Imagine yourself in charge of a traditional HiFi speaker company - a segment where sales are trending relatively flat (or worse) for the past decade or so. You look at the market and salivate at the rising sales figures of the "personal audio" category, pondering how you might get a piece of that action. Slowly, cautiously, you begin having your team translate their design prowess from speakers to headphones, under the assumption that they have a lot in common - it certainly makes more sense than designing turntables (the other hot category at the moment).
If this sounds too measured and reasonable, an alternate version has the boss sending excited emails: "Headphones are hot! I want a set of our headphones on store shelves within the next 6 months!!"
I suspect one of these scenarios has unfolded numerous times throughout the audio world; hence recent launches of headphones from KEF, Polk, Sonus Faber, PSB, Focal, Paradigm, Bowers & Wilkins, and Klipsch, with plenty more to follow.
It was only a matter of time before a similar scenario took place on the amplification side of things. Why should brands relatively unknown outside of headphone circles - Woo Audio, Violectric, Cavalli, and Eddie Current among others - have all the fun? Thus we now have dedicated headphone amps from the likes of Pass Labs, Bryston, ModWright Instruments, and Manley, just to name a few, with more certainly on the way as time passes.
Well, now you can add veteran Canadian firm Simaudio to the list. Their Moon Neo 430HA sets out to offer world class heaphone amplification along with preamp and optional DAC duties, all in a very traditional Simaudio enclosure. Ever notice how a lot of headphone amps are oddly sized and/or shaped? The 430HA fits right in with the entire line of Simaudio Neo products, and wouldn't feel out of place in most any proper audio rack stuffed with full-size audio components.
Let's clarify before we go any further - the "base model" 430HA is a $3,500 beast purely dealing with analog ins and outs. Adding the optional DAC board brings the cost up to $4,300 and updates the name to 430HAD. Or, at least that's what I've seen it called all over the web. And it makes sense - D for Digital, right? Thing is, I don't see that extra D mentioned anywhere in Simaudio's technical papers, nor have I ever seen their marketing actually use the term. Go ahead, check their website - you won't find it. So, I'm going to resist the urge to use what is essentially a nickname at this point, but I will be discussing the DAC board since I feel it is one of the strong points of the product, regardless of moniker.
Let's talk versatility. Perhaps owing to it's relatively large size compared to many headphone amps, the 430HA has a generous amount of connectivity. Remember, this thing can be a full-fledged pre-amp as well, so the more choices the better. We get three analog inputs - two RCA and one XLR - along with a pair of RCA outputs in fixed and variable form. On the digital side there's a Toslink jack, a pair of coaxial inputs, and the ever-important, DSD-ready USB port. Less likely used but still potentially helpful are the proprietary SimLink ins and outs (for pairing with other Simaudio gear) plus a 12V trigger out, IR input, and RS232 for custom integration. That's already quite a bit and we haven't even covered the actual headphone jacks - ostensibly the most critical aspect of a device like this.
At first glace, the front panel looks simple - just a standard 1/4" headphone out, plus a little 1/8" input for quick use with iPhones or other portable devices. Take a closer look and... you probably still won't see anything beyond that. But wait - what's that little nub just left of the 1/4" jack? Sliding it left (with a buttery smooth action I might add) reveals balanced headphone outs in both 4-pin XLR and dual 3-pin XLR format. That means the 430HA handles every common headphone termination short of specialty stuff - I'm talking balanced connections on the Astell & Kern, HiFiMAN, and Pono devices, where each brand uses their own unique type. But as far as the vast majority of gear goes, Simaudio has us well covered.
Internally, the 430HA is just as ambitious. Simaudio describes it as a "fully balanced, pure analog amplifier" using a "discrete transconductance circuit topology". The power supply features two shielded torroidal transformers, 35,000uF worth of capacitance, and a total of 7 stages of voltage regulation. Design inspiration is taken from Simaudio's Evolution series models such as the 740P preamp ($9.5K) and the 810LP phono stage ($12K). That's not bad company to be in.
Significant engineering was brought to bear on the volume control - an absolutely critical aspect of any high-end headphone amp. It usesSimaudio's proprietary M-eVOL2 design, again borrowed from other tried and true models in the Simaudio portfolio. This essentially boils down to a pair of current steering R2R ladder DACs on each channel (so four total, as is befitting a true balanced design) to vary the amplitude of the signal. It gets a bit complex but just know that the audio signal remains in the analog domain at all times, unlike some digital attenuation schemes which throw out bits as the volume drops. The end result here is an obscenely black background, essentially perfect channel matching, and 530 total steps in .1dB increments. It's a brilliant execution that you really have to "feel" for yourself to fully appreciate.
Expensive headphone amps should give correspondingly high performance, and that's the context in which I judged the 430HA. On the plus side, this thing drives any pair of headphones you can throw at it without breaking a sweat. It's capable of dumping 8 watts into 50 ohm loads, yet delicate enough to drive sensitive IEMs without unwanted noise. That last bit is a serious difficulty with powerful desktop amps, and is often overlooked in many reviews. Lots of amps are powerful, but a silent background and ability to drive very sensitive IEMs well is a mark of excellent design. I mean it - this thing works with any headphone except electrostatic models (of course).
Now, you've no doubt heard that statement in reviews of other headphone amps from a variety of publications. Those reviewers likely then proceeded to list the 3 or 4 or 5 headphones they used to arrive at that conclusion. Which is cool - that seems thorough enough right?
Me, I like overkill, so I tested no less than a dozen headphones on this thing, plus a half-dozen in-ear monitors just to seal the deal. I tried everything from the 600 ohm beyerdynamic T1 to the AKG K3003 which dips down into single digit impedance. I used some balanced-armature-based custom IEMs with sensitivity in the 120dB range, and then switched to the HiFiMAN HE-6 rated at just 83.5dB. I used cables with 1/4" termination,1/8" plus adapter, 4-pin XLR, and even dual 3-pin XLR which is a style I thoroughly dislike. Through all this I can say the 430HA never missed a beat. That volume control is superb - I never once found myself unable to dial in the perfect level for a given headphone or IEM. There are two gain settings (14dB and 20dB) but I found that the lower option worked for me 99% of the time.
Surprisingly, I also quite enjoyed the selectable crossfeed option. Crossfeed is a method of blending information from the left channel into the right channel and vice versa, with the intention of creating a more natural sound. Headphones, by nature of their design, completely isolate the signal going to each ear. This can take away their sense of realism at times - especially if you're mainly accustomed to speaker listening where the channels obviously mix before hitting the ears. There are many ways of implementing crossfeed and much of the time I find it more obnoxious than helpful.... it tends to collapse the soundstage and make the timbre all wonky, while the "natural" effect it strives for never really materializes.
In this case I find it actually listenable. No, scratch that, I find it pretty damn convincing. It's not too strong but not too subtle either. It doesn't change the tone of Lee Morgan's trumpet. It's not dark and compressed. All of these things I've heard from other attempts at crossfeed, so I'd call Simaudio's implementation a success. Nothing's perfect though, and I do hear a somewhat diminished sense of imaging in exchange for the "out of head" sound being produced. Image specificity is a bit hazy and indistinct compared to what I'm used to, though I suspect speaker listeners might not agree. Headphone listening is, after all, something of an acquired taste, and I'm so used to the standard presentation that I may not be the best judge of something like this. For speaker listeners, the crossfeed circuit may well be preferable even in the imaging department. Me, I still use it off and on, especially with hard panned older jazz and classic rock material.
By now I've established that the 430HA has no shortage of power, while retaining the delicacy required to successfully drive IEMs. I've also praised the crossfeed implementation as one of the best I've heard. But aside from that, how does this thing sound? Why am I dancing around on that stuff when I have yet to paint the sonic picture of how this amp is voiced?
I suspect my delay is related to the mixed feelings I have. On the one hand, this amp does numerous things right. In some aspects - volume control, connectivity, and the ability to drive any headphone - it may well be the best headphone amp on the market today. It's an incredibly well-built amp with a thoughtful design, using quality parts, and it comes from a veteran audio firm with enormous pedigree. Which is why it's difficult to admit, but the actual sound signature of the amp itself just isn't what I hoped it would be.
To my ears, across a wide range of headphones, the 430HA has a powerful sound which I'd describe as "musical". There's a distinct warmth involved - from Gary Karr's "1611 Amati" (which turned out to be neither) to Pastorius and Mingus, and forward in time to well recorded electro from Mr. Oizo, Infected Mushroom, and Photek, the 430HA has low end guts very few competitors can match. If you like a healthy does of sledgehammer-in-the-face, this amp can certainly do that. If you like beautiful, nuanced, full-bodied tone, it can do that too. If you want a more measured and delicate response without any added warmth whatsoever.... the 430HA isn't necessarily the best match. It wasn't so obvious at first but the more time I spent with it the more I realized this coloration was always present. Did it make the music sound more enjoyable at times? Absolutely. If it was just this one bit of coloration I probably wouldn't complain. Problem is, the warm signature doesn't stop there.
Detail retrieval is what I'd call good but not great. It helps to have that inky black background, and with some (many?) headphones it seems to unlock all the resolution they are capable of producing. But with a Sennheiser HD800, an AKG K812, a HiFiMAN HE-6, or a Jomo Audio 6R IEM, I get the impression some detail is being glossed over. I'm all for warmth and smoothness but this goes just a bit far for my taste. The resulting sound is a bit slower than I'd like, and not really as transparent as I would have expected either. Piano and strings in particular just don't have the proper sense of bite required to sound totally convincing. Female vocals are generally acceptable but at times feel a bit lacking too. This would be fine for a tube amp where I had options to roll in a different signature if desired. But on a reference caliber solid-state amp I guess I just expected more transparency.
And that's where my complaint gets complicated. You see, I actually quite enjoy listening to the 430HA in the right context. Paired with the very neutral Anedio D2 DAC, and driving the HiFiMAN HE-6 which is occasionally bothersome in the treble range, I find the resulting sound to be very listenable. Or, switch out the Anedio for the Resonessence Labs Invicta Mirus Pro (using the spectacular new ES9028Pro DAC chip), and maybe swap out the HE-6 for the analytical Sennheiser HD800, and again we get a system I could jam to all day. Trouble is, I don't feel it's quite worthy of the high price tag - I can definitely assemble a similarly musical system for less dough. It's frustrating that although the amp will happily drive any headphone in existence, it won't necessarily have the proper synergy with each one. In fact I'd say there are more misses than hits overall - any somewhat darker headphone just isn't a good match in my book.
What's the deal here? Is this amp just a failure? How did that happen? I'll come right out and say that I feel Simaudio voiced this amp for speaker-listeners. It seems very intentionally designed to avoid listener fatigue, which can be a big issue when the distance from transducer-to-ear drops from 12 feet to about an inch. When that happens, the amount of micro detail coming through grows significantly. That album which you've always found ever-so-slightly bright on your speaker rig? It can become intolerable if you're not used to anything but speakers - even on a system which headphone aficionados would call "neutral".
My theory is that Simaudio had this very thing in mind when putting the finishing touches on the 430HA. Compared to other "reference" style amps such as the Auralic Taurus MKII, the HeadAmp GS-X MK2, or a pair of Questyle CMA800R amps in dual-mono mode, the 430HA sounds a bit slow and - as much as it pains me to say this - almost boring in a way. Yet those amps might be seen as overly bright or aggressive to ears more accustomed to speaker listening. Which, I'll happily admit, is not the demographic I fall in to. So the thought occurs to me that this may well be an issue with my preferences and expectations rather than a real deficiency with the amp itself. I suppose it's a matter of perspective.
My experiences with other Simaudio gear throughout the years gave me certain expectations. I loved every amp of theirs I've encountered, from their entry-level integrated units to their big Evolution amps. In contrast, I've never really clicked with their digital stuff. I've owned or auditioned various CD players of theirs in the low-to-mid range and even tried some of the (rather expensive at the time) DVD players like the Stellar and Orbiter back in the early 2000s. None of it was terrible but neither did it strike me as being anything special in a sea of worthy competition. I really wanted to love them based on my history with Simaudio amps - but I just couldn't.
So you can imagine my surprise when the amp section of this dedicated high-end headphone amp didn't blow me away, yet the $800 add-on DAC section managed to stand out as being a huge success. Seriously... most add-on DACs begin at "forgettable" and go downhill from there. Not this thing. It's got excellent resolution, impressive imaging, and a tonal balance that just works. I'd happily put it up against any sanely priced DAC I've heard in the last few years.
And that's not just hyperbole. Direct comparisons are easy thanks to the multitude of inputs/outputs on the 430HA, so I took the opportunity to run it through its paces with a few other units I have on hand. Compared directly to the Woo Audio WDS-1 ($1,195), the Simaudio DAC is more open and airy sounding, with a much more believable top end. It's not even a close contest. The M2Tech Young DAC ($1,695) has a touch more midrange liquidity, and thus initially seemed more organic than the relatively matter-of-fact Simaudio DAC. Yet after much back and forth I discovered the Young doesn't satisfy in terms of bass impact and texture. It sounds loose and sloppy where the Simaudio is very tight and impactful. And again, that Simaudio top end is so clean, making the otherwise respectable M2Tech unit seem a touch dull in comparison. Out of these three models I would choose the Simaudio DAC every single time.
I suppose it's an unfair comparison though. The DAC card only "costs" $800 but ends up piggybacking on the existing power supply and output stage. Which means it would cost quite a bit more if offered as a stand-alone product. In any case, you'll have to move up to something substantially more costly to improve on this experience - an Auralic Vega or an Exogal Comet Plus for example. Unless you already own or have plans to own a REALLY nice stand-alone DAC, I'd say go for the built-in option and simplify your system. It's that good.
As a preamp, the 430HA is about on the same level as the DAC. Which is to say: highly satisfying, though in this case I'm not surprised in the least. I have less experience with Simaudio's line-stage gear as compared to their DACs and amps, but what I have heard I've really enjoyed. The most recent example I had in my system was the Moon 350P from just a few years back. It was their most affordable preamplifier at $2,500 and did a bang up job in that class and beyond. Despite being primarily focused on headphone amplification, the 430HA is easily just as capable a preamp as the 350P - perhaps even a bit better as far as purity of sound. It does give up a bit in terms of inputs/outputs but makes up for that in transparency. Not to mention that volume control which is so much more satisfying to use. The 350P volume control was perfectly fine but the 430HA feels much more precise and, in a word, expensive. Unless you absolutely need all those extra ins and outs, the 430HA is hands down the better preamp.
Conclusions
In the end, I am somewhat torn on the 430HA. I love the look and feel of it, and very much enjoy the crossfeed option too. I could easily see using this thing as the heart of all but the most complex system thanks to its generous connectivity options. It would sound great as an integrated DAC and preamp, being very competitive in those areas. If I was shopping for that sort of device in the sub-$5K range I would certainly consider this device regardless of the headphone aspect.
Having said all that, I'm not completely sold on it as a reference class headphone amplifier. It just seems to lack the level of transparency I crave. Mind you, it's still an excellent headphone amp - superior to the BHA-1 from Canadian competitor Bryston ($1,695) to name one example. But for $3,500 I expect to be blown away and in this case it just doesn't happen. I prefer the warmth of my Violectric V281 which doesn't sacrifice detail in the process, and doesn't cost as much either. And the Pass Labs HPA-1 is clearly the better amp as far as I'm concerned (though, as with the Violectric, you lose out on the non-headphone related features compared to the 430HA).
I admit to being in the minority here. Headphone maestro Tyll Hertsens raved about the 430HA as have many others in the community. Then again, Audio legend Bob Katz described the 430HA as "overly soft" so I know I'm not crazy. Perhaps this is ultimately one of those products like the Chord Hugo and the Beyerdynamic T1 where you really need to try it for yourself to judge. Where I hear a lack of transparency and finesse, others may very well hear a speaker-like, fatigue-free presentation unique among top solid-state headphone amps.
Despite my misgivings, I'm still thrilled to see a company like Simaudio take the plunge into headphone gear. They recently launched a sibling model dubbed the 230HAD which is a smaller integrated DAC/headphone amp without the balanced outs. At nearly 1/3 the price of a DAC-equipped 430HA, that could well be the product I was looking for all along. I definitely look forward to taking it for a spin one of these days.