Aune BU2 Review
Disclaimer: Your mileage may vary.
Contents:
The packaging of the Aune BU2 is clean and simple. On the front is the basic product 2D drawing, and below it is the basic specs of the BU2. It slides to reveal the main inscribed box. Here are the contents;
Aune BU2 Portable DAC AMP
USB A to USB C Cable
Short USB C to USB C Cable
4.4mm Female Balanced to 2.5mm Male Balanced Adapter
USB C Female to Apple Lightning Male Adapter
Stacking Band
Quick Start Guide
Accessories:
USB A to USB C Cable
- One thing that I've noticed with this cable and the Type C to Lightning adapter is that they are branded. With this cable made by UGREEN and the Type C to Lightning adapter is made by ZEPHONE. Usually, companies just provide unbranded accessories in their products.
Knowing UGREEN as most of my cable and the cables that my family uses in their gadgets are from UGREEN, the quality of this cable is very good. Although I wish that it was a bit longer. Other than that everything is very good.
Short USB C to USB C Cable
- The short USB C to USB C cable is well-built. The two angled male Type C makes it easier to use with smartphones. The cable of this short cable is tightly sheathed and is stiff. Personally I am not a fan of this kind of cable, for short cables like this I prefer softer ones.
4.4mm Female Balanced to 2.5mm Male Balanced Adapter
- The Aune BU2 only has 3.5mm SE and 2.5mm BAL ports. In order to accommodate 4.4mm BAL cables, they included this adapter. The build of the adapter is well-built. Sturdy 4.4mm Female Jack and 2.5mm Male Jack. Braided 8-Core Cable. Works like a charm.
USB C Female to Apple Lightning Male Adapter
- This is something that I didn't use as I don't have any Apple products in my possession, nor in anyone in the family.
Stacking Band
- It's a stacking band, but why is there only one of it? Usually the number of included stacking bands in portable DAC AMPs are two or more, but here it's only one. Well most of the time I used the BU2 via Bluetooth so I didn't really use the stacking band.
Aune BU2 DAC AMP
Specifications:
DAC: Dual ESS ES9318
Output level: 1.8Vrms(3.5mm SE), 3.6Vrms(2.5mm BAL)
THD+N: 0.000145%
SNR: -120dB
Frequency response range: 20Hz-20kHz
Output Power(2.5mm Bal): Up to 265mW @ 32Ω
Output Power(3.5mm SE): 100mW @ 32Ω
Build Quality:
- The Aune BU2 has an all-metal build with smooth powdered finish. The size is comparable to early android phones. Holding it in my hands, it feels really dense despite its size. On top of the BU2 is a tiny screen that is responsible for navigating through the BU2. The utility knob is located at the top of the device. If you look closely, you can see that the knob is surrounded. This knob is the only way to use the BU2 as there are no other physical controls other than it. Below there are two Type C ports, one for charging and one for USB DAC mode.
Although I have two personal issues with the build of the BU2. First is the surface of the BU2 is a smudge magnet. Holding it with my hands easily leaves handprints in it. And the marks do not disappear and need a good wipe to be clean again. As a solution to this I bought a pouch for the BU2 in which I use to avoid leaving marks on the device. Second is the metal part surrounding the knob. As a person with moderately large fingers, I am having difficulty in using the knob. I found a way to use it without pinching the knob, which is by slightly putting pressure on the top of the knob and rotate it.
Sound Quality (SL: apodizing fast roll-off filter)
- The sound quality of the Aune BU2 is simply astounding. It has a smooth natural signature that is slightly warm. I find it more musical sounding compared to my other sources (Zishan U1 ESS Version, Sony NW-A55 MrWalkman, VE MEGATRON). Soundstage is wide and imaging is accurate. I only used the default filter which is the SL. In terms of power, the SE is enough for IEMs and earbuds that are easy to drive. As for the BAL port, I haven't tested that much since the balanced cables that I ordered have not arrived. But if you're gonna use IEMs only, personally I think the SE is enough, unless you're planning to use IEMs like the Tin HiFi P1, 7Hz Timeless, KBEAR BElieve, etc.
To further customize your listening, these are filter modes that you could try;
SC: brick wall filter
SU: hybrid fast roll-off filter
SL: apodizing fast roll-off filter (default)
SI: minimum phase slow roll-off filter
SH: minimum phase fast roll-off filter
SE: linear phase slow roll-off filter
SD: linear phase fast roll-off filter
Battery Life
- The claim of 9 hours battery life on USB DAC mode seems to be reliable, and the battery life in BT mode seems to be longer than 9 hours. As a portable DAC AMP, having a long battery life is important. And the BU2 will surely keep you in company on long commute rides.
Connectivity
- There are two ways to connect to the BU2, one is via USB and one is via Bluetooth.
The USB DAC AMP function is seamless. Simple plug and play for Windows and Android devices (Again, I have no Apple products here.). UAPP and HiBy Music apps work well with the BU2, with just a few steps you can use it with bit-perfect mode to maximize the capability of the BU2.
The Bluetooth function also works really well. However you are limited only up to APTX-HD, as it doesn't have LDAC connectivity. Here in the Philippines it's fine as the mobile data is not as reliable in other countries, so I stream only at 320kbps. But in other countries with fast and reliable mobile data, they might prefer using LDAC and lossless streaming apps like Tidal.
Conclusion:
This is the first time that I've experienced using a Aune DAC/AMP, despite hearing a lot of good things about it in the past. And now that I've had my hands on the Aune BU2 for quite a while. I can say that it is an excellent DAC/AMP that covers all your basic needs as an audiophile on-the-go. There are also a lot of filter modes that you could fiddle around, further personalizing your experience with the BU2. If you're looking for a portable DAC/AMP that can do Bluetooth and is wired with lots of personalization, the Aune BU2 is a very good choice.
Disclaimer: Your mileage may vary.
Contents:
The packaging of the Aune BU2 is clean and simple. On the front is the basic product 2D drawing, and below it is the basic specs of the BU2. It slides to reveal the main inscribed box. Here are the contents;
Aune BU2 Portable DAC AMP
USB A to USB C Cable
Short USB C to USB C Cable
4.4mm Female Balanced to 2.5mm Male Balanced Adapter
USB C Female to Apple Lightning Male Adapter
Stacking Band
Quick Start Guide
Accessories:
USB A to USB C Cable
- One thing that I've noticed with this cable and the Type C to Lightning adapter is that they are branded. With this cable made by UGREEN and the Type C to Lightning adapter is made by ZEPHONE. Usually, companies just provide unbranded accessories in their products.
Knowing UGREEN as most of my cable and the cables that my family uses in their gadgets are from UGREEN, the quality of this cable is very good. Although I wish that it was a bit longer. Other than that everything is very good.
Short USB C to USB C Cable
- The short USB C to USB C cable is well-built. The two angled male Type C makes it easier to use with smartphones. The cable of this short cable is tightly sheathed and is stiff. Personally I am not a fan of this kind of cable, for short cables like this I prefer softer ones.
4.4mm Female Balanced to 2.5mm Male Balanced Adapter
- The Aune BU2 only has 3.5mm SE and 2.5mm BAL ports. In order to accommodate 4.4mm BAL cables, they included this adapter. The build of the adapter is well-built. Sturdy 4.4mm Female Jack and 2.5mm Male Jack. Braided 8-Core Cable. Works like a charm.
USB C Female to Apple Lightning Male Adapter
- This is something that I didn't use as I don't have any Apple products in my possession, nor in anyone in the family.
Stacking Band
- It's a stacking band, but why is there only one of it? Usually the number of included stacking bands in portable DAC AMPs are two or more, but here it's only one. Well most of the time I used the BU2 via Bluetooth so I didn't really use the stacking band.
Aune BU2 DAC AMP
Specifications:
DAC: Dual ESS ES9318
Output level: 1.8Vrms(3.5mm SE), 3.6Vrms(2.5mm BAL)
THD+N: 0.000145%
SNR: -120dB
Frequency response range: 20Hz-20kHz
Output Power(2.5mm Bal): Up to 265mW @ 32Ω
Output Power(3.5mm SE): 100mW @ 32Ω
Build Quality:
- The Aune BU2 has an all-metal build with smooth powdered finish. The size is comparable to early android phones. Holding it in my hands, it feels really dense despite its size. On top of the BU2 is a tiny screen that is responsible for navigating through the BU2. The utility knob is located at the top of the device. If you look closely, you can see that the knob is surrounded. This knob is the only way to use the BU2 as there are no other physical controls other than it. Below there are two Type C ports, one for charging and one for USB DAC mode.
Although I have two personal issues with the build of the BU2. First is the surface of the BU2 is a smudge magnet. Holding it with my hands easily leaves handprints in it. And the marks do not disappear and need a good wipe to be clean again. As a solution to this I bought a pouch for the BU2 in which I use to avoid leaving marks on the device. Second is the metal part surrounding the knob. As a person with moderately large fingers, I am having difficulty in using the knob. I found a way to use it without pinching the knob, which is by slightly putting pressure on the top of the knob and rotate it.
Sound Quality (SL: apodizing fast roll-off filter)
- The sound quality of the Aune BU2 is simply astounding. It has a smooth natural signature that is slightly warm. I find it more musical sounding compared to my other sources (Zishan U1 ESS Version, Sony NW-A55 MrWalkman, VE MEGATRON). Soundstage is wide and imaging is accurate. I only used the default filter which is the SL. In terms of power, the SE is enough for IEMs and earbuds that are easy to drive. As for the BAL port, I haven't tested that much since the balanced cables that I ordered have not arrived. But if you're gonna use IEMs only, personally I think the SE is enough, unless you're planning to use IEMs like the Tin HiFi P1, 7Hz Timeless, KBEAR BElieve, etc.
To further customize your listening, these are filter modes that you could try;
SC: brick wall filter
SU: hybrid fast roll-off filter
SL: apodizing fast roll-off filter (default)
SI: minimum phase slow roll-off filter
SH: minimum phase fast roll-off filter
SE: linear phase slow roll-off filter
SD: linear phase fast roll-off filter
Battery Life
- The claim of 9 hours battery life on USB DAC mode seems to be reliable, and the battery life in BT mode seems to be longer than 9 hours. As a portable DAC AMP, having a long battery life is important. And the BU2 will surely keep you in company on long commute rides.
Connectivity
- There are two ways to connect to the BU2, one is via USB and one is via Bluetooth.
The USB DAC AMP function is seamless. Simple plug and play for Windows and Android devices (Again, I have no Apple products here.). UAPP and HiBy Music apps work well with the BU2, with just a few steps you can use it with bit-perfect mode to maximize the capability of the BU2.
The Bluetooth function also works really well. However you are limited only up to APTX-HD, as it doesn't have LDAC connectivity. Here in the Philippines it's fine as the mobile data is not as reliable in other countries, so I stream only at 320kbps. But in other countries with fast and reliable mobile data, they might prefer using LDAC and lossless streaming apps like Tidal.
Conclusion:
This is the first time that I've experienced using a Aune DAC/AMP, despite hearing a lot of good things about it in the past. And now that I've had my hands on the Aune BU2 for quite a while. I can say that it is an excellent DAC/AMP that covers all your basic needs as an audiophile on-the-go. There are also a lot of filter modes that you could fiddle around, further personalizing your experience with the BU2. If you're looking for a portable DAC/AMP that can do Bluetooth and is wired with lots of personalization, the Aune BU2 is a very good choice.