[project86]

 
Audinst, makers of the popular HUD-mx1 and AMP_HP units, released a new device recently called the HUD-mini. It's even smaller than the mx1, and sells for a lower price too ($129).
 
Audinst website
 
eBay store
 
DESIGN
I've had this little guy in for review for a while but have not had a chance to write anything about it yet. I still haven't finalized my opinion about it, but I'm starting this thread for general info, and will eventually add my final thoughts.
 
The mini differs from the mx1 in several ways. First off is the size - the mini is about the size of a portable amp (in fact it is barely larger than their AMP-HP). The mini uses USB power only with no option to add an external PSU like the mx1. It also has fixed RCA outs rather than variable, which will actually be considered by some as an improvement. The mini has a different USB implementation, the VIA VT1728A, that can accept all sample rates up to 96kHz - the mx1 has a Tenor TE7022L which does not handle 88.2kHz data. They make a big deal of pointing out this fact which makes me think they had a lot of complaints about the mx1. Which is odd because 88.2kHz is a small subset of hi-res music, which is itself a growing but still relatively tiny selection of most music. In any case I'm glad it is supported now. 
 
Aside from that, the mini shares a lot with the mx1. It has dual headphone jacks for 1/4" and 1/8" jacks. It has a switch to go from RCA out to headphone out. It uses the same volume knob and I believe the same potentiometer as well. Both have a Toslink output which means they could be used as a USB to SPDIF converter in addition to their DAC and amp duties. 
 
The HUD-mini is based around a TI PCM1791A DAC chip clocked by a quality TCXO oscillator. It uses a National Semiconductor LME49860 for DAC output and an Analog Devices AD8397 for headphone output. I believe they are socketed just like the other Audinst gear but I need to open the case again to double check (it's been a few weeks since I looked). 
 
 

 
 
 

 
 

 
 

 
 

 
 

 
 
INITIAL IMPRESSIONS
I removed my Audiotrak DR.DAC2 DX Muses Edition from my desktop setup, and replaced it with the HUD-mini. RCA outputs connected to the Emotiva Airmotiv5 speakers, and headphone jack was used with a variety of headphones - VMODA M80, Heir Audio 4.A, HiFiMAN HE400, and others. I did try some of my higher-end headphones but I tended to stick with the lower priced stuff, since it makes better sense that the HUD-mini would end up being paired with more entry level (but still good!) headphones rather than flagship models.
 
The first thing I noticed was that I missed the preamp functionality of the Audiotrak unit or the HUD-mx1. The Airmotiv5 active monitors have individual volume control on each speaker and it becomes somewhat annoying to try matching them precisely. Aside from that, I didn't immediately feel underwhelmed by the sound. That's impressive because the Audiotrak unit is nearly three times the cost of the HUD-mini. I did feel a loss of soundstage definition, and a bit of a "smoothing over" of the sound compared to the more detailed and revealing Audiotrak unit. But overall I was not shocked by the change, and after some time for mental adjustment I was quite satisfied with the sound made by the little HUD-mini.
 
It seems quite capable of driving a wide range of headphones, from sensitive custom IEMs to the planar HE400s. The sound is clean and mostly clear, with just a small reduction in detail compared to more expensive units. I did notice that the mini doesn't play as loudly as the mx1 when it comes to higher impedance headphones. I tried the Sennheiser HD650 (300 ohms) as well as a 600 ohm AKG K240DF, and neither of them got very loud. Certainly not as loud as the mx1. But I would not hesitate to use the HUD-mini with any IEMs, Denons, Audio Technicas, Ultrasones, or anything else that we consider "lower impedance" headphones.
 
As with the HUD-mx1, the HUD-mini is capable of delivering the essential experience, and it falls short in areas that are not offensive. So while you do miss out on some things like top end airiness and soundstage expansiveness, you also miss out on the undesirables that some budget items have - top end glare, flat dynamics, loose bass, or clearly unrealistic timbre. The HUD-mini is a solid starting point for someone new to this hobby, or even a suitable "2nd system" for an experienced audiophile to use at work or in a bedroom rig. 
 
I'll have more thoughts as time allows, including pictures. Any other early HUD-mini users feel free to post here as well. eBay shows that they have sold 30+ units already and probably more from their direct web store. I imagine that most early users would be HeadFi members as well, so maybe we can have them chime in.
 
UPDATED IMPRESSIONS - 9/17/12
So I've spent some more time with the HUD-mini and have come to some fairly solid conclusions. I still need to take more pictures and add them but for the most part this is my final review. 
 
Essentially, I've listened for a good amount of time and come right back where I started - as stated in the above section, this is a good sounding unit if not quite reaching amazing/giant killer status. I compared it quite extensively to the original HUD-mx1, and I don't notice any major differences between the two. In fact I think that the HUD-mini is in some ways superior as a DAC - I hear a slight improvement in terms of inner detail. Background events, like the cough in the first few seconds of Stravinsky: The Firebird Suite - Infernal Dance (Eiji Oue and Minnesota Orchestra), come through a little more clearly, while the exceptional low frequency impact hits just as hard if not a bit harder.
 
Speaking of this track: I played the version from the Reference Recordings HRx format, which means high-resolution 24-bit/176.4kHz. Since the HUD-mini tops out at 96kHz sample rate, it can't play this file in the native format. But it can handle it when software downsampling is applied, resulting in an 88.2kHz sample rate (exactly half the native rate). This presents a much easier and cleaner conversion, and the loss of fidelity is negligible. In comparison, the Audinst HUD-mx1 can't handle the 88.2kHz sample rate due to its USB receiver. That means it has to A) convert to 96kHz which is not an integer and thus requires manipulating the data more than is optimal, or B) reduce all the way to 44.1kHz, which is a 4X reduction in sample rate. Does it still sound good when played these ways? Yes. I'd be lying if I said it sounded terrible. But the HUD-mini is superior.
 
So aside from that track, what is the sonic character of this device? For the most part I'd call it clean and neutral, while erring on the side of being a little forgiving. This is appreciated because at times I hear a hint of digital grain or grit on the top end. So I'm glad they didn't try to push this as a hyper-revealing device. That would not have worked as well for my tastes. Overall the sound is on par with what I'd expect from an entry level CD player: think NAD C515BEE, Cambridge Audio 350C, or maybe even the excellent Marantz CD5004. Obviously these all have their own unique sonic character, and I'm not saying the Audinst HUD-mini is exactly like any one of them, but it does play in the same league. And that's impressive. Audinst has the advantage in that they don't need to spend their budget on a large enclosure, LCD display, remote, or a disc transport mechanism - all things that CD players need but compact USB devices don't. This means they can pour a larger majority of the budget into the audio circuitry and still keep a lower price than those other units (which all go for $350 or so). So I consider that a good thing.
 
I do have to say that while I think the HUD-mini may be slightly better than the HUD-mx1 in terms of DAC performance, it ends up being not quite as good in the amplification section. The difference is small and not easily noticed unless using more difficult headphones such as the previously mentioned 300 and 600 ohm models. Even if we discount the maximum volume difference, the HUD-mini still sounds a little "soft" and indistinct with those headphones. Using IEMs or low impedance headphones returns the two devices return to equality, again with the mini possibly being superior due to the DAC section. 
 
CONCLUSION
Overall the Audinst HUD-mini is a worthwhile device for the $130 asking price. It gives you a good amount of performance for a small amount of cash, and has a lot of convenience as well - the USB to SPDIF (Toslink) conversion is handy to have, and the integrated amp is respectable.
 
I'm still not quite sure who this is intended for; the mx-1 is similar enough to where they might be creating competition for themselves. Then again the mini is smaller so perhaps they intended that to be the defining characteristic. In any case, Audinst has another winner on their hands and I'm happy to recommend it for newcomers to the hobby or anyone needing a small 2nd setup. 

 

[xtend]

I considered one of these for my 2nd rig at work but was holding off due to the lack of reviews.
 
And they had a good sale in their ebay store till the end of july. But even for the normal price it sounds like a keeper.. 

 
I love that i has a 1/4" jack, not very common for small devices.

 

[spartan86]

Thank you for the review. I'll be buying my own unit soon. My plan is to pair it with HD598. I think it's a good combination for a semi-mobile rig (laptop). 

 

[project86]

Quote:

I considered one of these for my 2nd rig at work but was holding off due to the lack of reviews.
 
And they had a good sale in their ebay store till the end of july. But even for the normal price it sounds like a keeper.. 

 
I love that i has a 1/4" jack, not very common for small devices.

 
1/4" jack: exactly. It doesn't seem like a big deal because you can just use an adapter, but I still prefer to have both options. Most devices this small do not.
 
Quote:

Thank you for the review. I'll be buying my own unit soon. My plan is to pair it with HD598. I think it's a good combination for a semi-mobile rig (laptop). 

 
Thanks! I just realized you had already posted a thread about this device. If I had noticed it I would not have started my own. Oh well. 

 

[spartan86]

Don't sweat it All is fine. Here is a review from headfonia.
They suggest an OPA change.

 

[project86]

Quote:

Don't sweat it All is fine. Here is a review from headfonia.
They suggest an OPA change.

 
Thanks. Mike must be busy because that's the shortest review I've ever seen him do. I can relate to being busy though!
 
I wonder if his unit was faulty or something, because I'm not getting that same feeling at all with mine. The stock LME49860 is a quality part and should not cause issues like that. Mine sounds very close to the HUD-mx1, with a little more emphasis on clarity versus warmth. It's a good sound overall and very competitive at the price they are asking. 
 
I was using it with the Ultrasone Signature Pro, which is very sensitive to noise, and it was nice and quiet. I also just got the new Lear LCM-5 customs and was using the HUD-mini to drive those. Very clear and sparkly but not overly so. For a $129 unit I'd happily recommend this little guy. 

 

[spartan86]

Thank you for more impressions. I did a little research and LME49860 looks superior in every way. Maybe he got a faulty chip as you said???
Here is a comment about these two Op-Amps:

Let's get it straight - the OPA2227 is terrible wherever you use it. Dull, dark, slow, boring, with poor resolution. The best dual op-amps I know are LME49720, LME49860 (a bit warmer), LME49725 (again something towards warmness). If you like "vintage", the OPA2111 is quite good sounding and still under production. I prefer it to a pair of OPA627 even from BP series. Best single op-amps I know are OPA211ID and AD797BRZ. Both outperform OPA627. There was a direct comparison between the AD and the OPA by one user, as well as you can read the review from my signature.

Looking for ultra-expensive vintage hardcore? Buy a pair of OP27E! 

 
I'll buy it stock. From my experience Audinst is a very good company when it comes to price/quality.

 

[project86]

Quote:

Thank you for more impressions. I did a little research and LME49860 looks superior in every way. Maybe he got a faulty chip as you said???
Here is a comment about these two Op-Amps:
 
I'll buy it stock. From my experience Audinst is a very good company when it comes to price/quality.

 
Keep in mind: in this case, the opamp in question is used for the DAC output. There's a whole separate opamp in the headphone stage. 
 
The comment you posted about was referencing a CMOY design, where the opamp is driving the headphones directly. That's one of the basic designs where you will more clearly hear differences in opamps. But that doesn't always translate to other designs, especially when the opamp is being used in a different context. 

 

[cky8]

I find myself often disagreeing with Mike. That is perfectly okay. Though he seems to always look for that particular sound that matches his preferences. There is nothing wrong with that, but I would like to see things more put into perspective. The Op-Amp may have some general attributes like being warm. But implementation matters in different designs. Op-Amp X is not the end of the story.
 
That said I am patiently waiting for your full review project86! This might be a good candidate to recommend to a friend with somewhat limited funds.

 

[wj888]

Updated experience of using Via Envy Audio USB driver with QSound.
 
You can download the Via Envy USB Driver from Audinst website to enable Qsound.
Qsound is quite similar to Creative's THX settings and the dolby headphone setting in PowerDVD player.
If you turned Qsound on , you can enable the QRUMBLE(bass) and QSizzler(Mid/hi) to give your music an enhanced sound. This is much like Crystalizer in the THX's setting.
QXenable and QHeadphones seems to be simulating the Dolby Headphone.
 
Anyway, with those turned on, the music and game played becomes much like I'm using Creative's X-FI 5.1 Surround Pro.
The downside will be Qsound is only applicable if you set the sample rate downwards to 44.1/48khz 
So I think it's good only for games and movies. But it's a good add-on product you will not find in Cmoy tin cans or E17. 
This makes it more versatile for many applications in my opinion.
 
_____________________________________________________________________________
Profile of Me :- LAPTOP WARRIOR and so seldom used the DAC/Amp outside of the Laptop.
 
Setting on HUD-Mini :- Volume at 75%
 
Headphones I tested with without external amplifier to achieve comfortable listening :-
1) Creative Aurvana Live ! --> Vol at 8 oclock 
2) Sennheiser HD518 --> Vol at 9 oclock
3) AKG Q701 --> Vol at 11 oclock
 
One advantage of HUD-Mini, with a headphone input splitter, I can connect both my AKG and Creative at the 3.5mm socket and Sennheiser HD518 on the other socket without pulling out anything! I can do A/B test easily ! ..lol..
 
Below Comparison using only Creative at 9 oclock position (a little louder than my normal listening position)
 
[size=13.63636302947998px] I received my hud-mini within a week and i have to agree with Mike(Headfonia) that opa2227 sounds very spacious and warm at the expense of details and bass impact when compared to the default LME op-amp. You can hear alot of details and bass impact in the LME (very good if you like listening at low volume). Vis-a-vis , at 9 oclock position, the OPA2227 loses out in resolution to the LME.[/size]

[size=13.63636302947998px]  [/size]

[size=13.63636302947998px] For soundstage, I use the Virtual Barber as it has a lot of details and bi-aural information in it (Just go to Youtube).[/size]

[size=13.63636302947998px] Using the OPA2227, The soundstage is definitely WIDER. At the beginning of the clip, you can hear the door opening and closing at a further distance than compared to LME.[/size]

[size=13.63636302947998px] You can also hear a further depth in distance when the 1st guy called the barber out and he walked over to pull the chair(for himself to sit i believe) and turn on some music. [/size]

[size=13.63636302947998px] At this point, you can see the LME wins out in details as the backgroud music is more evident and detailed as compared to the OPA.[/size]

[size=13.63636302947998px] Listen to the rest of the clip and you will see the difference. Tonality wise, I prefer OPA as it gives a much more accurate tonality to sounds at the barber shop having a hair cut. [/size]

[size=13.63636302947998px]  [/size]

[size=13.63636302947998px] For Music, I go to http://www.jlabaudio.com/test_tracks.php and those 3 musical tracks(96kbps and above) represents a wide genre of bass, mids and highs.[/size]

[size=13.63636302947998px] With the OPA, you can hear its very warm and soothing. Very easy on the ears and immersive.[/size]

[size=13.63636302947998px] With the LME, you can hear the details and you will noticed bass impact is fuller and harder. But it appears a bit cold and analytical as compared to the OPA.[/size]

[size=13.63636302947998px]  [/size]

[size=13.63636302947998px] For Gaming, I am playing League of Legends and you can feel the LME has better details(resolution) and definitely more fun to play. [/size]

[size=13.63636302947998px] Anyway, I kept the opa2227 On as I liked it better I'm more of the warm and laid back sound guy.[/size]

[size=13.63636302947998px] Improvements and Alternatives:-[/size]

[size=13.63636302947998px] I'm also thinking for about the same price, the E17 have treble and bass control and both amp and dac. I loved having the ability to adjust using an idiot-proof way (-6 to +6) the treble and bass ranges(without EQing the specific 7band freq) to suit the different headphones. My E11 amp (sold away) was specifically used to boost the bass and give warmth to the sound of the AKG Q701 while I used a Creative X-FI 5.1 Surround Pro. The creative is underrated. It is definitely good at details (resolutions) and can do 24bit/96khz like E17 and HUD-Mini. The THX software is used to expand the soundstage and ambience.[/size]

[size=13.63636302947998px] Anyway, now I've to decide with keeping the Creative or selling the HUD-Mini. Both have RCA Line out which the E17 does not have. I loved using hte RCA Line out to connect to my Bravo Audio Tube Amp. [/size]
[size=13.63636302947998px]  [/size]
[size=13.63636302947998px] But all in all , I find the HUD-Mini a worthy buy if you do not have any DAC. Or if you are considering a cmoy tin-can, why not just get something better which also can op-amp roll and is great for desktop usage as well as if you want to mix-match DAC and AMp, this one is well worth it 'coz of the RCA line out and Opt Out.[/size]
[size=13.63636302947998px]  [/size]

 

[spartan86]

Thanks for clarification guys. I feel like I'm a little bit less ignorant now
I'm still going for the stock unit, but will probably buy OPA2227 in the future.
If I got you right, I need to decide for myself which sound sig I prefer.

 

[wj888]

Quote:

Thanks for clarification guys. I feel like I'm a little bit less ignorant now
I'm still going for the stock unit, but will probably buy OPA2227 in the future.
If I got you right, I need to decide for myself which sound sig I prefer.

If you intend to buy HUD-Mini, just buy the OPA2227 from them. It will save your shipping cost and maybe they will give you a discount on the chip? 

 

[project86]

Quote:

I find myself often disagreeing with Mike. That is perfectly okay. Though he seems to always look for that particular sound that matches his preferences. There is nothing wrong with that, but I would like to see things more put into perspective. The Op-Amp may have some general attributes like being warm. But implementation matters in different designs. Op-Amp X is not the end of the story.
 
That said I am patiently waiting for your full review project86! This might be a good candidate to recommend to a friend with somewhat limited funds.

 
Yeah, I don't want to give the wrong impression. I often disagree with Mike but he's a fantastic person, very nice to talk to and very passionate about the hobby. He's also very humble which is rare and always appreciated. I'm sure he reads some of my opinions and rolls his eyes as well.... and that's perfectly fine!
 
 
Quote:

SNIP

 
Thanks for your impressions, good stuff! I do think that at this size and price level, there's probably not going to be one single unit that blows all others out of the water. There's going to be some poor designs here and there, and then several good ones that do everything right (within the limits of their capabilities of course). Sounds like maybe you've got three such devices all together in your comparison. Then it just becomes a matter of picking the small details that matter most, in sound signature and features.
 
I do have to point out that your test tracks are between 96 and 192 kbps, not kHz. I saw your post and thought "Wow somebody has hi-res streaming test tracks online? That's a first!" But then I realized they are actually lossy, low bitrate compressed files. Not that it invalidates your testing, but still.
 
Quote:

Thanks for clarification guys. I feel like I'm a little bit less ignorant now
I'm still going for the stock unit, but will probably buy OPA2227 in the future.
If I got you right, I need to decide for myself which sound sig I prefer.

 
It couldn't hurt. Despite what I said earlier, opamp rolling is cheap and can be fun, provided you keep your expectations realistic. 

 

[wj888]

Thanks project86 for pointing out the error.
 
Ya, i'm not too bothered with having to play thru lossless formats. I piped music thru' spotify and youtube videos and movies/dramas thru' amazon and netflix.

 

[RacKhoun]

I've been trying to decide whether the HUD-mini or the Fiio E17 would be better for my needs.  There are tons of reviews for the E17 understandably since it was released a while.  However, is it me or does it seem unusual that there are so little reviews for the HUD-mini so far?  I don't have experience with the timeline for these newly released products, but headfonia's review and project86's impressions seem to be the only feedback I can find.