Centrance DACmini PX Audiophile Desktop System in Review
Centrance’ entrance at TouchMyApps is the Mac mini-sized DACmini PX, an all-in-one DAC/headphone amp/power amp that plays with the big guys. Most of you already know Centrance and are familiar with their excellent USB DACs for guitar, microphone, and headphones. You know that their audio devices are free of noise. You know that they put on a steady and graceful show no matter what they are driving. You know that this review will end with a kiss.
Resolution: 24-bit (Also supports 16-bit)
Sample Rate: USB: Up to 96kHz, S/PDIF: Up to 192 kHz
Interface: USB1.1 or 2.0, driverless
Local clock: 10 ppm precision, unmeasurable jitter
Compatibility: Any computer running Mac, PC, or Linux
Nominal Output level: +6.0dBV (RCA outputs, line level)
Frequency Response: 20Hz…40kHz; +0.0dB / -0.1dB (Line or Digital inputs)
S/N Ratio: (A-wght) 144dB (Line inputs); 113dB (Digital inputs)
THD+N: 0.00022% (Line inputs); 0.001% (Digital inputs)
Crosstalk: -128dB (Line inputs); 118dB (Digital inputs)
Output Impedance: 25 Ohms (Line output); 10 Ohm (Headphone output) **
Output Power 1.5W: (headphone output, total), drives 32…600 Ohm headphones
Output Power 50W: (speaker output, total), drives 4…8 Ohm speakers
Max Output level:* +13.5dBV (headphone output, 32 Ohms load)
+18.6dBV (headphone output, 300 Ohms load)
+19.0dBV (headphone output, 600 Ohms load)
8817 Mango Ave
Morton Grove, IL
TEL: +1 847-581-0500
FAX: +1 847-581-0901
Class A Inside
I had coffee with Michael Goodman, Centrance’ Chief product architect. He’s a nice bloke who’s just become a daddy. He has a better beard than me. He may also be more down to earth – it’s probably the beard.
Speaking of earth, one of the features Centrance have been trumpeting is Class-A circuitry buried in their amps. The DACmini’s got it. Defining what it is is a marketing study. Put simply, it is a circuit whose output never idles. This dissipates a LOT more heat, but when done right, can result in very clean output, and, according to experts (and certain online demagogues), less distortion in the high frequencies.
That said, when Class-AB or D are done properly, the result can be very clean, with the added benefit of less heat dissipation. I can attest to the fact that the DACmini’s Class-A circuitry gets warm when powering a pair of headphones.
Let’s get onto the review.
Centrance’ machining is very nice indeed. All internal parts of the DACmini PX are hidden by at least 3mm of aluminium. The analogue and digital portions of the amp lie on separate circuit boards. So, too, does the split-ground transformer-isolated power supply. Centrance do all of this in the name of fidelity. There should be less cross-talk between components in a layout like this.
The insides are supported by aluminium tongues that Centrance dub ‘Antivibration stalibizer and internal EMC barrier’. I certainly hope the engineers and marketers got together over some good drinks, as, well, there’s a lot of hocus-pocus going on under the bonnet in the PX. You can read all about it here.
Despite housing so many different parts and warming so much air in its vast internal cavity, the PX is built very well. It’s not just the thick aluminium shells. It’s the firm and smooth volume pot and sturdy ringbolt-fastened headphone output. Neither its RCA ins and outs flex under straing. Every part comes perfectly flush with the aluminium fenders. It’s a study in utility.
In terms of build, Centrance cut no corners.
Ergonomics and Polish
Centrance flex their engineering muscles here more than anywhere else. Bristling with knobs and ports, the PX is a veritable armoury of inputs and outputs. It’s trim, but spare – utilitarian in all aspects.
It has several nice design touches. One is its pre-2011 Mac Mini footprint. The other, is its volume pot, which I’ve already mentioned. It is smooth and perfectly aligned. Some hack with a screwdriver didn’t battle it to the chassis. Next to it is the ingenious input selector, a small nub that looks for all the world like the MyST volume pot. It cycles through the various inputs with a flick forward or backward and switches instantaneously. Better still, as you cycle from source to source, music merely pops in. There is no sudden thud or pop accompanying input changes.
The PX comes with rubber feet that cover up the bolts on the bottom of the amp. They are dime a dozen in design, but do their job admirably. Remember, you’re not paying for user-aligned conical feet, backlights, VU meters, etc. and so on. Your money has gone into user-friendly design, a glut of digital and analogue inputs, and good sound.
Still, Centrance market this as part of the Audiophile Desktop System. I’m convinced of its audio fidelity and have no reason to doubt that it could be used in studios, but its primary market is the fickle (and easily swayed) audiophile. Audiophiles like two things: price/performance, and flash. The PX has price/performance, but it is about as flashy as a woollen driver’s cap. Its shape, being associated with a Mac mini, may do it no favours either, as Apple are one of the companies loyal audiophiles love to bag on.
The U Factor
The DACmini PX ADS is the ultimate all-in-one system. Tipping the scales at just below 2000$ makes it enticing enough for those who’ve eyed more expensive options, but it remains precious enough that it will attract the eyes of the upgrader.
At headfi at least, the DACmini PX was one of the components that introduced headphone geeks to the world of speakers. It’s not a bad step at all. In fact, I fully recommend it. I think it possible that some spec-drunk potential customers be turned off by the 25w*25w power amp. Shame. The power amp section is a D-class power amp. D-class amps have always been extremely efficient, and many really are audiophile powerhouses, rivalling, in some cases, the best AB and A-class amps. In terms of overall power, a 25w*25w D-class power amp can power sensitive speakers to insane levels. The speakers that come with the DACmini PX are very good matches to the DACmini power system, though you can do better.
If you live in Japan, or have no beef with your neighbours, it may be all you ever need. In Canada, Australia and other countries with vast tracks of land and houses the size of a block of apartments, the DACmini fills ‘smaller’ rooms perfectly. At 44m squared, my flat is considered generously sized. I’ve not once raised its volume passed 60%. Ever. The speakers can handle quite a bit of input power, but are small speakers. Push them too far and you will get compressed dynamics the same as you will with headphones.
While Centrance economised the power amp due to space confines, they most certainly did NOT on their headphone amp. A fine-sounding class-A headphone amp sits inside and puts the DACmini in a class all its own. In my flat, it fits under a small IKEA bookshelf. My DT880’s 3-metre cable runs perfectly to there from my TV, and with Mountain Lion at the helm of my Airport Express, I can use my Apple MacBook Pro remote to control the volume so I don’t have to wander over to my laptop or to the amp. Wonderful.
I’ve been without speakers since 2006. My former amp was a Sharp Auvi 1-bit Class D amp that output exactly 25mW per channel. Before that I used an ancient integrated Tannoy system.
I remember unboxing the Auvi back in 2001 or 2002. Perfunct packaging and slim, its refined lines made it a looker. I was 21 and impressionable. I was exactly the sort of person then that is probably looking at the ADS now. Except that, after reviewing so many pieces of audio gear, I’ve become even more impressionable. Experienced headphone geeks are always looking further afield. If not this year, next year they will have the new Burson integrated amp and a Beyerdynamic T1. Or STAX. As a hobby, there is no end in sight. But again I say, the DACmini may be the last headphone amp/DAC you ever need. It may in fact, be the last power amp you ever need.
Or, it will be the stepping stone for headphone lovers to cross over to the much more involving and better sounding world of speakers.
There are few amps as well-featured as the DACmini PX. Remember the Travagans Red? As small as a bar of soap, the Red sports a headphone amp and power amp, both of which do the job remarkably for their sub 300$ price. The Red plays with the big boys.
The DACmini PX is a big boy that plays with the bigger boys. It is fully 24bit 192kHz compatible, and effortlessly upsamples your music. If you want to plug in coaxial input, just plug it in. Turn the front dial to COAX, and go. Same with optical, line, or USB. There’s nothing to learn.
I think a few people may decry the lack of sampling/bit rate display, which I understand. When you play with the big boys (who often display sampling rate in LED arrays or OLED readouts), you should be ready to show them up. But that’s not part of the DACmini experience of no frills. What it boasts (beside its wonderful amp/DAC section) is incredibly strong, well-sealed connections and a good pre-amp output. The RCA and speaker terminals are as solid as oaks from their bristling positions on the outside of the chassis. I’ve used a number of gear at varying price positions that is no where near as strong or reliable. Centrance took care to ensure your investment will stick around.
Speaking of sticking around, the DACmini PX system comes in a giant Pelican case that’s about the size of a large carry-on. It is splash and soak-proof, crush proof, and and sturdy. After unpacking everything (if you live in America or Canada), toss it in your walk-in closet or garage. If you live in Japan… I’m still trying to find out what to do with it. Whatever the case, Centrance didn’t leave things to chance; they shipped your precious cargo in a box that will outlast your feeble bones. This attention, paid to detail and utility, is just one example of Centrance’ pursuit of customer satisfaction.
One other thing sets the DACmini apart: power settings. There is no off/on switch. The amp has an idle setting, enacted by turning the input selector to one extreme or the other, then flicking it once more in the same direction. Effectively, the machine falls asleep. It still draws a certain amount of power (all electronics do, even in off states) more than it would in an OFF state, but is a simple and effective method of combining motley functions.
Sound – Headphones
At first, I was just going to borrow the PX. It took about three days for me to decide that I wanted to keep it. I’m still scraping the last few yen together to pay it off, but this PX will be mine, and well, I can’t live without it. (My wife just rolled her eyes.)
But it’s true. The first three days with any new amp/DAC are pretty simple: set up, trial, error, and the frustration of matching curtains to anodised aluminium. After that, comfort sets in. This fully integrated system argues its case better than any other integrated system I’ve used. Size, power, build, simplicity – all in its favour.
Centrance made this thing for music. And made it well they have.
Let’s start off with background noise. Combined with the vast majority of headphones out there, the DACmini will exhibit no noise at all. That includes earphones. It goes without saying that with heavy weights such as the Beyerdynamic DT880 (of any impedance) it will render the blackest of blacks. It is in fact as black as many battery-powered portable players are.
The only time you may find noise is when you plug in sensitive earphones such as the FitEar To Go! 334 or Private 333. Still, the noise that will come out of either earphone is minimal, and compares rather favourably to the likes of the Vorzuge VorzAMP, an excellent amp made for on the go listening. Moving down the sensitivity ladder to something like the Grado GR8 and noise is completely gone.
Better yet, volume balance is extremely good. If the volume is off at the pot position of 6:35, by 6:37 it is completely balanced with FitEar To Go! 334. For less sensitive earphones and headphones, comfortable volume and balance are achieved simultaneously.
Yet, despite such finesse in noise and volume balance, there is no end of quality power for the biggies. My DT880 600Ω (again, not that hard to drive, but hard to get to very high volumes) are at their best when plugged into the DACmini. Even when fed by the comparatively weak line out of an iPod, I never rotate the volume past 1 o’clock (just past half way up – and that is when a train is passing). When adolescents on muffler-less motorbikes aren’t riding down nearby highways at 12 AM, the volume never veers past 11 o’clock. I often set the volume much lower.
Of course, I’ve done the typical stupid reviewer thing and rotated the volume pot way past safe listening levels with my headphones on their stand (aka Ikea lamp), and no matter the position on the volume pot, there is no crackle and pop from the DT880. Absolutely not phase errors. Part of that reason is the gain on the DACmini isn’t aggressive. Part of it is that Centrance have concentrated on bringing high quality rather than excessive volume to their amps.
People intent on destroying their hearing (and headphones) may be disappointed. I am sure that, if gained up, the DACmini would be capable of delivering another 10-15 decibels of noise to the DT880 with little to no distortion, but it doesn’t. It’s quality sound, not noise, that Centrance aimed for.
Regarding One area that I tend to be a stickler about is stereo separation – a facet of audio that can, when rendered at the correct frequency, make or break a ‘detailed’ sound. The DACmini is an interesting specimen. Typically, both mains and battery amps deliver best results in midrange or high bass frequencies; treble and/or low bass tend to bleed a little. Not so with the DACmini. Straight from the nigh inaudible frequencies of 20-40Hz, all the way to 20.000Hz, stereo separation stays a steady course. It doesn’t carve out great caverns of detail, but no one frequency takes the lead over another. Each is good, not great, but hammered together (assuming you are using headphones over 40Ω), the effect is altogether pleasing.
The one caveat with the DACmini is what seems to be a rather high Ω headphone output. The numbers I hear thrown around pin it at 10Ω. That means that low Ω earphones, and especially multi balanced armature earphones, will render a distorted signal. The Earsonics SM2, for example, loses up to a couple of decibels of bass and ‘gains’ hot upper midrange bloom. The SM2 is a difficult to drive earphone, proving many dedicated portable amps not up to their task, so consider the DACmini – a desktop amp – put up against a product it probably wasn’t meant to cope with. Centrance do offer an upgrade system where you can have the output lowered to 0 Ω. If you frequently use low Ω headphones and earphones, the upgrade will render your DACmini into the perfect desktop amp.
Quality of Sound
Apart from excellent balance, low noise, and nearly perfect control even at high volumes, the DACmini effuses a simple, straight sound that one could almost characterise as wire-with-gain. It is ever so slightly warmer than that tired trope, though.
The overall effect is effortless and smooth, and viscous in parts. It favours energetic headphones, which are exactly what I favour, too. The spacious Beyerdynamic DT880 is an excellent match and so is the energetic ES10. The DACmini also pairs well with the cantankerous Audeze LCD-2, though I can imagine a few people wanting even more drive volume – who they would be, and how long they’ve boxed professionally, however, is anyone’s guess.
Viscosity shows up in the low to middle midrange, enhancing vocals, strings, and guitar. Where it will impress the most is in acoustic music. Nick Cave’s pianos shine a bit more here and there, and the sweet Nicki Parrot sings sweetly as ever. I’m reminded of the intimacy of the MyST 1866, but delighted by this amp’s more linear output.
The DACmini plays a disappearing act. It isn’t grainy or harsh and it’s not overly warm, either. It has no jitter artefacts to speak of and as mentioned above, no noise. It’s a conglomerate of hasn’ts and isn’ts, but in the best way possible.
Its sound is more studio than it is live. Nicki Parrot’s rendition of Sakura Sakura is equal part vocals, equal part background instruments, until, that is, you sit back and relax. It’s all Nicki from here on in. The DACmini renders her forward and fleshy. She tickles your ears from the front and centre (for lack of a better term). You have the stars, and you have their satellites. Yet, despite central intimacy, satellites get no less detail. But here, subjective warmth meets its bounds.
Perhaps it is down to the DACmini’s negligible levels of signal distortion, or minimal ringing, whatever the case, this headphone amp comes off as pleasing. It’s wonderful, but not addictive. I’m a strong believer that anything addictive is in some way flawed or odd. Take Kraft Dinner for instance. It’s a cheap meal, and combined with SPAM, onions, garlic, and pepper sauce, the best thing for movie nights. But, suck it down more than once a month and you’re sure to beat your poor heart to a gooey death. And then there is Oktoberfest in Tokyo. Usually miffed, tight faces are smiling and singing above drinking and dancing bodies. But, it’s only for a few weeks per year and the sausages cost too much. The next morning, the train is as full of dead eyes as it ever was.
Addictive audio equipment has its appeal, but whether because of tuning or technical faults, it comes with a slew of caveats. High ohm output comes to mind. So, too, does distortion, roll off, and a fist full of other terms. The DACmini has no real faults in its headphone output – nothing at least that would lump it in the oddly addictive category.
Again, its Achilles heal is the rather high output impedance of 10 Ω. I suggest that the majority of headphone listeners will not be bothered by it simply because they are probably plugging in heavy-duty headphones, not earphones, into the DACmini. Still, if you are the type that uses earphones with desktop amplifiers, that 10Ω output is audible.
Overall, the DACmini is detailed, but not too detailed, warm but not too warm, linear, but not too linear, smooth- You get the drift. So, why am I purchasing it? Remember the part about the Japanese flat? The shiny black Aquos? Size has a lot to do with it. I neither need nor want a larger amp. Nor do I want a hot piece of aluminium burning a hole in my rubber floor (horrible Japanese invention). It took me about three days to acclimatise to the DACmini PX ADS. Had I listened in that time to headphones only, I may not have decided to purchase it. Why? Because I have like a billion other headphone amps. One, a fine unit from Graham Slee, does just about as good a job as the DACmini with the headphones I prefer.
Rather, it is because the DACmini does EVERYTHING very well. Everything, folks, includes amping speakers for small to medium-sized spaces.
I was forced into headphones in the early 2000s. Forced isn’t the best term. I love headphones and have since I was twelve.
As much as I like them, for me, the love for headphones was borne out of necessity. At twelve, I hadn’t the bank to roll a pair of speakers, appropriate amp(s), cables, CD/LP player, and power supply. I did have enough to hoard raisins and Pearson’s mints. Strangely, it was music, not cavities, that I collected through my teen years.
That lasted till I hit 20 in the year 2000, and landed a fantastically boring 9-5 job as a painter. I invested in a decent living room setup almost immediately. But, things as they are (and thanks to constant moving), I sold my living room setup. By 2006, I was speakerless and ampless, a poor man by any audiophile definition.
Only recently have my wife and I moved into a place that has the 30cm x 30cm space necessary to lay a speaker down on either side of the telly. Lo and behold, the ADS comes with two speakers. Being a DAC/amp company, Centrance’s marketing literature didn’t sell me on their speakers. All-in-one companies rarely do well across the entire gamut of their portfolio. I’m sure you can understand my penchant for honesty when I say I didn’t expect much from their speakers, ‘Masterclass’ moniker or no. The name grates against my better senses as much as the terms ‘authentic’, ‘professional’, and ‘audiophile’ do.
But in the weeks (and now months) since, I’ve begun to see beyond the name. The Masterclass speakers are compact, solidly made, and easy to hide from guests. Their piano finish is a little gaudy for this 33 year old (oops), but so is the nasty Sharp TV that towers over them (oops again). With the towering Aquos above, the trio look part and parcel of an Apple OSX screenshot from the early 2000s. Yikes. Then again, flash may be your thing. If they are, you will probably enjoy the view I saw in my photo studio.
Looks aside, Centrance’ speakers are pretty damn good. Centrance would have you believe that including the tweeter in the low-mid manifold allows more direct communication between the entire frequency spectrum and your ears. Basically, no delay. There are certainly no delay problems in this set of speakers, but then again, in order to settle that scientifically, you have to sit pretty damn far from the speakers and hunker down with noisome equipment. You also probably won’t have graduated with Honours with a degree in English Literature.
The Masterclass 2504 sound is an interesting mix of studio monitor and pill box gunner. Despite housing a single low-mid driver and one tweeter, low bass hits with ferocity. It is also strangely detailed for having come from such small speakers. Yet, unlike some ferocious speakers that pound you in the chest again and again, Centrance’ Masterclass speakers generally tread tenderly. They handle the midrange first from a resolving position, and secondly, from a position of intimacy. Let’s get back to Nicki Parrot’s Sakura Sakura for a moment. Nicki, singing in a tongue far from her home, has somewhat of a lisp. Fortunately, a Parrot lisp is nothing like a shiggy lisp. The DACmini PX/Masterclass combo renders her soft voice just as softly as a the Beyerdynamic DT880 does. What you get is the wet sounds of singing lips and throat, but nothing too graphic. Similar to its headphone out, the DACmini PX won’t render your favourite records into just bits. There is space for a few errors, but nothing large. Generally, for most music, the detail in the midrange and lower highs is simply spot on, and with good placement on a desk or on small stands, the speakers render sonorous mids.
Still, what is most impressive is the sheer amount of bass the small Masterclass speakers can dish out. In a small apartment like mine, a subwoofer is right out. Simply unnecessary.
Fine resolution is delivered down to the lowest quoted spec and the DACmini drives their load just fine. There is plenty of stretch in the high region and excellent positioning, though that is heavily dependent on where and how you set them.
I would suggest bringing them up off the floor, or angling them slightly up, to get the best frequency range from them. On the floor, lower mids can tend to boom. This is especially the case when watching movies. Very few studio albums of mine exhibit this boom, but just about every movie from Lord of the Rings to Jabberwocky and Eat the Peach drives part of me mad with tedious boom when set on the floor. Why? Probably because of the bass reflex port on the bottom. It needs to breath. If you don’t set the speakers optimally, that bass port will reflect high bass/low mids back up into the co-planar cone and back in your face. If you can set them a metre from the ground, they will treat you to their best.
Unfortunately, these masterclass speakers lack mounting hardware or cleats. If you’re as hard-put as I am to find a nice speaker stand, why not try a plastic Ikea stool? The three-legged version works wonders for the midrange, and its glaring plastic hues offset the piano finish somewhat.
Midrange boom eliminated, I can fully endorse these speakers. In fact, set up properly, they can be at the centre of a pretty decent audio system.
Plug & Play and iPad
If you have a Mac, PC, or an iPad, just slip in your USB and get grooving. There is nothing to set up – that is, unless you want 24bit/192kHz, in which case, PC people are stuck at 96kHz. The iPad has its limitations, too, but with a Camera Connection Kit, music is plug & play.
The DACmini’s DAC derives its power from the mains, so there is no worry about the iPad’s 20mA USB output. Jailbreakers: iPod touch 4/5G and iPhone 4/s (and presumably an iPhone 5), can use the Camera Connection Kit, too, with the purchase of Big Boss’ CameraConnector, which rings in at 99 cents.
In fact, I am currently enjoying Nick Cave’s Brompton Oratory from an iPod touch 4, which is wonderful. There are a number of DAC units out there that require more than 20mA to run, essentially requiring a netbook, or a USB hub.
Alternatively, you could use the optical output from the Venturecraft Unit 4.0 or the the coaxial out from the AlgoRythm Solo.
All that said, the DACmini PX and ADS isn’t without its faults. Each is quite small relative to the performance and cost effectiveness that it serves; nonetheless, take note.
1. Volume pot static
Firstly, when using sensitive earphones and headphones, turning the volume pot will reveal static from the headphone output. I do not notice this via the speaker terminals. The good news is that the static only affects output whilst the volume pot moves and with sensitive earphones.
2. High Ω headphone output
As mentioned elsewhere in this review, the DACmini has a rather high Ω output from its headphone output. Again, this is a desktop amp/DAC. Quantitatively, fewer sensitive earphones will be plugged into it than, say, a Venturecraft Unit 4.0 (which is comparatively naff). Centrance measured the DACmini’s output at 10Ω. It’s not high enough that headphones like the Audio Technica ES10, AKG K701, and certainly the DT880 will hear andy differences, but as noted above, the FitEar ToGo! 334 and Private 333, will sound dull when plugged in. Centrance offer a 0Ω modification that will bring full resolution to every headphone in your collection. You will have to decide for yourself if it is worthwhile or not. So will I.
Finally (and perhaps most annoying), is DAC freezing. Typically, I plug several items into a single amp at one time. The DACmini is simultaneously plugged into a Macbook Pro (optical), iPod touch (USB), iBasso DX100 (coaxial), and an iPod nano (line input). Plugging and unplugging the USB from the iPod touch and into the MacBook Pro and vise versa, can cause the input selector to freeze, followed, at times, by the DAC.
The simple fix is as simple as just resetting by unplugging the power and replugging it in again. Annoying, but a solution. I am not sure if a firmware update can fix this issue or not.
Centrance’ focus on utility and construction quality is practically myopic; there is simply nothing they leave to chance. While I don’t suggest dropping or blending your DACmini, I do believe that it could withstand quite a beating. The DACPort opened my eyes when I demoed it back in Korea in 2010. I didn’t expect such a small item to sound and work so well. But the DACmini bests it in every quantifiable metric except size. It boasts the same black background, but is much more powerful, and bristles with useful ports. But the killer feature for audiophiles on the move, is that it serves as a decent power amp as well. Bought as part of the ADS package, the PX takes centre stage. Through speakers or headphones, it is a level-headed, reference-quality machine that has my full recommendation.
Good power amp and speakers
Myriad standard connectsions
Fully mains-powered DAC
Static in the volume pot (with sensitive earphones)
High Ω headphone output
Hot damn! Headphones really are a rockin’ way to enjoy music, right? Feel free to explore TMA’s headphone oubliette
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