ATOLL ST200 Signature Streamer / DAC / Preamplifier Review
There aren't many devices like the ATOLL ST200 Signature. It's a streamer, a DAC, and a full-blooded preamplifier in one case. And while trends dictate that DACs / streamers be incorporated with one kind of volume control or another, it is clear that they rarely represent a real preamplifier solution and volume control takes place most often in the digital domain, mainly by reducing resolution. Few have built-in analog volume control systems, and even rarer devices like the ATOLL Electronique ST200 Signature, have a built-in and right preamplifier.
Add to this the volume control performed by a resistor network, which is a more precise solution than a conventional potentiometer, and it will become clear to you that the ATOLL ST200 Signature is a well-designed and elaborate device. And this design and elaboration continue with a look at other applied solutions, which you will not find in the vast majority of other similar and less similar devices.
So let's start with the power supply: it is solved with two separate transformers, for analog and digital signals, with a power of 30 VA and 10 VA, while filtration is done by electrolytic capacitors with a total capacity of 27,000 μF. The selection of the D/A chip is also interesting. In ATOLL, they decided to use burr-brown PCM1792, a chip that processes input signals with resolutions PCM up to 24-bits / 192kHz and DSD64 and DSD128.
DAC output and preamplifier are made in discrete technique, discrete transistors, and no feedback, tuned for operation in Class A, with ESA series output Clarity Cap audio MKP capacitors. For a price of €2000 – impressive. With an output impedance of 22 Ohms and an output voltage of maximum RMS 2.6V, the ATOLL ST200 Signature will launch the largest number of output amplifiers on the market.
We have already mentioned several times that the ST200 Signature and preamplifier, which, in addition to four digital inputs (two S/PDIF coaxial and two TosLink optical plus Bluetooth, one network RJ45 Ethernet and two USB-A inputs), is evidenced by two analog line inputs. All that's missing is a turntable preamplifier so the ST200 Signature can fulfill any wish. To connect to the rest of the audio system, the ST200 Signature also has one stereo analog output and two digital outputs – S/PDIF coaxial and TosLink optical.
As the most important purpose of this device is the streaming (streaming) of audio content, in functional and technical terms, special attention has been paid to these tasks and ST200 Signature represents an intelligent and comprehensive solution, which is not only interestingly conceived but also excellently executed.
Although it has a large and readable color TFT display (5" with a resolution of 800 x 480), the device comes with an excellent remote control, which, coupled with large and well-readable text on the screen, allows easy and easy control of functions and content without using the application. If only other manufacturers would resort to such a solution because the remote control is easier, faster, and simpler than an application for many. Speaking of apps, it's great. It is a self-developed ATOLL Signature app (for Android and iOS) that can control music content and device functions.
Integration with music services Deezer, Tidal, Spotify, Qobuz, Hi-Res Audio is enabled, but even better, Tidal Connect and Spotify Connect are also built in, for direct streaming from native applications. Of course the ATOLL ST200 Signature DAC/Streamer supports both DLNA and UPnP protocols, and for Roon fans, know that the device is both Roon Ready and performs this function flawlessly. With Roon, we mostly used the ATOLL ST200 Signature. In addition to the above, playback is also possible via Bluetooth.
If you have your music on a local server or on a hard drive (which you connect to one of the two USB ports), you can easily control the stored music, create local playlists, etc. Of course, it is possible to listen to numerous internet radio stations, which the ST200 Signature is fully adapted to – 100,000 internet radio stations are available through the menu within the application. While this unit is compatible with the recent proprietary lossy MQA specification (which is in receivership / bankruptcy as of this writing), we need to remember that MQA may very soon go the way of mp3PRO, HDCD, and other defunct / now unsupported non-standard digital formats.
Few more words about the screen – it's big, clear, readable from a distance of three meters and it's a pleasure to use it in conjunction with the remote. The physical dimensions of the device are common for this class and type of device and are 440 x 284 x 95 mm, with a mass of 6 kgs.
A comparison with the much cheaper and very popular and ubiquitous DAC, SMSL's SU9 (connected directly to the output amplifier, with SMSL's digital volume control) reveals that the ST200 Signature demonstrates a deeper but not particularly wider space (they are probably similar in size), while the overall picture of ATOLL is painted with more color and a few details more. The SMSL SU9 undoubtedly shows that it is a great device that throws further than it should, but it is also clear that a more expensive device brings more sound.
Thus, with ATOLL, the cymbals sound clearer and more natural, sparkler and with less roughness, although in terms of explosiveness and dynamics the SU9 somewhat surpasses the ST200. A similar power-quality ratio between these devices has been maintained regardless of the recording quality or genre of music, so it is clear that in terms of sound, ATOLL will always provide more diverse and playful reproduction, with a more clearly expressed color of each instrument.
SMSL SU9 in terms of naturalness and accuracy cannot match ATOLL, although we could live long and happily with any of these devices. Compared to the standalone SU9 sound image at ATOLLo is more withdrawn and calmer, which in turn will not appeal to everyone, because the SU9 sounds a little firmer and more compact, and the ST200 more fluttering and relaxed, with more air and weight around the instruments in the lower registers and something more natural. In short, SMSL keeps you alert and concentrated, the ATOLL ST200 Signature is more relaxed, with less worry about details and dynamics compared to the SU9. We can say it another way: the sound of the SU9 is more immediate, the sound image is closer to the speaker line and more explosive. The ATOLL, however, seems more natural, relaxed, adult and mature.
Overall, SMSL sounds more raw though, and the ATOLL ST200 Signature has a greater depth, a slightly darker background, more pronounced embossing of the sound image, and a more natural sound. The differences are not too great, but significant, especially if it is about the parameters that are important to you. Don't forget that with ATOLL, we still have to put an excellent server, support for music services, a very good preamplifier and two analog inputs into the equation. Therefore, the ST200 Signature is a more complete and comprehensive, versatile device.
For first impressions of the quality of ATOLL as a preamplifier, we continued with the same combination, connecting analog outputs from SU9 to the ATOLLa line input. As a preamplifier, the ST200 Signature proved to be a great device that does not change character from the one we experienced listening to it as a unique device. We are pleased to find that ATOLL helped SMSL to breathe further and now the small Chinese DAC has shown even more sparkle and dynamism, so we can conclude that the main character of ATOLL derives from its digital-analog section.
So, ATOLL as a preamplifier works great, transparency is undoubted, because SMSL SU9 connected via ATOLL did not show a lack of detail and definition in relation to the direct connection with the output amplifier. On the contrary, in the segments in which it was directly connected in the XA25 showed flaws, now everything fell into place because ATOLL made life easier and more bearable for SMSL and it sounded cleaner and more flowing. Somehow it seems that the ST200 Signature allowed the SU9 to show even greater ranges in definition, extension, and listening.
Only in comparison with the home reference (DIY NOS DAC with AD1865 and tube output) it turned out that ATOLL lacked only a little color, while we expected a somewhat deeper and more luxurious sound image. In the context of the comparison, let's mention that the resident DAC easily matches commercial devices much more expensive than ATOLL, so things sit in the right place, because higher-class devices offer the naturalness and openness of the midrange area and the authenticity and naturalness of the bass.
However, the same is hard to notice when listening to the ST200 Signature on your own. It is a good test of stringed instruments by which bow strokes can collapse the entire system if they are not natural and authentic enough (e.g. Fortaleza, from the album Méditerranées by Renauda Garcia-Fonsa) and turn into their opposites and can sound irritating. Fortunately, ATOLL passed this test with a very good one, because it showed a satisfactory level of naturalness and only slightly less air around the instrument.
We compared the capabilities of the ATOLL as a preamplifier with the Schiit Freya Plus preamplifier in tube mode and convinced ourselves that the ATOLL as a preamplifier is a more transparent, life-like, solid, and musical device. Compared to the ST200 Signature Freya Plus sounds like it drives with the brakes on and failed to fully free itself in the home system, while in buffer mode Freya Plus could stand alongside ATOLL in terms of transparency and persuasiveness.
We compared the ATOLL ST200 Signature with one of the most famous DACs in the class of up to 2,000 € in recent times – Denafrips' Pontus II. We connected Pontus II to the analog inputs of the ATOLL. As a digital source, we used the built-in ATOLL streamer. Both devices also shared ATOLL's analog output. Given the architecture and R2R structure of Pontus, it is perhaps not surprising how easily we discerned that the ATOLL offers a hint of more energy in the global sense, but also on the micro level, which means that almost every tone is played more energetically and sharply, with a more striking loud-silent relationship.
Pontus is in all situations calmer and a little softer sounding device, sometimes perhaps with less energy, which is its characteristic that it expressed in all constellations and environments in which it found itself. I'm not sure if we can attribute all these characteristics to the R2R structure and NOS mode, because the home DAC is packed with energy and explosiveness. True, Pontus II sounds calmer and a little refining in relation to ATOLL, with a slightly darker background and on the corresponding musical materials more delicate (see e.g. Visita Boa, Yamandu Costa).
The space at Pontus is more layered, but some instruments are slightly watered down and with less relative density. However, in the complex passages, Pontus II is held more organized. Overall, ATOLL may just be a little less natural, but I wouldn't be willing to bet on that, because it sounds faster, with sharper individual tones outlined more clearly, just like in real life. There are no winners here, these DACs are different enough to target diametrically different audiences.