This is a review for a beautiful chinese made amp - the AUNE headphone amp with a built in DAC.
Cost - This amp costs $140 on ebay. Please keep that in mind
Specs - This amp is supposed to have the following:
Burr Brown 1793 DAC
Burr Brown 2134 amp stage (I'm not very sure about this - it's definitely a Burr Brown though)
ALPS Blue Pot
What I like about the amp-
Built well. The whole thing feels solid. It has a nice feel to it as well.
The amp is SUPER quiet. There is absolutely no hiss when I am using this amp with either the Sony V6 or the Beyer DT880 600ohms. In comparison a lot of fancier more expensive amps tend to have a hiss. Even when I turn the volume all the way up I cannot hear any hiss.
Lots of input options -
1. The amp can be directly connected to a CD player.
2. It also has a pre-out which allows you to hook it upto another amp if needed
3. It has a coax input and a USB input as well
What I did not like about the amp -
The RCA connectors in the back feel a bit cheap. This is just a quible cause at $140 you can't expect them to use 100$ connectors.
Before I get into the sound - you have to understand that equipment like this is built to a price. When you do that you have to choices. Make an error or omission or an error or an error of commision. An error of omission is when the designer does not act smart and understands that there will be limitations in terms of the sound. Example - a speaker designer making a small bookshelf understands that at a price one can only purchase drivers and a cabinet of say quality X. Hence he rather make a bookshelf that has a beautiful high and mid range while he would roll of the bass. This is an error of omission. An error of commision is when the designer tries and makes the speaker do too much. What you end up with is a speaker that tried to reproduce the entire spectrum but ends up have a bloated loose bass and piercing highs. I rather have a desginer use the error of omission approach when I'm buying budget equipment.
The sound -
Equipment used - Beyerdynamic DT880, AUNE headphone amp, Sim Audio Equinox SE
Tracks - David Roth, Sarah Brightman, Mary Black, Zac Brown band live
In general - The amp has a very controlled sound. It sounds very flat. I can't feel it emphasizing any particular frequency spectrum as such. If I had to describe this amp in one word I would sum it up as superb control.
Treble - The amp is smooth and controlled here. It is a litle grainy but then again a this price I should not be nit picking. It is not harsh at all and is VERY listenable. It seems a bit rolled off but then again that probably is why it has so much control. Don't expect this amp to extend all the way up when Sarah Brightman goes for one of her high notes. The amp will make it sound as if Brightman is controlling and holding back her voice rather than just letting it extend without any restrain. Once again I would presume that this is a design limitation due to the price and I rather have Sraha Brightman under control than a Sarah Brightman who keeps yelling at me!
Mid Range - This is again ery similar to the treble. I wish it had more resolution. It is very clean (has a little grain but very clean at the price). It isn't laid back as some cheaper amps. Vocals have a lot of body without becoming chesty and heavy. I just wish that they were more open with more resolution which would make it a lot more musical. Don't get me wrong - Im not saying the mid range is bad. Im just saying that it is a little too controlled kudos to the designer for achieving a good amount of body in the sound. The vocals never sound imbalanced i.e. a male vocals sound like they are coming from a barrel or excessively lean.
Bass - Once again control - the bass does not extend as much as more expensive amps but whatever is there is very full bodied and controlled. It will not boom at all nor will you find the amp lacking in bass. It just won't extend as much as more costlier designs. It will hit you with a fist but that is at whatever frequencies it is capable of reproducing. The bass is not in excess at all. It is perfectly balanced with the mids and highs.
Whenever someone reviews an amp I always look for resolution, transparency, extension at extremes and speed or timing. However most reviewers do not cover these important points (Skylab it would be good if you covered these parameters as well since you review a lot of equipment). This is what differentiates expensive equipment from cheaper equipment. This is also an acquired skill which is why your friend who listens to his ipod cannot understand why you spent $1000 on a HD800. Also as we get more sensitized we get used to what we hear which is why everyone here has a tendency to uprade their equipment so often. The HD800 will not sound the same as it did when you first bought it because you get used to the sound.
Resolution - This is the ability of the amp to uncover detail within detail. It is like that hidden guitar pluck that you never knew existed. It is the different layers in Sarah Brightman vocals as she extends her voice. It is the vibrations and reflections that different instruments generate. If an amp lacks resolution it will make music sound one notish. That is all the highs will sound like they are being generated around a particular note and so on. This is what according to me gives a component its character.
When you hit a piano key you generate the freq desired but you also generate a lot of overtones. Thisis why 600HZ on a Piano sounds different from say 600HZ on a violin. The better the resolution the more natural and musical an instrument sounds.
I found that the HD800 had a scary amount of resolution in the highs and lows but lacked the same a bit in the mids, which is why I sold them. Coming back to this amp. DO NOT expect this to be a resolution monster. The amp is very controlled and while it does try and convey some amount of detail it is not going to show you the finer nuances of the recording. You are not going to hear the reverbations in the singers voice as clearly separated as a more expensive amp. Don't get me wrong - most cheap amps sound very one notish and the AUNE does a good job of trying to reveal detail but this is it's greatest weakness. It simply does not have enough resolution to make it go that extra mile and beat costlier designs. In comparison headrooms micro amp ($399) offers a lot more resolution in the mids and bass region.
Transparency - this is like looking out of a window. If there isn't any glass you can see clearly. As we add a glass sheet to the pane it taks away something from our view. As we add dust to the glass it further obscures the view. Transparency in sound is the same principle. One of the reasons why live sounds live is because there is nothing between you and the singer!
This is where the AUNE does a very good job. I can't find anything to really crib about at this price. You can hear clearly without instruments sounding muddied together. Everything is spaced out well and separated from each other. There is a good sense of space between instruments and voices as well. Very good job here AUNE, kudos.
Extension - As said before the AUNE is limited in extension in the highs and the lows. Then again I rather have it not try and generate the freq rather than mess it up. I just wish it had more resolution and extended a bit more at both the extremes.
Speed - This is the ability of the component to time correctly. Whenever a singer sings or plays an instrument it is done in conjunction with a count. The count is what we call beats per minute. We tend to do this naturally without realising it. When people start clapping in concert with what a singer is singing, one will notice that the claps automatically follow a certain timing. We have a natural ability to do that and when a component reproduces that it is called real freaking music.
The AUNE is a bit slow here. This could be a function of that control that I have been ranting about. It isn't lead trodden but I do feel it tends to lag down a very little bit. It doesn't flow as freely as I would have liked it to.
The internal DAC - The internal DAC is pretty musical. It isn't as cleanly separated as my Sim Audio but then again the Sim costs 20 times the price of the entire unit! If I had to find one area where the AUNE really shines it is the DAC section. It is very clean, has a decent amount of resolution (i.e. does not sound one notish at all). It does tend to club things closer than the Sim does but then again you can't expect eveything at this price.
If I had to sum up the internal DAC I would say it tends to stick out a bit in the upper mid range (think trumpets). This is its main character and it wil emphasize this a bit.
Soundstage - I don't think headphones generate a real soundstage. They tend to separate instruments around your head but I don't think I would talk of this phenomen like a soundstage that one gets from speakers. The AUNE when connected to my Sim did a fantastic job of keeping everything separated - like I said it is very controlled. However when you use the internal DAC things sound slightly closer to the center. You can call this the soundstage if you like but this is just my opinion.
Burn in - out of the box it will sound a bit too controlled - run it in for about 50hrs atleast and it will open up a bit. My experience regarding burn in - I don't believe in burning any component continuously for say 100 hrs or so. You need to run it for sometime and then give it a break. This allows the components to return to the original stage. The capacitors need to charge AND discharge a bit before they are able to hold their optimum charge. The voice coils of a headphone need to heat up, expand a bit and then cool down before they can truly be considered run in. If you run a headphone in for say 100 hrs continuously you are heating up the voice coils way to much. Once again this is just my opinion - I prefer to run an equipment for 5-6 hrs and give it a break for 2-3 hrs and then continue again.
To sum it up - This is a terrific amp for $140. I just wish that they had two versions - a budget one and a higher end one which added extension, resoltuion and let loose a bit of that control that the amp exhibits so much. I would gladly pay $250 for this amp if it improved in those areas. I suspect that the biggest culprit is the PCB which looks like a cheap PCB. That could be followed by the power stage as it uses an external wal wart. Whenever an amp is power starved it will begin to control the sound or will begint o clip. I think these two factors (PCB and power stage) is what is holding this beast back. If the AUNE designer is reading this please try using a higher quality PCB, RCA inputs, selector switches and build a bigger power stage. You have come so close, yet you are a bit far...
