⌈ DiDiT is a company from the Netherlands (until recently - Holland), offering only two products: the DAC212SEII digital-to-analog converter and the AMP212 power amplifier. The most important product for them is the DAC. It features a volume control, a balanced headphone amplifier and will soon receive another important functionality - the ability to play files from NAS drives. We test this device as the second magazine in the world. ⌋

he DAC market is the fastest growing audio sector. I'm sure that Cambridge Audio engineers, when introducing the world's first two-box Compact Disc player in 1985, with a separate transport and digital-to-analog converter, model CD1, had no idea what they had just started.

The first D/A | Three years later, two other British companies, quite independently of each other, presented free-standing "dacs" - these were: Musical Fidelity with the Digilog model and Arcam with a device called the Black Box. Both devices were conceived as an "add-on" to a system, that was supposed to improve the sound quality of older CD players. The link that was then chosen to send the digital signal was S/PDIF (Sony/Philips Digital Interface), a transmission protocol proposed by Sony and Philips (the letters' S 'and' P 'in the name).

Much has changed since then, and the renaissance of these devices probably surprised everyone. Although, if one had a good look at the changes in the audio market, this could have been predicted, as well as the supremacy of headphones. The causative factor was the development of computer audio. For a long time, the only sources of the audio signal from files were personal computers. To improve the sound quality, you had to bypass the internal sound card and output the signal via the USB (Universal Serial Bus) link.

Contemporary D/A | Since USB was originally intended for completely different tasks, its adaptation to the audio needs required a lot of effort. First of all, one had to think about how to re-clock signal at the receiver side to minimize digital distortion called jitter. This is how asynchronous USB receivers were created, which clocked the signal again, without connection with the USB signal clocking. One could send PCM signal up to 24/96 in this way.

To go even further, up to 192 kHz, and also to send DSD signal from a PC, it needed special – AISO (Audio Stream Input/Output) driver. This way the contemporary D/A Converters were born, often referred to as USB DACs, because USB port is their main input.

| DAC212SEII

In this way, we reach the subject of this test, the DAC212SEII from the Dutch company DiDiT. Established in 2007, it started operations with one product, a DAC212RCA model with an integrated headphone amplifier. Some time later its successor, the DAC212SE model, was launched, and its latest version DAC212SEII at the beginning of this year .

Maybe you should have started with a brief description of the device being tested, but I wanted you to have an idea about the company we are talking about. This is important because it is one of those manufacturers - next to, for example, Mytek - who have specialized in digital signal processing. Its offer includes only one DAC model, as well as a stylistically matching, technologically related, AMP212 power amplifier.

RIENTS STEENBECK
Co-founder | engineer

WOJCIECH PACUŁA: Tell me a little about yourself…
RIENTS STEENBECK: DiDiT is not so much about me but more about the partners. Those guys are just amazing at what they do and what they can accomplish. DiDiT consists of 4 more partners beside me. Roy van der Hulst, is an industrial designer, Patrick Schoon, is an electronic engineer, Sebastiaan de Vries is an audio designer and Harry van der Berg the software developer. All of us have our own history and background either in audio or other related fields, but it would take too long to elaborate on that, we all share a very holistic approach to audio and design.

WP: How did DiDiT start and why?
RS: DiDiT started more or less by coincident. Through one common factor, parts supplier who happened to be me at that moment, all of the partners met and became acquainted. As it goes in audio and with aqcuintenses we started to talk, soon it became apparent that beside our shared passion for music we shared the same philosophy about audio equipment design.

In our view equipment should be designed correctly from the ground up and both the electronics as well as aesthetics taking the user and their partners in to account. Sebastiaan de Vries who previously ran an audio modification service, noticed that in many even very expensive and audiophile equipment there are many minor but also major design flaws with room for improvement.

Patrick Schoon as electronic engineer who worked on many pro-audio devices and in the recording studios has the ability to make everything work in terms of computer logic and internal communications. Roy van der Hulst as designer and long time music lover believes that any device should not just be functional but also a joy to use and to look at.

So all in all we had the right ingredients to develop the ideal device. After starting to work initially on an all-in-one device in 2007, we had to abandon this project because in 2007/2008 the audio playback software was not suitable in terms of user interface to match our demands. So instead of this we moved to a DA converter with exquisite properties. Our first attempt was the DAC212 with RCA output. Although this device was very good, it somehow missed the power and authority we would have liked it to have.

Beside that customers were requesting balanced outputs. Although the DAC212 was fully balanced from input to output it had RCA connectors. Instead of just exchanging the RCA connectors for XLR with minor design modifications, we opted for the more elaborate solution. Which was to balance the entire output section, making it double balanced, and adding additional buffers before and after the output stage.

The result was the DAC212SE, which really stood it's ground in terms of performance. Independent listening panels concluded that it easily outperformed DA converters costing double the price.

Now with streaming audio becoming more and more popular we have come to the next iteration of the DAC212SE, namely the DAC212SEII. For the DAC212SEII we added an additional headphone connector, so balanced headphones can be used or 2 conventional stereo headphones. We added a LAN connector and the DAC212SEII will be fully supported by Roon, DLNA and UPnP. We only had to sacrifice one coaxial input. And the DAC chip was updated to the latest standards.

WP: What is unique about DiDiT?
RS: At DiDiT we don't follow the main stream opinions but we have our own ideas, philosophy and are pretty stubborn in these, in a healthy way common sense way. For example, many audiophiles detest switched mode power supplies and believe in that linear power supplies are far superiors. They just love the brands that use enormous transformers and huge buffer capacitors. Indeed that looks good, it looks powerful and impressive. We on the other hand use small switched mode power supplies with many local power regulators and ample (smaller) buffer capacitors, which reacts much faster when a lot of power is demanded.

This does not look impressive, it does not look very „powerful” but it outperforms, when applied correctly, the linear power supplies by far in terms of musicality. Another example, many brands use the very good and clearly recognizable red WIMA capacitors. Indeed they are very good and suitable for certain applications, we on the other hand decided for a SMD variant which in our application sounds and performs better, although not clearly visible nor recognizable.

As mentioned before we look at the entire design, each and every aspect is taken into consideration. And of course all brands claim to do this, but we actually pretty much really do this. Our PCB design is unique in this price range, we use 6-layer PCB (not that uncommon) but all PCB traces are designed as to minimize any electro-magnetic interference from either other PCB traces, components or the outside.

Even our choice of components is in part based on reducing the EMI, like the a fore mentioned capacitor. This combined with our very clean power supply results in a very pure audio signal. Our products simply do not add anything in terms of sound, they let you listen to the recordings in the way the sound engineer intended it to be. It may take some time to get used to it, as many are used to their own particular sound.

WP: What's your opinion, is there a limit of sampling frequency for hi-res files? At which point does it stop making sense?
RS: Hi-Res is very nice and our present infra structure allows for ever increasing sample rates. However as it is with our device, one should not merely focus on the sample rate but on the entire chain of recording. We have some old CD's recorded in 44.1kHz which just sound fantastic because of the attention to detail during the recording, from the placing of microphones to the final mastering.

It seems nowadays that many of us focus on one thing, be it the sample rate or  in equipment which DAC chip used to just name big one thing. However it is the entire process or design that determines the resultant performance.

One reviewer (it's about Dick Olsher from „The Absolute Sound” – ed.) who is really in to R2R DA conversion and has an aversion against standard delta sigma DAC chips decided to use our DAC as his reference DAC. Contrary to what he expected our DAC simply outperformed his own R2R DAC. This is not because our DAC chip is superior, or that R2R is inferior but because it is the entire design that determines the performance. The same with hi res recordings!

WP: What do you think about DSD?
RS: It would be great if recording studios would record in hi-res, starting from 192kHz minimum to 384kHz to DSD. In our opinion this initial hi resolution recording is the most important step. At a later stage PCM can be converted to DSD. But it all starts at the recording and the resolution during the recording.

WP: What are your future plans?
RS: We are working on an all-in-one device which encompasses much of the technology used in both our DAC212SEII and AMP212. By the way the company name is DiDiT and not DiDit like many call us sometimes. DiDiT stands for Different in Design Different in Technology. Our logo is a styled version of the mathematical delta sign which is used in calculations. This sign delta sign means difference. We at DiDiT think we make a difference audio and design. ♦

⁜

The looks | The DAC212SEII is a small device, but extremely nice looking and professionally made. Its chassis was milled out of aluminum and placed on three feet made of stainless steel and sorbotane; the feet have been calculated so as to minimize vibrations of the device of this particular weight. The housing measures 212 x 212 mm and that's where - as I assume - the name of the device came from.

The front is optically divided into three parts - it is a solution that in audio is found surprisingly often. In the middle there is a very large, legible display based on a dot-matrix LED matrix, hidden under a grid. I have seen such solutions before - for example in the Oxygene amplifier from the Roksan company and the Mytek Manhattan D/A converter - and I like them very much. When the power is turned off, the backlight disappears and only the intriguing holes remain, so there is no "TV off" effect. Below there is a standby switch with a red border, and on the right a double headphone output.

I mentioned Mytek not by accident, because - as I see it - both companies share a similar product philosophy. It is to be based on engineering and listening sessions (in this order) and is to be the result of own studies. Mytek's form resulted from its studio applications (1U height, half the rack width), and DiDiT, although ostentatiously "home-use", repeats it to some extent, at least in terms of dimensions. From Linn, on the other hand, it has taken an overhead cover that shields the sockets and protects them from breaking out. The downside of this solution is not much space for a power cable - no IEC plug from the top shelf will fit there.

Functionality | If you look at the header of this test, you will see that I assigned the tested DAC212SEII device to two categories, although I try to avoid it. Normally I would write that this is an audio player, because that's what I called Mytek Brooklyn Bridge. This is because the DiDiT in the SEII version is prepared to "unpack" audio files sent via an Ethernet cable. It works with NAS drives as standard DLNA (Digital Living Network Alliance) - i.e. via a router in your home network. It is also a so-called "End-point" for the ROON system.

At the time of writing, the final production version of the DAC was not yet available. The manufacturer has sent us a prototype - although almost fully functional - version in which the Ethernet input was inactive. Why? Already cited Rients Steenbeck, one of the co-founders of DiDiT, explains it this way:

DAC212SEII now uses the new version of the software known from DAC212SE. We are currently working on new software, prepared especially for the new DAC212SEII, with all advanced settings allowed by the system. At the moment you can use the settings for DAC212SE, this is just a "guide", and the final software will have (slightly) different and more advanced settings when it comes to filters and volume control.

DAC212SEII can stream data from NAS etc. However, due to the Roon certificate, we had to (for now) turn off the entire LAN section. Roon EndPoint software is installed on the microprocessor board, and the only way to completely disable the Roon non-certified software was to disable the entire board. It also means that DLNA and UPnP had to be turned off for this demonstration copy. As soon as we get the certificate, we will be able to activate this PCB.

That is why I added the second part: a digital-to-analog converter. That's what it is at the moment and I would like to focus on that. This is a DAC with five digital inputs: AES/EBU (XLR; PCM 24/192), S/PDIF (RCA and Toslink; PCM 24/192), USB (PCM 24/384, DSD DSD512) and I2S (HDMI). The latter is used to connect external file transports (PS Audio) or CD (NuForce). Although this cannot be seen, the signal can also be sent wirelessly using the Bluetooth aptX HD link.

The basis of this DAC is the ESS Sabre32 ES9038PRO system configured with four DACs per channel. It works with a digital filter written, if I understand it correctly, by DiDiT engineers. In the menu one can choose the type and filter parameters and whether an oversampling is active; there is also quite a unique feature - the user can also enable the dither.

The device has an adjustable output voltage and was designed so that it can work directly with the power amplifier. The adjustment takes place in the digital domain, but Rients says that compared to the analog volume control, the resolution losses are not large, and in addition there is less noise introduced by the analog attenuator. After the DAC section there is a buffer working in class A, than an analogue gain stage and again a buffer in class A. Rient says that after applying the buffers they noticed a significant improvement in terms of sound's authority. This increased the costs of implementation and more heat has to dissipated, but - he says – it paid off.

The device offers a significant output (4000 mW) and sends the signal to both analog outputs - only XLR ones (we can choose their gain: 0 or +6 dB) or headphone outputs. From what I understand, there is no separate headphone amplifier here, because the headphones are driven by the output circuit of the device. This is a lot of power and DiDiT engineers believe that it is enough to drive any amplifier and any headphones. Compared to the SE version, the change is that the headphone output is balanced, based on two 6.3 mm jack sockets. The whole circuit is DC coupled, that means there are no capacitors in the signal's path.

| HOW WE LISTENED TO IT

Because the streamer (audio file player) section was not yet active at the time of the test, I had a simplified case - I treated the DAC212SEII as a classic digital-to-analog converter. The device stood next to the Mytek Brooklyn Bridge file player and was compared to both this device and the Ayon Audio CD-35 HF Edition CD player (№ 1/50 ). The source of the digital signal was the CD transport section in the player (RCA input), as well as the HP Pavilion dv7 laptop with Windows 10 Pro and JPLAY Femto (USB).

Because it features an adjustable analog output, I listened to it in two configurations. In the first one, its output was connected directly to the Soulution 710 power amplifier, via balanced Acoustic Revive Triple-C FM cables. In the second variant, the signal ran additionally through the Ayon Audio Spheris III preamplifier, using the same XLR cables. I devoted a separate listening session to assessing its headphone output. I used the dynamic headphones Sennheiser HD800 and planar HiFiMAN HE-1000 v2.

With an external preamplifier | It will be a short part because there is not much to talk about. The Ayon Audio Spheris III I use, a preamplifier costing about PLN 130,000, with a power cable for PLN 25,000 and an interconnect for PLN 40,000, is one of the best products of this type I know. Maybe not absolutely the best, but it belongs among the top ones.

In the system with the tested converter, however, it proved to be an obstacle, a hindrance. It seems that the DAC212SEII was designed to operate directly with the power amplifier. It could have been achieved either by calculation or by listening sessions. Its sound was tuned when combined with a power amplifier. Although Ayon brought mass, saturation and scale to the sound, it also reduced the resolution, aggravated the differentiation and flattened the dynamics.

It is not his fault, but simply the cumulative effect of many choices made by DAC designers. Although we do not get everything that a high-class, external preamplifier brings, we will benefit from other advantages in return. However, for music lovers this is good news - it will allow you to focus on the other components for your system and spend more money on it.

Without an external preamplifier | So I devoted all the available time to listening to the DiDiT DAC in a system in which it drove the powerful power amplifier Soulution 710, inside which 40 such DACs could fit... It was no accident that I mentioned spending money on other components of the system. This is because the DAC212SEII is excellent. This is a rare case where the device looks much cheaper than it is, and sounds much better than its price would suggest.

The Dutch DAC is amazingly resolving. This is a feature that hit me while listening through the headphones, but which manifested itself with full power when I listened to the music through the speakers. Surprised by its sound, at first I listened to over a dozen Master CD-Rs burned for me in various recording studios, because I wanted to be sure that I actually heard what I thought I did. It seemed I was right. Differentiation, resolution and amazingly mannerly presentation - it was true for each CD I listened to.

And so it was with Go Right by Andrzej Kurylewicz Quintet and Polish Jazz Quartet, or some of the most important Polish jazz recordings. The tested DAC showed perfectly the differences in the recording venues, in the tone, in the imaging and phrasing of the saxophone by Jan Ptaszyn Wróblewski and the trumpet with a silencer by Andrzej Kurylewicz. They were shown by the recording producer almost together, but they are different instruments. This is not always so clear-cut, as with the DAC212SEII.

Spatial differentiation also helps in tonal differentiation. The DiDiT shows incredibly, simply shockingly natural imaging. Maybe not entirely within the bodies, which are not very large and have no tangible, three-dimensional textures, but within the sound stage itself. We get the sound shifted towards the depth of the stage, further than with the DAC section in Mytek and the analog output of the Ayon player. There is a large, very natural space where a lot is happening. There is also the foreground, just behind the line connecting the speakers, there is also everything behind it. There is no division here into "better" plans and "worse" ones, it is a beautiful, coherent whole.

So, there is a highly resolving, differentiating sound with outstanding spatiality. But there is something else that binds it into a beautiful whole: it is the effortlessness of the sound. You see, with this "dac" you can listen to music in absolute comfort. And yet it is an open sound with a strong, reliable treble. To some extent, this sound is a reverse of what I have with Ayon as a source and with an external preamplifier. Let me explain.

One of the features of the tested DAC is the open sound. The cymbals are strong, carrying, expressive, just like the upper parts of the trumpet, violin, etc. This usually ends in failure and sharpening of the sound. But not here. The Dutch DAC plays with an incredibly cultural sound and it has never, in my system had a sharp or even underlined treble. While the sound of the CD-35 HF Edition player goes in the direction of the sound of an analogue tape recorder, the sound of Mytek is an example of excellent decoding of hi-res PCM files, then I would compare the sound of the tested device to the sound of DSD files.

Especially from this point of view, I listened to a lot of discs that are valued for the music they contain, but also are appreciated by audiophiles, although most of them don't even know what they appreciate. A good example of what I am talking about are: Café Blue by Patricia Barber (I have it in Gold HDCD version) and Mark Hollis by Mark Hollis. Both valued for the incredible space and natural sound are known from the 1/2" analog master.

But hardly anyone knows that they were really recorded on a Mitsubishi X-850 digital multi-track tape recorder, i.e. a 16-bit machine, with a sampling frequency of 48 kHz. Barber directly this way, and Hollis secondarily - a stereo track was recorded in analogue, but later was uploaded to Mitsubishi and mixed with additional instruments sampled from it.

In any case, the point is that these are 16/44.1 digital projects, although made using a top reel digital tape recorder and mixed in analogue domain. But with the DAC212SEII it sounded as it should, as I would expect from really expensive digital systems - in an open, rich with treble manner, but also cultural, orderly, I would say - "well-kept".

As I mentioned, it is a completely different sound than from my CD player. But - and I say it with full awareness - extremely interesting and engaging. Its otherness lies in a stronger treble and a lighter, not so full bass. Listen to it with a good transport and it turns out that its character does not bother at all, there is so much information there. Its sound will never be too light, even with discs like the Secret Messages by Electric Light Orchestra - and this is a disc recorded digitally on a Sony DASH reel-to-reel tape recorder, i.e. in times when sound engineers and producers knew very little about the digital recording.

| SUMMARY

The sound of the DiDiT DAC212SEII converter consists of many elements that usually do not appear together, because they are mutually exclusive. This creates a unique whole. This sound is incredibly resolving and differentiating, and at the same time one that is not overly detailed. The space offered by this device is insane, with our attention directed to the depth of the stage, not in front of it. The information from the foreground is therefore not tangible – resolving and with great dynamics - yes, but not "here and now".

This is a DAC not only for lovers of hi-res files, although it sounded great with them, but also for those who want to know what is there encoded on Compact Discs. Let's combine it with some nice CD transport - for example from CEC - and we will get a high-end sound source with a very, very good headphone amplifier which repeats all those features that I heard on the XLR output. While it will be difficult to prove that it is a DAC "without its own character", proving that its price is not excessive at all is piece of cake.

The chassis of the device is made of two main parts: a massive one, a shell milled from an aluminum block, and an equally rigid bottom which the electronics board is screwed to. The bottom also serves as a heat sink - the amplification circuits are pressed against it, and output buffer working in class A. The main part, i.e. the silver one, has been finished by sandblasting, and the bottom one is black. It has three feet screwed to the bottom - two at the front and one at the back - made of stainless steel and sorbotane.

The upper part of the housing has protruding fragments that divide the interior into three main parts: power supply, digital and analogue section. The power supply fits in a small metal casing that minimizes high frequency noise generated by a switched-mode power supply. Adjacent to it one finds many capacitors and chokes that additionally filter voltages. On the back, under the "overhang" of the housing's cover, there are all the sockets. This is not a very convenient solution, which forces the use of flat IEC plugs - unfortunately I do not know any good ones…

Digital section | In the middle of the board you will find digital circuits. They were divided into two parts: input circuits and DAC with digital filters and a clock, and a small board, plug-in from above, with the inscription "Streaming Audio Board". At the bottom there is a microchip controlling the device, and on the back an eight-channel D/A system ESS Sabre32 ES9038PRO, configured so that there are four DACs for each channel, which significantly minimizes noise. Next to it there is a precise Crystek Femto clock. I say "there is", but you can't really see these elements - they were hidden under a polished copper screen.

From the top, through the multipins, a plate with a streaming circuit (file player) is attached. It's Raspberry Pi Compute Module 3 microcomputer that we know of, for example, applications such as the Acuhorn R2R player. This is where the signal from the USB input goes.

Analogue stage | On the right (looking from the front) there is an analog section. It is a balanced design (power supply is also symmetrical), and the channels are separated from each other by a screen that is part of the housing. The input features OPA1612A IT integrated circuits, followed by four large chips (two per channel), which - if I understand correctly - amplify the signal. OPA1612A are high-end integrated circuits from the SoundPlus series with bipolar input. They are often used in high-end microphone preamplifiers. The output features, in turn, TL082Q chips - these features a JFET input.

Axiom relays are placed in the middle next to the outputs, with self-cleaning contacts, and all inputs and outputs - except the AES/EBU - are gold-plated. The RCA input looks best. Almost all components were surface soldered, and the board has six layers and was designed to minimize interference. It's a well-designed device.

Remote | The remote control is a nice complement to this device. It has the form of a cylinder, it is made of aluminum and has soft buttons on one side. The only problem may be the placement of a receiver in the DAC - which is between the headphone sockets. If you use the balanced output you will have to aim precisely to adjust the volume. ■

Technical specifications (according to manufacturer)

Supported sampling frequencies:
• PCM: 44.1, 48, 88.2, 96, 176.4, 192 (AES/EBU, RCA, Toslink, HDMI), 352.8, 384 kHz (USB)
• DSD: 2.8, 5.6, 11.2, 22.4 MHz
Word length:
• PCM: 16, 24, 32 bits
• DSD: 1 bit
• Transmission standards: 1000BASE-T/100BASE-TX/10BASE-T
• Connector: RJ45
• USB: USB 2.0 x 1
• Network protocols: UPnP, DLNA + ROON EndPoint
• Dimensions (W x H x D): 212 x 212 x 43 mm
• Weight: 1.2 kg