Pros: Versatile, well built, powerful
Cons: No analogue input, not the best value for money based on sound in its stock form
The Audinst HUD-DX1 was sent to me by Audinst as a free sample for the purpose of doing this review and including it in my recently started $250+ amp/DAC comparison thread. A big thank you to Audinst for sending it to me!
The Audinst HUD-DX1 is available from numerous online and domestic resellers with prices ranging from $399 to $450 at the time of this review. This is a link to the current Amazon listing for the HUD-DX1 :
For more information about the HUD-DX1 you can also visit the Audinst website:
I’m not in any way affiliated with Audinst Inc.
Short introduction to Audinst Inc.:
Audinst Inc. is a Korean based company that was established in 2009.
This is what they say about themselves on their website:
Audinst Inc. is audio component manufacturing company that launched in 2009. With the goal of bringing PC-based audio components to the hi-fi grade level, the company possesses technical staff with excellent know-how’s on digital and analog sound technology along with professional designing part with outstanding aesthetic senses in external-type equipment design. We are putting our utmost effort in making unique high quality products for both domestic and overseas markets, to become the unrivaled, leading company in the field.
About me:
I’m a 43 year old music and sound lover that changed my focus from speakers to headphones and IEM’s about five years ago. At that time I realized that it wasn’t realistic for me to have all the different setups that I wanted and still house a family of four children and a wife so my interest turned first to full sized headphones and later also IEM’s.
My preferences are towards full sized open headphones and I believe that also says something about what kind of sound signature I prefer (large soundstage in all directions, balanced and organic sound).
My music preferences are pretty much all over the place (only excluding classical music, jazz and really heavy metal). My all-time favorite band is Depeche Mode although I also listen to a lot of grunge/indie, singer/songwriter/acoustical stuff as well as the typical top 40 music.
I tend to value function over form within reasonable limits.
I do not use EQ, ever.
I’m a sucker for value for money on most things in life Head-Fi related stuff is no exception.
Built, accessories and functionality:
The Audinst HUD-DX1 is a solid state headphone amplifier and DAC combo.  
The HUD-DX1 is available in two different colors: black and white. I’ve got the black version.
Output power is rated to 1,500mW@ 32Ohm when running on DC power and 500mW@32Ohm when running on USB power. Output impedance is rated at 2Ohm.
The HUD-DX1 has a sturdy, albeit slightly generic looking, housing that feels durable. The physical controls available on it do feel reliable although I’d have preferred an even more solid volume knob. Speaking of physical controls those sums up to a switch to choose between headphones put or line out, input selector combined with an off switch and the already mentioned volume control. Although it doesn’t feel very heavy the overall build still feels solid enough for a desktop unit and its weight is actually identical to the iFi Micro iDSD
The HUD-DX1 offers one USB B digital audio input and one separate DC power input should you prefer to not use USB for powering it. It also offers both optical input as well as output. There’s also not one but two headphone out sockets: one 3.5mm one and one 6.3mm one. I find this very handy for comparisons but even more so for being able to use any headphones or IEM’s without the need for an adapter. In addition there’s also a RCA line out option, I’d like have liked an analogue input as well to be able to combine it with other, non-digital sources.
The HUD-DX1 works very well with Android when connected with an OTG cable and using USB Audio Player Pro (UAPP) as music player. Although Android and sound does not have a great reputation the HUD-DX1 have worked with every Android device I’ve tried it with (sometimes with the help of UAPP) even without using the DC power adapter but just from USB power. One feature of the HUD-DX1 that I really like is that it deliver less power when connected only to USB, this makes battery drain less as well as adding compatibility with more devices. That being said battery drain is still pretty severe when using it with a phone or tablet running on USB power alone.
The HUD-DX1 uses an Xmos USB receiver that is supposed to work with Apple devices using the Camera Connection Kit (CCK) but I haven’t been able to test this myself.
The HUD-DX1 support all popular file formats for audio up to DSD128 and 32bit/384kHz files.
The accessories included are:
1 USB cable (USB A to B Type, 1.5M)
1 User's Manual (including warranty card)
4 spikes for fixing (to attach the main body to the floor)
1 L-wrench (to attach and detach the volume knob)
1 Power adaptor (DC 12V~15V)
The specs:
Dimensions / Weight
104(mm) x 120(mm) x 34(mm) / 300g

Headphone Output
Type : 6.35mm Stereo phone jack / 3.5mm Stereo mini 4-pole jack
Max Out Level : ±10Vpp@600Ω(When removing the gain Jumper)
Max Output Power : 1.5W @ 32Ω
Output Impedance : 2Ω (Load : 16Ω ~ 600Ω)

Line Output
Type : Unbalanced RCA
Level : ±3.2Vpp max
Impedance : 200Ω

USB Audio
Type : Max 32bit 384kHz, USB 2.0 High-Speed
OS Support : Windows 7 / 8 / 8.1/ 10, Mac OS X Compatible

DSD Playback
Native DSD Support : DSD64 (2.8 MHz) / DSD128 (5.6 MHz)
DXD Playback
DXD Support : DXD 24bit 352.8 kHz ~ 32bit 384 kHz

PCM Playback
Bit depth : 16 / 24 / 32-bit
Sample rate : 44.1, 48.0, 88.2, 96.0, 176.4, 192.0 kHz

Digital Input / Output(PCM Only)
Type : S/PDIF Optical on TOS-LINK 44.1~192kHz
Format : IEC-60958, S/PDIF Compatible
Sample rate Detection : 44.1, 48.0, 88.2, 96.0, 176.4, 192.0 kHz

D/A Converter
Type : 32-bit Hyperstream Reference Stereo DAC
DNR : 127dB
THD+N : -120dB

Operating Voltage : ±12V(with DC Adapter), ±5V(USB Bus Power)
I/V Converter : MUSES8920E (SMD x 2)
Differential Amplifier : MUSES8920 (DIP)
Line Out : MUSES8920 (DIP)
Headphone Out : TPA6120A2 (SMD)

Power Supply
DC 12V ~ 15V
I’ve used the HUD-DX1 for the last couple of weeks and my unit has played for well over 100 hours.
Demo list:
Mark Knopfler – Sailing to Philadelphia
Røyksopp (Feat.Susanne Sundfør) – Save Me
Ane Brun – These Days
Michael Jackson – Dirty Diana
Metallica – Die Die My Darling
The Peter Malick Group – Immigrant
Eva Cassidy – Songbird
Thomas Dybdahl – A Lovestory
Norah Jones – Don’t Know Why
Celldweller – Unshakeable
Jack Johnson – Better Together
Seinabo Sey – Younger (Kygo remix)
Dire Straits- So Far Away
Björk - Moon
Lupe Fiasco - Deliver
Morrissey – Earth Is the Loneliest Planet
Sound impression:
I’ve got to be honest and admit that I find it pretty difficult to describe the sound from an amplifier. To me the sound of headphones/IEM’s is more easy to describe than that of amplifiers and DAC’s but I’ll do my best and hopefully the comparison section will also be of help.
The first thing that I noticed when I started to listen to the Audinst HUD DX-1 was the warm and engaging sound with great bass and dynamics drive it produces.  
Bass extension and quality is very good without any noticeable roll off in the lower frequencies. Mid- and upper-bass is well represented making the presentation more intimate than airy.  Although the impact of higher bass is quite high on the DX-1 it still feels fairly detailed in its presentation.
The midrange is liquid and lush with a good amount of warmth, with good help from the bass presence. Male vocal has good weight while female voices are full and smooth but lack some air and sparkle.  
The treble is also full warm and lush with good extension. The treble presentation stays well in line with the rest of the frequencies and once again I find myself wishing for some more air and sparkle.
The HUD-DX1 has better soundstage depth than width and I’d describe the presentation as intimate with good bass drive and dynamics but lacking some air and sparkle and actually sounding a bit dull with some pairings and music.
Please note that the comments in the comparison section are not in absolute terms but in comparison between subject A and B. This means (as an example) that if subject A is found to be brighter than subject B it does not necessarily mean that subject A is bright sounding in absolute terms. I hope this makes sense.
In these comparisons I’ve been listening through my AKG Q701’s.
I’ve been using the USB input when doing these comparisons. Both units has been hooked up to two different laptops both running Windows 7 with the same settings and I use MediaMonkey as my player of choice.
Burson Audio Conductor V2+ (1,499) vs Audinst HUD-DX1:
Compared to the HUD-DX1 the V2+ has more airiness in its presentation as well as a larger soundstage width. The V2+ has better bass presentation with a higher quality (better layering) while impact is pretty similar.  The greater bass quality makes the V2+ equally dynamic sounding but with better defined bass and more airy presentation while the DX1 is duller in its presentation in comparison. The DX1 is good when it comes to detail retrieval while the V2+ is top notch. In short I’d say that the V2+ is the more realistic sounding out of the two.  
The V2+ of course has some other advantages as well such as significantly higher power output (4W @32Ohms compared to 1.5W@32Ohm on the Audinst), two analogue RCA inputs and both pre-amp and DAC direct RCA outputs. In addition it also has a great quality remote control. The HUD-DX1 on the other hand offers an optical output, is if not portable so at least moveable around the house, work with only USB power and is of course smaller.
Although both these are both desktop units that offers multiple inputs and outputs the V2+ pulls ahead on both sound quality as well as build quality and should also do so costing almost four times that of the HUD DX-1.
iBasso D14 Bushmaster ($249) vs Audinst HUD-DX1:
Compared to the Audinst the D14 has a more airy and brighter presentation. The Audinst has more bass presence and is definitely the warmer sounding of the two. The D14, being brighter, also gives a perception of having better micro details while the Audinst offer more energy and attack while still maintaining warm and smooth. The treble on the D14 is more airy, detailed and natural to my ears. Overall the D14 is brighter and more detailed while the DX1 is more dynamic and warmer sounding.
Feature wise the D14 offers both coaxial and optical inputs in addition to the mini USB input. It does also have an analogue input which the HUD DX-1 does not have. The Auidinst has an old school USB type B sound input in addition to an optical input. The Audinst also has both optical and RCA line outputs while the D14 has a 3.5 mm line out in addition to its 3.5mmheadphones output. The Audinst has the dual headphone outputs, one 3.5 and one 6.3mm. The D14 also has an internal battery making it more versatile when used with phones and tablets on the go. The footprint of the D14 is quite a bit smaller. Build quality feels very solid on both units with the D14 pulling slightly ahead.
For even further comparisons feel free to visit this thread for breakdown between more $250+ amp/DAC units (this is a work in progress and several other units will follow in the near future).
Op Amp rolling:
The HUD-DX1 come equipped with the highly regarded MUSES 8920E op amps in its stock form. I happen to have a couple of Burson Audio V5i op amps around  (thanks to Burson Audio for sending me the samples) that is compatible as a direct replacement for the 8920 so let’s see what happen if we switch the op amps.
The op amp’s in the HUD-DX1 is DIP 8 socket mounted so they’re very easy to replace. If you’d like to try this for yourself make sure that you put the op amps in the correct way and that the op amps in use are compatible with the DX1, as long as you’ve got this covered it’s a very simple procedure to switch them.
The Burson Audio V5i ($39 for one or $69 for two) is available from here:
After having properly installed the V5i instead of the 8920 I started listen with the VE Zen 2.0 since they were the last pair I used while doing the matching section and WOW!!!!
This was truly a surprise. Although I’ve done quite a bit of op amp rolling before I’ve always considered it to be fine tuning and the changes to be pretty subtle. That’s certainly not the case here. When listening to the HUD-DX1 with the V5i installed it’s really as if a vail is lifted from the stock sound. The DX1 does still have a prominent low end with good drive but now it’s supported by a lot more airy midrange and treble and an easily detectable wider soundstage. The overall sound does now remind me a lot more of that from the Conductor V2+ although not necessarily with the same quality.
To me the $69 V5i op amps take the DX1 from being OK sound wise to being very good.  This is a highly recommended tweak in my opinion and I honestly cannot believe the difference in sound quality that’s achieved by using changing the op amps.
The output impedance of the headphone out on the HUD-DX1 is rated to 2Ohm. This means that it may not be the ideal partner with headphones and IEM’s with lower impedance than 16 Ohm.
In this section I’ve tested how some of my favorite headphones but also one earbud and one pair of IEM’s pairs up with the Mojo.  
AKG Q701 ($300):
The Q’s pairs up very nicely with the HUD-DX1. The warm and dynamic sound of the DX1 suits the Q’s very well. The Q’s has enough energy in the higher midrange by themselves to never feel dull or unengaging with the DX1 and the treble feels full and well-articulated in this pairing. The DX1 has no problem at all to power the Q’s to louder listening levels even when only powered from my phone.
Philips Fidelio X2 ($300):
I’d suspect that the X2’s, being quite warm and full by itself, wouldn’t be the best match for the DX1 but this is actually not the case. The X2 sounds very engaging and fun in this pairing. This is exactly the way I love the X2’s with great dynamics and a presentation that never gets boring in any way.
VE Zen 2.0 ($138):
The Zen 2.0 is a 300Ohm earbud that I like a lot and tend to use instead of closed headphones.
The soft and smooth signature from the Zen 2.0 works very well with the more dynamic presentation of the HUD-DX1. The full and smooth presentation of the HUD-DX1 gives the Zen 2.0 a great drive and this combination is very enjoyable
Aurisonics ASG-1PLUS ($500):
The ASG-1PLUS is an 11Ohm hybrid IEM (1 DD + 1 BA).
The 1PLUS has an excellent out of head presentation and its bass (especially mid- and upper bass) is a bit subdued. This works really well with the character of the DX1 that fills in more bass giving the 1PLUS a dynamic and enjoyable presentation.  
Super Audio 6 ($250):
The Super Audio 6 (SA6) is a six BA driver Chines DIY offering. It has a warm, smooth, intimate and mid-centric overall presentation.
The combination of the HUD-DX1 and SA 6 makes for a relatively unengaging listening experience in my opinion. The SA 6 lacks a bit of energy and is intimate enough it its own signature and this is even more obvious when paired with the DX1. To be honest this combination is not the best I’ve heard the SA6’s but it’s a big difference between that and it sounding bad, which it’s not.
To sum up the matching section the signature of the HUD-DX1 does make some of my headphones and IEM’s sound very good while some lack a bit in performing their best when paired with the DX1.  The DX1 do have some low amount of audible hiss when paired to my most sensitive IEM’s so for those very sensitive to this it may be worth noticing. This is not something that bothers me much, especially not with music playing. The DX1 does have enough power for all my full sized headphones which still make it very versatile in practical use.
The Audinst HUD-DX1 is a Swiss Army knife for your office or home desktop. It provides all crucial inputs and outputs accept for an analogue input and can even work as a bridge between your computer/laptop and a DAC lacking USB input thanks to its optical output.
Priced at $400 it may not offer the best value when it comes to sound but if you value its great amount of connections it may still be a worthy contender for your new rig. Also if you’ve got headphones or IEM’s that match the sound signature of the HUD-DX1 I’d still rate it as a very good performer. Adding another $69 to the total cost by upgrading the op amps to the Burson Audio V5i is highly recommended in my opinion. Not only does this upgrade delivers the biggest difference in sound that I’ve ever experienced from op amp rolling so far but it actually makes the overall value of the Audinst HUD-DX1 better since it holds up much better to other competitors in the price class this way.
Audio Quality: 3.5
Design: 4
Quality: 4.5
Value: 3.5
Features: 4.5
With the V5i op amps mounted in the HUD-DX1 I’d probably rate the total Audio Quality to 4-4.5 and value to 4.

Once again the light box was occupied when I came to do the photos :wink:
To focus on item I deleted and read and. no surprise.
Great review :)
Good luck with the list and evaluation of DAC/AMP's. Great idea!!
Nice work m8!
Thank you guys! I really appreciate your comments :)


Reviewer: PMR Audio
Pros: DSD/DXD Capable, Musical and Engaging, Nice Trim
Cons: Gain Switch Lacking, True Lineout, Not Airy
An all-in-one DAC/Amp Solution.


All-in-one DAC/Amp for 500?  Correction – make it 398.  Well, what is the HUD-DX1?  Made by Korean audio company Audinst, the HUD-DX1 currently represents the pinnacle of the Audinst DAC/Amp development tree.  It’s just about packed everything possible into its rather small 104 x 120 mm industrial metal enclosure –including the latest (and depending on who you ask, the greatest) means of playback.  Yes, native DSD/DXD. Let’s not also forget the list of other fairly impressive features and components.  But wait you say–it’s more than twice the price of the original MX1!  And here is where I do apologize.  I’ve never had the opportunity to try the HUD-MX1 or MX2, so I can’t say with certainty how much of an improvement it is over these older models.  But it is an opportunity to look at the HUD-DX1 from an independent perspective.
Disclaimer: This unit was provided by Audinst for the purposes of this review.  I am neither an affiliate nor an employee of Audinst.  All media rights reserved.



The Audinst HUD-DX1 comes in a small, unassuming white cardboard box with glossy photos on the front.  Fairly standard fare.  Inside is the unit along with the power supply unit, USB cable, Allen key, metal feet, literature and a EU plug adaptor.  All the electronic components came nicely sealed in clear plastic bags, along with a pack of desiccant for the main unit.  It’s a thoughtful and extremely nice touch on the part of Audinst.  Overall, nothing particularly difficult to understand, and the DX1 was up and running in less than five minutes.  


The HUD-DX1 has a solid build.  While neither as heavy nor as finely machined as the stoic DACmini, the DX1 is nonetheless able to hold its own in terms of general build quality.  It is definitely small and light enough to be used meaningfully as a portable device (not portable setup!)  The black and gold trim is stunningly elegant, and the overall aesthetic is rather good.  The machined lines could definitely go though, as these make the DX1 look strangely reminiscent of the O2.  The unit can sometimes run slightly warmer than one would expect.  As a final touch, the DX1 can be run off of both USB bus power or from a socket.​
Amplification comes in the form of the MUSE8920 OPAMP (used for I/V and filtering) and the TPA6120 headphone amp. The DAC chip is none other than the Sabre ES9018K2M, which is fairly well implemented in this setup.  Noise regulation and protective circuits are also present on the DX1.  More information can be found on the DX1’s webpage, which seems to source components from the MX2 page (DX1 is strangely referred to as the MX2 on some occasions).  All quirks aside, it is a technically competent build and one that would be hard to fault.​
Usability is sometimes problematic. 1/4th and 1/8th headphone outs and two switches occupy the front panel of the DX1.  The first switch toggles between headphone out and lineout.  The second between optical and optical inputs, as well as the power-saving mode.  Strangely absent is the gain switch.  Like previous models, you need to take apart the DX1 and manually adjust the gain on the PCB.  To do this, unscrew the volume knob with the Allen key, and then unscrew the back panel, which pulls out to reveal the PCB.  From there, find the jumpers and follow the instructions provided in the manual.  5 minutes for the inexperienced, two for the familiar.  But that’s still two minutes more than I’d like to spend adjusting gain.  Also absent is a true lineout.  Given the very nice DAC section on the DX1, a true lineout would’ve complemented the unit very nicely, especially if used to scale with a better amp section.  Apart from that, the DX1 works smoothly with very few actual hiccups. ​
The specifications page for the DX1 can be found here.​


The DX1 sounds very good.  Generally, I’d describe the sound as being smooth and polite.  The bass is rounded nicely and carries excellent body.  It’s got enough presence that I’d describe this as warmer sounding, and the transition into the weighty mids makes this all the more apparent.  Vocal tracks sounded overwhelmingly pleasant, and some of my favorite Bossa Nova tracks were rendered in a truly engaging, albeit sometimes intimate, fashion. Highs do have some sparkle, but lack a certain airiness that would’ve otherwise opened up the sound.  Take Só Danço Samba (Stan and Getz).  The guitar is portrayed with a slight sparkle and the bass line really hits home.  It's a situation in which the DX1 shines.​
Compared to the DACmini DAC/amp, the DX1 sounds significantly more engaging and lively.  It simply has more presence than the somewhat flat sounding DACmini.  However, when running the T1, it became obvious that the DX1 didn’t always have enough power behind it, even after removing the jumpers to adjust to high-gain.  At higher volumes, a slight graininess started leaking into the sound.  Compared to the iFi iCAN, the DX1 wasn't as speedy or as powerful, and didn't have the cleaner sound either.   In addition, the 3D Holographic feature on the iCAN really dwarfed the soundstage on the DX1. However, the overall musicality and liveliness of sound made the DX1 a fun and compelling option, and with certain tracks it simply sounded better.  ​



The HUD-DX1 isn't breaking new ground with its hardware or performance.  However, it does feature a refined and highly likable sound, one that works very nicely with most headphones.  Aside from its odd design quirks, the DX1 functions almost flawlessly, and interfaces with most devices without a hitch.  It is well suited for portable setups, being small/light and easily transportable.    It's got a wide range of features, and the added DSD/DXD playback option means that the DX1 has secured a place among newer DACs.  If DSD/DXD support and portability are key factors in determining your next DAC/Amp purchase, then I'd recommend the HUD-DX1 for your consideration.​


Line level is for amps not for speakers. If the volume control remains in the signal path than it acts as Preamp, which is a useful feature. If you want a fixed level output, than preamp function must be performed externally. I'm guessing what you're after is a dac with a fixed line out so you can provide your own preamp/amp. What Audinst should have done here is to provide a switch for variable and fixed for the line out which would make this device more versatile indeed.
Frankly, I find the price quite stiff compared to other offers on the market (ifi iDSD micro and others).
@LajostheHun Good points raised.  I think the reason why we've arrived at the topic is simple.  Audinst describes their speaker out as a Line-Out.  As you've mentioned already, the pre-amp functionality makes this a misleading feature description.  Hence, a "true" line-out is in order.  Semantics may be the issue here.  And yes, I do strongly agree that a switch would have made for a far more versatile device.
@musikaladin indeed, the competition at this price point is very tough.


Headphoneus Supremus
Pros: Bold, lively sound from the DAC portion, headphone amp powerful enough for planars, rock-solid stability over USB
Cons: Gain is too high for some headphones and especially IEMs, price isn't as low as I'd like
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There simply can't be too many affordable devices on the market. It's not possible. More choice is always a good thing. This assumes, of course, that at least some of these options will be solid performers. But if we think about it, the odds are in our favor when more and more devices hit the street. If we assume an arbitrary number of products - say 50% - will be terrible, with perhaps 30% being decent and the remaining 20% being good... a larger pool of designs to choose from will result in more "good" options standing out from the crowd. Makes sense right?
When people say "affordable", they don't always mean the same thing. In some circles "affordable" components are those costing less than $10,000 (give or take a used Honda Civic). So what we might consider a Summit-Fi headphone system would actually cost less than one "affordable" pre-amp or set of speakers. In other situations "affordable" is taken to the extreme, where a Sennheiser HD600 then becomes prohibitively expensive and headphone amps or DACs costing several hundred dollars shouldn't even exist. Most of us probably fall somewhere in between those two, where gear around $200-400 or so can be considered somewhat on the affordable side. 
To that end, companies like Audinst are great to have around. For several years now, Audinst has been churning out one solid budget device after another. Nothing world-shattering, just competent, well-done gear offering good sound at a reasonable price. I believe their most pricey offering was the HUD-mx2 at around $250. Not bad for a DAC and headphone amp which could drive most anything decently well, and control volume on a pair of active monitors too. 
The latest design from Audinst continues that tradition of quality for a good price, though the quantity of each seems to be creeping upward. Is that a good thing? I suppose it depends on your needs. At $398 direct from Audinst the new HUD-DX1 is another all-in-wonder handling DAC duties, headphone amplification, preamp functionality, and even USB to SPDIF as a bonus. So far so similar to the last few models right? The mx2 seemed like a reworked, upgraded version of the mx1, and this new model doesn't stray far from that same concept. A redone enclosure looks and feels a bit more upscale. I got my review unit in black with gold accents, but one could just as easily snag the white and silver model to match their modern Ikea desk.
The gold feet are a nice touch:
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This time around we get an ESS ES9018K2M DAC chip, being fed by an XMOS-based asynchronous USB input capable of DSD and DXD. If you recall the prior model used a TI PCM1796 DAC with an adaptive-mode USB implementation from chip maker VIA, topping out at 24/96. Audinst now hangs their figurative hat on the JRC Muses8920 opamp - a rather nice choice indeed - where the prior model had a mix of OPA2134, OPA2227, and LME49860 opamps. That means I/V conversion, differential amplifier, and line-out are all handled by the Muses chips. Headphone driver remains the same TPA6120A2 tweaked for 2 ohm output impedance. Max output is 1.5W into 32 ohm loads, and 10Vpp at 600 ohms. Reaching full amplifier potential will require tweaking an internal jumper and running on AC power as opposed to USB. 
Aside from those changes (and the driver software, obviously, due to the new USB solution) this is classic Audinst. The enclosure may look a bit different but the ins/outs remain identical. The front panel has the dedicated jacks for 1/4" and 1/8" headphones, switches for headphone or line-out activation as well as USB or optical input. Rear panel has Toslink in and out, USB in, RCA out, and a spot for the power adapter to connect. It's all quite familiar by now. I go back and forth between being disappointed by the lack of innovation, and satisfied by the "If it ain't broke, don't fix it" mentality. After roughly 5 years without any functionality updates, Audinst still has one of the most feature-packed devices out there.... so I guess there's no compelling reason for a change.
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Internal pics show a largely similar layout to the prior models. As mentioned, we do get the new ESS/XMOS combo which requires some accommodation in the surrounding design. I also notice there's no longer a dedicated chip for receiving digital inputs - the Sabre chip itself has onboard DIR capabilities so Audinst must be taking full advantage of that feature. Aside from that, and the Muses opamps being utilized, the remainder of the board looks 95% unchanged. 
Total of four Muses8920 chips (only two are socketed)
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TPA6120A2 headphone driver:
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XMOS USB input:
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ES9018K2M DAC chip:
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I'm very familiar with the prior HUD-mx2. It was an evolution of the mx1 with which I was also quite well acquainted. The DX1 comes along using a very similar design so I naturally assume the sound will follow suite. And I find myself being wrong, as this is something of a departure from the earlier Audinst house sound. Not that I'm complaining, mind you. Prior gear was mainly neutral, as transparent as could be expected for a budget all-in-one. It worked well with a variety of headphones and in exchange could be perceived as being just a tad boring in some instances. The new DX1 is far more lively - robust bass impact, thick, rich, weighty mids, and top-end sparkle like never before. I wouldn't necessarily call it an overly colored presentation, but in comparison the older mx2 sounds downright vanilla. Is this an insult? Not necessarily. Some people love vanilla. 
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I noticed the change right away when listening with the Fostex TH-X00. While the mx2 did a respectable, even-handed job with these excellent "sealed" headphones, the DX1 turned the excitement up to 11. Bold, impactful bass was the order of the day. Vocals more engaging. Cymbals more splashy and extended. I rather enjoyed it though I can see how long term listening might favor the mx2 in this particular instance... depending on your musical preferences, the TH-X00 might be exciting enough already without the extra help. DX1 is excellent for shorter stints though, and its liveliness is exactly what I want for artists such as Infected Mushroom, Lotic, Floating Points, Arca, etc. 
The AKG K812, however, sounds quite a bit more enjoyable on the DX1, across all genres. The mx2 renders a somewhat flat presentation, lacking a bit of passion. DX1 drives it with attitude. The K812 gets less respect than HD800 as a proper flagship but I find it on par and in some ways superior to Sennheiser's offering - this being one of those times. The HD800 needs substantial amplification to bring out its best while K812 can sound very good from a portable amp, integrated DAC/amp unit, or even a DAP. Driving my HD800 from the DX1 is mediocre at best (though still better than the mx2) but the DX1 plus K812 combo is very respectable. I particularly like how dynamic it sounds with Holst and Bassie - two selections which don't sound the least bit convincing without a proper sense of scale. 
I tend to run off USB power most of the time. It's nice to have flexibility to add more juice via AC power brick, but I find it makes just a small contribution to the overall sonic picture. Specifically when driving planar magnetic headphones. For the most part I find USB power good enough to satisfy. As a DAC only I can' really hear any difference which means the USB power supply is well sorted. And I can't imagine an instance where I'd mess with that internal gain jumper - perhaps running the HE-6 without an external amp? An unrealistic scenario to be sure. 
I switched to my Noble Audio K10 custom IEMs and was somewhat disappointed. The DX1 has rather large amount of gain which means volume is unnecessarily high. There's very little usable range with sensitive headphones and IEMs seem to universally show more background hiss than I'd like. This is disappointing since the older models were very usable with IEMs. The only good match I was able to find was using my Lear LCM-5 custom IEMs with their Monitor Tune Adaptor. This brings impedance way up into the 300 ohm range and drops sensitivity as well, allowing these otherwise highly-sensitive IEMs to work well even with tube amps. The DX1 is an excellent match in this case, but unfortunately this is not representative of the usual IEM experience. 
Since the headphone amp section isn't significantly changed - the new opamp still drives the same amplifier chip - I strongly suspected the DAC portion was responsible for these improvements. To test this, I let the DX1 do DAC duty with some heavyweight dedicated amps - the SimAudio 430HA, Violectric V281, and Questyle CMA800R. I would normally reach for my Stax setup in this situation but my KGSSHV amplifier has just a single pair of XLR inputs and is thus not the easiest to use with a pair of single-ended DACs. In any case, using external amplification confirmed my theory - the DAC portion of the DX1 contains the exciting sound signature, while the headphone output remains largely neutral. I do think the Muses opamp allows for a more revealing performance but it comes at the expense of background noise on sensitive headphones. So it's a trade-off which some people might prefer not to make. Swapping the headphone opamp is always an option but I haven't spent time on that just yet. It would be fun to try out something like the Burson Supreme V5 discrete opamp though I'd have to double check the literature to make sure the Audinst circuit meets the proper voltage requirements.  
It sounds like I'm complaining about the headphone section. And to some degree I am. I'm thinking Audinst has reached the limit of this particular setup and may need to revisit their choice of TPA6120A2 next time around. That said, the DX1 still sounds remarkably clean and clear using the right headphones. K812, as mentioned, but also the LCD-2 and HD650, and to a lesser extent the HE500. I wouldn't go any brighter than that - I'm thinking HE560 is going to be a problem - but stick with neutral or somewhat darker headphones and you'll be pleased with the results. K812, a seemingly bright headphone at times, seems to be an exception which somehow just works really well regardless. 
As a DAC, I'm far more enamored with the DX1. It doesn't feel like a weak link even when mated with very nice amplification. I even ran it in a speaker-based setup using a Jeff Rowland pre, Parasound Halo amplification, and Sonus Faber speakers. And guess what? Among these multi-thousand-dollar components, the little Audinst didn't stick out like a sore thumb. In fact it sounded right at home while playing DSD tracks fed by a Surface Pro 3. The bold, exciting sound remains controlled in the upper mids and highs, with very little glare, and is backed up by an impressively solid low-end response. As enjoyable as the mx2 was, I put it in this system and it quickly feels out of place. Boring, dry, flat; a cardboard cutout of what the DX1 is capable of. 
I find DSD capabilities to be generally useful despite the limited amount of music available. I actually started ripping my SACD collection and am enjoying that stuff more often than my collection of DSD downloads purchased from various sites. The selection feels more relevant for day to day listening. The process is no fun but I've finished most of my discs so I can't complaint much. I'm glad the little DX1 can handle DSD and DXD too, but I wouldn't call that a must-have feature on a device like this. It's becoming more of a standard thing and if it matters to you, great, but I suspect many people won't care all that much. 
More important to me is the improved overall performance. Take the combination of superior DAC, vastly improved USB processing, and those expensive Muses opamps, and the DX1 becomes a formidable competitor in this crowded field. The problem, however, is exactly that - there are TONS of excellent devices to choose from in this space. If someone could stretch to $499 I heartily recommend the Grace Design M9XX. It's arguably the better DAC and very easily the better amp. Only problem is the limited availability - Massdrop and Grace Design only launch batches here and there, and it's often sold out. Audinst is available right this second and trumps many others I've heard in this class such as the Pro-Ject Headbox DS and PS Audio Sprout (though I find the Sprout terrible so it's not really tough competition). Actually, now that I think of it, this is a somewhat unusual pricing area. Lots of stuff is available around $200-300, much of it portable or semi-portable. And then there's a lot out there in the $500 to $600 range, most of it decidedly non-portable. The Audinst fits in between those two categories in both price and feature set. 
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Overall I find the Audinst DX1 to be a solid if not quite amazing entry into the sub-$500 category. It does everything you might want, and sounds (mostly) enjoyable while doing so. The sonic signature is something like a junior version of the excellent Matrix X-Sabre DAC - bold, exciting, and highly engaging. I find it to be an improvement on the HUD-mx2 but I can see how some people may not like this new sonic direction. I do question the high gain on the headphone output but in every other way the device is fairly impressive. Back to my original statement, I'll conclude that the Audinst HUD-DX1 certainly does qualify as another worthwhile budget option to consider. 
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Let's see: Concero HP is still the better DAC, more detailed and transparent. DX1 wins on feature set and also when driving power hungry planars. But that's about it. K812 works great with Concero HP! As for HE-400i, I haven't had a chance to try that one yet. 
Thats what i wanted to hear, i have no need for more driving power to be honest. Cheers dude ive yet to hear the K812... i am a lover of v shaped or u shaped cans. So im not a 100% sure if the K812 with its so called wonky highs is what im after. May have a listen to them sometime soon though to make sure.
Thanks project86, that's an excellent review : detailed, concise & very helpful.  Good job.


1000+ Head-Fier
Pros: stylish look, connectivity, driving power, neutral sound
Cons: to loud for sensitive IEMs, a bit pricy
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I don't know why, but there is not much information about Audinst's new DAC/amp combo on Head-Fi. So, I've decided to correct this, and write my impressions about this really worthy device.

For last 5 years, I've auditioned lots of different gear, from expensive Hi-End DACs, down to small micro-amps. But only few of them stayed with me for all this time constantly, and Audinst HUD-MX2 was definitely one of my most favourite devices. Pretty inexpensive, small, stylish DAC/amp combo with nice, little warmish sound and lots of output power paired greatly with almost any headphones that I own. But recently Audinst introduced new device, tailored with all new trendy features, and it's HUD-DX1.

While DX1 shares common chassis shape with MX2, inside it's and absolutely different device. PCM DAC chip was replaced with Sabre 9018K2M, amplifier build with MUSE8920 and TPA6120A2, and USB-interface is now handled by XMOS. So, DX1 now "understands" all modern formats like native DSD and DXD. You can find more details on Audinst's main website [].

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Audinst used high quality details inside (TXCOs, capacitors, resistors, etc.) and made well-thought protection circuits, to avoid possible damage of your headphones during on/off and PSU connect.

All good new features came at price, and DX1 became more expensive, it costs $400, so DX1 is a higher model in Audinst's lineup, not an MX2 new revision.

DX1 shares same chassis shape with MX2, but now it offers two stylish color options — black with gold and white with silver. Both of them looks really great, but I prefer white option, unusual in the audio gear world.

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DX1 came in glossy cardboard box, inside you'll find device itself, USB cable, PSU, great self-glued feets (I wonder, where I can buy them separately for my other gear, they are so great…), hexagonal "unscrewer", manuals and adapter for EU plugs (not sure will it be in all boxes). So, everything you'll need to use device.

This DAC/amp combo is packed with features, so it's both sides is full of different sockets and controls. On the back side you'll find: 2 RCA sockets of line out, USB input, optical in and out (yes, you can use DX1 as USB-to-optical converter) and socket for PSU. As it's predecessor, DX1 can work without plugging PSU, using USB power. It's pretty convenient for portable life. You'll only need to plug PSU for really power hungry headphones, or if your PC produces too many noise into USB power line.

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On the front panel there are 2 headphones out (one 3.5 and other 6.3, very convenient, can be used simultaneously), output switch (headphones or line out), input switch (USB, optical and device off) and volume knob. DX1 uses good quality potentiometer, so channel imbalance is almost absent, and there is no noise during knob rotation.

HUD-DX have really impressive measurements, DR is 127 dB, THD+N is about -120 dB, and it's driving is really awesome, it delivers about 1.5 W into 32Ω load (±10 Vpp @ 600Ω). It can drive almost all headphones with ease, even 2 headphones simultaneously isn't a problem.

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Audinst worked great with sound, while MX2 has a little darkened sound, DX1 is close to neutral and fair representation. In combination with 1.5 watts of power, it gives us universal device for almost any headphones.

Bass is fast, tight and pretty punchy. It has good depth and body. Lows are controlled greatly and doesn't bleed into mids. Mids are a bit on colder side, offering great detalisation, which suits female vocals and male tenors greatly. On other hand, male vocalists with lower then tenor voices lose a bit of intimacy. But it's an only my claim to DX1's sound. Good resolution gives you a nice sense of small music details and nuances and allows DX1 to build decent scene, both in depth and width.

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Treble also doesn't have any problems. Audinst managed to avoid harshness, typical to some ESS Sabre implementations, so highs of DX1 isn't fatiguing (with exception of really bright headphones) and adds nice sense of airness to device's sound.

DX1 is a great option for power-hungry cans, but on the other side of the scale we have lots of sensitive IEMS. They are also usable with DX1, except of most sensitive ones. Background noise is almost inaudible. DX1 have 2Ω of output impedance, but I didn't have any problems with multi-driver BAs that I have (but some models can have issues though).

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So, DX1 is really interesting device for those, who wants small, powerful DAC/amp, especially for fulls-sized headphones.

I want to thank to Audinst for providing me a review unit in exchange of my honest opinion. And, as usual, sorry for my english :D

I actually didnt know about Nuprime. If you get a chance to review the dac10h sometime please do so. Looks like a fabulous unit. Couple of monoblocks and id be set for a headphone and speaker set up. Looks great!
If you have to choose between DX1 and CEntrance DACportable what would be your choiсe in terms of sound quality? Thank you