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Aune B1

  1. bhazard
    A very good Class A portable amp
    Written by bhazard
    Published Aug 18, 2015
    Pros - Sound, Build Quality
    Cons - Low battery life, Large.
    Aune B1
    If you’ve ever wondered how a Class A, discrete amp would sound with your portable music rig, Aune has given you the chance with the B1.
    While I’m not going to go into the details of Class A nor comparisons to other amp types (Class AB, Class D), Class A is considered the best by many. I’ve found amps in all topologies that are so good that you’d never consider or care what type they are, so I don’t necessarily prefer one type over another. The design and components are what matters most.
    1. Frequency range: 10 Hz – 20 KHz ± 0,15 dB
    2. THD+N: <0,0008% @ 1 KHz, 600Ω
    3. Signal/noise ratio: >124 dB @ 600Ω
    4. Channel separation: > 110 дБ @ 1 КГц, 600Ω
    5. Output power: 25 mW @ 16Ω, 50 mW @ 32Ω, 100 mW @ 300Ω
    6. Headphone impedance: 16Ω — 300Ω
    7. Battery: 4000 mA/h
    8. Life time: 10 hours for 20 mA, 5 hours for 40 mA
    9. Size: 65 mm × 110 mm × 18 mm
    10. Weight: 230 g
    Build Quality: 
    1. Quality Aluminum Chassis
    2. Unique window design showcasing internals
    3. Stylish Faux Leather
    4. Confusing switch placement
    The B1 is a somewhat hefty amp to carry around, about the size of a smartphone lengthwise, and about 3-4 phones wide in girth. While it may be a bit wieldy to carry around, the actual quality of the device is high. The aluminum chassis and clear window casing showing the internals of the device provides a sleek look with a sturdy feel. The faux leather along the chassis also fits the design quite well without taking away from the overall appeal.
    The switches and volume knobs did take away from the build though. I found the gain switch and volume knob placement to feel unnatural when I went to adjust them. It was nothing too distracting, but I’ve also used many amps that felt much better (Fiio and Cayin come to mind).
    Battery life is not the greatest. The Class A design really eats up the battery, with 5-10 hours being the norm depending on your gain setting.
    Sound Quality:
    1. Good but not great power overall.
    2. Slight bass tilt, 40mA mode better
    3. Neutral sound
    The B1 has plenty of power for most applications, and it excels at powering high impedance headphones. I ended up finding out that low impedance multi driver earphones do not do well with the B1 however (Havi B3). My smartphone drove the B3 at the same power level (even in high gain), which is not something I want in a $200+ amp. Every other IEM and headphone sounded stellar however. The O2 amplifier comes to mind with the overall neutral aspect of the sound.
    Compared to my Geek Out 1000 V1, I found the GO1000 to be slightly more engaging and more powerful, with a slight edge in soundstage. Treble was enhanced over the B1, but I found the B1 more pleasing.
    There is a lot to like about the B1. I would very much recommend it as a portable amp for a high impedance headphone. For a portable IEM solution, I find that there are better dac/amp combo options available at similar pricing.
    As a fan of Aune and their past products, I applaud their effort in making a unique amp that can satisfy a lot of people.
  2. dan.gheorghe
    Best portable amplifier I have heard to date
    Written by dan.gheorghe
    Published Aug 11, 2016
    Pros - Natural sound, excellent bass, superb midrange, very clean, good details, spacious and natural soundstage
    Cons - positioning of volume knob and gain switches are not very fortunate
    This amplifier is a jaw breaker from my perspective. Ok, there are some areas where you can find better. It doesn't shine with very, very efficient IEMs, and of course it won't amplify HE6. 
    However, if you will be using it with a moderate power requiring headphone, I think that it would be very hard to find a portable amplifier better than this... at any price. 
    What I love about it the most is the effortless, natural sound signature it has, followed by an excellent bass, superb midrange,  *very* clean sound, spacious and holographic soundstage.
    It also has good details and natural transient response. The sound signature is a little bit on the warm side. 
    To get all from this amplifier, you should pair it with a good DAC. Will try it with Chord Mojo soon! 
    Small Comparison to FiiO E12A
    I won’t loose too much time on this comparison. Overall I ended up preferring the Aune B1 and not by a small margin. B1 sounds considerably more natural and organic. The sound is more dynamic and decompressed on B1 (E12A sounding a little flat/dry in comparison) , with better transparency and details.
    The bass on B1 kicks ass compared to the one on E12A, the midrange is better textured and more detailed, while the treble is smoother and more detailed in the same time on Aune.
    1. Excellent bass with wonderful extension, control and punch
    2. Rich and detailed midrange
    3. Smooth, detailed and sparkly treble
    4. Excellent vocals
    5. Very natural and clean sound
    6. Very spacious and natural soundstage
    7. Very good transients
    8. Very good imaging and instrument separation
    9. Excellent price for what it offers
    1. The volume knob and switches are made of plastic
    2. Position of the volume knob and gain switch are not very fortunate
    3. Gets quite hot if you want to use it in your pockets. If it's winter this is a pro :))
      kissmevn likes this.
    1. View previous replies...
    2. drbluenewmexico
      you nailed it!
      drbluenewmexico, Aug 11, 2016
    3. swannie007
      Nice review, I must concur with your findings. I have numerous portable amps but this is my daily driver, and says it all.
      swannie007, Aug 11, 2016
    4. theMUKe
      Totally agree with your review! This is a great amp!
      theMUKe, Aug 22, 2016
  3. nmatheis
    Aune B1 Quick Review
    Written by nmatheis
    Published Aug 22, 2015
    Pros - Unique aesthetics. Powerful. Good soundstage and separation.
    Cons - Mid-centric. Plastic volume knob and switches don't inspire confidence. Too powerful for IEM.
    I was provided the Aune B1 as part of a mini-tour @money4me247put together after he reviewed the B1.  I am in no way affiliated with Aune, and this is my honest opinion of the B1.  I would like to thank @money4me247 for giving me the chance to test drive the B1, and I hope my thoughts prove useful for fellow Head-Fi members as well as for Aune.


    Ok, so why review the Aune B1?  When I saw it announced, I wondered how the B1 wold to my Fiio gear (E12A, E12 DIY & X5).  I was also intrigued by the discrete circuitry and Class A feature.  


    I'm a 43 year old father who loves music.  From electronic (Autechre, Boards of Canada) to modern/minimalist composition (John Cage, Philip Glass) to alternative rock (Flaming Lips, Radiohead) to jazz (John Coltrane and Miles Davis) to metal (Behemoth, King Diamond) to classic rock (Eagles, Rush), I listen to a wide variety of genres and artists. 
    My portable music journey started with the venerable Sony Cassette Walkman and then progressed to portable CD players, minidisc recorders (still have my Sharp DR7), and finally on to DAPs like the Rio Karma, iRiver IHP-1xx, iPod 5.5, iPhones, and the newer crop of DAPs from Fiio and iBasso. 
    I typically listen with IEMs from my ever-growing collection from budget to mid-fi. Less often, I grab a pair of full-size cans.  Recently, I've been listening a lot with various earbuds and IEM I have in for testing.  I do have a lot of other gear, though.  You can always check my profile for a reasonably up to date gear list. 
    As with a lot of people my age, I've got some hearing issues.  I've got mild tinnitus and suffer from allergies, which can affect hearing in my right ear.  I'll admit it, I'm not blessed with a pair of golden ears.  That said, I've been listening to portable gear for a long time and feel confident in assessing audio gear - just wanted to be transparent up front. 
    Please refer to this LINK for official specs.
    External packaging is a simple black & white.  I hate gaudy packaging and highly approve of the approach Aune took here!
    Open the box and you see the B1 and accessories.
    Here's what you get: A micro USB cable, and 3.5mm IC, and the owner's manual.  No bands and no carrying case.  Hmm...
    The B1 comes in either black aluminum with black leather pads or or silver aluminum with red pads.  The tour B1 was the black model.  I'll go over the various features in pictorial fashion below.
    The front 3.5mm input and output jacks and the volume knob.  Plugs slip in smoothly without clicking in place, but I had no problems with them coming loose.  The volume knob was disappointing, quite frankly.  It feels like cheap plastic and has no marking to let you know how far you've turned the knob.  I hope Aune rethinks this with future models and replaces it with a nice matching metal knob with an indicator line.  Despite not being up to the overall quality and aesthetics of the B1, the volume knob has very smooth movement and allowed for easy fine-grained volume adjustment.
    On the back, we see the micro USB receptacle.
    On the left side, we find the battery indicator LED.  You push the small, flush button, and the number of times the LED flashes indicates the charge level.  I would've preferred three or four LEDs instead of just one that flashes, but it gets the job done.  Maybe next time...
    On the right side, we find the Power, Class A, and Gain slider switches.  As with the volume knob, these cheap, wobbly plastic sliders feel out of place on the B1.  Replacing them with metal switches would fit much better with the overall aesthetics, in my opinion.  It would also make them feel more solid as they're operated.  In particular, the Class A switch should be designed as a recessed switch, since it's not supposed to be operated when the B1 is powered on.  Very odd design choice to make this a raised slider switch.
    On the top, you get two windows showing off the internals.  There are also two green LEDs that light up during operation.  I think a lot of people geek out on seeing the internals.  I know I'm going against the tide, but I personally feel like these windows, and especially the green LEDs, are yet another disjointed design feature that Aune should've left out.  Of course, your mileage may vary.
    On the bottom are the two black leather (pleather?) pads.  I quite like the look on the back with the white lettering on the black metal and black leather pads.  Very nice, and functional, too as the pads serve to protect any surface you lay the B1 on.  No need for those little silicone feet with the B1!
    How big is the B1?  Just about the same footprint as my E12A but about half again thicker.
    Here's another view with the Shanling H3 thrown in for comparison.
    I’m the first to admit that describing sound isn’t an easy thing to do, so I’ll try to describe this as clearly and concisely as possible without waxing eloquent about subtle nuances that only the highly-trained ear will hear.  If you’re looking for that, there are other reviews that meet your needs.  I mainly used my HiFiMan HE400 and the relatively new VE Zen earbuds with the B1.  Volume matching with the HE400 was performed with a 1kHz test tone and the Decibel 10th iPhone app.  With all that disclaimer type stuff out of the way, here are my thoughts on the B1: 
    HE400 with 1kHz test tone @ 80dB
    X5: HG 65/120
    B1: HG slightly over 9 o’clock
    E12A: HG 10 o’clock

    B1 vs. Fiio Gear (E12A, X5) with HE400

    * B1 has less bass extension and impact.
    * B1 has a more mid-forward, energetic sound.

    * Upper register instruments and vocals can sound a bit aggressive / piercing.
    * B1 has splashier highs and isn't as crisp
    * B1 has a more holographic soundstage with better instrument separation and placement
    * B1 has a richer, more engaging sound that can become fatiguing more quickly

    * NOTE: The Fiio gear has a distinctive "house sound" sound, so I grouped them together for comparative purposes.
    B1 with VE Zen
    The B1 drove the VE Zen marvelously on HG, striking a great balance between lushness and technicality.  I did a lot of listening with this pairing and was quite happy with the sound!
    B1 with AKG K553 
    * It's ok at lower listening levels, but going over 12 o’clock with my AKG553 gets too loud and far too splashy.  I found the K553 was a much better pairing with my Fiio gear!

    Class A
    * I didn’t notice a difference with either the HE400 or Zen.

    Driving Power
    * The B1's volume knob goes from 8 o’clock to just past 6 o’clock.
    * I found Low Gain too powerful for sensitive IEM - barely audible at 9 o’clock, loud at 10 o’clock, and really loud at 11 o’clock.
    * I got great use out of the volume knob on LG with HE400.  On HG, I wouldn’t want to go over 12 o’clock.
    * NOTE: I've ben informed that the B1 has been updated with a lower Low Gain setting to better accommodate IEMs but haven't experienced this myself.
    Channel Imbalance
    * There’s a slight bit of channel imbalance at very, very low listening levels - probably won’t be an issue for anyone.
    I found the battery life estimates Aune provides are very good.  It could go about 8-10 hours in A/B mode and 4-5 hours in A mode.
    The Aune B1 is an interesting amp.  It's design is a mixed bag of industrial aesthetics, durable metal, and cheap, wobbly plastic.  The volume knob and slider switches were a real let down.  While I didn't care for the windowed design, I can see where many would find this quite pleasing.  For me, the sound was a bit of a mixed bag, as well.  With the VE Zen, the synergy was just outstanding!  With HE400, it was ok but nothing special.  With K553, it was only ok at low listening levels - higher listening levels made the K553's upper end far too aggressive for my taste.
    I'd be happy to see an updated B1 with metal slider switches and metal volume knob with a volume indicator line.  I think it'd be much easier to estimate battery life with multiple LEDs instead of one blinking LED.  And at this price point, there's really no excuse not to provide a case or pouch of some sort to protect the B1 in your bag.  I mean, really!
    I wouldn't expect Aune to alter the sound, but I can't see the B1 or other Aune products with this mid-centric sound signature becoming a go-to device for me.
    Thanks again to @money4me247 for giving me the opportunity to give the B1 a listen!
      hakushondaimao likes this.
  4. LostInMyDream
    A bit of suprise...
    Written by LostInMyDream
    Published Aug 11, 2015
    1. This is an Aune B1 Canadian tour unit. The tour was organized by hakushondaimao, and many thanks for his efforts. I had the B1 for a week and as the last tour member I sent it back to hakushondaimao. This review is not a required precondition of tour participation.
    2. I'm in no way associated with Aune.
    3. I don't believe in burn-in. I almost always use stock cable or the cheapest one I can find and call it a day. I don't believe I can distinguish lossless formats from 320kbps mp3 in a blind test regardless of any gear used, but always use lossless where possible.
    Gears used:
    Source: mainly Astell & Kern Jr. Other source components include Schiit Modi 2U, Modi, and Wyrd, kindly loaned by mikoss.
    Amp: ALO Rx (newer one for IEM).
    Amp/Dac: Schiit Fulla, Audioquest Dragonfly 1.2.
    Headphones/Earphones: TH900, HE400S, UERM
    1. Average usage was 2 hours a day at 20mA mode.
    2. Most listening was done on-the-go with UERM. TH900 and HE400S were used occasionally. My UERM might be an outlier: it's slightly bassy, compared with say Noble 4.
    - Runs very warm on 40mA mode.
    - A bit too big for me. I have small hands.
    - Nice finish. Button layouts are just right. Quite an eye-catcher.
    - Volume pot prone to rubbing.
    - Tons of power. As long as one doesn't throw an HE6 to it, there should be no big issue in terms of volume.
    - The downside of the above one is that even at low gain, low-z-high-efficiency headphones/earphones don't have much volume range. I put the Jr+B1 stack into my bag and the volume pot was accidently touched ----> huge increase/decrease of volume. Quite a bit of hassle.
    - Overall, quite thick, not overly so. Unavoidable solid state grain. No glaring. Notes have good body. Plenty of driving power, but not brutal. Not an aggressive sound signature.
    - A minor, but apparent bass boost.  It doesn't add quality to bass, only quantity. In other words, things just get louder, but no significant improvements in definition. Depending on personal tastes, B1 lies on the boarder between neutral to fun. In no way offensive, and occasionally can make things fun. However, people who seek a strict neutral sounding portable amp should avoid B1.
    - Smeared lowest/highest ends, particularly evident with UERM. I strongly suspect this a result of impedance mismatch. The output impedance of B1 may be over 5 ohm. If this was true, it's the biggest downside for me.
    - Ultimately 2D soundstage. Good width but not much depth. 
    - Outstanding instrument separation to the extent that it might be distracting. An excellent trait in my book. My personal favourite trait of B1.
    - Hot switching between 20mA and 40mA modes made no major difference for me. 
    - Higher volume levels may produce distortions and clicks.
    - Maybe not a good match with my low-z-high-efficiency cans and IEMs. If I had something like HD650 in my hand, I would expect a lot of improvements.
    - Slightly bassy for me.
    - Considering most portable transducers are low-z-high-efficiency, B1 may be better considered as an around-home-kind portable amp.
      aluweer likes this.
  5. derGabe
    Der B1 ist ein potenter Kopfhörerverstärker mit geringen Schwächen im Design
    Written by derGabe
    Published Jul 12, 2015
    Pros - genug Leistung für die meisten Kopfhörer
    Cons - Kanalschwankungen im untersten Lautstärkebereich, Schwächen im Design
    AUNE B1 / Portable Headphone Amplifier

    Vorwort: Portable Kopfhörerverstärker sind in den letzten Jahren zu einem neuen Phänomen im Bereich der HiFi bzw. Kopfhörercommunity geworden. Kaum ein renommiertes Unternehmen hat es sich nehmen lassen, einen eigenen portablen Kopfhörerverstärker auf den Markt zu bringen. Als Beispiele dienen hier Sony mir Ihrer PHA Serie oder zuletzt Oppo mit dem hervorragenden "HA-2", der allerdings gleichzeitig auch ein DAC ist (aber auch einzeln nur als Kopfhörerverstärker per Line-In funktioniert).

    Nun stößt auch die chinesische Audio Firma "AUNE" auf diesen Markt vor. Wir nehmen im nachfolgenden Test den "AUNE B1" etwas genauer unter die Lupe und vergleichen ihn mit seinen aktuellen Konkurrenten. 

    Beim B1 handelt es sich um einen Class A Amplifier. Die meisten werden sich jetzt bereits fragen, ob ich mich hier am falschen Buchstaben bedient habe. Dies kann ich getrost verneinen, denn der B1 agiert tatsächlich als Class A Amplifier und bietet dadurch auf dem Papier eine extrem geringe Verzerrung im Nulldurchgangsbereich und eine erhöhte Linearität im Vergleich zu anderen Verstärker Klassen. Den großen Nachteil von Class A Verstärkern, dass diese im Betrieb sehr warm werden können, habe ich beim B1 nicht feststellen können. Ohne Frage, der B1 erreicht eine gewisse Wärme unter voller Last, allerdings ist diese zu keiner Zeit störend oder sehr auffällig.

    Design:  Der B1 steht in zwei farblich unterschiedlichen Varianten zur Auswahl. Da wäre zum einen die klassische schwarze Variante mit schwarzen Kunstleder Streifen auf der Rückseite und den 2 Sichtfenstern (die Einblick auf die Platine gewähren) auf der Frontseite. Als zweite Variante gibt es ein Design in Silber mit roten Kunstlederstreifen auf der Rückseite. Das CNC-gefräste Chassis besteht bei beiden Varianten aus 100 % Aluminium und hinterlässt einen sehr wertigen Eindruck. Die Entscheidung, dem Nutzer einen Blick in das innere des Kopfhörerverstärkers zu gewährleisten, empfinde ich als elegant und zugleich technisch ansprechend gelöst. Kleine Schwächen zeigen sich allerdings beim Drehknopf für die Lautstärke. Warum hier nur auf Plastik und damit verbunden einer geringeren Wertigkeit gesetzt wurde, kann ich nicht nachvollziehen. Außerdem fehlt mir persönlich eine Markierung auf dem Drehknopf, die anzeigt in welcher Stellung sich besagter Lautstärkeregler befindet.

    Klang: Für den ersten Test haben wir ein iPhone 5s mit dem Oppo-HA2 (hier nur als DAC) zusammen mit dem Aune B1 betrieben. Als Kopfhörer diente ein Beyerdynamic DT 770 Pro (80 Ohm Version). Die Musik kam dabei kraftvoll aus dem B1, wurde klar und überaus detailliert wiedergegeben. Im direkten Vergleich zum Kopfhörerausgang des iPhone konnte der B1 mit einer größeren Bühne und besserer Instrumentenseparation punkten. 

    Ohne den Oppo HA-2 als DAC am iPhone sah das Ergebnis dann vergleichbar aus. Da der interne DAC-Chip des iPhones nicht mit den DAC vom Oppo HA-2 mithalten kann, fällt das Ergebnis etwas „flacher“ und weniger lebendig aus. Nichtsdestotrotz klang der B1 am iPhone besser als der direkte Kopfhörerausgang dessen.

    Für den zweiten Test haben wir den B1 dann am IBasso DX90 mittels Line-Out verwendet. Als Kopfhörer wurde ein Beyerdynamic T1 benutzt. Mit dem T1 stößt der DX90 schon etwas an seine Leistungsgrenzen, zumindest wenn es um mein persönliches Lautstärkeempfinden geht. Dazu muss erwähnt sein, dass ich persönlich Musik gerne etwas lauter als die Norm höre. In Kombination mit dem Aune B1 konnte der DX90 dann mit dem T1 überzeugen. Den B1 hatten wir hierbei auf der höheren Gain-Einstellung. Etwas mehr Power hätte ich mir persönlich noch gewünscht, für die meisten Hörer wird die erreichte Lautstärke aber wohl vollkommen ausreichen. Als Konkurrent für den B1 sehe ich hier den Cayin C5, der einfach noch mehr Dampf macht und die Leistungsreserven aus so ziemlich allen Kopfhörern rausholt.

    Zuletzt haben wir den B1 dann noch am iPod Touch 5G verwendet. Als Kopfhörer dienten hierbei die Stagediver SD2 von „InEars“. Da diese In Ear Monitore sehr effizient arbeiten, reichte hier die niedrigste Gain-Stellung am B1 aus. Leider sind uns hierbei in den niedrigsten Lautstärken geringe Kanalschwankungen aufgefallen. Sobald man die Lautstärke etwas anhebt, verschwinden diese allerdings recht schnell. Aber gerade für IEM’s könnte das bei manchen Hörern für gewisse Enttäuschung sorgen. Nichtsdestotrotz konnte der B1 auch in Kombination mit dem Stagediver SD2 punkten. Die Bühne wirkte geringfügig weiter und dreidimensionaler. Veränderungen am Frequenzverlauf konnte ich in keinen der 3 Tests feststellen. 

    Fazit: Aune ist mit dem B1 ein potenter Kopfhörerverstärker gelungen. Die geringen angesprochenen Schwächen im Design kann man verzeihen wenn man einen leistungsstarken Kopfhörerverstärker mit genug Leistung für die meisten Kopfhörer sucht. Sehr leistungshungrige Kopfhörer würde ich allerdings eher mit dem Cayin C5 verwenden, da dieser doch noch das letzte bisschen Potential aus den Kopfhörern kitzelt. Im Vergleich zu den Kopfhörerverstärkern aus dem Hause Fiio braucht sich der B1 allerdings nicht zu verstecken. Hier würde ich den B1 sogar klar favorisieren, da mir die Bühnendarstellung sowie der relativ neutrale Frequenzverlauf besser gefallen. Am Oppo HA-2 kommt er nicht vorbei, allerdings wäre ein Vergleich hier auch nicht fair, da der Oppo HA-2 neben dem sehr guten Kopfhörerverstärker auch noch einen großartigen DAC an Bord hat und somit als Gesamtkonzept für mich als jemand mit iPod Touch 5G oder iPhone 5S deutlich interessanter ist. Für alle anderen Anwendungen ist der B1 von Aune aber ein überaus geeigneter Kopfhörerverstärker.

      thelonious58 likes this.
    1. derGabe
      This is the German Review for the Aune B1. An english Version is coming in the next Days.
      derGabe, Jul 12, 2015
    2. Wildcatsare1
      Thank you, my German is a bit rusty!
      Wildcatsare1, Jul 13, 2015
    3. h1f1add1cted
      Haha ich dachte ich lese nicht richtig, ein deutsches Review auf Head-Fi :) Hättest auch gerne z.B. im Hifi-Forum berichten können, aber dennoch danke. Mich würde das Grundrauschen vom B1 interessieren, gab es da keins mit dem StageDiver 2?
      h1f1add1cted, Aug 5, 2015
  6. jjacq
    Great IEM/Headphone amplifier for the money.
    Written by jjacq
    Published Jul 11, 2015
    Pros - Clear mids, great bass control
    Cons - A bit too big for portable, volume knob could've been better.


    Intro: I have spent adequate amounts of time with the B1, mainly after working so it was something I used to relax. I have an AK100ii I compared it with with a JH13. The Cayin C5 is having a few problems right now so I felt that it was not best to test it at this time.

    Packaging and Item finish






    Upon opening the package, you get a charger, 3.5mm interconnect, paperwork and the device itself. The device itself has a solid weight on it but with the surprise of the plastic volume knob. Another issue with the volume knob might be accidentally turning it when it's in your pocket which can be a real issue. It has a good feel when you turn it but I feel like plastic is still not the best choice for it.


    It has a similar form factor with the Cayin C5 and it fits pretty well with the AK100ii as shown below.








    The lighting is nice and pleasant but can be a bit annoying if you use it at night The alignment of certain setups also determines if the lighted parts will show or not, in my case it was covered by the AK100ii.



    Sound Quality



    AK100ii+Cayin C5+JH13



    The stack with a JDS labs mini interconnect.


    The sound reminds me of the AK100ii amplifier with subtle differences. There is no hiss coming out of these headphones and no noises in the volume knob. Bass response did improve a bit with the JH13 giving more emphasis on the bass than it usually does with treble. The AK100ii on the other hand gives slightly more emphasis on the treble which can make the JH13 a bit too piercing in the ears. I've also noticed that instrument separation with the JH13 is slightly less compared to my typical setup. Mids are just as good as the AK100ii to my ears. I did not hear any difference with the Class A mode with my IEM but YMMV.





    The Aune B1 on a Pelican 1020 micro case. It is a snug fit.


    Conclusion/Thoughts on Value
    I wanted to keep this short and sweet and as objective as I can. Comparing A and B and recording what I perceived. I have pondered upon what audience they were trying to target with this and I think it does very well with IEMs and portable headphones. Since I already own the Cayin C5, I won't be buying this but the build quality and sound quality itself makes me give it a double take. I remember disliking the E12 a while back because it felt too bright and thin and this wasn't like this at all. I think this is one of those things that would pair well with any transport with a sub-par amplifier assuming you are not burdened with its size. What I could think of would be a FiiO X1 or DX50 which I think would go well with this. Value-wise, it's a bit higher than the competition with the FiiO E12, FiiO E11K and the Cayin C5 but you are getting the Class A feature which you do not see in any of these units. Having owned the C5 and E12, I think the B1 can hold its place pretty well. It's rated at slightly less compared to the C5 and E12 @ 500mW@32 ohms compared to the competition at 800mW@32 ohms. The advantage of this is that the volume knob is not too "sensitive" as I use my JH13 with the C5 at 3'o-clock to get to listenable levels. 

      money4me247 likes this.
  7. Cotnijoe
    Aune B1 Amplifier: Gorgeous Inside and Out!
    Written by Cotnijoe
    Published May 27, 2015
    Pros - Sexy Design and Build, Fantastic Sound
    Cons - Slight Channel Imbalance Issue
    One of my favorite parts of this hobby that I've grown to love over the past few years is trying new things and just experiencing how different components (or combination of components) have their own unique way of expressing what is essentially the same music. So when Aune Audio began looking for reviewers of their B1 amplifier, I jumped on that train real fast. I’d like to give a big thank you to Aune Audio for providing me a unit to review and, of course, my review is solely my own opinions and I am in no way affiliated with Aune Audio.
    Packaging and Accessories:
                The Aune Audio B1 came well packaged in a DHL bag, a brown box, and finally its actual box. The box is sturdy and simple. Inside, you find the amp, manual, a business card, a USB cord for charging, and a short 3.5mm to 3.5mm cable. The overall presentation is simple but very nice, and Aune provides everything you may need to get the B1 up and running. The only thing that I would have liked to see is some sort of storage case, or even just a nice little bag for it.
    IMG_0058.jpg IMG_0059.jpg
    IMG_0060.jpg IMG_0062.jpg
    Inside of the packaging. Nice and simple!
    Build and Design:
                The Aune B1 is built like a tank, and it’s a damn good looking amp. Its chassis is built from brushed aluminum with only its volume knob being made of plastic. The B1 feels solid and has a nice heft to it. The build quality leave little to be desired and a whole lot to admire. My unit did come with two tiny tiny scratches, on at the bottom of the amp, and one on the volume knob that made me a little sad. Honestly though, build is awesome!
                It’s clear that the engineers over at Aune Audio paid a lot of attention to detail when designing the B1. The “highlight” of the B1’s design is obvious its two windows that show the components inside the amplifier. When I first saw a picture of the B1, I thought it was some sort of portable tube amp. I mean c’mon… looking at the tubes is half the fun! Now obviously the B1 isn’t a tube amp, but I still think displaying its internal components was a pretty cool little feature and is definitely a bonus in terms of aesthetics. The LED lights just make things even more awesome to look at.
                The buttons around the B1 are also well designed. Most of the functions of the B1 are controlled by sliding switches, where you slide it to turn a feature on or off. To prevent the switches from being easily changed, Aune had the chassis on the sides slightly indented. I don’t think that’ll solve the problem completely, but I personally had absolutely no problems with the amp accidentally shutting off or accidentally blowing my brains out by switching to high gain, so hey… what do I know, maybe it’s doing its job just fine.
                The back side of the B1 is well designed with two strips of material that keep the amp from sliding too much on a flat surface and prevent the amp from scratching. Now I won’t pretend to know what material it is, but I would guess that its pleather (I don’t think its real leather?). All I know is it looks very nice and gets its job done.
    Size wise, I think the B1 is very reasonable. It’s a little taller than my iBasso DX90 with about the same width. The two as a pair looks very nice!
    My only gripe about the B1’s design is that if you decide to make a portable stack by rubberbanding a DAP to it, it’ll block off the gorgeous display of its components unless you use the other side. But then that defeats the purpose of the pleathery material protecting the amp and you risk scratching the amp. Oh well… it seems inevitable.
    Again though – Built like a tank and damn good looking.
                The B1 is quite a special little device. Not only is it a class A portable amp, which is not all that common, it also has an interesting current switch that gives it a bit more flexibility in driving more demanding headphones. In addition to that, the B1 also includes an on/off switch, micro USB charging port, battery indicator, and of course a volume knob, input jack, and headphone out jack.
    Being a class A amp, the B1 does get quite warm after using it for some time. It remains very safe to touch though and never gets overly hot by any means – definitely still very safe to keep in your pocket or to use portably.
    What’s kinda bizzare is the current switch. In the B1 manual, Aune quotes in RED, “Never flip [the current switch] under B1 is working.” Ignoring the slightly broken English, it doesn’t sound like Aune is messing around. I wonder what would happen if I just … …
    Battery Life:
                The B1 is advertised to be able to run for 10 hours with low current and 5 hours with high current. I did run the battery dry on low current and got approximately 9 or 10 hours out of it. I didn’t keep a strict count, but the battery life is certainly around what it’s advertising to be. 10 hours isn’t bad, but it is trumped by other portable amps that can last 20, 40, or more hours (The most I’ve heard of is like 80 hours or something. That’s pretty insane.). However, remembering that most high quality audiophile DAPs currently on the market can barely last 10 hours, it’s not a problem at all. You’ll just have to remember to bring two chargers along when going on a long trip! Plus, remember that it’s a class A amp and, thus, fairly inefficient, I guess 10 hours is actually pretty good.
                I didn’t bother running the B1 on high current to see how long it lasts, as I don’t see that as necessary. If I’m running it with high current, I’ll probably be using a fairly demanding headphone, which means it’s not portable and I’ll probably be near some sort of power source where I can freely charge up my B1.
                       Listening was done with my iBasso DX90 as the source running line out into the B1 and then into my Earwerkz Supra 2, HIFIMAN HE560, and HIFIMAN HE1000 (just for fun and cuz I have it with me as a beta unit… why not). Basically all genres are covered and all audio files ranging from 256kbps and up (with the exception of DSD files) are used for my sound impressions.
    FullSizeRender2.jpg IMG_0067.jpg
    iBasso DX90 > Aune B1 > Earwerkz Supra 2 using plusSound Cables.
    Noise Floor
    The B1 is quiet. With my Earwerkz Supra 2, one of the most sensitive I know, it does have a tiny bit of hiss, but a VERY manageable and hardly noticeable amount. It is one of the quietest amps I’ve had the pleasure of listening to and I wouldn’t worry about it hissing at all honestly – very nice and very dark background. The DX90’s amp section still trumps it in terms of noise floor, but it’s hardly a difference at this point.
    Channel Imbalance
    The B1 does have a bit of channel imbalance issue that could be problematic, as the B1 also happens to be pretty loud. Running DX90 > Aune B1 > Earwerkz Supra 2, I had to set the line out volume of the DX90 to 200/255, which is the lowest I’ve ever had to set it, in order overcome the regions on the volume knob where the B1 has its channel imbalance. So what does that mean? Well first off, those using the most sensitive IEMs may need to do a bit more research or to give the B1 a listen first to make sure that the B1 is a good match with the sensitive IEM. And second off, those that do not have digital control over their line out signal may also need to do more research. It’s really unfortunate to see that this may be the dealbreaking point for those using the most sensitive of IEMs because of the sound that the B1 produces (hint: it’s awesome).
    Sound (For Real Now)
                As a whole, I think the B1 is one of the most neutral portable amps that I’ve ever heard, and is certainly the flattest sounding in the sub-300 dollar range that I know of. And that’s a good thing. I really like this neutrality that the B1 has.
    B1 compared to Amp section of DX90 (Using Earwerkz Supra 2)
                I love my DX90 and I consider it to be one of the best (if not the best) DAP currently available under 500 dollars. I do have a few gripes about it though, as I feel that it is just a bit warmer and smoother sounding than I would prefer it to be. The B1 addresses that issue for me quite beautifully. When connected to the DX90 via its line out, the improvement over using just the DX90 alone is significant.
                The most obvious change and improvement come in the bass department. The B1 removes the midbass bump that I find the DX90 to have, and bring on better bass extension. What you get is a much cleaner, tighter, and faster bass that retains a very fun sound all while making the sound straight out of the DX90 seem muddy and bloated in comparison.
                The midrange of the current firmware I’m using on the DX90 (FW 2.2.0) was a little forward and can be just a bit thin and unnatural sounding for me. The B1 also helps the DX90 out here. It pulls the forwardness back just a tiny bit while giving the midrange more fullness by presenting a flatter upper midrange that fixes the DX90’s slightly unnatural tone.
               The treble from the B1 extends better than that of the amp from the DX90, giving the sound slightly more air. The B1 also adds a nice crispness to the sound, but never making the sound harsh or bright.
                The other major improvement that comes with the B1 is the soundstage and separation. You get a significantly larger soundstage, particularly in width, which really opens the sound up. Separation is also a very big step up compared to listening with just the DX90. The sound from the DX90 alone is claustrophobic and congested in comparison to the very nice and open sound when you add the B1 into the picture.
                After spending some time with the DX90 connected to the Aune B1, it’s honestly very hard to go back to listening with just the DX90 as the B1 just tightens and cleans up the sound so fantastically well. This is not to discredit the DX90 of course. It’s a 400 dollar all-in-one box solution with everything stuffed into a very small box. On the other hand, the B1 is 200 dollar standalone amp that’s bigger than the DX90. Hell it better be better than the amp section of the DX90. What is awesome, however, is just how much better it is. The B1 really is a fantastic sounding amp and if you’re willing to sacrifice some portability, it is very well worth the additional 200 dollars and extra bulkiness. This thing simply sounds fantastic.
    DX90 > B1 > HE560/HE1000
                This portable combo drives the HIFIMAN headphones quite admirably if I must say, and in the event that I’m traveling and staying at a hotel or something where I can use my full size headphones but obviously couldn’t bring along my full size amplifier, I would be happy to live with this combo for the time being.
                Some things that it tends to lack while driving these headphones in comparison to my Asus Essence III:
    -The bass extension and punch is good, but it does lack the last bit of bass extension that gives the rumble that planar magnetics are so famous for
    -Overall soundstage is a bit smaller but holds its own. The B1 tends to lack a bit of depth, and that really comes out when paired with the HE1000. The HE1000 is a fantastically layered headphone with great out-of-head imaging, and it clearly doesn’t perform its best in terms of soundstage and layering when paired with this combo.
    -Not surprisingly, the detail retrieval of this portable set up is not on par with the much more expensive Essence III, but for the price, it does a very respectable job.
                So I also tried listening to the HIFIMAN headphones with different current settings, and honestly I don’t hear all that much a difference. The HE560 and HE1000 are not notoriously hard to drive. If anything, they’re some of the easiest orthodynamics on the market. I would guess that perhaps the current switch would make more significant of a difference on headphones that are more difficult to drive. I would swear that the HE1000’s treble is just a teeny tiny bit sharper when the current is set to high, but I would really not bet my money on it. For me, the difference between the two settings was pretty much nonexistent.
    Summary on Sound
                What you get from the Aune B1 is an impressively detailed sound that is very well balanced and gives a great sense of space. I wouldn’t be inclined to call this amp warm nor cold. To me, it’s simply pleasantly balanced and uncolored. Despite that, the B1 is in no way boring to me as it has a very tight, crisp, and detailed sound that just begs you to take notice of it. I’m very happy with what the B1 offers and I think it is of fantastic value at its MSRP of 200 dollars.
    Final Thoughts:
                Aune Audio was a company that I was aware of, but never paid all that much attention to. I know they made some well-regarded desktop friendly components, and I thought their company logo was pretty slick looking, but that’s about it. My experience with their B1 amplifier really put them on my radar. I obviously hold the B1 in very high regard, and I think it’s a gorgeous piece of gear – inside and out. I would like to thank Aune again for the opportunity to demo this beautiful portable amplifier, and I’ve very excited to see what products they have planned for the future!
                Do I recommend this product? Absolutely yes. The only thing keeping me from giving the B1 a full 5/5 is its channel imbalance issue. If Aune is able to resolve that issue somehow, I think this amp would be an easy recommendation to just about anyone looking for a portable amplifier at this price. But for now, those using a DAC with a powerful line out signal combined with a sensitive IEM may want to think twice about purchasing this amp. For anyone else, go crazy! 
      thelonious58 likes this.
    1. avitron142
      Nice review! Our reviews seem to agree on most parts of the sound department, with the exception of the soundstage and separation. Are you sure you could pick out the instruments from the crowd? Mine seem to blend in musically so it was hard to do so, IMO.
      avitron142, May 27, 2015
    2. Cotnijoe
      It could very much be a pairing issue for you. I have no idea. I did find the soundstage to lack a bit in layering and depth, but besides that the sound is crisp and clear especially with my in ears.
      Cotnijoe, May 27, 2015
  8. Army-Firedawg
    Small powerhouse that provides tube like sound and musicality but with the ease of use of a solid state.
    Written by Army-Firedawg
    Published Apr 3, 2016
    Pros - Amazing sound and build quality
    Cons - Aluminum strip on the back can lead to scratches, un-indicating indicating light for the battery
         Firstly I must give a large and heartfelt thank you to both @AuneAudio for approving me a period with this and @nmatheis for organizing things in a way so that my time with this corresponded with the Carolina Canfest 5 audio meet that was being hosted in Charlotte then also I have to give thanks to @Podster for sending it to me within the correct time frame, which lately has become a rarity for most tours. So to all of you I both tip my hat and sincerely thank you. 
    I'm a 25 year old firefighter currently for the U.S. Army North Carolina National Guard. I was formerly a civilian firefighter in Kentucky with the Millard Fire Department before I enlisted and moved to my current location in Charlotte, North Carolina. My current goal is to begin my career again in the civilian fire service, and yes, I am the cliché of wanting to do that since as far as I can remember.
        My interests/hobbies are powerlifting, fishing and relaxing to audio products and reviewing them to help other decide on what products would work for them. On that note over the years I've really came to an understanding of what it is I like and look for in audio products.
        What I look for is a relaxing, warm and sensual sound that just drifts me away in the emotional experience of the music being performed. Yes, accuracy is still important but I will happily sacrifice that if I'm presented with a clean, warm sound that can wisp me away into an experience that makes me yearn for more.
        My ideal signature are that of respectably forward mids and upper bass range with the bass being controlled but with some slight decay. I like my treble to have great extension and detail reveal but I don't like artificial treble in order to achieve that. Examples of products that have given me chills and keep giving me the yearning for more feels are the Bowers & Wilkins P7, Oppo PM-1/2, Empire Ears Hermes VI, Audeze LCD-XC, Meze Headphones 99 Classics & Stax SR009.
    The Opening Experience
        The opening experience of the B1, I’m not exactly sure if this is how it comes from the factory of if it was only for this tour.. In addition, the only thing included with said package was a small aux cable. So, for this reason I cannot justify giving any sort of unboxing experience impressions on the Aune B1.
    20160325_211422.jpg     20160325_211555.jpg      20160325_211616.jpg      
        The build quality on the Aune B1 portable headphone amp. is  absolutely top notch. It’s carries an aluminum body throughout and on the back there’s either a real or faux leather that gives the B1 not just a nice grip when holding it but also a refined look as well. However a quick downside (that’s incredibly small and user dependent) is that on the back where the leatherique material is, is down the middle is an aluminum line. This is a bad thing because most of us who use a portable amp with our mobile device etc… simply rubber band them together. The issue here is with the aluminum you’re almost begging to have both your mobile and the amp. to  get scratches all over them.
        The top of the amp. holds a very responsive volume button and standard 1/16th” jack. The side holds the power button, gain switch, and class A amp. switch (which I’m not going to lie I’m not really sure what this switch did so I just left it on). The front has 2 glass windows to allow you to look into the inner circuitry which is a subtle but very nice touch that I really enjoyed. Another downside before I go onto the sound section, is that the battery life indicator is quite useless. When you press the button, at least on my unit, it never shown anything except green. This was greatly annoying for after a few hours of listening I’d check the indicator and it’d show green and a few minutes later it died; what’s the purpose of an indicator if it doesn’t indicate anything?
        So how well does the newest mobile amp. offering from Aune stack up? Amazingly well is the clear answer to that, The ease it drove any headphone I put through it was incredible, from my Empire Ears Hermes to my Sennheiser HD650 it powered them incredibly and provided a sense of depth that even some (similar priced) home units can’t provide me.
        The background wasn’t completely black as my ciems still had that ever present hiss but when listening to normal resistance headphones there was no issue at all and the only thing I was presented with was a very impressive sound that provided a subtle but welcomed amount of warmth.
        On the note of warmth, the Aune B1 isn’t a flat amp. Instead it gives the music a subtle yet very nice and soft sense of warmth and musicality to it that really reminded me of a tube amp. (which the glowing led’s on the front even adds to the look of a tube amp. as well). My favorite pairing however was with my Bowers & Wilkins P7 and the Meze Headphones 99 Classic (tour). The B1 complemented the sound of those two headphones so well it made it ridiculously difficult to take them off when I had to do that adult thing called work.
        I believe this is my shortest and quickest review (at least off the top of my head) but this is a pretty straightforward amp. The sound is very clean, powerful, controlling and possesses a slight warmth to it that adds well wanted (for me personally) musicality to the sound. The build quality is absolutely top notch and I’ve zero worries about it falling or easily breaking. I’d recommend the Aune B1 to anyone looking for an portable amp. only complement to their mobile device. It’s a great price/quality catch and will suffice even the truest of die hards.

    Also check out my unboxing and review videos, they’re pretty awesome AND you getta put a face to the Army-Firedawg name. If this review helped you out at all please hit that thumbs up button for it really helps me out as well. Till next time my friends, stay safe.
      thelonious58 and thejammonster like this.
    1. View previous replies...
    2. emrelights1973
      Will it be good addition to zx2 euro for driving sony z7? 
      emrelights1973, Apr 6, 2016
    3. Army-Firedawg
      @emrelights1973 Though I've personally not tried either of those two, I don't see any reason why it shouldn't. On high gain it drove my HD650's with ease
      Army-Firedawg, Apr 7, 2016
    4. Hi-Fi'er
      This is a pretty bad ass amp. It's my new best portable amp. It rivals my other top end portables for way more than half the cost.
      Hi-Fi'er, Apr 11, 2016
  9. Hi-Fi'er
    Wonderfully Clean and Powerful AMP
    Written by Hi-Fi'er
    Published Jan 21, 2016
    Pros - Clean, Fast, Quiet, Dark, Powerful for IEM's,
    Cons - Volume Knob, Battery Percentage Status
    This is a true Class A amp that is in a class of it's own! 
    I have put in a good 5 hours of straight listening with the B1 with all types of music just using my Creative Aurvana 3. I used these on purpose on the high gain to see if it would make a difference as they are not the best but not the worst earphones I have. 
    I used the high gain, and I have to say the B1 is quick, clean, powerful, and adds no coloration to the source and transfers over the source cleanly at all levels of listening, meaning it's clean and clear at low volume to full volume with 0% distortion. Some have said there is no background hiss. Well there is on high gain but it's extremely tiny and only detectable at more than 80% volume. Very very acceptable. Some have said it has a dark background, I agree 100%.  
    What impressed me the most is how it keeps it's clarity at full volume with authority. I love that! I like to listen to some favorite songs louder than others. This is how I determine what a portable amp can or can not do. Other amps I that I have seem to struggle out or distort at higher levels. I even tested some very high end recordings from Techmaster P.E.B and they sound clean, and clear at all levels. The bass is super heavy on from this artist and the B1 controlled the bass again with authority and no distortion. I even tried to throw in some EQ to see if I can cause any distortion and that idea failed miserably. It handled the added 40 and 80hz cleanly and accurately! I am impressed again.  
    The B1 makes me feel like I'm listening to my Asgard 2 which says a lot! I love the clarity and level of detail that it can produce. I have yet to really burn it in fully and I am already seeing this as my favorite next to my Cypherlabs and that was just out of my LG Optimus G Pro with ALAC and a line out! I can say this amp has made me end my search for a portable clean powerful amp.  
    I am kinda scared what it can do with my other earphones and other sources!
    Update: After some more time with the B1, I have to say that it's so very much similar sounding to my Ray Samuels P-51. The B1 having a larger current ability than the P-51 is evident in the oomp of the sound, but all else it matches the P-51 on all other aspects. That is pretty amazing considering the P-51 is/was $375.00!
    - Update 3/11/2016: I have to say this amp is equivalent to my Cypherlabs which says a lot as that cost over $500.00 amp alone. I am impressed with this amp the more I use it. It's not just a Class A amp, it's in a class of A! It drives my Havi's well and accurately and anything else I have at it IEM wise. Again for the price you can't go wrong with this amp. It's my new best sounding, smallest amp I have. It's going to be really hard for someone to beat this at this price.
      drbluenewmexico and thelonious58 like this.
    1. drbluenewmexico
      are you listening to the 2015 or 2016 version??
      drbluenewmexico, Jan 22, 2016
    2. Hi-Fi'er
      Hi-Fi'er, Mar 11, 2016
    3. Shotgunsingh
      What's the difference in 2015 and 2106 model. Any significant drawbacks in either
      Shotgunsingh, Jun 14, 2019
  10. ClieOS
    Full Discrete Class A portable amplifier
    Written by ClieOS
    Published Jun 13, 2015
    Pros - Sound Quality, Build Quality, Price.
    Cons - High Output Impedance, Short Battery Life, Relatively Low Output Power.
    Originally running a well-known audio DIY forum in China, the company behind the Aune brand has managed to turn itself into a fairly reputable audio brand in recent years, producing mainly PC based desktop Hi-Fi gears. As far as I know, the B1 portable amp that is going to be reviewed here is the company’s first foray into the portable amp market – and not a run-of-the-mill design at that. Not only does it has a fully discrete design, it is also running at Class A configuration. That sound promising on paper, but does it deliver?
    Recommended Headphone Impedance: 16~300ohm
    Size: 65 x 110 x 18mm
    Weight: 230g
    Typical THD: Less than 0.0008% @ 1 kHz, 600 ohm / -0dB
    SNR: More than 124dB @ 600 ohm
    Frequency Response: 10Hz ~ 20kHz, +/- 0.15dB
    Crosstalk: Less than 110dB @ 1kHz, 600 ohm
    Power (Class A): 25mW @ 16 ohm, 50mW @ 32 ohm, 100mW @ 300 ohm
    Gain: +5dB / +15dB
    Dual Quiescent Current: 20mA / 40mA
    Build Quality
    To say B1 is ‘well built’ is almost an understatement – it is drop-dead-gorgeous! The aluminium housing is very well machined, smooth to the touch without any sharp corner. Two transparent windows in the belly allow you to peek inside the amp circuit and two faux leather strips on the top that not only look good, but also serves as a cushion for any device you want to strap onto the B1.
    If there is any real complaint that I have, I’ll say the volume knob is a bit too low profiled / oddly shaped, making it harder to adjust volume, especially when there is two 3.5mm plug next to it. Last but not least – and not really a complaint here but more of a suggestion – as Aune warns that the current switch must not be used when B1 is turned on, I’ll think a more logical choice will be to make the switch even more recessed than it is now so it won’t get accidentally switched by any chance.
    Battery Life
    Aune quotes that B1 has a 10hours play time running on 20mA mode and half that with 40mA mode. I actually get a bit less, probably around 3~4 hours in 40mA, though it really depends on the load as well as the volume. Suffice to say, the battery life isn’t exactly great. Given it is a Class A amp that isn’t known for power efficiency, I guess that much is expected.
    Gain, Hiss and EMI
    B1 comes with two gain settings: +5db and +15dB. Personally, I’ll think it would have been better with +3dB and +12dB, as the current setting might be too high for sensitive headphone and IEM, getting too loud (or even worst, channel imbalance) with just a small turn of the volume knob. I will even consider a zero or negative gain setting being helpful for those with really sensitive custom IEM.
    There is almost no hiss to speak of. There is in fact almost no ‘click and pop’ during start up as well. B1 is very well behaved in those regard. There is however some EMI issue. Cell phone interference can be picked up in close proximity, though not particularly loud and therefore not a serious concern.
    Tech Prelude
    So what is Class A - and if it is that good, why didn’t we see more of it? To put it simple: music is in wave form, swing from one end to another and back for a whole 360 degree. A Class A amp is a device that continuously operates the whole 360 degree non-stop. In the process it usually will waste a lot of power and generate a lot of heat, though it is also considered to be better sounding by many. Most of the amp (and mainly the opamp used) in the market however are in Class A-B configuration, where only half the components are active. The active half is where the signal is, and the inactive half only switches on when the signal arrives. It is far more efficient than Class A, but has its own problems - namely more distortion as components are switched on and off all the time and signal gets distorted when traveling from one end to the other. But at the end, Class A-B is usually the choice for portable gears due to practicality, as the distortion really isn’t bad enough to outweigh the benefit of less heat and much longer battery life.
    Being full discrete means there is no integrated circuitry in the signal path. It is just another way of saying no opamp but rather individual discrete components (resistors, caps, transistors, etc) is used for amplification. B1 isn’t the first full discrete portable amp I have seen and this kind of implementation does require a lot of attention to detail, especially on parts matching, to show how good it is. A really well implementation can really sound exquisite, just as good as any top tier opamp based portable amp.
    Sound Quality
    As usually, my SQ assessment starts with an RMAA measurement, and the result is pretty good. No issue can be seen and the number match up with my reference O2 nicely, which is a very good sign. In fact, B1 outperforms O2 noticeably on stereo crosstalk, no doubt thanks to its dual-mono discrete circuitry that keeps the left and right channel further apart than what opamp usually does. However, the result on current output as well as output impedance is really less than stellar. First, the output impedance is rather high - measured and calculated to about 10 ohm, which is no good news for multi-drivers IEM. Second, current output is fairly low. Aune listed B1’s output power of 25mW @ 16ohm is quite low for a portable amp, and my measurement pretty much confirm it. In contrast, a FiiO E06 can pump out 4 times more power on the same load. One thing I noticed is that B1 @ 20mA mode begins to clip when I pushed the volume too high (regardless of gain setting) during my RMAA measurement (*with a 47ohm load). This is independent of the input volume so my guess is that it is running out of current to remain in Class A at such a high volume, as the clipping on high volume disappears once I retest it on 40mA mode. From both the prospective of SQ as well as battery life, I think easy-to-drive load probably can stay happy with 20mA mode, but anything more demanding should perform better in 40mA mode, though battery life will be cut short. Regardless, both modes don’t really have a lot of current output to speak of. In my opinion, this is very likely the inherent issue of being Class A – trying to push for higher output and you will end up with a portable heater that doesn’t run for very long; trying to keep everything reasonable and the output power will be limited, as in the case of B1. Technically speaking though, I think B1 is better suited for higher impedance headphone rather than lower one.
    Subjectively, B1 sounds really good, as good as any top-tier portable amp I have heard. It also sounds rather clean and neutral, pretty much comparable to my reference O2 for that matter. While still very clean sounding, the mid does sound slightly more hollow in 20mA mode, giving the illusion of extra airiness and a bass kick that is stronger than it ought to be, which can be interpreted as being more powerful than the amp is capable of, though not really the case as I find the texture on the midrange, especially vocal, incomplete. Bass note, while has a good kick to it, does sound thinner than it should. Everything however snaps back to normal once switched to 40mA mode – the vocal is restored and all elements are inline again, though no more ‘extra’ airiness. But I don’t consider that a loss as B1 already has a really excellent soundstage and imaging. It makes a pair of flat sounding ER4S feel almost like surround sound, and that’s a wonder of its own and pretty much the best soundstage I have ever heard on a portable amp that doesn’t have any EQ enhancement. Despite not having a lot of power in measurement, B1 doesn’t sound like it is lacking power in 40mA mode. It is not the tightest in control, but it doesn’t sound loose either. All and all, it holds up quite well
    Size Comparison (from left): FiiO E12DIY, Aune B1, and Leckerton Audio UHA-4
    I really like B1. It is well built and it sounds great – if it isn’t for multi-driver / very low impedance headphone and IEM, I have no problem recommending it. Aune took on the challenge to manufacture a Class A full discrete portable amp and they almost able to knock it out of the ballpark. Sure, there are still a few kinks here and there – but for as good as it is, Aune really deserves some credit. It isn’t the portable amp for every occasions – but where it does work, it works really well.
    This review is part of Aune Worldwide Review Tour:
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    1. View previous replies...
    2. Evshrug
      Nice review! Sounds appealing, though for something high-quality portable like this to NOT suit equally high-quality portable like the higher-end IEMs with 3-12 drivers does seem to be a head-scratcher. Good that it breathes new life into the classic Etymotic though!
      Evshrug, Jun 14, 2015
    3. AuneAudio
      Hello , thanks for the good review , we will upgrade  the headphone impedance in the next version of B1 , thanks 
      AuneAudio, Jun 15, 2015
    4. ClieOS
      Good to know. While under 1 ohm will be great, I think anything under 2 ohm will be good in my book.
      ClieOS, Jun 15, 2015