First of all let me say that I acknowedge that this is an expensive amplifier. Not extravagent in the big scheme of things, particularly if you consider some headphones but as a portable amp it is significantly more expensive than others on the market and for this reason it needs to justify itself (no pun intended).
 
I have stalked this amp for a while after seeing positive reviews around the place. I have just sold a Graham Slee Voyager and have had a Little Dot Mk1+ as my day to day portable amp up to now so I had the funds finally available to purchase and treat myself.
 
I purchased from one of the two retailers available in the UK and the parcel turned up the following day. Impressive. The packaging is quite basic with just the amp, some sticky feet and tools to open and adjust the amp itself. There was no instruction manual available but I can't imagine it would say much anyway as it is all very intuitive.
 
I have not had chance to listen to a great deal of music as yet so this is very much a first impressions review. I will add to it later on as I get familiar with it and what it is doing to my music.
 
One thing I find having read a number of reviews on here is that there is often a lack of context to reviews. Hifi is all about the music, not the kit or the preferences of the reviewer, but the music that is being listened to. For a reviewer to say that such and such an amplifier has a "solid bass" is not very helpful unless you know what they are listening to. If they love drum and bass it will help understand what sort of bass is being heard but if they are into acoustic folk music then maybe something else is being heard. Obviously we all have our tastes and one mans good sound is anothers bad. But I will try and relate what I am hearing and how it impacts the music I am listening to. If others find this helpful then great but please treat this as subjective, as all reviews inevitably are. As background I have used Beyerdynamic T50p headphones and Colorfly C3, RoCoo P and Cowon X7 players with this amp to date.
 
OK, so having got that off my chest what is the Just Audio AHA-120 like?
 
My first listening was to the Orb's debut album, all three disks of it. For this the amp gave a lovely clean presentation and the vocals were more clearly heard than I have ever heard them before. The speaking part of Little Fluffy Clouds was rendered beautifully with every intake of breath and nuance of the voice given space in front of the music. Minnie Ripperton was also given plenty of room.
 
Switching to Amiina's Kurr album I deliberately chose this because the instrumentation is sparse, haunting and at its best, spine tingling. The opening bars of the first track can leave me spell bound. Whilst I did not get the hairs on my neck standing up with the Just Audio it was appreciably more realistic than I have heard from any other portable equipment. My home set up can really do this album justice but the portable one is still a little way short in giving me the same experience. The voices and strings were both very realistic and seemed to eminate from a completely silent background. Iceland has a disproportiote amount of talent at the moment and this album was conveyed with as much emphasis on the space around the musicians as the music itself. There was nothing closed in or claustrophobic about it, something I have felt with my other amps in the past.
 
I also listened to Jean Michel Jarre's Oxygene. This too is a reference album for me and the way the synthesiser bounces around between the speakers at various points can make all the difference to the experience. I have to be honest and say that I was not captivated. The music did not grab my attention I was expecting it to. This unit does need time to open up like a flower before the morning sun (sorry - don't know what came over me there).
 
I have now had chance to listen to this with a bigger range of music and it is growing on me. I listened to Simon and Garfunkel and the simple arrangements and crisp vocals really stood out. Similarly the Beach Boys Friends album now had more emphasis on the glockenspiel than I have noticed before and you could really follow the individual voices on the harmonies. Even the Beatles benefitted with Ringo's drumming clearer and more separate than I have heard from portable equipment before. Also the musicians seemed to be better placed around my head with space between drummer and guitarist and vocalist etc. Kraftwerk's Autobahn sounded deeper and more foreboding in places than I have heard before.
 
I think what I am finding is that there is a commendable lack of fuss with this amplifier. You don't get an immediate rush of sparkle or rumble of bass, what you do get is clean, clear interpretation of the music you are playing. It does not flatter to deceive but just gets on with the job of replaying music accurately and cleanly. I am using the world clean a lot and I think this is it. There is no muddying of instruments and no fuzziness at the extremes. This might imply a dry, lean presentation but it isn't. It is just a lot more space than I am used to. Also any background hiss that I previously noticed with the RoCoo had disappeared. Silences are definitely silent with this amp.
 
I took this amp to the London Meet in April and had chance to compare my set up to some others. This reinforced to me just how good this amp is. Sure I could still get blown away by listening to kit two or three times as much again but it was not two or three times better. It even improved a Hifiman 801 I was fortunate enough to listen to. I am now seriously in love with the Just Audio AHA-120. Is it still relatively expensive? Sure. Is it worth the outlay? Yes.
 
In summary: This is a well made amplifier that is bigger than your normal portable amplifier but one that is ideal if you plan to be relatively sedentary with it. It is not really pocketable unless you have big pockets (and deep given the price) and recent experience has shown that it is not ideal to have when travelling on the train or underground, it's sheer bulk being inconvenient. Musically I have been impressed with and it is continuing to get better as hours progress. It is better than any portable amp I have heard. The instrumentation is clean and vocals in particular get given an excellent delivery in the range of music I have listened to. I am conscious that it still has to earn its price tag and I do have greater expectations of this amp than I do my Little Dot but so far I think it is worth the extra outlay, provided you do not plan to take it with you on the tube every day!
PS: I can also commend Justin's support to his products. I had a minor issue with the volume control and Justin sorted it out quickly and painlessly. Thank you Justin.

I bought this player to complement my larger Cowon players and on the strength of some of the opinions written elsewhere on this site. When I saw it for £70 on Ebay I decided to take the plunge.
 
Boy am I glad I did!
 
The unit comes nicely packaged but my initial impressions were not too positive as the unit needed a firmware upgrade and immediately froze. I could not operate any of the controls and it just sat, blinking at me. Luckily some good advice from fellow enthusiasts helped me sort the problem and the unit does not appear to have suffered any long term ill effects.
 
So now I could get to playing some music on it. It is simply stunning. I have a RoCoo P (reviewed elsewhere) and this stood as the best player I had heard to date. However the C3 shades it in just about every area. The background is dark and hiss free, the vocals emerge from the silence with breathtaking clarity, the instruments are further back but each has its own space. Dead Can Dance rise through the ether with all the mystic glory their music can evoke. Try some DIY krautrock from Amon Duul and the band have never sounded so together.
 
Unlike the RoCoo I do think the C3 benefits from amping, there is clearly not as much power behind it although I would not suggest for a second that it is weak in this area. It is just that the RoCoo has so much welly.
 
Downsides? Well the screen is small but remarkably clear, the touch screen gets a lot of paw prints and the UI is clunky. But really, none of this matters once the music starts to flow.
 
I was sold on the RoCoo until I heard the C3. Now I tend to find I reach for the C3 first if I want to listen to something I have on the MicroSD card. And more music seems to be finding its way onto MicroSD card!
 
Can I ask for anything more than that for £70?

I bought this on the back of buying a Little Dot Mk IV tube headphone amplifier earlier last year. I was very impressed with that unit and so thought I would extend this to my portable listening kit.
 
I have been using it now for a few months and overall I am impressed. It is a neat little unit with an all metal case and good solid controls. I don't use it on the move so it doesn't need to fit in pockets or bags but I can imagine it would be up to the task of being thrown about a bit. The only downside is that the sockets for the headphones and audio in seem to be a little loose and can crackle when the lead moves. But for me this is only minor and does seem to be reducing with time so maybe it is just bedding in.
 
One of the big advantages is the rechargeable battery and battery life. I have used this almost every working day for the last few months and I have only had to charge it twice. It just seems to go on and on! I listen for about an hour a day and at reasonable sound levels so I reckon the 30 hours life per charge is about right. Battery life just is not an issue. It would be nice to have a better recharging indicator but this is nit picky in a unit at this price.
 
So what about sound quality? Well this is a sweet sounding amp. I am not a bass head and don't want thundering, overbearing bass but this goes low with some of the darker ambient music I listen too. At the same time it brings the vocals to the front and I find myself hearing words I am not used to hearing. It is not the last word in resolution maybe and I don't want to analyse every beat and note but the way the music is presented is clear and clean. I find I do not suffer listening fatigue and can sit for a seven hour session without feeling drained (headphones notwithstanding). That has not been true of all the equipment I have ever had!
 
Overall I like this amp. It is robust, truly portable and complements the sounds I am getting from my players. There is very little to dislike and at the price I think it is a bargain.
 
 

I bought this to give my iPod (320Kps files) a boost and immediately noticed a difference. The sound became more relaxed and allowed more detail to percolate through. It seemed to take the rough edges off without making the sound mushy.
 
Since disposing of the iPod and moving to a Cowon X7 (FLAC files) I still hear improvements but maybe not as night-and-day as before. I use a variety of headphones and IEMs but I have not noticed anything significant between them using the Voyager, they all seem to benefit from having the amp in the signal path.
 
The amp itself is solidly constructed and feels like it could survive the tribulations of using it on the move. However it does add bulk, approximately the same as an iPod, and I found it awkward to use this when commuting on the train (when arguably the benefits are reduced still further due to ambient noise) but this would be true of any headphone amplifier. However used now in the office where mobility is less of an issue I enjoy all of the benefits with none of the downsides. It does not look glamorous, there are no shiny chrome bits or brushed aluminium but this neo-industrial look is not without charm.
 
I used this amp every day with my Cowon (but not with the RoCoo P as this does not seem to need any help) until recently and then sold it to help fund another (more expensive) headphone amplifier. Recommended.

I bought this on a recent trip to China (well, when in China do what the Chinese do and buy a valve headphone amp!) after doing some online research. This is my first valve amp but I already owned a Graham Slee headphone amp.
 
The amp out of the box gives off a good first impression. It is well built and feels solid. The instructions are adequate without ever feeling comprehensive but hey, what do you need to know? Stick the leads in this end and the phones in that and away you go! It is a little bigger than the photos suggested it was but by no means bulky. The volume dial has a good weight to it and the whole thing feels quality.
 
Once I got it home and installed in my system it was time to see just how good it was. I have done all my listening so far with my trusty HD600s. The impact was immediate. Compared to the Graham Slee amp (which I rate very highly but in a different way) the sense of space and air was amazing. The amp did not need much running in as it had been on display in the shop so I was listening to a more mature presentation from the off. Listening to acoustic material brought  more pluck to the guitar and breath to the voices. I could hear Mr Garfunkel standing beside Mr Simon in more focus and almost see the guitar strings being twanged. It was altogether a more relaxed presentation. Moving to more electronic music did reveal slightly less sharp bass and maybe a lack of really deep notes but nothing that was detracting from the overall flow of the music.
 
I have listened to a wide variety of music styles now through the LD Mk IV and think that acoustic definitely benefits the most. But even the odd Krautrock classic benefited and the new Ultravox album sounded very silky.
 
I have purchased some higher quality valves than the unit came with (mostly on the advice of others on this forum - thank you to those who have set their research out and offered their advice) so I hope that I can get more improvements in due course. So far I am very pleased and for such a modest outlay! Bargain of the century for me so far.

I'll keep this simple as I would probably only duplicate what is said elsewhere anyway but on the principle that the number of reviews says as much as the reviews themselves here I go.
 
I already have the ubiquitous iPod and a Cowon X7. Increasingly I have been ripping my CDs to FLAC as I move to a more streaming oriented home set up and I have been looking for a way to make the most of these files when on the move. The Cowon is already full and the iPod is now limited to lower quality rips so I was looking for a small DAP to augment the Cowon and hold some favourite music to listen to on the move.
 
I found this DAP when browsing online and (helped no end by the reviews already posted) I decided to take the plunge. Not a very deep plunge given the price compared to some competitors but a plunge nonetheless on a brand I am completely unfamiliar with.
 
I ordered directly from Hisoundaudio and despite the non-Amazon experience the process was completely painfree. They are helpful and professional and the DAP turned up nicely packaged a week or so after making payment.
 
After charging and loading some files on micro SD cards that I had lying around from various mobile phone purchases I got to the important part. The listening.
 
Now I will say that the unit is still burning in. I anticipate improvements in the sound quality, particularly in the bass and this review is based on the experience to date and only a few hours listening. All my listening has been with the Beyerdynamic T50p headphones. However I can say immediately that this has made my iPod sound flat and lifeless from the off. Admittedly this is comparing FLAC to MP3 but they are cut at 320kb so not completely lame.
 
This unit sounds fantastic. I put the Beach Boys Pet Sounds on followed by Friends and the vocals were truly outstanding. Clear, to the front of the mix and you could follow the individual voices with ease. The instruments were further back than I am used to but I think this is probably a more realistic interpretation of the music than I have had with the iPod previously. Moving to Jean Michel Jarre Oxygene 30 and the swirl and whoosh of the spacey 70's synthesisers was impressive with clarity and focus in all areas. This wasn't fatiguing either with a nice, organic completeness in the sound. Nothing seemed overly promoted or repressed.
 
The One Armed Bandit set from Jaga Jazzist was also clear and captured the complex instrumentality well. There was no mush or fuzziness I could detect anywhere.
 
The only issue I have with this unit is the interface. The screen is small but perfectly readable, the navigation is not always intuitive but does not take long to master, the menu options are logical and easy to understand. The irritation is when you are listening to a long piece of music and you have to pause. Either the phone rings or someone wants to talk to you, an everyday occurence even when on the daily commute. At this point when you restart the music you cannot pick up where you left off. Or at least if you can I have been a complete failure at finding out how. Instead the unit either picks a random track from the internal memory or starts the track again from the beginning. You have to remember where you were, navigate to the track, and start that track all over again. Why can't the system pause rather than just stop? An obvious firmware improvement hopefully.
 
That really is my only gripe. Build quality is excellent even if the unit were many times the price. It does attract fingerprints on it's nice shiny surfaces but I am fighting the inner OCD to clean it all the time. The unit is slightly smaller than I imagined but by no means fiddly, even with my stubby digits. I have not tried the bundled headphones but I did get some Hisoundaudio Crystal phones when I bought the RoCoo P. These are still burning in so I cannot comment on them yet. The unit powers my T50p headphones with no apparent difficulty, the battery life is perfectly acceptable with a recharge after a few hours listening through the mini USB port.
 
It goes without saying that I am delighted so far with the Hisoundaudio RoCoo P. I do expect it to improve further with time and I look forward to many happy hours of audio bliss. I would recommend most heartily but please, please, please Hisoundaudio, fix the pause.
 
UPDATE: Have spent many hours listening to a variety of music on the RoCoo P now and have enjoyed the way the music has been presented. Vocals are to the front, clear and the depth is amazing. The only thing I have noticed is the presence of a slight background hiss. This has really only been accentuated since I bought a Colorfly C3 and everything the RoCoo does the Colorfly does. Only slightly better. The C3 has no hiss and just as clear a presentation. So whilst the RoCoo is still one of my favourite players it is now playing second fiddle to the C3.