and offers a 30-day risk-free trial in the US and Canada. The products are designed and built in Canada. By now, regular readers will know how pleased I am when I find top-notch audio products made in Canada. I'm happy to add exaSound to that list, which includes Bryston, EMM Labs, Reference 3A, Totem, Magnum Dynalab, Muraudio, Gershman, Oracle and Verity among others.


exaSound Delta Server For Streaming Music Online Review


The Delta Server is a bare-bones computer running a very restricted Linux based operating system, using the most powerful Intel desktop processor and motherboard available that doesn't need a fan to keep it cool on maximum load. The chip in question is the Intel i9-9900. For nerds like me this eight-core chip runs from 3.1GHz to 5GHz. The Server is roughly cube-shaped and is offered standard without keyboard or touch-screen monitor, which you don't need for it to perform optimally. You can add a 7" monitor for troubleshooting network connections, or just to see what's playing. Inside the box there is room for three hard drives – SSDs preferred. The system drive in the standard configuration is a 128GB SSD SATA drive, although up to 2TB can be specified. This is attached to a M.2 slot on the motherboard. A partition on this drive holds the operating system, exaSound, and Rune Core software, while the second (shareable) partition (about 57GB in the standard configuration) is available to hold your music files and associated metadata.

The test unit came with a 256GB system drive, allowing about 185GB for my music files. There are two available 2.5" SATA3 6Gb/s connectors for more data drives, which can be up to 7.68TB each today and likely much more in the future. There are four external USB 3.0 ports – and you can add an expansion card to increase that number. I used one to connect the digital output to my DAC and a second to hold a SanDisk 256gb Ultra Fit USB 3.1 flash drive. There's a 60-Watt power supply, and 8GB of internal RAM, expandable to 32 GB. The power supply is external and provides 19V / 6.32A. An HDMI output is provided for the optional external monitor. Network connectivity is through a Gigabit Ethernet connection, and as a new option, an internal Intel 802.11 AC based wireless connection which can be used to support a limited number of zones. Eight zones are supported through the wired connection. If you want to rip CD's you have two options. You can attach a CD drive to a USB port, or exaSound can provide an internal top-loaded optical disk drive.

The Delta Server can operate as a Roon Core Server or as a UPnP server. The Roon Core manages your music collection, streams to your audio devices, and stores the Roon database on the internal system SSD drive. Music files can be stored on internal SSD storage, USB drives, and NAS (Network Attached Storage). Roon Core manages content from TIDAL and Qobuz and streams music to Roon Ready, AirPlay, Sonos, USB, and many other audio devices. You control playback through the Roon Remote app on your platform(s) of choice.




The Delta Server works closely with exaSound DACs, providing asynchronous packet streaming over USB that places very little load on the server's CPU. When connected to an exaSound DAC, the Delta acts as a certified Roon Ready player. Also, with USB-connected exaSound and third-party DACs the Delta works as Signalyst NAA endpoint, UPnP/OpenHome, and Airplay player. It supports high res PCM formats including FLAC, AIFF, WAV, and DSD (DSF and DFF). Its ENclusiv Hi-Res Audio support includes PCM sampling up to 768kHz/32-bit and DSD512.


exaSound Delta Server versus Roon Nucleus+ Server
Both servers offer the basics – automatic Roon updates, access to music on an internal SATA SSD, external USB drives, and network-attached storage (NAS). They can be used with all devices the Roon core supports – audio streamers, USB DACs, speakers, amps, stereo, and multi-channel HDMI-enabled devices.

But the Delta Server can also operate as a UPnP server and player, an Apple AirPlay player and Signalyst NAA Player.

Roon's Nucleus+ is a smaller server which uses a 30-Watt power supply and Intel NUC hardware, and an i7 processor, while the Delta Server uses a 60-Watt power supply, upgradable Mini-ITX hardware, and a more powerful i9 processor.

Roon Nucleus+ offers 8GB of RAM, an internal SSD 64GB SAS drive, supports one 2.5" SATA expansion drive, and includes two USB 3 ports. The Delta Server supports up to 32 GB of RAM (8GB standard), includes an internal 128GB SAS drive (up to 2TB optional), allows two additional internal 2.5" SSD SATA drives, and provides four USB 3 ports (and expansion options beyond that).

Since Roon is so convenient and popular, I used the Delta Server exclusively as a Roon Core Server, but it is good to know that if you decide not to use Roon and pay their subscription fees, or if Roon goes out of business or in a direction you don't like, you do have options. UPnP can stream music files stored on the internal SSD storage or attached USB drives using compatible player Apps such as MconnectHD or BubbleUPnP Hi-Fi Cast.


You can get the Delta Server in black or silver finish. Unusually, the connections are underneath rather than to the rear, and the box sits on a low frame. This means to attach a USB key you need to roll it over and the key can only be so long to avoid hitting the floor. The power switch is hidden from view under the box, and only a small light shining down indicates if the box is turned on. These are awkward ergonomics, but then again, you won't be touching this often, and to its credit, the unit is built like a tank. The case is one giant heatsink to allow it to run fanless and silent, so it needs to be built like a tank. And in my use, single-zone (eight supported) it runs cool to the touch. It may warm up when you run multiple zones – each zone controlled by a different Roon app.

For this review, I hooked up the Delta Server through the supplied USB cable to my EMM Labs DV2 DAC reviewed here. I don't have a wired Ethernet outlet in my listening room, and I did not have an internal or external wireless connection installed on the Delta Server. So, to connect to my MESH Wireless Network, I used a wired Ethernet connection to a Linksys RE6700 AC1200 WIFI Range Extender which plugs into a power outlet in the listening room and offers a wired Ethernet connection in addition to its wireless output. Once connected, I turned off the wireless output which was no longer needed. I never experienced any problems with the connection. It proved rock solid. I was thinking of adding a hard-wired Ethernet port to my listening room, but this inexpensive option worked so well I forgot about it.


exaSound Delta Server For Streaming Music Online Review


You will use two interfaces with the Delta Server. The first, which you rarely touch, is a web connection to the Delta Server itself, used to setup and for various administrative, troubleshooting, and support options. Basically, set and forget, and you can expect exaSound support to help you through these processes. There are links there to Roon Help and to exaSound Tutorials and the Owner's Manual. You can see how much space you have left on your data drives (internal and external), make those drives shareable across your network, and view a performance monitor which shows you the processing load for each core, and the temperature of each core and its allowable values.

You complete the initial setup, including connecting to the various streaming sources (TIDAL, Qobuz) or music files (iPhone, iPad, Computer etc.), and the various outputs devices on the Roon app. Then you can use the Roon app on any device to play music on up to 8 zones in your home. It's best to use a tablet or a PC for this as one major feature is not supported on the phone version of the app. You can't use or set a Focus on the phone app. A Roon Focus limits your music searches to specific genres or performers or specific file resolutions and so on – anything the metadata provides. So, if I only want to listen to Mozart and Cannonball Adderley on DSD, I can set that combination up as a Focus and apply it whenever I like. Come on Roon, add this handy option to the iOS app.


exaSound Delta Server For Streaming Music Online Review


I won't review Roon for you here, but I will say it's easy to navigate and more intuitive than JRiver Media Centre which has been my interface in the past, and more flexible and powerful than the familiar iTunes. I will just mention a couple of features I like. First is the ability to search across all the music sources on the network, on TIDAL, on Qobuz and on the Delta Server itself, and see every version of a particular recording. Second is the ability to see, when a track is playing, exactly what the source is, the type of file and its resolution, and how it is routed to my DAC, including any bit rate conversion or MQA processing going on. If the selected source material is at too high a resolution for your DAC, the Delta Server will translate it to the highest resolution your DAC will support. Cool.

What I will tell you is whether the package works as advertised, and what kind of sound quality am I getting. Well at first there was a glitch. Twice in the first couple of weeks, the server became unresponsive and needed a reboot. Using the Delta internet interface, I was able to upload the logs to exaSound and they were was quickly able to spot the problem – a line of C++ code containing the name of my DAC did not have the expected text terminator. A fix was made available to me and to all users in a couple of days.

As to the sound quality, I have no criticism whatsoever. My EMM Labs DV2 locked on instantly to the USB data stream, up to the maximum resolution it currently supports on DSD and PCM material, and it displays that on its front panel, down to the MQA designation on suitable TIDAL Master material. I compared the sound quality from the Delta Server from all of its sources with identical CDs or SACD's in my collection, routed from the XDS1 over EMM's proprietary glass connection. Damned if I could tell the difference. And often Qobuz would offer me a higher resolution than my physical CD and I could appreciate the improved resolution. I will not get into a full review of MQA on TIDAL because that's a whole new subject on its own. But I will give you some highlights on extremely well-recorded albums that my extended experience tells me are repeatable across all music tracks.


exaSound Delta Server For Streaming Music Online Review


Listening Comparisons – The XDS1 as transport against the Delta Server
Lilison Di Kunara Bambatulu "Ansa Djallo" [dep MUS 2-1119]: This Redbook CD is sadly out of print, and I couldn't find it on Tidal or Qobuz. But I compared the Apple Lossless tracks I had stored on a USB drive playing through the Delta Server with the original CD playing on the XDS1. At the touch of a button, I could switch between sources with both started at the same second. Even on the reference playback system – EMM Labs DV2 DAC, Soulution 511 Power Amp, YG Hailey 2.2, all wired together with Nordost Valhalla 2 cables – I could not detect any difference at all.

Keb' Mo' Just Like You "That's Not Love" [EK 67316]: This Redbook CD plays identically on TIDAL, Qobuz, WAV 44.1kHz/16-bit files on my computer, and the original CD.

Beethoven Symphony No 4 Haitink / LSO [LSO 0598]: This plays 1.5dB louder from the DSF DSD64 files on the Delta Server than from the SACD on the XDS1, but once adjusting for that sensitivity issue, the two sources are hard to separate, with a small edge to the SACD.

Sonny Rollins Saxophone Colossus [CAJP 7079 SA]: This Analogue Productions SACD is superb musically and sonically. The DSD64 files on the Delta server play 3dB louder than the SACD. While both are wonderful, I find the SACD just a little more relaxed and open to listen to. Not something you can tell on AB but it's audible on extended listening.

Buena Vista Social Club [Nonesuch 794782]: This plays 3dB louder from the 44.1kHz/16-bit files on the Delta Server than from the Redbook CD on the XDS1. There is a small gain in impact and relaxation on the CD, but it is so small it's not worth worrying about, especially since you can source higher resolution better sounding versions on Qobuz.

Biber Rosary Sonatas Rachel Podger violin [CCSSA 37315]: This superb album from Channel Classics sounds great wherever you source it – DSD64 on the Delta Server or SACD on the XDS1, after adjusting for a 2dB volume advantage on the Delta. After prolonged listening, I have a slight preference for the physical medium, but it's very close.

Sonny Rollins Alfie "Alfie's Theme": A Redbook comparison between my CD and the same 44.1kHz/16-bit resolution coming from Qobuz and TIDAL was identical in all respects. But TIDAL offers MQA versions at 96/24 and 192kHz/24-bit, all packaged into a 48kHz/16-bit stream. As the source resolution increased, I could hear the percussion more clearly, but I wouldn't say I enjoyed the experience more than Redbook. Qobuz offers both 96kHz/24-bit and 192kHz/24-bit versions which were certainly more enjoyable and more natural sounding than the Redbook, especially when the brass play flat out near the end.


For your entertainment, I'm including screen captures from my iPhone, showing the data path at each resolution and a picture of the front panel of my DAC, showing how it locks on to the signal.





I must add that I have greatly enjoyed listening to music through the Delta. The sound quality seems to depend only on the quality of the music files you feed it. On great Redbook recordings like Mozart String Quartets from the Alban Berg Quartet, or Daddy Lessons from Beyoncé and the Dixie Chicks, the detail, dynamics, and warmth are exemplary. Playing Hi-Res Music files, DSD, and PCM from Qobuz, or my personal files, show the greater imaging quality, fuller bass, relaxed atmosphere and extended, delicate treble that proves 44.1kHz/16-bit is not always enough.

This is what exaSound has set out to do – to provide a bit-perfect transfer of the data from wherever the source is, through careful control of low latency hardware and software. My DAC uses an asynchronous and galvanically isolated USB input to reject jitter and electrical noise, and I suspect those looking at an audiophile server will also possess a DAC with a sophisticated USB input. If not, you can use a network bridge to connect a wired Ethernet stream to your DAC's best input. Or you can upgrade your DAC now or in the future to take advantage of the high-quality digital stream the Delta Server can provide. You may also choose an exaSound DAC which offers even greater integration and flexibility. Like the reference EMM Labs DV2, exaSound DACs also feature galvanic isolation and asynchronous transfer.

Are there alternatives out there? Yes of course. Roon offers the Nucleus+ Server, which is a smaller lower powered box with far fewer expansion capabilities and no UPnP option, but still capable of bit-perfect transmission and high sound quality. And there are others, at a variety of price points. I can only comment on this one. The value proposition is high. It sounds great. I like it a lot. It's a keeper.




Sub–bass (10Hz – 60Hz)

Mid–bass (80Hz – 200Hz)

Midrange (200Hz – 3,000Hz)

High Frequencies (3,000Hz On Up)



Inner Resolution

Soundscape Width Front

Soundscape Width Rear
Soundscape Depth

Soundscape Extension Into Room


Fit And Finish

Self Noise

Value For The Money



Type: Digital music server
FrexaSound Delta Server M100 – Roon Server and Roon Player
CPU: Intel i9-9900
RAM: 8GB (up to 32GB max)
System SSD Drive: 128GB (up to 2TB max)
Internal Storage: Two 2.5" SSD SATA drives
Music library: > 200,000 tracks
Network Connection: Gigabit Ethernet (wireless optional)
USB ports: Four USB 3 ports (more optional)
Volume control: ZeroResolutionLoss. Bypassable. 
HDMI: Audio output, User interface for configuration
Resolution supported: DSD64, DSD 128, DSD256, DSD512, DXD 352.8/32, and PCM 44.1/16 to 384/32. MQA full unfold with supported DACs
HDMI Port: Audio output
Power supply: External, 100-240V/2A. Output 19V/6.32A
Chassis: Premium grade extruded aluminum panels.
Finish: Black or silver
Weight: 21 lbs.
Dimensions: 10.3" x 10.3" x 10.8" (WxDxH)
Price: $2999
    Options: 7" touch screen $280
    1TB internal drive instead of 128GB $ 150



Company Information
exaSound Audio Design
3219 Yonge Street, Suite 354
Canada M4N 3S1

E-mail: customerservice@exasound.com
Website: www.exaSound.com
















































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