So I got this unit from Aune as a part of their worldwide review tour. This is actually the second Aune product that I got the chance to tinker with. First one being Aune T1 MKII Tube DAC/amp, which I bought a while ago and has been using ever since. If you wanna read my review on the T1 MKII, you can find it here. I like to think that both of them is like brother and sister 
On with this review then.
Unboxing
One thing I like about Aune is their box presentation. Aune's products are mostly in the middle level price range, but their box looks so nice and elegant. The box alone instill the sense of 'class' to anyone who sees it.
Open it up, and you'll find a few stuffs inside. From left to right:
- USB to micro USB cable for charging.
- Mini stereo 3.5mm to 3.5mm interconnect cable, gold plated.
- The main unit, the B1 Headphone Amp (I will be referring it as 'B1' from here on)
- The box
- Aune's business card. The writings on it are all in Kanji (Chinese) though, so I couldn't make any sense of it except for phone numbers and e-mail addresses.
- User manual.
Now this unit is beeeaaauuuutiful!! I really love the design. They come in 2 variant/color scheme, the all black, and the silver/red like the one in the picture. Usually I like my devices all black, but I couldn't resist that beautiful silver-red combo. It's simply stunning!. Honestly, it's the most stylish portable amp I've ever seen.
The design reminds me a bit of those liquor hip flasks, especially the volume knob on top. The leather side is actually the back side of the amp. The leather layer protrudes a bit, making it a soft cushion when you put it on hard surfaces, avoiding scratches and dusts to the aluminum case.
This is the front side of the amp. It got a twin window to showcase the discreet amp parts (more about this later), and two LEDs that lights up when it's powered on.
The unit measures approximately 12 cm + 6 mm protruding button = 12.6 cm height, 16.5 cm wide, and 1.7mm thickness. It's about as big as an Iphone, but thicker.
On one side, there are 3 buttons, the power button, 'class A' (current gain) button, and the volume gain button. On the other side, there's a battery checker button with a small LED. Press this button, and the LED will blink to show how much battery is left. 5 blinks = full, down to 1 blinks = 10%.
On the top side, there are two jacks. The left one for audio output, the right one for line/signal input. Volume knob in the middle.
On the bottom side, there's a micro USB input for charging.
Now what really make the B1 so special compared to other portable amps, are 4 things: the design, class-A amp architecture, discreet op-amp, and high current setting. The design part was already explained above, so I won't go further with that part.
- Amp class. You can find more info about various audio amp class in wiki and articles on the net. In short, class-A amp is an amp architecture that's both simple and has the least distortion, compared to other amp architectures/classes. The drawback of a class-A amp is that it needs constant electric current running through it, even when there's no signals to be processed. Because of this fact, there are two more drawbacks, which are: bigger power consumption, and more excess heat. The B1 gets warm after about 30 minutes of continuous use. Not dangerous hot, of course, just warm. Warmer compared to other portable amps. If you got a vintage speaker amp that's very heavy and got a big heatsink in the back, it may very well be a class-A amp. Because of the drawbacks, especially the power consumption, class-A architecture is rarely implemented in a portable amp. That's one of the thing that sets the B1 apart. It's like they're breaking through the common stereotype. Of course they got the battery to match the bigger power consumption.
The warm temperature is a bit of a let down actually, especially for those who live in tropical climate like me (southeast Asia). Again, it's not too hot to touch (which would indicate something is horribly wrong with the device), just lukewarm. When used in tandem with my T1 (on my PC desk), I just point a USB fan to the B1, and it effectively countered the heat effect.
- Discreet op-amp. Portable amps usually use op-amp chips, because they're less space-consuming, and more efficient. Discreet op-amp basically means they substitute an op-amp chip with a whole set of electronic circuit, pictured in the twin window of the B1. The benefit of this is that they can then fine tune each components (resistors, capacitors, etc) the way they like it, as oppose to plugging a factory-made op-amp chip, and accept whatever the result will be. This is of course debatable, whether or not the discreet op-amp implementation gives a better result than an op-amp chip, because the end results aren't fully determined by the op-amp part alone. Nevertheless, the use of discreet op-amps (1 for each channel) makes the B1 unique.
- High current setting. When it's set to off, or 'low', the B1 will give out 20mA of current. When it's set to on, or 'high', the B1 will give out 40mA of current. The bigger current amount is useful when it's used to power less sensitive and low impedance headphones. This is usually the case with older generation of planar headphones, like the Hifiman HE-400 I'm using. Lacking in current in the signal output will mostly make the sound distorted, like when you turn the volume of your speaker amp too high, and the speakers start to sound unpleasant. Let's see if I can 'show' you:
*sorry about the noises in the left channel. I think it's the left mic's cabling. The right channel is working normally. I only found out about this when uploading to youtube, and I'm too tired to record a new one...
Maybe I'll record a new one later.
** oh and that small piece of tissue paper is not part of the setup. It's there because the headphone is too big on the dummy head.
That dummy head got a pair of separate channel mics embedded in its ears. So the sound you're hearing is actually the sounds coming from the headphone. The recording volume was set to very low, because in reality that was quite loud. I have to set it loud, to the distorting level, to show the effect. Now of course this video can't be treated as 'this is how the B1 or the headphone sounds', because the stuffs I got there (mics, cables and connections, and ADC) aren't studio recording standard. This setup degrades the original sounds by quite a lot. I'm just trying to show how the current gain affects the sound.
The video encoding seems to alter the sound a bit. This is the WAV extracted from that video: https://soundcloud.com/marcus-sudjojo/current-gain The difference is more audible in the WAV version.
Pay attention to the first part (current gain switched to low), the kicks were distorting. Not much, but still audible. In the second part (current gain switched to high), the kicks weren't distorting, and got tighter and more 'dense'.
This is also a special case, powering an inefficient and low impedance headphone with a portable amp. For portables uses, such as on-ear headphones or IEMs, the low current gain setting is more than enough, because portable stuffs are usually pretty efficient anyway.
Current gain is NOT a volume gain, so setting it higher does not mean you will get louder volume. The B1 already got a separate volume gain switch for that. So if you're using the B1 at the low current gain setting, and you don't hear any distortions, it's best to leave it at low setting, to preserve the battery, and make it run longer.
I have to be honest, with the current gain switch like that, it's a bit of a design faux pas from Aune. They explicitly state that the switch must not be flipped when the B1 is running. Problem is, with the design and position of the switch, it's very easy to flip it by mistake/accident. If you ask me, they should have implement some sort of locking mechanism, so the switch can't be flipped unless you open the lock first. Fortunately, I asked them if there are any danger if the switch is flipped accidentally while running, and they replied, there are no danger, plus the headphone plugged to it is perfectly safe.
One more thing to note is their long life battery. Their 4000mAh built-in battery is claimed to be able to run it continuously for 10 hours at low current gain setting, or 5 hours in high current gain setting. Of course with big battery capacity comes the counter-effect: longer charging time. I charged the B1 with my Ipad 10W wall charger, and it still took a couple of hours. The good news is, it can continue running while charging. So for example, the battery dies when you're on the road. Well, you can plug the USB charger cable to your power bank, and you can keep enjoying your music.
The B1 also got a good electronic architecture that enables it to output the same stable good sounds until the battery runs out. I've encountered a few portable amps that output deteriorating sounds as the batteries are about to run out. That's not the case with the B1. I was enjoying my songs when the sounds suddenly stopped because the battery ran out, with no deteriorating sounds whatsoever.
Oi, enough about the technicalities, we wanna know how it actually performs....
Well, first I'd have to state the fact that I believe: out of the whole chain (DAC - amp - headphone/speaker), the headphone/speaker got the most margin of difference between one another. The DAC and amp got less margin of difference in that chain. So you can't, for example, buy a $1000 amp, plug a $30 headphone to it, and expect it to magically transform the headphone into a $1000 one. Different DACs and amps can, and will, alter the resulting sound to some extent, for better or worse, just in a smaller scale than different headphones will. So keep in mind that what I'm saying next is in a smaller scale.
I tested the B1 with 3 headphones:
- Audio Technica AD700 (without X)
- AKG Q701
- Hifiman HE-400
First impression I got when I plug the B1 to my Ipad (yeah, I'm not too crazy on portable devices) is that the B1 is dead silent. The 'silent test' is usually the first thing I test in headphone amps. Plug it to the source, with nothing playing, max out the volume knob. If there's any noise floor audible, then it's not really a good headphone amp. Well, like I said, the B1 is dead silent, or 'black' as some people prefer to call it. After the silent test, comes the actual listening test. The B1 'smoothen' out the edges in the songs. It's not a big secret that older generations of idevices (mine is the ipad 3) only got mediocre internal amp. When plugged to the B1 (via LOD), the mediocre quality of my ipad's internal amp got pointed out immediately. The songs sound as smooth as silk. There are no 'rough edges' between different frequencies and instruments. You might say it's a lot more transparent and less distorting. The frequency separation is very good. I could even hear some subtle sounds that weren't there when I plug a headphone straight to the headphone jack of the ipad.
I played various songs, like Celine Dion's that's known for 'unforgiving' to bad devices (thus make a good test song). Her voice could sound very rough and sharp when played through bad devices. From Celine Dion, to U2, to Tong Li, to EDM like in the video. Every songs I tried came out so much better compared to the ipad's internal amp. Even my old (and mediocre) AD700 sounds so much better with the B1.
But wait, like said above, I already got the T1, right? The T1 can output line out through the RCA jacks in the back. So of course I'd give it a go. Man, the B1 really outperforms the T1's internal amp. T1's internal amp is already quite good (that's why I'm using it daily, as my main device), but the B1 amp is really 1 level above it. Fed from the tube DAC of the T1, the B1 really performs its money worth, and beyond!! The sound I got was spacious, warm, rich, and yet smooth, with minimal rough edges.
For people who are used to V-curved sound (like myself), the low frequencies will feel a bit lacking at first. It's lacking, not completely gone, though. I could still fully enjoy EDM songs with the B1. What it's lacking, it gives back in clarity and frequency separation. The high frequencies are very clear but not intrusive. The mids got more density to it.
Now I think I understand why Aune insists on implementing class-A architecture in the B1. To be honest, I've never encountered any portable amps that give this kind of result. If you have auditioned various portable amps, try the B1, and most probably you'll agree with me.
Now if your music preferences is 'rocking it out loud', and you're looking for something that's 'head-kicking, bass-thumping, heart-pumping' kind of sounds, the B1 might not be the perfect choice for you. I'd say the B1 is more aimed for quality, not quantity.
The 'siblings', T1 tube DAC/amp and the B1 Headphone amp. Zippo for size.
On with this review then.
Unboxing
One thing I like about Aune is their box presentation. Aune's products are mostly in the middle level price range, but their box looks so nice and elegant. The box alone instill the sense of 'class' to anyone who sees it.
Open it up, and you'll find a few stuffs inside. From left to right:
- USB to micro USB cable for charging.
- Mini stereo 3.5mm to 3.5mm interconnect cable, gold plated.
- The main unit, the B1 Headphone Amp (I will be referring it as 'B1' from here on)
- The box
- Aune's business card. The writings on it are all in Kanji (Chinese) though, so I couldn't make any sense of it except for phone numbers and e-mail addresses.
- User manual.
Now this unit is beeeaaauuuutiful!! I really love the design. They come in 2 variant/color scheme, the all black, and the silver/red like the one in the picture. Usually I like my devices all black, but I couldn't resist that beautiful silver-red combo. It's simply stunning!. Honestly, it's the most stylish portable amp I've ever seen.
The design reminds me a bit of those liquor hip flasks, especially the volume knob on top. The leather side is actually the back side of the amp. The leather layer protrudes a bit, making it a soft cushion when you put it on hard surfaces, avoiding scratches and dusts to the aluminum case.
This is the front side of the amp. It got a twin window to showcase the discreet amp parts (more about this later), and two LEDs that lights up when it's powered on.
The unit measures approximately 12 cm + 6 mm protruding button = 12.6 cm height, 16.5 cm wide, and 1.7mm thickness. It's about as big as an Iphone, but thicker.
On one side, there are 3 buttons, the power button, 'class A' (current gain) button, and the volume gain button. On the other side, there's a battery checker button with a small LED. Press this button, and the LED will blink to show how much battery is left. 5 blinks = full, down to 1 blinks = 10%.
On the top side, there are two jacks. The left one for audio output, the right one for line/signal input. Volume knob in the middle.
On the bottom side, there's a micro USB input for charging.
Now what really make the B1 so special compared to other portable amps, are 4 things: the design, class-A amp architecture, discreet op-amp, and high current setting. The design part was already explained above, so I won't go further with that part.
- Amp class. You can find more info about various audio amp class in wiki and articles on the net. In short, class-A amp is an amp architecture that's both simple and has the least distortion, compared to other amp architectures/classes. The drawback of a class-A amp is that it needs constant electric current running through it, even when there's no signals to be processed. Because of this fact, there are two more drawbacks, which are: bigger power consumption, and more excess heat. The B1 gets warm after about 30 minutes of continuous use. Not dangerous hot, of course, just warm. Warmer compared to other portable amps. If you got a vintage speaker amp that's very heavy and got a big heatsink in the back, it may very well be a class-A amp. Because of the drawbacks, especially the power consumption, class-A architecture is rarely implemented in a portable amp. That's one of the thing that sets the B1 apart. It's like they're breaking through the common stereotype. Of course they got the battery to match the bigger power consumption.
The warm temperature is a bit of a let down actually, especially for those who live in tropical climate like me (southeast Asia). Again, it's not too hot to touch (which would indicate something is horribly wrong with the device), just lukewarm. When used in tandem with my T1 (on my PC desk), I just point a USB fan to the B1, and it effectively countered the heat effect.
- Discreet op-amp. Portable amps usually use op-amp chips, because they're less space-consuming, and more efficient. Discreet op-amp basically means they substitute an op-amp chip with a whole set of electronic circuit, pictured in the twin window of the B1. The benefit of this is that they can then fine tune each components (resistors, capacitors, etc) the way they like it, as oppose to plugging a factory-made op-amp chip, and accept whatever the result will be. This is of course debatable, whether or not the discreet op-amp implementation gives a better result than an op-amp chip, because the end results aren't fully determined by the op-amp part alone. Nevertheless, the use of discreet op-amps (1 for each channel) makes the B1 unique.
- High current setting. When it's set to off, or 'low', the B1 will give out 20mA of current. When it's set to on, or 'high', the B1 will give out 40mA of current. The bigger current amount is useful when it's used to power less sensitive and low impedance headphones. This is usually the case with older generation of planar headphones, like the Hifiman HE-400 I'm using. Lacking in current in the signal output will mostly make the sound distorted, like when you turn the volume of your speaker amp too high, and the speakers start to sound unpleasant. Let's see if I can 'show' you:
*sorry about the noises in the left channel. I think it's the left mic's cabling. The right channel is working normally. I only found out about this when uploading to youtube, and I'm too tired to record a new one...
** oh and that small piece of tissue paper is not part of the setup. It's there because the headphone is too big on the dummy head.
That dummy head got a pair of separate channel mics embedded in its ears. So the sound you're hearing is actually the sounds coming from the headphone. The recording volume was set to very low, because in reality that was quite loud. I have to set it loud, to the distorting level, to show the effect. Now of course this video can't be treated as 'this is how the B1 or the headphone sounds', because the stuffs I got there (mics, cables and connections, and ADC) aren't studio recording standard. This setup degrades the original sounds by quite a lot. I'm just trying to show how the current gain affects the sound.
The video encoding seems to alter the sound a bit. This is the WAV extracted from that video: https://soundcloud.com/marcus-sudjojo/current-gain The difference is more audible in the WAV version.
Pay attention to the first part (current gain switched to low), the kicks were distorting. Not much, but still audible. In the second part (current gain switched to high), the kicks weren't distorting, and got tighter and more 'dense'.
This is also a special case, powering an inefficient and low impedance headphone with a portable amp. For portables uses, such as on-ear headphones or IEMs, the low current gain setting is more than enough, because portable stuffs are usually pretty efficient anyway.
Current gain is NOT a volume gain, so setting it higher does not mean you will get louder volume. The B1 already got a separate volume gain switch for that. So if you're using the B1 at the low current gain setting, and you don't hear any distortions, it's best to leave it at low setting, to preserve the battery, and make it run longer.
I have to be honest, with the current gain switch like that, it's a bit of a design faux pas from Aune. They explicitly state that the switch must not be flipped when the B1 is running. Problem is, with the design and position of the switch, it's very easy to flip it by mistake/accident. If you ask me, they should have implement some sort of locking mechanism, so the switch can't be flipped unless you open the lock first. Fortunately, I asked them if there are any danger if the switch is flipped accidentally while running, and they replied, there are no danger, plus the headphone plugged to it is perfectly safe.
One more thing to note is their long life battery. Their 4000mAh built-in battery is claimed to be able to run it continuously for 10 hours at low current gain setting, or 5 hours in high current gain setting. Of course with big battery capacity comes the counter-effect: longer charging time. I charged the B1 with my Ipad 10W wall charger, and it still took a couple of hours. The good news is, it can continue running while charging. So for example, the battery dies when you're on the road. Well, you can plug the USB charger cable to your power bank, and you can keep enjoying your music.
The B1 also got a good electronic architecture that enables it to output the same stable good sounds until the battery runs out. I've encountered a few portable amps that output deteriorating sounds as the batteries are about to run out. That's not the case with the B1. I was enjoying my songs when the sounds suddenly stopped because the battery ran out, with no deteriorating sounds whatsoever.
Oi, enough about the technicalities, we wanna know how it actually performs....
Well, first I'd have to state the fact that I believe: out of the whole chain (DAC - amp - headphone/speaker), the headphone/speaker got the most margin of difference between one another. The DAC and amp got less margin of difference in that chain. So you can't, for example, buy a $1000 amp, plug a $30 headphone to it, and expect it to magically transform the headphone into a $1000 one. Different DACs and amps can, and will, alter the resulting sound to some extent, for better or worse, just in a smaller scale than different headphones will. So keep in mind that what I'm saying next is in a smaller scale.
I tested the B1 with 3 headphones:
- Audio Technica AD700 (without X)
- AKG Q701
- Hifiman HE-400
First impression I got when I plug the B1 to my Ipad (yeah, I'm not too crazy on portable devices) is that the B1 is dead silent. The 'silent test' is usually the first thing I test in headphone amps. Plug it to the source, with nothing playing, max out the volume knob. If there's any noise floor audible, then it's not really a good headphone amp. Well, like I said, the B1 is dead silent, or 'black' as some people prefer to call it. After the silent test, comes the actual listening test. The B1 'smoothen' out the edges in the songs. It's not a big secret that older generations of idevices (mine is the ipad 3) only got mediocre internal amp. When plugged to the B1 (via LOD), the mediocre quality of my ipad's internal amp got pointed out immediately. The songs sound as smooth as silk. There are no 'rough edges' between different frequencies and instruments. You might say it's a lot more transparent and less distorting. The frequency separation is very good. I could even hear some subtle sounds that weren't there when I plug a headphone straight to the headphone jack of the ipad.
I played various songs, like Celine Dion's that's known for 'unforgiving' to bad devices (thus make a good test song). Her voice could sound very rough and sharp when played through bad devices. From Celine Dion, to U2, to Tong Li, to EDM like in the video. Every songs I tried came out so much better compared to the ipad's internal amp. Even my old (and mediocre) AD700 sounds so much better with the B1.
But wait, like said above, I already got the T1, right? The T1 can output line out through the RCA jacks in the back. So of course I'd give it a go. Man, the B1 really outperforms the T1's internal amp. T1's internal amp is already quite good (that's why I'm using it daily, as my main device), but the B1 amp is really 1 level above it. Fed from the tube DAC of the T1, the B1 really performs its money worth, and beyond!! The sound I got was spacious, warm, rich, and yet smooth, with minimal rough edges.
For people who are used to V-curved sound (like myself), the low frequencies will feel a bit lacking at first. It's lacking, not completely gone, though. I could still fully enjoy EDM songs with the B1. What it's lacking, it gives back in clarity and frequency separation. The high frequencies are very clear but not intrusive. The mids got more density to it.
Now I think I understand why Aune insists on implementing class-A architecture in the B1. To be honest, I've never encountered any portable amps that give this kind of result. If you have auditioned various portable amps, try the B1, and most probably you'll agree with me.
Now if your music preferences is 'rocking it out loud', and you're looking for something that's 'head-kicking, bass-thumping, heart-pumping' kind of sounds, the B1 might not be the perfect choice for you. I'd say the B1 is more aimed for quality, not quantity.
The 'siblings', T1 tube DAC/amp and the B1 Headphone amp. Zippo for size.
