Calyx 24/192 DAC

List Price: $1,799

 

Review by

Malcolm Gomes

If you lived through the 1970s you may remember how products from Japanese brands like Toyota and Honda were considered to be jokes by consumers in North America and Western Europe. By the 1980, these companies made huge leaps in terms of quality, performance and design and by the 1990s they were regarded to be as good if not better than many American and European brands.

Over the past couple of decades, I saw history repeating itself with South Korean companies. In the early 1990s, South Korean brands like Hyundai were laughed at. However, over the past decade, these brands improved in leaps and bounds and today, they are considered to be comparable with many American, European and Japanese brands. I can see the same scenario now playing out in the world of high-end audio.

Just a decade ago, audio products from South Korea were not even on the radar of most audiophile in North America and Europe. There were considered to be ‘cheap’ in every sense of the word. Over the past few years, that perception has begun to gradually change and now we have begun to see products coming out of Korea, that are getting noticed by audiophiles in the West.

Granted, they are still far from SOTA, but the pace at which South Korean products are improving, it is not entirely incomprehensible to imagine that, over the next decade, they will garner a lot more respect than they do now.

One of the companies leading the South Korean charge is Digital & Analog. Established in 1999, D & A has been OEM suppliers of class D amplification and integrated circuits to many brands around the world. Then in 2008, they shifted gears and started designing and manufacturing audio products with ever increasing sophistication.

The President and CEO of D & A, Seungmuk Yi likes to portray the Company’s philosophy by quoting a well know Chinese poet Bai Ju Yi of the Tang Dynasty, when he described music as “A poem that has passion at its roots, words as its buds, sound as its flower and meaning as its fruit”.  

D & A have begun offering audio products under the brand name Calyx, which means the ‘corolla of music’. An earlier product introduced under the Calyx banner was the Coffee. It has a built in headphone amplifier that is priced very aggressively for the features and performance it delivered. Following the introduction of the ‘Coffee’, D & A decided to get serious and so they threw down the gauntlet with the introduction of the Calyx 24/192 DAC a simple, no-nonsense name befitting a simple, no-nonsense product.

The first thing that strikes you about the 24/192, is its design and build quality. It is as sleek and streamlined as any North American or European audio product. It is also built like a tank with an extruded solid aluminum casing, that resembles the Mac Mini but with dimensions that are larger and with a weight to match.

Contributing to its sleek styling is the total absence of any controls, buttons or any ornamentation on the top and side panels of the unit. The only feature that adorns the front panel is a tiny red light that turns violet when the unit locks on to any signal. In fact, until you view the back, the unit looks and even feels like a solid block of aluminum.  

The back of the unit features a USB and a SPDIF coaxial input and a set each of balanced and RCA outputs. There is a 5V input that connects to the (provided) wall wart power supply. supply, the 24/192 has a built in clean power regenerator which purifies the power received, to improve performance. Between the power supply and the USB input is a toggle switch that lets you choose between the external power supply and obtaining the same from the computer via the USB. Between the USB and the SPDIF input there is another toggle switch to set the unit to either the USB or SPDIF input mode.

The 24/192 offers the superior asynchronous type USB implementation, i.e. this DAC’s clock slaves the clock in the computer feeding it to ensure a more uniform data transfer from the computer to the DAC. This circuit is equipped with an XMOS controller chipset.

One feature of the 24/192, which is not very common even among some mega priced DACs , is the fact that it has two clocks. The first clock is optimized to process signals belonging to the 44.1 kHz family (44.1, 88.2, 176.4 kHz). The other clock is optimized for the 48 kHz family of signals (48, 96, 192  kHz). This is the first DAC in this price range that I have reviewed that has this feature.

At the heart of the 24/196 is an ESS 9018 DAC chip which has a claim to fame of being the only one of its kind that can accept and maintain a true 32-bit PCM data path all the way to the stage where the digital signal gets converted into analog. This chip is capable of handling 32-bit, 400 kHz data streams and since it has an 8-channel architecture it is used in the 24/192 in a dual-differential, parallel circuit topography which in plain English means that it has two DAC channels for each phase of each of the two stereo channels. This implementation results in better dynamic range and signal to noise ratio. It also allows the unit to run fully balanced all the way to its XLR outputs. This is a chip that you will find in some of the best DACs available today. Publisher’s note: You might want to read  the “Dirty Little Secret” about “32-bit DACs” in my review of the Eastern Electric Tube+ DAC. In short, there are no 32-bit music files available and none in the foreseeable future. Reason? There are no digital recorders in commercial recording studios capable of recording 32-bit music. In addition, the availability of even 24-bit music is very limited even today and with the predominance of MP3 purchases (the general public is sadly satisfied with such) and the cost of licensing music by major artists, it is not likely that will change significantly in the near future. For now, the “32-bit” designation is mostly marketing hype. BUT, to this company's credit, they do not market this as a 32-bit DAC, thus the 24/192 moniker.

When used with any computer from the Mac family that runs on Mac OS X 10.6.3 or higher, the 24/192 is a plug and play DAC with nothing to add or modify. On the other hand, if you run a Windows based computer, you will need to install a Thesyscon UAC2 class driver that natively supports WDM and ASIO. For optimum ASIA latency, you are required to adjust the buffer setting in the control panel to an appropriate level for your application and machine performance.   

If you wish to stream music to the 24/192 in “integer mode” via USB, you can achieve this by using Audirvana for Mac OS. The advantage of this configuration is that it virtually converts the 24/192 into an extension of the computer you are using and the signal can potentially preserve bit perfect integrity right up to the stage where the digital signal is converted into analog.

The SPDIF input is designed to handle signals up to 32-bit, 192 kHz, provided you use the DAC Firmware release 3.1 or higher for Mac OS X. However this is academic, because getting a transport that is able to dance at this level will be a challenge. Also, the 24/192’s current XMOS implementation effectively truncates the signal down to 24-bit anyway.  Like I said, “32-bit” = Marketing hype. You won’t hear that anywhere else.

A look under the hood revealed that the chassis is a block of solid aluminum with around 45% of the inside machined out to house a single circuit board with all parts surface mounted.

On the specifications front, the 24/192 does well in its price class. It has a THD+N of 0.0005% @ 1kHz, 0dBFS a signal to noise ratio of 124 dB A-weighted and channel separation of 140 dB @ 1kHz and 130 dB @ 20 kHz. It outputs a signal of 2.2 Vrms (unbalanced) and a hefty 6.8 Vrms in balanced mode. With these relatively impressive specs, I was enthusiastically looking forward to finding out how it translated to sound quality.

For the purpose of the review, I used the latest iMac running the latest Snow Leopard software (not Lion - that's a whole 'nother ballgame) in tandem with the latest Amarra program 2.3 (4344) with the equalization defeated. The iMac was connected to the 24/192 via a Cardas USB cable. To test the SPDIP input I used the Sooloos 5, the Bryston BCD-1 and the Bryston BDP-1. The SPDIF cable used was the Transparent Reference. When I compared the single ended output of the 24/192 to its balanced output, I could detect a distinct improvement with the latter. The reproduction was cleaner, the transients were faster and there was more air around the instruments and voices.  

The minimalist styling of the 24/192 extends to the features of this DAC. You will not find a display, a volume control, a remote control, a headphone amplifier/output or lights to indicate the resolution of the signal. In fact, on the features side of things, the 24/192 is one of the most bare bones DACs that you could ever hope to encounter.  Perhaps this indicates that the designer put his design money where his ears are rather than his eyes.

For the review, I compared the 24/192 to the Neko D100 MK2 and the Benchmark DAC-1 HDR which are both in the same price range. The sources for the review included my iMac running the latest Amarra and Decibel, a Sooloos 5, the Bryston BDP-1 and the Bryston BCD-1. Since the 24/192 unit which I received was fully burnt in, I could skip this step and get to the auditioning stage right away.

To begin, I started with the SPDIF input, first connected to the Sooloos, then the Bryston BCD-1 and finally the Bryston BDP-1. Right from the get go, I found it a pain to switch sources because of the fact that the 24/192 had only one SPDIF input. Even though this is a bare-bones unit, I believe D & A should consider increasing the number of SPDIF inputs to at least 2 co-axial and one optical for future models.

I have a library of well over 72,000 tracks, spanning most genres with the exception of rap and hip-hop, so I was able to throw a wide variety of music at the 24/192. Via the SPDIF input, using the Sooloos and the BCD-1 as sources, the performance was par for the course in its price range. It has nothing special to give it any sonic advantages over its like priced competition. There was, however, a distinct improvement when I switched to the Bryston BDP-1. The sound was a lot cleaner, the tonality improved and there was a lot more air around and between the instruments.

The 24/192 excelled at reproducing string and percussion instruments. It was also good with voices, especially female vocals, which were delivered with a fair amount of emotion and palpability. What struck me was how quiet this DAC is. This allowed me to hear micro details without straining to do so.

The midrange reproduction, where most of the music resides, was quite detailed while still fairly smooth. The bass was a tad deeper and tighter than most of the DACs I’ve heard in this price range. Digital harshness was not very apparent and although, in my opinion in this mode, it is a long way from emulating a good turntable with a great cartridge, the 24/192 still delivers music with not too much listening fatigue.

Switching to the USB input was a real revelation. My first reaction was “Whoa”, could it be the same DAC?  The performance jumped significantly. Of all the DACs I have reviewed, this has got to be the one with the biggest chasm between the performance level of the SPDIF and the USB. What took me by surprise is that the whole sound stage opened up quite exponentially. The music was rendered in a much more effortless and relaxed fashion, reducing listener fatigue significantly. The sound stage was distinctly more holographic and voices were so much more palpable. Every instrument sounded more rounded, better defined and with a lot more focus. The bass was deeper, tighter and more tuneful, the highs were more liquid and the midrange was more full bodied. I could play my favorite tunes a lot louder before detecting any hint of compression.

It was then that I realized why Calyx refers to its SPDIF output as an “extra” input. The design goal of the 24/192 seems to have been to optimize the performance via the USB input. As I mentioned before, the performance gap between USB and SPDIF narrowed a bit when I switched SPDIF sources from the Sooloos and Bryston BCD-1 to a Bryston BDP-1 to feed the 24/192’s SPDIF input, but the USB performance still retained its edge.  Publisher’s note: Perhaps that’s why they did not implement more than one coaxial.

If you get into the technical aspects of asynchronous USB and SPDIF, you begin to understand why USB holds an advantage. When you send a digital signal via SPDIF, that signal consists of not just the sound data but also the bit clock, the master clock and the word clock data all transmitted along the same wire.  What this requires the SPDIF receiver to do is to separate all these different data streams and then convert the signal to I2S where the various signals travel separately before feeding the data to the digital to analog conversion circuitry. The increased complexity of this process, more often than not, results in increased jitter and deterioration in the ultimate sound quality that you hear.

Now compare this to an asynchronous USB implementation where an I2S signal is created, transmitted and sent to the DAC. This simplified system means that the only opportunity for jitter to be generated is the inherent jitter created by the oscillators themselves. This explains why, in many cases, if a DAC offers both asynchronous USB and SPDIF input options, the former usually outperforms the latter. 

Using the upgraded Calyx Linear Power Supply (CLPS) supply did make a subtle but easily perceptible difference to the performance of the 24/192. The sound became more fleshed out, the bass more tuneful and the noise floor was distinctly lower. There was also more ease in the way the music was rendered. Considering that the CLPS is less than $500, I felt that it is well worth the investment.

Inside the steel chassis of the CLPS, I found a well-designed EI (not toroidal) transformer. It also employed ten 470 uF capacitors that deliver better regulation. For those who believe in the superiority of better power cords, the CLPS has an IEC power input, which means you can knock yourself out trying your favorite power cords. I found that using the LessLoss Signature power cord instead of the one provided with the CLPS did result in a cleaner more open sound, especially in the treble region of the music.

Compared to other DACs in its price range, the 24/192 is par for the course via SPDIF, but it turns into a true outperformer via USB. Of all the DACs that I have reviewed, the 24/192 has got to be the DAC with the best USB performance in the $2,000 price category.

 

COMPARISONS

When compared to the Benchmark, the 24/192 had distinctively less glare and digititis. I could listen to the 24/192 for much longer without fatigue. When compared to the Neko, the 24/192 was more dynamic and served up more resolution, especially in the treble and bass regions.  However, when comparing SPDIF to SPDIF inputs, the Neko is definitely more analogue sounding. If you are an analogophile who is willing to trade resolution for a more relaxed presentation, the Neko is very likely to please you more than the 24/192.

In terms of features, the 24/192 is as minimalist as the Neko. The 24/192 offers just 2 inputs; a USB and a SPDIF co-axial. The Neko offers two SPDIF inputs, an RCA co-axial and an optical input. When comparing build quality and aesthetics, the 24/192 is way superior to both the Neko and the Benchmark. However when it comes to features, it is the Benchmark that rules the roost with substantially more connectivity, a volume control, a built-in pre amplifier, analog inputs and even a full function remote control.

Stereomojo has previously reviewed both the Benchmark and the Neko if you want to read up on them.

 

A SUPER CAYLX

D & A have a Calyx Super DAC in the pipeline with all the connectivity that you will ever need and with a jitter rate so low, it needs to be measured in femtoseconds rather than picoseconds as it has hitherto been done with high-end audio DACs. A picosecond is one trillionth of a second while a femtosecond is one quadrillionth of a second. To help you get a more real world understanding of these units of measure, let me put it in another way. The difference between a picosecond and a regular second is the difference between one regular second and 31,700 years.  As I finish this, I have just received the Calyx Super DAC and will be reviewing it soon. Be warned that it costs a lot more than this model – in the neighborhood of $7,000, so if that’s out of your wallet’s ball park, don’t wait for that reviewif you're in the market for a model in this price range.

As I mentioned before, one of the downsides of the Calyx 24/192 is that it offers just one SPDIF and one USB input. This is a big downside for audiophiles who have more than two digital sources. Also, although the better DACs have managed to squeeze an amazing amount of performance out of the USB 2.0 (which was not originally designed with high-end audio in mind), this interface has its speed limitations, which is motivating some manufacturers to look at better, faster interfaces like Thunderbolt (formerly known as Light Peak) and USB 3.0. There are whispers that some of the better brands are seriously considering replacing the USB input with something faster. On the other hand, some of the designers I have spoken to tell me that the speed offered by USB 2.0 is more than enough to obtain state-of-the-art performance and they did not feel the need to upgrade to a faster interface.

Intel is the company that developed Thunderbolt and they have managed to get Apple to throw their immense clout behind it. This technology was first designed, using fiber optics, to be a high-speed optical link. The problem with that design is that it would require gear that utilized it to have a new type connector, which would make it undesirable to most manufacturers. The design was therefore tweaked to work with the very ubiquitous copper cables and existing inputs that look like mini display port connectors.  Thunderbolt is designed to interface with monitors and external hard drives.

The attraction of Thunderbolt is that, in theory, it has the fastest interface, with a throughput of up to 10 GBps. Now that Apple has adopted Thunderbolt, there is a good chance that other manufacturers will do the same. To further encourage manufacturers to adopt this new interface, Intel is now building Thunderbolt into future motherboard chipsets. Intel has not committed to doing the same with USB 3.0 so if the current status quo is maintained, it will give Thunderbolt a distinct advantage over USB 3.0.

If you are in the camp that believes that performance can be enhanced significantly by using a faster interface than the USB 2.0, it would behoove you to think twice before spending mega bucks on USB 2.0 DACs without a facile and affordable upgrade path. A more prudent option would be to invest in a DAC that is modular and which offers you the option of switching out old technology cards with ones that offer the latest connectivity choices as and when they are introduced.

Schitt Audio has shown much foresight by being one of the first to take this route with their Bitfrost DAC offerings. The fact that they have priced it to compete with budget and entry level DACs is just icing on the cake. Hopefully, other DAC manufacturers will follow Schitt’s lead in this regard and offer modular based DACs of their own.  

 

You should seriously consider the 24/192 if you have most of your music on, and do most of your listening through, your computer or music server using a USB 2.0 interface. If you have more than 2 sources including an analog source (turntable or a tuner) and do not have or want a preamp, and convenience is of paramount importance, the Benchmark will probably be a better fit for you. But the sound will be sacrificed as well. We don’t recommend that you go that route.

On the other hand, if you have an aging CD player with only an optical output and a music server with only a SPDIF co-axial output and you love the sound of vinyl, then it would behoove you to consider the Neko (which we have reviewed) or read our other reviews of the Eastern Electric or other DACs for other opinions. Another outstanding DAC around $2,000 is the Lampizator Level 2 that James Darby is working on.

 

Associated equipment:

CD Player - Bryston BCD-1 (SS)

Digital Player – Bryston BDP-1 (SS)

Amp - Ars Sonum Filharmonia (Tube) Ayre V3 (SS)

Speaker Cables - Cardas Clear Beyond

Power Cords - LessLoss Signature

Single ended and balanced Interconnects - Cardas Clear and Transparent Reference MM2

Digital - Transparent Reference (digital co-axial), Analysis Plus (Toslink), Cardas (USB)

Stands and Racks

Black Diamond Racing (The Shelf for Sources and LM series) 

Black Diamond Racing cones 

Shelf placed on bed of pure silicone sand, equipment placed on the shelf via the cones

The gear being evaluated does not receive any of these tweaks or enhancements.

Reference DACs - Neko Audio D-100 Mk2 / Benchmark DAC1 HDR

Power Conditioner -  Isotek Sigma II

Music server - Sooloos 5 complete 3-piece system, iMac (latest) with Amarra 2.3 and Decibel media players 

Software - Audiophile CDs from Cheskys, Dorian, MFSL and Sheffield Lab

Hi-res tracks downloaded from Linn and HD Tracks. MFSL LPs

Listening room – 90% underground, 18’ X 27’ X 8’ with extensive room treatments and solid concrete walls (with drywall over Roxul Safe & Sound) and concrete floor (Berber carpet).

 

 

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