Back in February, I received a series of unsettling emails from Dalibor Kasac, my contact at Euphony Audio in Croatia, telling me about a discovery they'd made concerning how ESS Pro delta-sigma DAC chips process native DSD. And that Euphony had gotten a couple of the new Topping E70 Velvet DACs that incorporated the newest generation of chips from Asahi Kasei Microdevices (AKM). Dalibor went on to tell me that the AKM chips process native DSD very differently than those from ESS. In his opinion, the AKM implementation of DSD resulted in sound quality that bettered that of the ESS chips in every conceivable way; if I could possibly get my hands on one, I'd definitely be impressed! Despite Dalibor's enthusiasm for the Topping E70 Velvet DAC, I found his news particularly disturbing; my then-flagship Gustard X26 Pro DAC uses ESS Pro chips. Great.
I initially misinterpreted Dalibor's explanation of the problem with the ESS chips, thinking he meant the issue occurred when their chipsets processed native DSD via DoP (DSD over PCM). That's not the problem at all, it's more complicated, and it took several more emails from Dalibor and a significant amount of my own research to get me straightened out and headed down the correct path. That said, Dalibor and the guys at Euphony Audio are not entirely unconvinced that DoP is a completely benign process, and he's told me repeatedly that native DSD definitely sounds better than DoP. Unraveling the intricacies of DSD is a bit more complicated than PCM!
The root of the problem lies with how ESS Pro chips manage native DSD files as they traverse the digital filtering and delta-sigma modulation processes. During my research, I stumbled onto a host of audio forum threads where participants complained loudly about ESS' lack of transparency in accurately describing the process flow of native DSD files. If you take a look at the white papers for ESS Pro chips (all available online, HERE), something curious happens in the block diagrams for all their chips. All file sources, whether PCM, DSD, or DoP enter the digital filter process separately, then exit in a combined stream, entering what many have called a "black box," where no information is provided by ESS as to what exactly happens at each stage that follows.
I've seen this thoroughly discussed in multiple locations online: the PCM, DSD, and DoP files are combined in this "black box" into what's been called a "shared language." That's not to say that the combined files are converted to PCM—but no one knows exactly what happens. But it definitely appears (and sounds) like some processing is going on to the native DSD files while inside the "black box." ESS has been questioned about this repeatedly, but hasn't responded to any requests for clarification. All of this information was unknown to me prior to getting the emails from Dalibor Kasac a few months ago.
When the AKM factory burned in 2020, and as soon as existing inventories of their chips had been exhausted, manufacturers of delta-sigma DACs were forced to use ESS Pro chipsets. That didn't seem like a terribly bad alternative at the time, but when AKM came back online mid-2022 and introduced their newest flagship DAC chips, the discussion seems to have started all over again!
Pulling out all the stops to get a Topping E70 Velvet
I emailed Topping the same day in February Dalibor reached out to me, and it took a six long weeks of effort to get an E70 Velvet in house. Several days passed after I contacted Topping in China; I was then redirected to Apos Audio, their US distributor. Then several days passed before I was contacted by Apos; then about a week or so before I received a second contact from them, asking me for samples of my published work. I provided them with links to multiple published reviews from Copper, Positive Feedback, and even Stereophile; then at least another week or so passed. I was sitting on my computer one afternoon, when I happened to notice an instant message pop up from Howard Kneller (Copper, The Listening Chair, Sound & Vision). He asked if I'd reached out to Apos about getting a review sample of a DAC; they wanted him to verify that I was in fact Tom Gibbs, and not just some scam artist.
I confirmed to Howard that, yes, I had reached out to them, and yes, I'm probably also a big-time scammer! Anyway, he gave me the necessary character reference (thanks, Howard!). A couple of weeks after that, I finally got an email telling me that my request had been approved, and the DAC would be shipping to me within four weeks! I sent my contact at Apos, John, an email asking would it actually take four weeks? That seemed like an excessively long period of time, especially since it's already been at least five weeks since I contacted them about getting the review sample. He told me no, that email was essentially a "form" letter with "industry standard" language, and I'd be getting a tracking number within a day or so. Oh, and Apos was in the process of moving to new offices, so that might delay things a bit further. The E70 V finally arrived on March 30.
I've been writing for the audio trade for twenty-plus years now, I maintain a fairly high profile, and I currently contribute regularly to a number of reputable audiophile web publications. And I've had reviews published in industry-standard print publications; one of them has the largest circulation of any audiophile magazine in the world. I don't consider myself to be just some schmo, and I've never had to put nearly as much effort into acquiring a review unit as I did with the Topping E70 Velvet. Howard Kneller told me that Apos had apparently encountered a rash of unscrupulous individuals passing themselves off as "reviewers," and that should explain their thoroughness in vetting me. The process was aggravating, to say the least, but my mania to experience an elevated level of native DSD playback knows no boundaries!
The Topping E70 Velvet finally arrives!
The E70 Velvet arrived encased in a shiny, textured black box, the kind the Chinese often refer to as a "beauty box." It presented an elegant first impression; it's a cultural phenomenon that we here in the US get little exposure to from manufacturers who cut their costs at every point of the process. A beautiful box is a nice touch, but it really has nothing to do with a product's performance, though, does it? But if Topping put this level of care into the packaging, it only reasons that the E70 Velvet itself would also reach a higher standard of technical excellence. Right?
The E70 Velvet is available in your choice of smart looking black or silver cases. And the display can easily be seen from across the room!
The E70 V is offered in black or silver case finishes; my review sample arrived in black, and its appearance was stylish and sophisticated. The beauty box had hidden compartments that stored a substantial looking 110V AC power cord, a USB cable, a Bluetooth antenna, and the remote. The remote is small and made of plastic, but functionally well laid-out, and looks remarkably similar to the remotes supplied by Gustard (they're probably sourced from the same supplier). The box also included a printed manual and a warranty card; the manual is an absolute necessity, as the setup process is somewhat less than intuitive. As is my usual process, I used upgraded, aftermarket cables for my evaluation, including a Rite Audio HC power cable, a pair of AudioQuest Yukon balanced interconnect cables, as well as a Pangea Premier Silver USB cable (the cables cost more than the DAC!). I attached the included Bluetooth antenna, but never explored its functionality; I still believe—at this point, at least—that Bluetooth technology is still a bit half-baked, and isn't capable of providing true audiophile sound quality.
The E70 V's back panel is very well laid-out, and features the main power switch, a standard IEC power input, inputs for a 12V trigger and pass-through, and the connection socket for the Bluetooth antenna. Digital inputs included USB, coaxial, and optical; I only evaluated the unit using the USB input, which featured the highest level of file and bit-rate compatibility of the three available choices. Analog outputs included a pair of single-ended coaxial jacks and a pair of balanced XLR jacks. The outer case was substantial, and the unit had sufficient heft that prevented it from moving about or tilting backwards when the heavier aftermarket cables were inserted—that's always a nice feature in a smaller form-factor product. Fit and finish and construction detail were superb; the E70 V scores points on looks alone, and doesn't appear at all to be a sub-$500 product. And upon turn-on, you're greeted by a nicely proportioned display, which allows you to see the rate of the file playing in really large characters that can easily be seen from across the room.
Setup of the E70 Velvet
As I mentioned earlier, proper setup of the E70 Velvet requires you to read the DAC's manual, which will help you get the best sound quality—especially with native DSD files. Preamp functions like volume control, input selection, and balance control are provided should you require them or choose to use them. The E70 V seems to be as much directed at headphone users as it is for use as an audiophile DAC, and the preamp functions allow for easy integration with a headphone amp. That said, I'm using the E70 in an audiophile setup with a dedicated preamplifier, which makes those functions redundant, so I either disabled them or simply didn't use them during my evaluation. Which was strictly for use of the E70 V as a digital to analog converter in a relatively high-end audio system.
The E70 Velvet actually uses a dual-AKM chip configuration that accomplishes digital filtering, delta-sigma modulation, and the digital-to-analog conversion functions. That configuration is responsible for the magic that gives the E70 V its sterling sound quality with native DSD files. The "Velvet" part of the E70 Velvet's name comes from the use of a single AKM AK4191EQ chip, which is a digital data converter chip that separates the digital filtering and delta-sigma modulation processes prior to sending the music signal to the flagship AK4499EXEQ chip for digital to analog conversion. AKM calls this trademarked configuration and signal flow "VELVETSOUND™"; the process minimizes the effects of digital noise in the analog output, and results in a significant improvement in the E70 Velvet's signal-to-noise ratio. Yielding a dramatic improvement in sound quality, especially that of native DSD files. This dual-chipset configuration has the potential to establish a new benchmark of precision, performance, and musicality, which is particularly promising considering the E70 V's low price point.
When the user disables the E70 Velvet's internal volume control, AKM's dual-chip VELVETSOUND process re-routes the signal flow for digital filtering and delta-sigma modulation, and doesn't subject the native DSD signal to any PCM processing. This allows the native DSD signal reach the digital to analog conversion stage unaltered.
Robert Devcic of Euphony Audio had also reached out to me in advance of my getting the E70 Velvet. He informed me that I needed to make certain the unit's volume control was disabled during the setup process. This allows the internal "magic" of the VELVETSOUND process to occur that gives the E70 V the edge over other delta-sigma DACs. Disabling the volume control allows native DSD signals to pass through the dual chip configuration without grouping them with PCM files, and without any conversion. Digital volume control is virtually always a PCM function; leaving the volume control set to "on" routes native DSD signals into the same circuit path with PCM signals. Thereby, combining them into a "shared language" that slightly diminishes the overall quality of native DSD playback. This was of paramount importance to me, because I personally consider DSD to be a superior playback format, and I have hundreds of DSD files in my digital library. Listening to native DSD files was one of my main areas of focus while testing the E70 V, but I also thoroughly evaluated its capabilities with PCM files of every available bit and sample rate.
With the rear-panel power switch turned on, the E70 V remains in standby state; you then have to either turn the power on from the front panel's multi-function touch button or with the remote. You're then greeted by the really nicely-proportioned display, which is HUGE compared to other DACs I've encountered in this price range. To enter the setup menu, first turn off the rear panel power switch, then press the front panel volume knob while turning the power switch on again. The volume knob now becomes a multi-function selector, and allows you to rotate through the various menu choices. Which include display function (always on or auto-on) and brightness level, output level (4V or 5V, I chose 5V to match the output of my Gustard X26 Pro DAC), choice of PCM digital filter (I chose the default), the various internal preamp options like channel balance and volume control (which I disabled), and selections for Bluetooth use (which I also disabled). You then press and hold the volume knob until "8-8" appears on screen, indicating that the E70 V is now set up and has saved your selections. You can also accomplish the setup routine using the supplied remote.
Use and listening tests
Clicking on my name in the header above will show you the components in my two audio systems; only the equipment in my digital system was used in the evaluation of the Topping E70 Velvet. The arrival of the E70 V coincided with a review I'd been working on for the German-made Naiu Laboratory Ella Mark 3 power amplifier. I inserted the E70 V into my digital system mid-stream in that review process; you can read my review of the Naiu Ella amp HERE. My hope was to replicate Dalibor Kasac's positive impressions of a $450 DAC's impressive sound quality with native DSD files—while it was playing into a system that included an $11,000 amplifier. I was also keen to see how the Topping E70 Velvet would perform compared to the Gustard X26 Pro DAC ($1,500 MSRP) and Gustard C18 Constant Temperature clock unit ($1,600 MSRP) combo that are my current references. The Gustard pair retails for nearly nine-times (!) the $450 MSRP of the Topping E70 Velvet. And for full disclosure, the Gustard X26 Pro DAC—which came into production after the AKM fire in 2020—uses a pair of ESS ES9038 Pro DAC chips.
My digital system is fully balanced; the PS Audio Stellar Gain Cell preamplifier provides system control, and the digital input chain is fed by a dual-box streaming setup that includes the Euphony Summus and Endpoint units. The Euphony equipment is built around their own Stylus operating system; the Summus handles library management, file storage, and music playback. The Endpoint streams the digital signal to the Gustard X26 Pro DAC via an i2S connection; a 10mHz BNC connection shares the signal with the Gustard C18 external clock. Stereo balanced outputs on the Gustard DAC send the analog signal to the preamplifier, which in turn feeds the Naiu Lab Ella amplifier, which is connected to a pair of Magneplanar LRS+ loudspeakers with a REL subwoofer. It's a fairly elegant digital playback system.
Adding the Topping E70 Velvet seemed at first to be a step backwards; the unit doesn't feature either i2S or BNC connections, so a comparison between the Topping and Gustard units won't exactly be apples-to-apples. The only possible option is to use the ubiquitous USB connection between the Euphony equipment and the E70 V. But USB has come a long way, and the USB playback capabilities of the E70 V either match or exceed those of the Gustard X26 Pro. For comparison between the Gustard and Topping equipment, I used each unit's USB connection. But I also made listening comparisons with the same native DSD and PCM files between the E70 V via USB and the Gustard setup via i2S.
My main thrust for this review was playback of DSD files, including the hundreds of DSD64 rips from my collection of SACDs, as well as native DSD downloads across a range of DSD64, DSD128, and DSD256 rates. I also listened to countless sources of PCM files, many of which were 16-bit/44.1kHz rips from my fairly vast collection of compact discs. My digital library also contains PCM rips of many DVD-Audio discs and Blu-ray discs at 24-bit/96kHz and 24-bit/192kHz, as well as some 32-bit/384kHz DXD downloads. Throughout the process, I continually compared A-to-B back-and-forth between the Topping E70 V and the Gustard X26 Pro/C18 combo.
I listen to a very broad range of music of all genres, including classic jazz, jazz vocals, folk, classical, chamber music, opera, rock (including alternative, classic rock, and progressive rock), and even some metal, rap, and country/bluegrass. While I lean towards acquiring higher sample and bit rate files for my library, I've found that in my day-to-day listening, I generally get as much pleasure from a PCM rip of one of my favorite CD's as I do from a much higher resolution file. High resolution files generally hold up better for critical listening, but the vast majority of my digital music library contains 16 bit/44.1kHz rips of my CD collection, outnumbering all other file sources by about 7-to-1 overall.
I listened to countless albums over the evaluation process, far too many to detail my impressions of each in a Topping versus Gustard scenario. But I did observe particular trends over the time spent comparing the two setups.
Topping vs. Gustard with native DSD files
The Topping E70 Velvet is the clear winner here; it bettered the much more expensive Gustard X26 Pro/C18 combo in every possible way with native DSD files of every provenance. AKM's VELVETSOUND, dual-chip process flow provides a clear path for native DSD files that allows them to proceed through the DAC unaltered, all the way to the conversion from digital to analog. At the point when the AKM fire happened three years ago, a lot of folks online bemoaned the lack of availability of AKM chips—which I'd never heard at the time, in any implementation. I now fully understand their despair; the AKM chips are undoubtedly the very best available, especially in terms of how they process native DSD playback.
Both the Topping and Gustard setups employed matching Pangea Premier Silver USB cables. Constant comparison between the Gustard setup—which is nearly nine times more expensive than the Topping unit—revealed that the E70 V produced a sound that not only had improved levels of transparency and clarity, but was overall more musical than the Gustard setup. And the native DSD files as played through the Topping exhibited a more pronounced stereo image that helped my system project a greater illusion of reality during playback. Not even the addition of the C18 master clock—which more than doubled the Gustard system MSRP—provided a level of improvement to its overall musicality to give it an advantage over the $450 Topping E70 V. Even switching to the i2S connection with the X26 Pro failed to yield any kind of advantage for the Gustard combo with native DSD—lay the blame squarely on the Gustard's use of ESS Pro chips and that mysterious "black box" processing.
The sound from the E70 V was very slightly lusher, richer, and more analog-like than what I heard from the Gustard setup. There was an added level of sparkle that was present during playback from the E70 V that was not as completely evident from the Gustard combo. I'd definitely attribute that to the more straightforward path of the E70 V's VELVETSOUND chip implementation, and thanks to Robert Devcic for flagging me with regard to defeating the unit's internal volume control. I might not have otherwise stumbled onto that discovery as quickly as I did! When Dalibor Kasac of Euphony Audio first emailed me about this, I was incredulous that any of this might even be possible, and that totally depressed me. But after the arrival of the E70 V, trust me, hearing is definitely believing.
Topping vs. Gustard with PCM files
I gave the definite edge to the Gustard X26 Pro/C18 combo here. The Topping E70 Velvet acquitted itself exceptionally well playing PCM files via USB, but there was a role-reversal of sorts going on that resulted in the same kind of playback improvement for the Gustard combo with PCM files that I witnessed with the Topping unit and native DSD files. I attribute that to the addition of the Gustard C18 master clock, which lifts the performance of the Gustard X26 Pro DAC exponentially; there was a greater level of midrange liquidity, high frequency sparkle, improved transparency, and greater realism with PCM files as played through the Gustard setup vs. the Topping E70 Velvet. That was especially true with CD quality rips, which almost approached the level of higher resolution files when played through the Gustard combo. Which is significantly more expensive and overbuilt compared to the E70 V; it's no surprise that the Topping unit couldn't match the Gustard's overall sound quality with PCM files.
One other thing with regard to PCM playback with the Gustard equipment: it's MQA capable. Those in the audiophile world who are vested in MQA are doubtless unhappy with the recent events surrounding MQA's financial troubles, and the end may be in sight for the nascent audio format. That said, at the point when I made the request for a review sample of the Topping E70 V, I didn't notice that it wasn't equipped for MQA decoding and playback. That's not a deal breaker for me, because at that point, I didn't have a Tidal streaming account, and I didn't have a single MQA file in my library.
But in the protracted period it took to get a review sample, I decided (on a lark) to order a Japanese MQA-enabled compact disc of the Yes album Drama. Which is one my favorite albums by the band, and one of their albums that hasn't been remixed or remastered by Steven Wilson (and probably won't be in the foreseeable future). I mainly ordered it to take a serious listen to the MQA format for the very first time, and it was only about $14, so no great loss if the experiment flopped. After getting the disc and ripping it to MQA-enabled FLAC files, I then attempted to play it back over the Topping E70 Velvet. I could only get 44.1kHz PCM to display on the unit's front panel; after an hour of consternation and failure, I started digging online and discovered that the E70 V is not, in fact, MQA enabled.
How I missed that, I'm not completely sure, and whether Topping had some advance warning that MQA as such might be going away soon is an unknown. Regardless, I then routed playback of the MQA-enabled files through the Gustard setup, and I thought Drama sounded really great—maybe even better than I'd ever heard, other than perhaps my original LP. I liked it so very much that I ordered the MQA CDs for both Yes albums Tormato and 90125. The day after placing my order, the news hit that MQA had filed for administration, which is the EU equivalent of bankruptcy restructuring in the US. Talk about bad timing! YMMV, and you may (pretty much like me) not have any deep rooted feelings regarding MQA, but if MQA is an itch you have to scratch, the E70 Velvet can't assist you in that area!
Conclusion
When dealing with high-end audio gear, I've often found that a fairly substantial investment in equipment has to be made to achieve a relatively minimal improvement in overall sound quality. That simply is not the case with the Topping E70 Velvet and its ability to render native DSD sound with a level of detail, clarity, and musicality that an ESS-equipped, delta-sigma DAC at many multiples of its price point couldn't quite match. The Topping is an exceptionally well-made unit, and the VELVETSOUND, dual AKM chipset implementation is clearly the principal reason for its impressive performance. I intend to explore the implementation of AKM vs. ESS chips again in the near future here at Positive Feedback.
The E70 V is no slouch with PCM files, but it was outclassed by the slightest of margins by a Gustard combo that sells for nine-times the Topping's MSRP—that's no great surprise. But this review process has definitely given me pause to reconsider how the price point of high-end audio equipment relates to sound quality—sometimes less is definitely more! The E70 Velvet DAC could easily be considered budget gear, but it sounds like a million bucks; I liked it so much, I bought the review sample. The Topping E70 Velvet comes very highly recommended!
Topping E70 Velvet DAC
Retail: $449 MSRP
Apos Audio
Topping
All images courtesy of Topping, Apos Audio, AKM, and the author
