aune B1s: The Only Class A Portable Amp You Need



Original article:

I have always thought that I could get something better from my portable setup without breaking the bank. In a search for an affordable Android DAP with two micro SD card slots, I end up with Pioneer XDP-100r. I love the versatility and its great sound, but I felt like something is missing. When I listen to my desktop setup, I can hear more detail, great nuance across the spectrum and more impactful but I would not mind that considering the price difference with my desktop setup and my DAP. The only thing that I am looking for with my portable rig is a fuller sound and I only get that only with Aune B1S so far.
First and foremost, I want to thank Aune and @mshenay for organizing this tour and they did an amazing job in making sure that everyone gets their turn in a timely manner. The amp is sent to me in exchange for my honest review thus I have no affiliation with the company, but I will try my best to be as neutral as I could. Honestly, it is hard to not be biased when you love something but hopefully, I am not overhyping it too much :D
Lately, I just started to be more serious on having a good portable setup but I don’t have any portable amp that I could compare with although I did extensively listen to iDSD Nano BL, iDSD Micro BL, and Chord Mojo; comparing with something that only exist in memory would not be fair for the sake of review. But, I’ll try to maximize every gear that I have in delivering a proper review on how the amp would sound and for whom it made.

What’s in the box?
Out from the box, you will get the amp itself, Aune B1s, a 3.5mm to 3.5mm short Aux cable and a USB cable for charging purposes. The accessories provided are nothing fancy in fact it would be amazing if Aune could throw in two or three rubber bands for stacking purpose. An inclusive case (or even sack) could be something that they can improve on the package bundle especially with the amp of this size, having something like a small bag is indeed convenient. The amp has a great build and it does feel solid in hand. However, the shape can be a little bulky for some, but it pairs nicely with my DAP. The back of the amp has a layer of leather for better grip and avoid any scratch or dent when stacking together with DAP. At one side, it has the gain, Class-A implementation and On/Off Switch slider and battery indicator on the other. At the bottom, you can it has the female micro USB port for charging and volume knob, line-in and 3.5mm headphone jack at the top. It has every feature that exists in the previous version of Aune B1 and the only difference is the addition of ‘s’ on the cover to indicate the differences. Of course, it has a slightly different circuit board implementation to lower down the output impedance to 1 ohm and has a better THD at 0.00015%. These little changes are what makes B1s a better version and a worthy upgrade from B1.

From Penon Audio
· The B1s is the 2nd generation of the B1, a portable amplifier which was well received across the world. With fully discrete transistors circuit design and output transistor with class-A biasing, the B1s is an extraordinary portable amplifier.
· In 2014, to break the saying that “portable class-A amplifiers are impossible”, we strove to create the B1, which marked the beginning of a new era of portable amplifiers.
· The design of the B1s presents the beauty of balance, behind which is Aune’s 12 years of design philosophy.
· The B1 was the choice of over ten thousand audiophiles from around world. It received praise not only from users, but also media.
· In 2015 & 2016, the B1 was on the annual recommendation list of Soomal twice in a row, and in 2016 the B1 received the award of Best Creative Technology at Guangzhou HiFi Headphones & Digital Audio Expo by ERJI.NET.
The heritage of the classic
· The B1s is the latest generation of the worldwide well received B1. It’s born to be extraordinary.
High-quality yet affordable
· Natural and musical tuning, vivid reproduction, now affordable to all of you
Unique class-A output, mellow sounding
· In addition to the high resolution, great dynamics and ultra low distortion, the B1s uses class-A amplification, giving the sound a bit of warmth and tenderness.
Powerful and portable
· The B1s aims to extract every bit of potential from headphones with the rarely seen internal design of high voltage ±9V. While designing the amplifier circuits and tuning, we tested various headphones including those with high impedance and low sensitivity. The switches on the left side enable you to adjust the gain and current to fit different loads. The abundant power and excellent control make driving big cans like HD650 possible.
The perfect partner your DAP has been waiting for
· DAPs have developed very fast over the years. It’s time for headphone amplifier technical specifications to better match those of today’s DAPs. The B1s, with class-leading distortion lower than 0.0002%, is the headphone amplifier your DAP has been waiting for. In fact, few DAPs have distortion that low.
Great compatibility
· We used a wide variety of headphones and IEMs for tuning and optimized the entire circuit design, so the B1s has better control for headphones with low impedance and delicateness of high & mid impedance. Its compatibility with headphones had been significantly enhanced.
· Power supply is extremely important to an amplifier. The bipolar ultra-low-ripple regulator, together with the high-efficiency power supply design that enables the duration to exceed 10 hours (with current output set to 20mA), supports the B1s with constant purified power.
· Typical line output indicators
· Frequency response (from 10 Hz to 20 kHz): ±0.02dB
· Output Impedance: 1 Ohm
· THD + n: 0.00015% @300Ω
· SNR: 124dB @300Ω
· Crosstalk: <110dB @300Ω
· Max output: 6.443Vrms 18.4dBu(10Hz to 20kHz)
· Headphone output power: @300Ω 84mW , @600Ω 42mW ,@32Ω 74mW
· Class-A: 25mW/16R 50mW/32R
· Size: 125×65×18(mm)
· Weight:230g
Gear used for this review:
Headphones: Takstar Pro 82 modded, Sennheiser HD6XX modded and HD800SDR
IEMs: Westone 30, KZ ZS6 and ZSR
DAP: Pioneer XDP 100r
Amp: Aune B1S and Aune B1

Mellow sounding with tons of clarity. B1s is a kind of amp that let you immense with the music for hours without sacrificing any of those minute details. I am a fan of the modern song like EDM that sometimes needs an extra warmth for them to be more enjoyable. It doesn’t color the sound but stays transparent as Class A amplifier. Some might find that the amp is not warm enough, but not for me; it fits my taste perfectly. All of my dedicated solid-state amps are transparent and neutral but has a tube sound it. Not gooey, lush kind of warm but it gives a smoother top end without being rolled off. The highs are smooth with a great amount of detail enthrall the listener and shower them with enjoyment. The bass has a good body and articulate, but it does lack in sub-bass. I don’t have any dedicated headphone to focus on the sub-bass so take this with a grain of salt. Phenomenal vocal! Engaging vocal response with fantastic midrange is what keeps me coming back to this amp. The spacious sound makes every song sounded full and wide. The depth is above average, but the width is very noticeable especially with jazz, acoustic, classical and orchestra genre.

Neutral sounding, spacious and smooth. I really love the spacious sound coming from the amp and with HD800, it did add more space, and everything seems so distant. I thought that this is the widest that I ever heard in a portable setup. Is that a good thing? Maybe but not for me because I felt like it’s not natural. The midrange lacks in body and lack in tonal density. Although, it does have a great tonal balance and I still enjoy them with a live concert and classical song but less so with modern songs. The bass could have more body and texture. HD800 is known for its clean and thumping bass but not like planar kind of bass. At times, the bass sounds a little thin and I am not basshead by all means but I do feel like the neutrality somehow sever the bass texture. When I play them with Fragile by Robert Lan (DSD), I noticed how smooth this combo is. The upper midrange is smooth and pleasing but did not sacrifice the details. Everything just sounds and flow well with the music. Oh My! I am loving what I heard. That’s for sure. I found that it does very well with DSD. I enjoy the whole show as if I am there in front of the band and not struggling to pick up every single detail in the songs.


HD6XX modded
Fuller sound, great imaging, spacious, musical and well-controlled bass. By far, this is the best synergy I have heard to date for my HD6XX for portable setup; they are so good to a point that I am buying the amp next month. The HD6XX/650 works great with my main setup and really enjoy them but with never like the headphone with a portable setup. With XDP-100r, I have tried Chord Mojo, iDSD Micro BL and iDSD Nano BL pair with HD6XX; while they are good, I am not really a fan of the synergy because I felt like something is missing. I have used line-out and USB connections with the amps and my DAP, but they never satisfied me; the case is different with B1S. I am utterly amazed at how full the sound was after a minute of listening to them. The ‘veil’ has been lifted and everything is just so detail. The great but smooth clarity, clear separations, spacious sound and well-extended treble. What can I say? I really fall in love with this. I tried them with the various genre from classical to rock and even metal (a genre that I never listen to in the past so take this with a grain of salt). The combo excels in every song that I listen to. The fuller sound and very engaging mids are what made me finds it hard to take the headphone off my head. Great tonal balance across the spectrum and the bass has more body and well-controlled. Again, I am surprised how good this combo is. If you already own Pioneer XDPX00 dap or Onkyo DP-1 and HD650/6XX, I would encourage you to try to listen to AUNE B1S. You’ll be amazed at how good they sound.


Takstar Pro 82 modded
Good tonal balance, engaging mids and spacious. Takstar Pro 82 is very transparent and really depends on your chain. After listening to the amp for at least 3 hours every day in a week, I can confidently tell that the amp has spacious sound, vivid and beautiful mids, great tonal balance, well-controlled bass and neutral overall. That is what it sounds like through Pro 82. It is more articulate, and I do find that it excels with most genre. I did not have the opportunity to listen to every genre but with most popular genre like pop, rock, alternative, punk, EDM, classical and jazz, it does quite well. However, the sounds can be a little thin and lack of sub bass. The treble is kind of rolled off with busy songs, but the bass still maintains clean with a better body. As I mentioned, the three things that really hooks me with this combo is how balanced it sounds, lively and engaging mids and its wide space albeit the lack of depth.
IEMs pair


Westone 30
Balanced, great detail, good separation, and wider soundstage. Westone 30 has the best depth compare to my other IEM albeit a quite small width. I thought it sounds similar to HD650 but lack of vivid vocal; with Aune B1S, the problem pretty much solved. I really enjoy vocals and mids with this combo. It brought the singer a few steps back that allows for more space to breathe. I used to enjoy modern genre more than classical with this IEM but enjoy them equally now; cleaner bass elevates the capability of W30 to sounds amazing with every song I listen to. The drum thumps at the right time and I can virtually point out where it came from in the song. I am a fan of W30 but I do think that it could do a little better in detail retrieval and the solution has appeared right before my eyes.

Articulate instrumental timbre, amazing detail retrieval, and clean sounding. I would expect the amp will sound amazing with KZ flagship’s lineup. The sound is surprisingly clean at any volume level with an output impedance of 1 Ohm. ZS6 can sound thin especially with classical and jazz songs but its wide soundstage and amazing separation compensate the weakness in those genres. Aune B1S adds thicker sound to most instruments plays through the ZS6 and it sounds uniquely articulate. I am genuinely amazed by the realism that it brings to the music. More energy coming from drums and guitars but never overwhelm of being harsh or fatigue. I noticed that zs6 biggest issue, the treble spike, is solved. The highs are much softer and articulate; I do enjoy more songs with the ZS6 now than how I was before. I found that male vocal is more dominant in this combo. Female vocal could be softer because the combo makes female singer to sound strong and masculine. Bass still lacking in quantity but has a better body and goes slightly low. With Aune B1 (2015 edition), the bass is punchier, but I still prefer B1s because it excels in every other part.


Smooth, airy, great clarity, spacious, musical and clean sounding. ZSR is a smoother version of ZS6 especially in the top end but also not as detail. B1s brings an awesome musicality to ZSR and provides a very balanced sound across the spectrum. Smooth sounding and very articulate treble. Every KZ ZSX flagship owner kind of had an issue with them but not anymore. The music has more space and wider soundstage. Also, it allows you to breathe throughout the song and notably helps when you play a complex song that longed to be fatigue at long listening hours. They are airier like HD650 despite being isolated as an IEM. It goes deeper and wider that gives fuller sound to ZSR. It has been forever since the last time I enjoy Pink Floyd because they could sound thin without proper headphone/IEM, but now, I enjoy them so much with ZSR. Imaging improve greatly; if you’re listening to concert and orchestra, you will feel like you’re in the front row. Instruments separation are more noticeable and let you immense with the music. Just you and the music. The overall sound is balanced, thicker and more vivid. The bass has more texture and well-controlled. It is definitely a better combo than ZS6 and does I love them? Heck yeah, I do!


VS Aune B1 (1st Gen)
I am amazed by the B1s performance then I had this thought in mind, “how does this compare to the first gen?”. Thus, I decided to look for a used Aune B1 (2015 edition) and gauge how far does the B1s evolve. Unfortunately, I received my B1 the day after I ship the B1s to other people on the tour. How unlucky. But hey, I still remembered the sound. I think. After I received the amp and stack them up together with my DAP and ZSR, my first impression was… YUCK! This amp is worse than I thought. Well, I guess it’s not fair to judge it too early since the previous owner only uses it once. I let the amp burned it for about 100 hours and give them a second try. It sounded much better but still does not meet my expectation. The 2015 edition has output impedance 10 ohm which quite high and not the best condition for a super sensitive IEM. I also noticed the treble is harsher and more on the brighter side compares to the B1s. The vocal is less engaging but still clear and detail. The bass has more quantity and body but not as articulate. I noticed a distant hiss when I pair them with ZS6; not a big of a problem but could be an issue for some. Out of all my IEMs, I only enjoy the amp with Westone 30 because with every other IEMs especially KZs, I find it too bright to my taste and fatiguing. Honestly, I am not disappointed because it is quite good; transparent, great clarity, more bass quantity and good imaging with above average separation. But, as I spoiled my ears with B1s first, I can’t move on with how good it was. Thus, I decided to sell the B1 and get myself a B1s and as I am typing this, the B1s is already on its way. At this point, I can rest assured knowing that I am good with portable setup and not needing any other gears.
I tried to be very honest in any of my review, but I am confident to say a lot of wonderful things about something when I love them myself. As always, take this review with a grain of salt but if you’re looking for a mellow sounding amp that has tons of detail and clarity, look no further because Aune B1s got you covered. I heard what I heard. Period.