John Kenny Ciunas USB DAC Review 
Home Theater Preamplifiers Stereo Preamps
Written by Andre Marc   
Monday, 14 October 2013

To say the USB market is saturated would be an understatement. To say the affordable USB DAC market is crowded, would be even more so. I define “affordable” as under $1000. There are a slew of new products under $300 that have flooded the market, but those are mostly, if not all, considered “portable” devices. Affordable USB DACs come in every conceivable size and shape, with varying resolution capabilities, power schemes, and build quality. Most offer a single USB input, since a computer is the assumed source, but others offer additional S/PDIF inputs as well.   

USB DACs have taken high-end audio by storm due the popularity of using computers as digital source components. The optical disc player is going the way of the dinosaur according to those who claim to be ahead of the curve. This may be partly due to the fact that USB DACs can be made these days with a small footprint, and are easy to integrate into a system.

Affordable USB DACs are most often hub powered. This means they get juice from your computer via the same USB cable the data is sent through. Some also are supplied with external wal wart power supplies, and some are even upgradable with aftermarket linear power units. In general, affordable USB DACs are also no frills, focusing on sound quality. This means you rarely see a sample rate indicator, or even a power off switch. This purist approach keeps costs down and keeps the focus on sonics.

We have the Ciunas, the latest DAC from John Kenny, in for review. As DAC designer based in Ireland, Kenny has been making USB to S/PDIF converters and USB DACs for a number of years now. And if you'd like to know more about him and his products, check out the interview at the conclusion of this review.

The Ciunas is housed in a small but sturdy chassis, and the build quality is very nice indeed. There is an on/off switch on the front, a USB input, and a pair of RCA outputs. The DAC is 192 Khz, 24 bit capable, and is compatible with Mac and Windows, the latter requiring a driver which you can download. The chassis can be finished in black or silver. The DAC is priced 550 Euros, plus shipping; the US price will be around $750 depending on conversion rate.

According to Kenny, "the Ciunas feeds an I2S signal to a PCM5102 BB/TI DAC chip. The PCM5102 DAC sounds superior to the ESS Sabre DAC ES9023 used in one of my previous DAC products. Each element, significant to achieving the best possible signal quality, has been addressed. Battery power provides extremely low PS noise - one of the most important factors in digital audio. The high current output battery used (120 Amps instantaneous current) is the most stable power supply available for digital circuitry. Using this isolated power supply avoids issues of common mode noise & ground loop noise, often associated with non-isolated power supplies. Whereas other USB devices use 'add ons' such as isolators, special power supplies (often battery PS), ground lift techniques, etc., there is no need or advantage to such devices with the Ciúnas range - these issues are already dealt with & designed in from the ground up. The self-powered Ciúnas mitigates the influence of the PC's noisy power supply. As the 5V USB feed is not used or connected in any of the Ciúnas devices there is no influence from this supply; this means special USB cables, which separate out the 5V Vbus, wire are not needed - a wider range of options are available when choosing a USB cable which are not limited by this consideration."

Above, Kenny describes the power scheme used in the Ciunas, which may be its secret weapon. Specifically, it is battery powered, so it does not have any of the noise issues associated with hub power. However, there is a special twist. The battery is drip charged with either a supplied USB charger cable, plugged into a separate USB port on your computer, OR via an external power supply that can be rated between 5V and 12V, which you can purchase for a few dollars.

Kenny says, "the battery is charged via an internal charger, powered from a 5V supply. A USB charger cable is supplied which allows charging from a spare USB port or alternatively an external 5V PS can be used. The quality of this PS is immaterial as the device uses a battery shunt configuration & is continuously trickle charged. The battery has a lifetime of 20 years when operated in this manner."

In my experience, this design is unique, and takes the worry of battery replacement out of the equation. Kenny does however, recommend powering off the DAC if it will not be used for an extended period of time to allow it to get to full charge. I followed this advice and during the review period the DAC and the battery operated without a hitch.

Describing the audio circuitry, Kenny says, "two high quality audio clocks are used to time the audio signals. These clocks are used directly at the DAC chip's input to re-synch the signal timing in order to achieve the lowest jitter feasible. No capacitors in the signal path from the output of the DAC chip. The DAC will operate with native universal audio class 2 (UAC2) USB drivers found in MAC OS 10.6+, Linux/Unix. It will also operate with PC using a downloadable driver & with Squeezebox Touch (when using the EDO plugin)."

John Kenny Ciunas DAC

Set Up & Listening

I first used the Ciunas DAC in two separate systems. First, the Squeezebox Touch with the Enhanced Digital Output applet installed, connected to McIntosh MA6600 integrated amp, driving Harbeth Compact 7ES3 speakers, and briefly a pair of KEF LS50s, which are scheduled for a review. Cabling was Transparent, except for the USB cable, which was from DH Labs. My entire digital music collection spans resolutions from standard Redbook to 192 Khz, all in FLAC. The Ciunas replaced a just departed Burson Conductor DAC, and my usual Musical Fidelity V-DAC II.

The first thing I noticed was how spacious the Ciunas sounded. The soundstage seemed to widen, especially compared to the V-DAC II. I then was impressed with the unit’s detail retrieval and overall musical accuracy. Nothing stood out as out of place. No midrange glare, no upper frequency hash or flatness in the treble. To quote Radiohead, "everything was in its right place."

I always start reviews with albums I have had in heavy rotation, and here I began with Valerie June’s stupendous Pushin’ Against A Stone (48 Khz, 24 bit download). All of the music’s rustic flavor came through in spades. Part country, part blues, part folk, the songs have a lot of ambient touches, and the Ciunas really did make the music come alive.  

On Eric Clapton and B.B. King’s stupendous 2000 collaboration, Riding With The King (88.2 Khz, 24 bit download), the Ciunas did a superb job of capturing the vibe of this excellent recording. Special nod to Clapton for the great, natural sounding production. I don’t think King’s voice or guitar was ever better recorded. With the system in full flight, I found the sheer weight and life-like qualities on this album to mesmerizing.

I then moved the Ciunas into my main system, where a Bryston BDA-1 DAC usually resides with a CIAudio PLC-1 MKII passive controller and a Rogue ST 100 tube amp driving Thiel CS2.4 speakers. Cabling was Transparent and the same DH Labs USB cable. I used my HP Windows 7 laptop running Jriver 19. All that was needed was to download and install the device driver from the supplied link. Getting everything running was painless and took less than 5 minutes.

As good as the Ciunas sounded with the Squeezebox Touch, it sounded even better with the laptop. The transparency, quiet backgrounds, and tonal quality went to another level. One can say the Ciunas will sound better the higher quality the source you feed it.

19-year-old U.K. singer-songwriter Jake Bugg’s terrific self-titled debut album was a sheer joy to listen to via the Ciunas. Bugg mines pre-1966 British sounds, at times leaning towards Donovan, the Beatles, Gerry and the Pacemakers, and even our own Bob Dylan. Having seen him live recently, I can confirm the recording, which even emulates classic 60s analog, is a good representation of Bugg’s talent. The Ciunas did a great job of uncovering recorded detail, and creating a whole, coherent picture, and it spotlight the smart, uncluttered arrangements.

The Ciunas managed to sound big and bold, yet nuanced and delicate, depending on what each recording brought to the table. On Gordon Lightfoot’s early acoustic take of his classic "The Way I Feel", from The United Artists Collection, the Ciunas conveyed all the deep emotion in Lightfoot’s singing and playing. The stable imaging really shone through here, and artifacts of the recording such as tape hiss were not smoothed over.

The Ciunas handled all sample rates up to 192 Khz as advertised. I streamed a healthy dose of high-resolution albums in 48, 88.2, 96, 176.4, and 192 Khz with no issues. Also, in operation, the Ciunas was flawless. It never failed to charge or be recognized by the source devices. We are talking plug-and-play. Readers know my usual knit pick is the lack of a sample rate indicator, but at this price point, that is certainly rare to find. I had to stretch here to find something to complain about, as you can see.

John Kenny Ciunas


The John Kenny Ciunas DAC, at roughly $750, is a terrific sounding USB DAC that will fit into any space. It features a proprietary battery power scheme that works very well and, to my mind, clearly gives it an edge over similarly priced products. Kenny also makes USB converters as well that uses similar technology. All products are available via his website.


John Kenny Interview

1) Can you tell us a bit about your background, and how you got into the business of designing and selling USB DACs?

John Kenny: My professional background doesn't involve audio - Degree in Biochemistry & Maths, working life spent in IT owning & running an IT company. My audio hobby for 20+ years branched into DIY 10 years ago. The launch of the Musiland & Hiface USB audio devices defined a new value benchmark & spurred me into investigating computer audio. I guess from then on I have been married to researching what improvements are possible in computer/digital audio & incorporating what I can into my devices. After making substantial improvements to the Musiland device, I tried the Hiface which, out of the box, sounded nearly as good as my modified Musiland. I modified the Hiface & documented it on a DIY site. Others followed suit & reported very good results. Many requests to do these modifications for others led me to providing it as a service. At the time I also introduced the DIY community to the first DAC in the ESS family of Sabre DAC chips which sounded very good & around which I had built my first USB DAC. Always in search of better sound, I have since moved to using a different USB receiver board & a TI/BB DAC chip which sounds even better than the Sabre DAC. The sound I'm attuned to is an organic, full-bodied sound with all the detail intact which conveys a great sound stage & excellent instrument timbre. In other words sounding as much like real instruments, voices, as possible.

2) What are some of the most critical aspects of setting up a computer audio system to get it to perform as a state of the art front end?

John Kenny: Source is a more apt term as it is the most critical element to get right in the audio chain. Any damage to the signal occurring at this point cannot be undone further downstream. Inaccurate source signal can result in a skewing of the rest of the system in order to compensate for the shortcomings. For instance, if the source has a tendency towards stridency or brightness downstream elements are often chosen to try to reduce or compensate for this. I wonder if that term "synergy", often heard with regard to matching devices/components, is not actually this compensation in action. I aim to try to work from as accurate & neutral a source as possible & select the rest of the system accordingly.

I still find very good turntable sources as quite a high reference point against which to judge digital sources. Recently I have been finding my CA sources to outstrip the high-end Turn Table sources, I have heard. This is not just in the bass area but across both frequency & timing. Now the sound stage, instrument timbre & realism of digital is surpassing what great analog can produce. This is only achieved through the application of & attention to power sources in the computer, OS, playback software & USB DAC. The separate experiments of a half dozen local people interested in CA have led us to the use of batteries as the best choice for power sources to individual elements of the PC.

One of the reasons why my audio devices use battery power is for these same reasons of avoiding issues that using mains connected power can cause. Ground loops and common mode noise being two of the biggest problem areas. Elimination of these influences results in cleaner reference signals, which greatly enhance the reduction in background noise & noise modulation. The ability to hear more subtle sounds & the stability of the resultant audio image has the psycho-acoustic effect of portraying additional realism, sound stage depth & realistic timbre.       

3) Lastly, Looking down the road ten or twenty years, where do you see computer audio/digital music systems going?

John Kenny: 10 years in computer audio is a lifetime considering the speed it has been advancing over the last 5 years. In the near future, I expect that there will be a move away from general purpose computers as audio sources & a shift towards a focus on specific, purpose built, cut-down devices with minimal multi-tasking & better appreciation of the source of & types of noise within digital audio handling devices.  

I really don't know what will be the state of digital audio ten years or twenty years from now. I hope current advances in computer/digital audio will inform our existing psycho-acoustic knowledge & advance it somewhat. I would like also to see a set of measurements that better correlates to what we hear.


John Kenny Ciunas DAC: approx $750
(depending on exchange rate)
Available in black or silver.

Review System 1

CD Transport: Musical Fidelity M1 CDT
Server: Squeezebox Touch w/ CIA VDC-SB power supply
via Ethernet to MAC Mini w/ Western Digital & Seagate
external drives.
DAC: Bryston BDA-1
Headphone Amp: Pro-Ject Head Box II
Headphones: Grado SR60
Preamp: Audio Research SP16
Amplifier: Audio Research VS55, Bob Carver Black Magic, Rogue ST 100
Speaker: Thiel CS2.4
Cables:  Complete Furutech Flux cable system, Stager Silver Solids, Darwin Ascension (IC), Transparent  MM2 Super (IC), Transparent Plus (Speaker) Acoustic Zen Tsunami II (AC),Transparent (AC).Shunyata Venom (AC) Element Cable Red Storm (Digital AC), DH Labs TosLink, DH Labs AES/EBU, Audioquest, Forest, WireWorld Ultraviolet, DH Labs USB(USB) DH Labs (USB)
Accessories: Symposium Rollerblocks, Shakti Stone, Audience Adept Response aR6 power conditioner,Salamander rack

Review System 2

CD Player: Onkyo C7000R
Music Server: Squeezebox Touch via Ethernet to
MAC Mini w/ Western Digital & Seagate external drives.
DAC: Musical Fidelity V-DAC II, Burson Conductor
Integrated Amplifier: McIntosh  MA6600,
Tape Deck: Revox A77
Speaker: Harbeth Compact 7ES3, KEF LS50
Cables: Darwin Cables Silver IC, Kimber Hero HB,  DH Labs White Lightning (IC),QED Transparent MusicWave (Speaker),PS Audio (AC), Mojo Audio (AC), DH Labs TosLink, Audioquest Forest USB, Wireworld Ultraviolet USB
Accessories:Cable Pro Noisetrapper, Sound Anchors Stands, Wiremold, KECES XPS

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