Audinst HUD-MX1

I just received my Audinst amp yesterday, and only have about 15 hours on it so far, so this is a review based on my early impressions..
 
This is my first serious, dedicated amp/DAC combo that I bought to power my Beyerdynamic DT 990 PRO (250 Ohm) as the FIIO E5 I had just wasn't cutting it. I'll be updating this review as the amp burns in, but I can say that at the moment, I am liking how the amp pairs with the DT990.
 
Review gear:  Macbook Pro > USB > Audinst HUD-MX1 > DT990
 
:: Looks ::
 
The Audinst is a small, small amp. From the pictures on the Audinst homepage or the internet, one would think it's bigger than it is, but it's really not much bigger than a Penguin paperback and quite light. For all that, it's quite solidly built, and all the switches, knobs and jacks feel secure and well made. 
 
The amp can run off either the supplied AC wallwart, or can be powered from your laptop's USB port. There is no power switch on the unit, as it automatically detects whether your computer is on and turns itself on and off accordingly. A nice feature.
 
:: Sound :: 
 
First off, this amp has plenty of gain, and anything beyond 10.30 -11 on the dial soon becomes deafeningly loud. There is an internal jumper that can be set to increase the gain for 300-600 Ohm headphones, but I can't imagine needing to do so even for higher impedance cans. 
 
Installation and setup on the Macbook Pro is a breeze. First, open Audio MIDI Setup and select the Audinst as audio output. Change the audio settings to output 24bit/96khz if you like. Open up System Preferences and select the Audinst for output and you're in business!  (Helpful hint - hold down the Option button and click on the volume icon in the menu bar to switch outputs without having to open System Preferences)
 
Note that iTunes automatically selects the Audinst for output, but for other programs like VLC, make sure the amp is plugged in and selected for output *before* playing music or movies. Took me a few minutes to troubleshoot that last night
 
So how does it sound? I selected a few songs from different genres that I used to test out various headphones before picking the DT990, so I knew what they sounded like through the E5, or straight from the MBP's headphone jack. All songs are 320 kbps MP3 or lossless FLAC.
 
Classical:
 
Martha Argerich - Chopin: Scherzo #3 In C Sharp Minor, Op. 39 - Presto Con Fuoco (Debut Recital)
 
This recording showcases Argerich's dynamic (some would say rough, but not I!) interpretation of Chopin, and this track runs the gamut from soft and intricate almost whispered chords, to symphonically brash peaks. The Audinst renders the rather intimate recording quite nicely, and I can pick up some overtones that I didn't catch before. The soundstage is not as large as it could be, but it's more a case of being in the second or third row (or in the back of the studio for the Scherzo). 
 
Electronic:
 
Magnetic Man - Anthemic (Magnetic Man)
 

 
Opening with a scratchy, fuzzy, white-noisey beat before the typical dubstep-y bass drop wibble-wobble, I use this track to test for lower-end bass, and the Audinst delivers here. With the DT990's already bass-heavy presentation, the Audinst gives a cleaner, firmer bass whump to the opening kickdrum, and really opens up the lower-end to let the DT990's reach down for bass that I imagine should be vibrating in my chest. Definite improvement to the sound here.
 
Rock(ish):
 
Moto boy - Blue Motorbike (Moto boy)
 
I chose this track because by un-amped DT990's sounded quite bright (almost shrill) reproducing the higher treble of the metal guitar Oskar Humlebo uses here. Happily, the Audinst tames the ear-piercing treble without rolling it off too much, and you can enjoy the twee, Twin-Peaksy warble of Oskar's unique voice without wincing as he reaches for those upper chords.
 
Music from the homeland:
 
I listen to a lot of African music, which employs a lot of instruments and vocal styles not heard much in Western music, so I'm always keen to hear how well an amp can reproduce the sound given the varying qualities of the source material.
 
Khaira Arby - Goumou (Timbuktu Taarab)
 

 
Another track that the unamped DT990s struggled with. Again the Audinst stepped up to the plate delivering better instrument separation, and letting Khaira Arby's voice ring out clearly without making it sound like she's reaching (and struggling) for the notes. 
 
Toumani Diabate - Si Naani  (Mande Variations)
 
Just gorgeous, shimmering, and a treat to listen to. 
 
Koffi Olomide  - Victoire (Attentat)
 

 
One of my transfers from cassette tape to MP3, and it sounds like it. Well, I wasn't expecting  the Audinst to make this sound like a clean master by any means, but it does it's best to make it listenable with revealing headphones.
 
:: Summary ::
 
The Audinst is a reasonably priced, and quite capable DAC/amp combo that should suit anyone just starting out in high. With the ability to roll opamps and to use this little box as a DAC with better amps (I'd like to try it with the Matrix M-Stage someday) I think this is a great buy at less than $200.
 

http://www.head-fi.org/forum/thread/484235/review-audinst-hud-mx1-usb-dac-amp
 
That's my full detailed review. In summary:
 
The Audinst is still one of my most often recommended pieces of gear, especially for people just getting into this hobby. As a DAC it is detailed and transparent with no specific weak points. As a headphone amp it is very poweful but of course has it's limits (could use more refinement but what do you expect for the price?). The overall package is very well done, with lots of nice features like an optical out for transcoding from USB to toslink, a front panel switch for disabling the RCA output when listening to headphones, and variable volume outputs allowing it to act as a pre-amp. It even lets you swap out opamps if you are interested in tweaking it a bit.
 
There are plenty of great products in this price range but I keep coming back to this as my recommendation.

For less than 200 dollars, there's not a lot to complain about here. The MX1's amp sounds quite good and powers K702s without trouble, and the DAC does a respectable job and sounds even better when hooked up to a separate amp.
 
One problem I have with the MX1 is the gain is a little too high. With most of my headphones, I can barely turn the volume control past the 8 o'clock level, which causes some channel imbalance. As a preamp, though, I don't have this problem, probably because my headphone amp allows me to further adjust the volume.
 
I fully recommend the MX1 as a convenient, one-piece solution to get great sound out of a computer. Although it's not the last word in sound quality, as a solid-state DAC/headphone amp combo, it's hard to beat in terms of value.

I have been researching a more potent amp for my desktop system and all I have to say is Wow! I just plugged the MX1 into my office system for the first time and I am very impressed. The amp section is robust enough to drive my HD650 in a similar (not quite as refined) fashion as my Schiit Lyr in my main system. Great extension in the bass with solid mid, airy and extended top end indicating a respectable DAC stage to go with the powerful amp. And I can easily switch between HP and desktop speaker out with the RCA line out on the back panel. Overall I give it a 4 out of 5.

Way overhyped...nice build quality for a small piece of equipment. but that is honestly the only positive thing I have to say about the Mx1. 
 
Customer service is slow to respond and does not resolve issues. Constant static out of headphone jack.  Tried numerous headphones, made changes to setting, etc. it did not go away.
 
Even when there was no static, it sounded exactly the same as both of my laptop headphone jacks.
 
 
 
 

I purchased this DAC/Amplifier with the expectation it would perform at least to the level of the Asus Essence STx it was replacing. The unit was purchased from
amazon.com, and delivered relatively quickly. Box/Manual/Packaging were all very nicely done. Now to the meat of the review, my initial impression. 
 
The unit felt pretty well constructed, with a decent heft, however the volume control is a cheap rubber knob id expect on something in the 30 dollar range, poor 
decision audinst! This is not a cheap device, and the knob most used makes it feel like crap, what were you thinking, a aluminum knob is not that expensive...
 
The initial audio quality was great, so I thought. Over the next few days I listened to a good variety of uncompressed audio ripped from cd's I own, and I noticed more
random static and popping in the higher frequency range the more I listened, which was very demoralizing from such an expensive unit. I even went to the extent of 
trying a new LME49990 op-amp to see if maybe the factory op-amp was defective, which it was not.
 
After a few days, more issues arose, such as the unit not detecting half of the time, and when it did, sometimes the audio is completely garbled and grainy, like there
is some issue with the DAC portion of the unit. Additionally, the auto off feature is an absolute nightmare if you plan on using this unit connected to the XLR inputs of 
any studio monitor, you get constant popping every time the unit "decides" its a good time to power down. PLEASE GIVE US A POWER SWITCH!
 
I wasn't expecting the world of this unit, but it severely disappointed me, directly comparing it to my Essence STX, well there was no comparison, the Essence STX was
higher quality in every aspect. I could not and would not recommend any Audinst product going forward, for this amount of money, it should at least play clear audio and 
detect regularly, these defects are a fatal flaw.
 
In the end, I would not recommend this unit to anyone who switches between headphones and the RCA outs, as the volume levels are not balanced at all. You're much 
better looking to an established company such as Schiit for a good unit (Asgard 2).