Cen.Grand 9i-906 Silver Fox

The Background
I recently completed a roughly two-year journey to find a new reference DAC. The project involved listening to dozens of highly-regarded options, comparing and contrasting them in endless combinations, and attempting to judge them all on features, value, and sonic performance. In the end I chose the Cen.Grand DSDAC 1.0 Deluxe as my new reference, which resulted in one of the longest write-ups I've ever done. You can read that HERE if you've got a decent amount of spare time on your hands.

My approach to reviewing the Cen.Grand Silver Fox headphone amplifier will go in the opposite direction. Rather than a sprawling comparison, I hope to keep things focused and concise, getting to the core of what makes the amplifier tick and who it may - or may not - appeal to.



The Amp
My DSDAC review covered the history of Cen.Grand so I won't rehash any of that here. As for the Silver Fox, the full name is technically the 9i-906, in keeping with the naming conventions the company has used for years. I personally find those hard to identify with so I will stick with calling it the Silver Fox, whilst recognizing how that might feel a bit odd for users of the black version (yes, the Silver Fox can also be had in a very fetching black enclosure).

The Silver Fox sells for just under USD$4,200 which puts it somewhat on the affordable side when it comes to all-out, cost-no-object headphone amplifiers. You can certainly get a great amplifier for a lot less money, but you can also spend double, triple, or even more for a headphone amplifier if you have money to burn. I never thought I'd be complimenting a $4k+ headphone amplifier for its relative affordability but such is the market in 2023, so here we are.



Fit and finish is exemplary. The enclosure has various fine details which keeps it from becoming yet another anonymous silver (or black, if you chose that version) box in the audio rack. I particularly like the side panel venting details as well as the little angled recess on the upper middle portion of the faceplate which proclaims "music is my soul" - a common design theme among many Cen.Grand devices. Silver Fox tips the scales at roughly 26 pounds, comes equipped with fancy footers for vibration control, and generally feels like a truly high-end piece of kit.





Note that this is purely a headphone amplifier: no preamp capabilities, and no digital inputs. Multi-function devices are quite popular these days but the Silver Fox sticks with a singular task and does it extremely well. The matching DSDAC 1.0 devices do have preamplifier capabilities (including analog inputs on the Deluxe model) which helps explain why Cen.Grand didn't want to duplicate functionality here. Instead we get 4 inputs to work with - 2 each of XLR and RCA. I don't know how useful that might be for the average listener but for a reviewer comparing DACs it is quite handy.



The Silver Fox handles nearly any headphone connection I can think of. There's a 1/4" jack for standard headphones, and then 3 sets of balanced outputs in the form of 4-pin XLR, dual 3-pin XLR, and 4.4mm. The only thing technically missing is a 1/8" jack which is easily achieved by using the 1/4" option with the usual adapter. A reasonably large front panel display lets us cycle between inputs, choose from 4 impedance settings, and also select between 4 different operation modes - Normal, BTL, Parallel, and Active Ground. These each take a different approach to amplification in terms of output current and grounding method, with each giving a slightly different flavor. The amp is capable of putting out a massive 20W into 30 ohm loads which means it is able to drive even the most difficult headphone loads with authority.



Internally, the amp is centered around an array of 8 Exicon lateral mosfets. Clever readers may recognize those same transistors as being at the heart of the highly-regarded Enleum AMP-23R (USD$5k), with the distinction being that Cen.Grand offers twice as many. Those numbers make sense as this is a fully balanced design, thus 2 per channel times 4 channels (the Enleum is not balanced so 2x2 is adequate). Beyond that we get substantial power capacitance, a large custom toroidal transformer, and top quality parts throughout. Those Exicon mosfets use the massive chassis as heatsink which helps distribute the thermal load - the device gets a little warm but nothing unmanageable in the least.






For further technical detail, I'm actually going to do something I almost never do, which is point you to another review. That would be the in-depth exploration over at 6moons which is definitely worth the read. I know some folks find Srajan's writing style and sonic descriptions a bit difficult to follow, but I think we can all agree he does a great job digging into the technical aspects of the design as well as the company history and motivation behind the product. If nothing else, it says a lot when a reviewer with access to vast quantities of HiFi gear chooses a relatively unknown brand as a reference... and note that he's done it twice now with the Cen.Grand DSDAC as well as the Silver Fox.

One thing I do want to quickly point out is that the Silver Fox now ships in either black or pure silver in color. My earlier production unit (as well as the one seen at 6moons) has a few gold accents, including a gold volume knob, but that is no longer the case with the latest production models. Not a massive difference but I just want to be clear about the pictures seen here versus what someone will actually receive if they purchase this amp in the silver option. At some point I'll swap mine out so my pictures reflect the actual look of the current product.


The System
For the majority of my evaluation, I listened via my main system fed with balanced power from an Equi=Core 1800 power conditioner. AC and signal cabling was all from Audio Art, with the exception of an iFi Gemini3.0 USB cable and various headphone cable upgrades from Effect Audio. My source was usually a Euphony Summus music server fed by a Keces P8 linear PSU, which then streamed to a Stack Audio Link II Ethernet bridge with the matching Stack Audio VOLT power supply. I also used a Matrix Element S as well as an Eversolo DMP-A6, both streaming via Roon. On DAC duty, the obvious pairing was the DSDAC 1.0 Deluxe, but I also spent lots of time using a Musician Audio Aquarius, Yulong DA1, Wyred4Sound Anniversary, Cayin CS-100DAC, and various others which were listed in my earlier DSDAC article. Headphones included the ZMF Caldera and Atrium Closed, Meze Elite, Audeze LCD-5 and LCD-24 Limited, Kennerton Thekk, Sendy Peacock, Campfire Cascade, HiFiMAN HE-6, Sennheiser HD800 and HD660S, and more. So I think it's fair to say I've given the Silver Fox a thorough workout.








The Sound
In keeping with my goal to keep this write-up concise, I'll explain the sonic performance of the silver Fox using bullet points. Feel free to ask any follow up questions if I end up not exploring some aspects to your liking.


+The general signature of the Silver Fox is big, bold, and authoritative. I'd still call it a neutral sound overall but with an emphasis towards a more engaging "live" feeling rather than a stereotypically clinical studio reproduction.

+Detail retrieval is top-tier, yet the rich tonality keeps it from ever feeling the least bit sterile. This is not an analytical amp in the negative sense of the word, but it does excavate deep into the music to seemingly unearth everything there is to be found in a recording. This aspect can be emphasized or minimized based on your choice of settings.

+Despite the level of transparency and that "live music" excitement I mentioned earlier, I hear zero trace of any objectionable treble zing. In fact this is some of the most well balanced, articulate, convincing treble out there. But it seems to be presented as "quality over quantity", meaning no artificial boost or attempt to fool the listener with elevated treble energy.

+There's a sense of tonal richness that likely exceeds any other headphone amp I've experienced to date. The balance is perfect for my taste - I'm not saying this is the thickest sound I've heard, but rather the most satisfyingly rich tone without going overboard.

+It drives any headphone you throw at it with ease, and has enough subtlety and nuance to pair well with tricky designs like the HD800 and Kennerton Thekk.

+The volume control uses a Muses resistor ladder solution from New Japan Radio Corporation, which cycles through the 70dB range in .5dB steps. Which I very much appreciate. Contrast that with my reference tube amp which has a custom stepped attenuator with only 24 steps, and that simply isn't enough precision for certain circumstances.

+Output tops out at 20W into 30 ohm loads which is absolutely massive. I notice lots of amps these days which claim to do 5W or 10W etc, but then specify that rating as being for 16 ohm loads - meaning it really does roughly half or even a quarter of that number into the more useful 30-60 ohm range where a lot of headphones actually live. Silver Fox will have zero issues driving any headphones with full authority and having plenty in reserve for dynamic swells.

+Partially due to the potent output, but also just the general signature, the Silver Fox presentation feels totally effortless. No treble etch or extraneous grit, supreme bass control, fluid midrange expression. I can crank volume up indefinitely without the amplifier becoming the weak link. Lots of amps can sound unobjectionable at lower volumes, yet begin to lose the plot as volume increases. Silver Fox has no such limitations, so be careful. I'm generally not a very loud listener to begin with but with this amp I find myself boosting the volume here and there, almost without noticing, since everything sounds so composed and unforced. Eventually I realize I am playing things far louder than normal, and remind myself to back off a bit. Thankfully when I do, I still hear a rich dynamic presentation. Some amps only really come alive at higher volumes and tend to sound flat/boring until you reach those levels. But not this amp.

+Soundstage is superbly well defined. This perhaps relates to the effortless nature of the amp as previously mentioned, but it often feels like I'm bumping up against the limits of the recording itself rather than being constrained by the amp. This assumes a suitably high caliber of DAC, transport, headphones, and ancillary gear, but when all those pieces fall into place, the result is magical. There's a sense of dimensionality and space which is very rarely achieved. Have I heard better? Yes, my experience is that a select few top-tier valve amplifiers using vintage (aka expensive) glass can sound even more holographic than this. But the delta is not huge and the cost difference is fairly extreme. Not to mention there are other things such as impact and immediacy which I don't think any tube amp I've heard can match. So it really comes down to priorities in the end. Suffice to say the Silver Fox resides at the pinnacle as far as solid state designs go.

+I already mentioned the macro scale and dynamics of this amp, but I'm also constantly impressed by its inner detail and subtleties. Listening to three different versions of Yo-Yo Ma playing the Bach cello suites - his original 1983 recording, followed by his 1997 release, and finally his latest 2017 version - the Silver Fox allows me to hear every variation in pitch, inflection, pace, and rhythmic intensity. And that's just the performance itself. There's also the difference in recording and mastering which, although all are very well done in their own ways, reveal changes in focus from one release to the next. The list of amplifiers capable of showcasing these differences, to this extent, is vanishingly small.

+Likewise the sense of speed and control is mindblowing, particularly when playing more complex material. For my musical diet that often leans toward various metal from around the globe: the absurdly complex technical death metal of German band Obscura, atmospheric black metal with folk elements from Romanian group Dordeduh, densely layered Danish prog metal from Vola, Melbourne-based Ne Obliviscaris with their classical inspired extreme progressive style, the virtuosic skill of instrumental supergroup Blotted Science from the USA, or the elaborate symphonic death metal of Italy's Fleshgod Apocalypse. To the uninitiated, these all might just sound like aggressive noise, but to me they are wonderfully diverse and totally unique. Many systems cannot do them justice, which can often be blamed on the recordings or even the genre in general. But with an excellent system featuring the Silver Fox and a suitably accomplished headphone (ZMF Caldera and LCD-5 are my favorites for these genres at the moment) I am blown away at the layering, the rhythmic interplay, and just the overall technical capabilities in general. Would I love all of them to be pristinely recorded/mastered by an audiophile label such as Chesky or Reference Recordings? Sure. But even so, there is plenty of quality to be extracted if your system is up to the task.

+Well recorded vocals sound spooky real with the Silver Fox. From Corinne Bailey Rae to Eric Bibb, Sufjan Stevens to Aoife O'Donovan, this amp captures the unique nuances of each voice and reproduces them in a completely lifelike manner. If you're reading this, it's a safe bet you probably enjoy music as often as possible. But consider for a moment how often we hear real voices in our daily lives. It's a sort of benchmark that we probably don't even think about. Yet we are all likely much more well versed in evaluating the realism of voices than any other instrument. So when a chain does something even slightly wrong in reproducing vocals, it really stands out, even if our brains can't really pinpoint where the deficiency might be. The Silver Fox will absolutely not be the weak link in accomplishing this task.




Settings
As far as the different impedance options go, the naming is actually a little confusing. The "low impedance" settings actually involve added resistance to the output - low 1 adds 50 ohms, low 2 adds 100 ohm, and low 3 adds 150 ohms of output impedance. Meanwhile the so-called high impedance setting is actually the original signal with less than 1 ohm output impedance. So what they really seem to mean is those "low" settings are intended for more sensitive headphones which show background noise and/or just aren't suited for the full power output. Likewise, BTL mode is said to give us the full output voltage, while the other three modes are reduced - but still plenty potent for the majority of headphones. That means using "high" with the BTL setting results in a full power output whilst the other options all mix and match for some type of reduced (but again still extremely powerful) output.

The "low" settings having higher output impedances may be an issue for certain headphones, particularly those with dynamic or balanced armature drivers and interesting impedance swings. That said there are certain situations where people actually like having a higher output impedance available, so this is not always a bad thing. Meanwhile planar magnetic designs, with their generally flat impedance curves, don't seem to care much either way. Again, it's nice to have different options to play with, even if the naming scheme is somewhat confusing.

Cycling through the four modes seems to make a larger impact on sound, though it can be unpredictable as far as how it will interact with each headphone. This makes it sort of an adventure which can bring interesting surprises. Some headphones react quite strongly to the different modes while others show hardly any difference at all. In the most extreme cases there will be a significant change in gain, a shift or reordering in soundstage width and focus, and just an overall different feel to the presentation.

If I have to generalize, I'd say BTL mode consistently works best with difficult to drive headphones, sounding very full bodied and authoritative. But it can be used even with easier loads and the sound may prove worthwhile. Active Ground mode can help with sensitive headphones which need assistance squashing slight noise-floor issues, and sometimes this mode feels like the most nuanced, detail-oriented option. Normal mode is well-balanced and realistically a safe bet the majority of the time. Parallel mode tends to have the most open, expansive signature, and sounds a little like a mixture of normal and BTL.

But I'm making it seem like these are consistent results, which they totally aren't - this is a vague pattern gleaned after months of listening, which is accurate about as often as not. So I won't bother trying to describe the modes further as they are so unpredictable. It really is nice to have different options to mess with though - again, you never know which one might be the best fit for a particular headphone.



Pairings
As mentioned earlier, the Silver Fox plays well with every headphone I've thrown at it. I don't have a HiFiMAN Susvara here any longer but based on my experience using it to drive an original HE-6, it should have no trouble at all making big, bold, well controlled sound from the HiFiMAN flagship. Ditto other power-hungry cans such as the HEDDphone, AKG K1000, and the Abyss models. Sensitive models from Grado or the always-fun Campfire Audio Cascade also pair extremely well, proving the Silver Fox has more to it than just brute force.

A massive powerhouse like this is not typically my first choice to use with ultra-sensitive in-ear monitors. These things need power in the milliwatt range while this amp has thousands of times that much. Despite that, the Silver Fox does surprisingly well, at least in many circumstances and depending on the model. The best match I can find is my Radioso tri-brid custom IEM from (apparently defunct) Korean firm AME Custom. These are relatively inefficient as IEMs go, which may be why they pair exceptionally well with the big Cen.Grand amp. Whatever the cause, the sense of scale, authority, and dynamic swing are top notch with this combo. The wide volume range leaves me with plenty of room for adjustment which is not always the case when using full-size gear with miniature in-ear monitors. The Ultimate Ears Reference Remastered CIEM also pairs extremely well, as does the 64 Audio A18t, both of which give results easily on par with some of the best full sized headphones out there. I do hear a bit of background hiss when using my most sensitive models though, so I imagine there will be some pairings which won't be ideal. But that's not unexpected considering the absurdity of the power levels involved.

Naturally, the matching Cen.Grand DSDAC1.0 Deluxe is a perfect partner for the Silver Fox. But it also pairs beautifully with a variety of other sources. Notable matches include the Cayin CS100DAC which gives a liquid, flowing, delicate performance with the tube output stage engaged, and a more snappy, visceral sound when using the solid-state output path. Meanwhile the Yulong DA1 brings out more of a sweet midrange feel, making music sound intimate and highly involving. The Wyred4Sound Anniversary DAC is bold and dynamic, whilst the Soul Note D2 is wonderfully gentle, delicate, and nuanced. The Silver Fox is ideal for comparing and contrasting sources.

Rather than continue discussing the details of every DAC combination I've tried, I'll just sum it up by saying the Silver Fox is simultaneously ultra revealing yet complementary to any upstream gear. It is revealing in terms of being deeply transparent to showcase the capabilities and limitations of the associated DAC and transport. But it also feels somewhat complementary in being so potent, rich, dynamic, and lively that it can make a boring DAC sound more exciting than it otherwise should. I'd say the Silver Fox is thus excellent whether listening for enjoyment or for evaluation purposes, as long as one remembers to take that complementary aspect into consideration.








Comparison
Although I have many excellent headphone amplifiers here at the moment, there's really only one that feels worthy of comparison - that would be the mighty Niimbus US4+. Everything else currently in the house from Pass Labs, Cayin, Violectric, SPL, Musician Audio, iFi, Feliks Audio - all amps that I greatly enjoy - are just not in the same league. For those unfamiliar, Niimbus is the summit-fi arm of Germany's Lake People brand, who also makes the highly-regarded Violectric line of gear. Niimbus later rebranded this amp as the US5 Pro which currently sells for $6,599 with the only difference being the addition of a 4.4mm balanced jack. I've used this amplifier for years as a reference and I'm still thoroughly impressed with it during each and every listening session.

Both of these amps are incredibly powerful, dynamic, clean, and focused, with superb detail retrieval and a lifelike sense of projection. Both have massive soundstage presentations, precise image localization, and thunderous bass response. Their main point of divergence is overall tonality where the Silver Fox comes across as thicker and a touch more laid back, making the Niimbus seem comparably energetic and wiry. Note weight is thicker on the Cen.Grand unit, and there's a bit more emphasis on decay trails where the German amp has a greater focus on transient attack and speed. Yet in absolute terms the Silver Fox is just as resolving of fine details, despite the difference in the way those details are presented.

In ultra-simplistic terms we might say the Silver Fox is "warmer" and the US4+ is "brighter". But as usual with simplifications, that doesn't really capture the full truth of the situation. It's not as if the Niimbus isn't stunning with the lively HD800, nor will the Silver Fox push an HD650 into the oblivion of darkness. They are both extremely competent amplifiers, with each having its own character and ultimately its own unique presentation.

I can happily listen to either one of them all day long without thinking I might be missing out by not using the other option. But I do notice myself using the Silver Fox more often these days, both for business and for pleasure. I realize that "new toy syndrome" is very real, but I've actually had the Cen.Grand amp for roughly 10 months by now, which by my standards is a rather long time (and certainly enough to get well-settled). If I'm honest, the Cen.Grand Silver Fox does seem to offer slightly more performance for significantly less money - roughly $2400 separates the two models, in favor of the Chinese option. So as much as I still love the Niimbus, I have to admit that the Silver Fox displaces it and takes the top spot in my headphone amp hierarchy.




Conclusion
It's been a big year for my audio system. Not only did I find myself a new reference DAC, but also a new reference headphone amplifier. The prior choices had been in place for years and I remained absolutely thrilled with their performance, so this was an unexpected development. Even more surprising was the fact that both replacement choices came from the same brand, which is something that has never happened before. I can think of multiple companies who offer superb DACs plus excellent speaker amplifiers but that list dwindles severely when we switch from speaker to headphone amplification. And to have both new references come from a company I had never heard of before? Unprecedented.

The Cen.Grand Silver Fox is a beast of an amp. In sound, design, build quality, and appearance, it is up there with the absolute pinnacle of the market, in a place where very few competitors dwell. The fact that it does this for a touch under $4,200, when others are charging thousands more, is extremely impressive. I can very enthusiastically recommend the Cen.Grand 9i-906 Silver Fox to anyone in the market for a top-tier headphone amplifier.

Or, to frame this another way: I've gotten in on the ground floor with quite a few brands over the years. I was among the very first, and in some cases actually had the exclusive world premier, on plenty which later went on to become "household names" (as far as that goes in the audiophile world). Examples include brands like Aurender, Noble Audio, Auralic, Empire Ears, Matrix Audio, Unique Melody, Violectric, 64 Audio, and certainly others that I can't recall at the moment, which are all staples in their respective categories by now. I'm not at all claiming I can take any credit for their accomplishments, but I might be justified in saying "I told you so" to the massive numbers of enthusiasts and fellow reviewers who went on to hear the same thing I heard.

Cen.Grand feels like another one that is destined to become a well-known and highly-regarded name in the audio scene. While they have been around for years in their own country, this seems like the beginning of their breakout on the world stage, and I would not be surprised to see Cen.Grand become far more mainstream in the coming years. And when that happens, I'll be happy to have been here from the start, pointing out how excellent their gear is.



Epilogue
With the main review finished, I figured it would possibly be illuminating to share a bit more about Cen.Grand founder/chief designer JianHui Deng. He's a fascinating guy with an interesting history - which is about to become even more unique in the coming months if all goes according to plan (unfortunately I can't give details on that yet). His philosophy seems to be that in order to fully understand a brand, where it comes from and where it may be going, you need to understand the core person/people behind the scenes. I agree with that sentiment. I've also noticed that in the audio world we do tend to learn all about the tiny, quirky boutique manufacturers and what makes them tick. Yet oftentimes we hear very little about the folks behind the products at slightly larger companies. There are of course exceptions but this got me thinking that I really would like to know much more about the designers or teams at all of my favorite audio brands. So this is my effort towards making that happen.

JianHui Deng seems to have a strong basis of music appreciation as one of his defining traits. He started at a young age playing clarinet and then added saxophone, guitar, and drums to his skillset. He played with various bands throughout his school career ranging from his early teens through his university years. Graduating university in the 1980s, he took a brief detour to work at a railway company, but soon moved on in order to start his own company designing and manufacturing audio equipment. This was in the 1990s when the Chinese HiFi scene was beginning to take off, and some of his amplifier products picked up critical acclaim and won industry awards. I was fascinated to learn about this as I feel like I have a decent knowledge of HiFi history as it pertains to my own region... but I am reminded that many areas have their own unique scenes, with their own history, and they can be very passionate and thriving in their own ways.

Moving forward to the 21st century, JianHui continued in his audio design pursuits. Realizing that the digital market was growing more rapidly than analog, he turned his attention to digital media players, which he felt had significant room for improvement on the audio side. He worked closely with US firm Marvell Technology who at the time was the premier supplier of high-end processing solutions for the then-new Blu-ray market. His goal was to improve audio performance by implementing an "independant dual clock architecture" - Marvell agreed, enabled "external clock mode" on their chips, and JianHui's solution became the standard for future digital audio players.

In 2011, JianHui Deng founded Cen.Grand, with the goal of pushing even digital audio beyond anything that had come before. His focus moved towards DSD and after being turned down in his attempts to license DSD tech from Playback Designs, he set out to develop his own solution. 5 years later, after extensive research, he and his team successfully launched their DSDAC1.0 featuring proprietary DSD1024 upsampling. The follow-up DSDAC1.0 Deluxe came two years later, which beat out dozens of worthy (and often more expensive) competitors to become my reference DAC. With the inclusion of several other proprietary aspects ("clock blocking" and "synchronous direct clock" technologies) JianHui Deng humbly suggests that he has taken DSD beyond even what its creators envisioned in terms of realized potential.

Moving back to his analog roots, JianHui launched the 9i-906 Silver Fox headphone amplifier, which is an extremely complex design made up of over 1100 individual components. His philosophy is that well-designed simple circuits can hit the desired target in terms of tuning, but it takes a much more complicated design to transcend that level of performance and achieve something truly special. Again, based on what I'm experiencing from the device, he appears to be on the right track here.

JianHui's ambitions for the future involve revisiting the media player aspect to launch a world-class digital transport. Like many others in the high-end space, JianHui is not necessarily a huge fan of USB as it pertains to digital audio transmission. He certainly makes it work quite well in his DAC designs, but argues that it is ultimately a flawed solution for audio applications, and he thus intends to develop a better alternative. To do this he is working with Intel on a new product called the GLS1.0 - I don't have a lot of details yet but I know it received a patent in his home country and supposedly he is the first person to work with Intel on this level, much like his partnership with Marvell over a decade ago. At one point he was planning on implementing a proprietary format using a twin-cable system with Toslink and BNC connectors, and later he mentioned using PCI Express - I'm not clear if those are two separate ideas or if they are both describing different aspects of the same technology. Either way the claim is that it achieves 100% lossless, synchronous data transmission, capable of handling extreme data rates and even multi-channel DSD. The clock and data streams are transmitted separately for maximum integrity and then perfectly reconstructed on the receiving end. The GLS1.0 streamer/server device will likely be the next big launch from Cen.Grand and I look forward to learning more about the unique connection with Intel - it could be a game changer.

As for JianHui Deng, he sent me a few pictures which show part of his audio journey over the decades. I post these here with permission - we all have our own journeys with music and I find each one unique and fascinating. I also learned that his son was recently hired by the prestigious Duke University as a math professor. Which goes to show how the ability to handle complex equations runs in the family. I wish I could share the rest of the news I alluded to earlier but suffice to say I think we'll continue to see innovation and fresh ideas from Cen.Grand for years to come.






(on drums)


(now, in the Cen.Grand demo room full of great equipment)