Chord Hugo TT2

Some time after the DAVE test, here we are again dealing with a product by Chord, a company that has always fascinated me for its original approach to the subject of Digital/Analog conversion, for which it avails itself of the collaboration of the celebrated external consultant Dr. Robert Watts, who for years has been developing a personal line of research that, judging by the results, has proved to be very fruitful. It is the Chord Hugo TT2 and, just to put it in context, I will say that it is the domestic version – TT stands in fact for Table Top – of the Hugo 2, the British company’s highly successful portable DAC/Player.

Chord Hugo TT2: framing.

The Hugo – in both its first and second versions – was born as a portable device and is therefore characterized by its particularly small size; this has not deterred legions of audiophiles around the world – including yours truly – from putting it in their home system. Paradoxically, the minimal dimensions and the negligible weight make the operation particularly inconvenient, with poor Hugo going hither and thither dragged by the rigid signal cables; moreover, the presence of the only Micro USB port present on that model is indeed not very digestible, at least for yours truly. In short, a number of reasons that triggered the demand from the audiophile community for a desktop product that led to the birth of the Hugo TT first series. For the second and revamped version, featured in today’s test, they at Chord decided to raise the bar quite a bit. The Chord Hugo TT2 is not a Hugo 2 put in a larger cabinet. It is certainly that, but it is also one of the more advanced implementations of R. Watts’ theories, which, in the meantime, had crystallized into a two other products: the DAC/preamp/headphone amplifier flagship, called DAVE(Digital Audio Veritas in Extremis) and the CD player with upscaler called BLU MK.2. For those who would like to learn more about the technique used by Watts I refer to the In-depth article, by M. Richard, published in Audio-2G. Here I will just mention that Chord is among that small group of manufacturers who do not make use of standard D/A conversion chipsets found on the market, such as ESS, AKM, etc., making use instead of a sophisticated system designed by R.Watts and implemented on an FPGA (Field Programmable Gate Array); in this specific case it is an Artix 7 from Xilinx with 86 cores working in parallel at 208 MHz, which uses complex digital filtering schemes and, having a large number of TAPs, is able to incorporate WTA filter algorithms (Watts Transient Aligned) owners of Watts.

WTA

What does high TAP number mean and what do the WTA algorithms do? In a seminar a few years ago at the Monaco High End, which I was fortunate enough to attend, Watts explained that even 44.1 kHz audio files, provided they were processed through a digital filter of nearly infinite TAP length, could produce analog waveforms just as accurate and complete as those produced by a high-resolution audio file, albeit with a higher noise floor. But what are these TAPs? Wanting to simplify as much as possible, we could say that they are basic elements of calculation (multiplication by a coefficient, delay and sum) and that a possible indicator of the quality of a FIR(Finite Impulse Response) filter is expressed by the number of TAPs, which, roughly speaking, expresses an indication of the amount of memory required to implement the filter, but above all of the frequency resolution that the filtering can implement. In fact, with the range 20-22,050 Hz remaining constant, as the number of computational “bricks” increases, the minimum frequency separation between one intervention and the next drops. The most popular commercial chipsets have reconstruction filters with rather limited TAP lengths, with 256 TAPs as one of the highest values and an average being around 100 TAPs. According to Watts, the cause of the synchronization errors on transients, which are also well audible, would be attributable to the low TAP value and consequently to the ineffective filtering algorithm employed. Watts’ early experiments with switching from 256 to 2048 TAP produced great improvements with greater focus, detail, smoothness, and a deep and accurate sound stage. The implicit conclusion in this reasoning is that the ideal solution would be an infinite TAP length! Or at least not less than the temporal resolution dictated by our senses. Current Chord DACs use filters that offer tens of thousands of TAPs or more (the DAVE, for example, has a filter with about 164,000 TAPs). Each time new, higher-performance FPGAs become available, Chord Electronics products increase the number of filters, and this, Watts says, implies that the WTA algorithm must be revised to take advantage of this additional processing power. Corresponding to this is an improvement in the sonic performance of the products. The “more TAPs per filter = better sound” equation has been the basis of Chord DAC designs for some time now and has been successfully implemented in transitions by Hugo, Hugo TT, DAVE, Hugo 2 and now in the new Chord Hugo TT2, featured in this test, which comes in at an impressive 98.304 TAPs per filter, a value, however, quite a bit lower than that of the DAVE DAC, which comes in at 164,000 TAPs, and a far cry from the staggering 1,015,808 to which the Hugo TT2’s potential “workmate,” that M Scaler of which we wrote about in the DAVE test.

Hugo TT2: description

If you observe the Chord’s website you will easily realize how each product features an atypical and very sophisticated design. In the interview you can find on the Audio-2G YouTube channel, company owner Mr. Franks, explained to us that he personally takes care of it. The Hugo TT2 also does not escape this rule and therefore presents itself in a very personal and elegant aesthetic appearance, enhanced by the high level of construction of the metal surfaces made of billet aluminum, which contribute to the reassuring weight of 2.53 kg. The object is nearly square in plan and rather low (5.2 x 23.5 x 23.8 cm (AxLxD) and, in keeping with Chord tradition, provides for the presence of two distinctive aesthetic elements: the large porthole located on the top panel that gives visibility to LEDs placed on the mainboard that change color to indicate the sample rate (or DSD) of the file being played, and the large plastic sphere for the volume control, which colors to show the gain with a color palette ranging from red to green and then from blue to purple, and finally to white (max). On the left side we find a glossy black acrylic portion that hides the antenna for Bluetooth connection with aptX CODEC, for streaming from cell phones or other Smart device such as tablets and portable players. Immediately below we find the small dot-matrix display that allows us to read the current set values and get feedback regarding navigation through the items in a settings menu that can be implemented by means of two small buttons, also spherical, located on the left side of the front panel, along with a third button that serves to put the machine on standby. On the right side of the panel we have the headphone outputs in number of three (!): two 6.35 mm jacks and one 3.5 mm mini jack. The amplification section allows driving headphones up to 16 ohms or lower, with a huge reserve of power, so even the most difficult ones should not be a problem. Still on the subject of playback via headphones, I point out the presence of the Crossfeed option between channels, adjustable to three levels, which, according to the manufacturer, should make it possible to achieve a presentation similar to that of a loudspeaker system. Connecting headphones implies automatic deactivation of the amplifier mode (i.e., the other analog outputs are muting).

Moving to the rear panel we find, starting from the right, a USB Class 2 Type B input fully galvanically isolated and capable of accepting native DSD up to x8 (DSD 512). If connecting the Chord Hugo TT2 to a Windows PC, it is necessary to download the appropriate driver from the Chord Electronics website, while on Mac OS and Linux there is no such need. Next to the USB we have two Toslink digital inputs for which cables are provided to ensure that the 192 kHz sample rate is achieved, two electrical S/PDIF inputs with BNC connectors, which can be used independently to accept a digital stream from external sources, or simultaneously as a DBNC (Dual BNC) input to accommodate the particular output of the M Scaler. Missing from the list is a balanced AES/EBU digital input. As for analog outputs, we have both unbalanced (RCA) and balanced (XLR) ones. Finally, on the far left, there are two digital outputs for use with future Chord Electronics products.

The user’s manual warns the user against underestimating the exorbitant power of the amplification section; even in the section on use in AMP mode it is specified that it is possible to connect bookshelf speakers with adequate efficiency or a horn system (always very efficient) directly to the Hugo TT2, provided that adequate wiring is used. In numerical terms this is expressed by a nameplate figure that is indeed remarkable: 7.3 W RMS into 8 Ohms from unbalanced outputs and 18 W RMS into 8 Ohms from balanced outputs. This exuberant power reserve is achieved through a discrete-component output section and a power supply section based on the use of 30 Farad super capacitors capable of a peak of 5A at 9.3V RMS. The actual power supply is external switching-type, plastic, 15V/4A, and is connected to the DAC by a rather long cable; note that, in contrast to the previous version that was equipped with batteries, the TT2 does not have them and therefore must always be connected to the mains via this power supply. In my system I found the possibility to select via menu the output level between High and Low definitely useful, limiting it in the latter configuration to 2.5 V. In the DAC mode the output level is fixed and is therefore the one provided in case you connect the Hugo TT2 to an amplifier or preamplifier; in the AMP mode, on the other hand, the spherical volume control is functional and is the one provided when you connect it directly to a power amplifier.

The Chord Hugo TT2, in addition to the push-button controls, can be operated by means of a small plastic remote control supplied, somewhat dim-looking but fully functional. Through it, one of four output filters can be sectioned On The Fly (on the fly): incisive neutral (Filter 1) which is, according to the manual, the “absolute reference,” the same filter but with high-frequency roll-off (Filter 2) to remove noise from high-resolution files with sampling rates of 88.1 kHz or higher. We then have (Filter 3) a “warmer tone” filter and again the same but with high-frequency roll-off (Filter 4). Note that they also work with DSD to reduce high-frequency noise (2 and 4).

Listening

For the listening test we wanted to force our hand a bit by inserting the Chord Hugo TT2 into the large system, where it replaced the Playback Designs MPD-8. The digital source used was the Antipodes Audio K30 G4 server/player. The rest of the system consisted of the Soulution 511+ pre and power amp. 525; Vivid Audio Kaya 90 loudspeakers; Mad Scientist Black Magic Ultra USB digital signal cabling; and Audioquest Mythical creatures regarding power supply and power. Given the configuration just described it should be obvious that the chosen mode of operation was DAC, that is, one in which the Hugo TT2 functions as a pure D/A converter, leaving the burden of volume control to the preamplifier. From the very first bars I had no difficulty in recognizing a setting familiar to me: that of the small – only in size – Hugo 2; the difference – and what a difference – is that here everything is more. For example, it is more the width of the stage , which achieves spectacular proportions in all three axes; I write about this at once not because I consider this aspect the most important, on the contrary, given how much this parameter can be manipulated in shooting and post-production. No, I mention it because of its evidence: even the most distracted listener can realize the difference between the Hugo TT2 and any other DAC, all the more so if it is in the same price range. But to refer to size alone would be to do the British converter a disservice, for there is more to it than that: listening to the beautiful Live in Hamburg by the E.S.T (Esbjorn Svensson Trio) I have come to appreciate how spatial articulation constitutes one of the most interesting aspects of this converter. The Hugo TT2 manages to place at the right place as much the instrumentalists as the cough of the spectator attending the concert; it succeeds, and this is true of all the Live records I enjoyed reviewing, in enhancing every minute detail of ambience to recreate in the listening room the formidable sensation of being part of the sound event. Okay, live magic you will say; but what about regular studio records? Well, even there there is a constant in the reproduction of this DAC: it seems that the instruments, all of them in a more or less obvious way depending on the recording, are represented in such a way that their contours are best perceived, so that the focus-this is the exact name of what I am referring to-is at the highest level. Mind you, this is not the first time that I have heard a source that excels in this area, my Playback MPD-8 in this is a real champion, the is that the gap in price makes it unnecessary to compare the two machines and, in any case, the way the Chord Hugo TT2 does it is different, and not a little, from the way my DAC does it.

Is that all there is to it? Is spatial reconstruction the only arrow in this product’s quiver? Absolutely not, because now I have to describe the timbre. The overall balance tends toward the cold, this after all was a characteristic I had also encountered in the portable version; by the way, if this were not the case, it would not explain the presence of filters 3 and 4, which have precisely the purpose of mitigating this aspect. What has fascinated me is the extreme complexity and richness of the harmonic textures reproduced; I give an example: in the track La petit Reine from Dominic Miller’s album entitled Absinthe (ECM) there is a percussion, rather distant and low level, that opens the piece. On most of the DACs tested you can hear it as an indistinct noise, with Playback you can hear its timbre, volume, position; with the Hugo TT2 you can clearly distinguish the percussive component from the subsequent harmonics. At the risk of being boring I repeat that I am comparing a little over four thousand Euro machine with one of about thirty thousand, if you know what I mean. Next comes Miller’s guitar and here too, while there is less body than I am used to hearing, there is an infinity of harmonic detail that casts a different light on the instrument’s sonority. A clear light that unravels and reveals. At this point, the idea begins to dawn on me that this DAC privileges a certain way of listening to music, moreover quite different from my ideal, which is more textural, dense and emotional; nevertheless, the Chord Hugo TT2 pursues such an aesthetic of sound with a lucidity and mastery that leaves one truly fascinated. A tour, rather a long one indeed, with the big orchestra took me, for example, to Shostakovich’s Symphony No. 5 (Pittsburgh Symphony Orchestra, Manfred Honeck (Reference Recordings)) and Mahler’s Symphony No. 3 (Budapest Festival Orchestra, Iván Fischer (Channel Classics)), both on DSD, in which I was able to appreciate, once again, the excellent capacity for spatial reconstruction, but also the extraordinary dynamics, which here finds a way to express itself at its best, together with the peculiar ability to dissect the complexities of the harmonic textures without omitting any detail. To conclude this excellent picture, I cannot fail to mention the commendable responsiveness to transients that makes the reproduction of string instruments and percussion a real joy.

Chord Hugo TT2: Conclusions

I am about to close a review that, you may have guessed, left me extremely satisfied. For the little more than four thousand euros charged, the Chord Hugo2 TT is, in my opinion, among the best DACs in its price range, and I would go so far as to say that to find a worthy competitor you have to be willing to spend quite a bit more. Not only is it a technologically cutting-edge product, despite being introduced in 2018, it is also one of those marked by a precise sonic philosophy that is being pursued with great determination. There remains at this point the regret that we could not experience firsthand how much and what benefits the adoption of the M Scaler partner could have brought in musical terms, since we have been returning it to the kind HiFight importer for a few months now.

Giulio Salvioni

Declared technical characteristics

Dynamic range: 127 dB A-weighted
Noise: 4 uV ‘A’ weighted (high gain), 1.7 uV ‘A’ weighted (low gain) with no measurable modulation of the noise floor;
Frequency response: 20Hz – 20kHz +/- 0.2dB;
Output stage: Class A;
Output impedance: 0.042Ω
Channel separation: 9 V RMS 300Ω -138dB
Output power (unbalanced): (@1% THD) 288 mW RMS 300Ω; 7.3 W RMS 8Ω;
Output power (balanced): (@1% THD) 1.15 W RMS 300Ω; 18W RMS 8Ω;
Digital inputs: 2 x optical toslink (24bit/192kHz), 2 x BNC (32bit/384kHz), 1 x USB Type B (32bit/384kHz)..;
Wireless input: Bluetooth (Apt X) 44.1kHz – 48kHz – 16bit;
Digital outputs: 2 x DX BNC (expansion outputs)
Analog outputs: Stereo XLR, Stereo RCA, 2 x 6.5mm headphone jack, 1x 3.5mm headphone jack.
PCM support: 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz, 192kHz, 358.8kHz, 384kHz, 705.6 and 768kHz–16 to 32bit.
DSD Support: Native DSD64 (Single) to DSD512 (Octa-DSD)
Volume control: digital. Output level stored at shutdown;
Line output mode: Enabled by menu;
Driver: not needed on Mac OS X and Linux, needed on Windows, downloadable from manufacturer’s site;
Materials: high-precision CNC-machined aluminum cabinet with steel ball buttons, glossy black acrylic signal window, glass viewing porthole, and dot-matrix display.
Colors: silver and satin black
Dimensions: (W x H x D) 23.5 x 23.8 x 5.2 cm.
Weight: 2.53 kg
User-configurable options:
Digital filters: 4 types.