xDuoo 05BL Pro Review
(Note: This article was written by Audiofool review)
I have worked with Xtenik to review several Xduoo products and recently got an invite to review the O5BL Pro for them. I’ll admit to having mixed emotions on this.
I love my XD05 and the pro improved on it, but in my view the 05BL was a weak link in the chain.
It degraded sound quality of an otherwise great device, and had some problems with cut-outs as well.
To date, I have recommended the XD-05 and more recently the plus version if you needed a potent portable amp, but I have been quick to say “as long as you don’t need bluetooth input”.
If the Pro version of this adapter was more of the same, then I saw little reason to get excited about it, but surely they learned something from the feedback right?
Well I agreed to give it a shot, and here is what I found out.
The 05BL is a purpose built product and even looking at the outside of the packaging you get the message that it is designed to pair with the XD-05 series amps.
Technically speaking, it can be used with any dac/amp with a coaxial 3.5mm input since that is the connection between 05BL and dac/amp but it looks rather out of place paired to anything other than the XD05.
Inside the box, I found the unit itself, a charging cable (USB-A to USB-C, and a hood for the volume knob to protect it. ) My understanding is kits are available in black or silver hoods, but the units themselves are all black so even with a silver unit, you end up with black last 1.5cm.

Installing the unit is as simple as plugging it in, while the hood requires removing the two screws on the right side of the unit and then adding the hood and using the longer screws provided to attach it.
A driver is provided so everything you need to perform the install is in the box. My unit also came with 3.6V on the battery (consistent with resting voltage of Li batteries) so was ready to use out of the box.
The XD05 is already a fairly substantial unit both size and weight wise so the 05Bl shaves weight where it can by using a plastic shell. Construction is still solid as the housing shows little flex or give under pressure.
The only drawback may be that is probably is not as impact resistant as a metal housing might have been.
I guess dropping the unit from any height is a bad idea regardless of construction. The rear face of the unit has a checkerboard pattern while the remainder of the unit is smooth with edges shaped to match those of the XD05.
The unit has two 3.5mm pin connectors but only one is active. The left pin is a coaxial connection to the host unit, while the right pin is just to hold the unit in place and has no connections inside the unit.
On the top of the unit (left to right from front) are the next/previous buttons, a star made of 5 small ports, a single LED used as a connection indicator, is a USB-c port for charging, and on the far right, the power/play/pause button which has the charging LED directly above it.
Worth noting, some of the early marketing pictures show a single LED where the star is on this unit and others show the star. I think early marketing materials probably featured the original 05BL shell, while production is slightly different and some of the materials simply didn’t get updated.
If there are caveats to be mentioned, they would be the lack of a pass through for power to the XD05, and the fact that two units have to be charged separately.
For the next generation, maybe put a USB port that passes through to power the XD05, and leave the battery off the 05BL and let it draw power directly from the XD05 instead.
The capacity required to run the 05BL is negligible when compared to the capacity the XD sports anyway, and this would allow you to keep the two connected and lower risk of breakage due to the constant on/off of the unit.
The other criticism is on the volume knob protector, which is a great addition and shipping it with extra screws and the wrench to install it is perfect, but why was this not included in the base model?
For those with a set of small tools for taking apart phones etc, the screws are the standard T6 Torx head screws.
I find it immensely useful even when not using O5BL as it prevents accidentally moving the knob when the XD05 is in a pocket and to my mind, it even improves the look of the unit. I am glad it is included in the kit for sure, but question why you have to buy the Bluetooth module to get it.
Specs are a bit confusing as the original 05BL was listed as supporting Bluetooth 5.0 as does the 05BL Pro but under the hood these are two different devices.
The older unit was designed with the CSR8670 chip at the heart of it. This does technically support bluetooth 5.0 but most of the optional codecs are not supported, so the original was limited to SBC, AAC, or the original implementation of AptX.
The newer unit utilizes the CSR8675 chip that adds AptX-LL, AptX-HD, and LDAC to its list of supported protocols in addition to the originals.
While debates still rage on which is best, I think we can all agree that having more choices is good and that the newer protocols offer the potential for better sound quality than the earlier standards.
I paired my Android phone to the 05BL Pro and using the developer options was able to force it to use AAC, AptX-HD, and LDAC in addition to forcing SBC.
In my case, I found LDAC to be the best compromise be sound quality and connection quality with AptX-HD a close 2nd.
The LED indicator on the unit will show what connection type is use by color. SBC is blue, AAC is cyan, APTX (or LL) is purple, AptX-HD is yellow and LDAC is white. This makes it easy to tell at a glance which codec is in use.
If there are caveats to be mentioned, they would be the lack of a pass through for power to the XD05, and the fact that two units have to be charged separately.
For the next generation, maybe put a USB port that passes through to power the XD05, and leave the battery off the 05BL and let it draw power directly from the XD05 instead.
The capacity required to run the 05BL is negligible when compared to the capacity the XD sports anyway, and this would allow you to keep the two connected and lower risk of breakage due to the constant on/off of the unit.
The other criticism is on the volume knob protector, which is a great addition and shipping it with extra screws and the wrench to install it is perfect, but why was this not included in the base model?
For those with a set of small tools for taking apart phones etc, the screws are the standard T6 Torx head screws.
I find it immensely useful even when not using O5BL as it prevents accidentally moving the knob when the XD05 is in a pocket and to my mind, it even improves the look of the unit. I am glad it is included in the kit for sure, but question why you have to buy the Bluetooth module to get it.
Now, I’ll be the first to admit, in the battle of streaming vs files and phones vs DAPs, I’ve always been a big proponent of DAPs and files rather than relying on streaming and phones.
Most of my argument doesn’t come from where you might expect though. Many argue for the same things I did purely from a sound quality standpoint, and they aren’t wrong, but for me, my phone is a first and foremost a business device so anything that drains the battery prematurely is not acceptable and secondly, I move around a lot for work, this meant either paying Verizon more than I wanted to stream over 4G (where I could get it), constantly be looking for Wifi where available, and be subject to being without my music where neither was available.
Those factors combined with the sound quality issue pushed me solidly into the I’d rather have a DAP with files on it camp.
Well times change, and 4G has gotten much better coverage and cheaper and wifi has become almost ubiquitous in areas where business is conducted.
AAC, AptX-HD, and LDAC all improve on the amount of information available to a DAC via a bluetooth connection and while arguable that they still have not reached their wired counterparts yet, for most portable use, I realistically am not looking for sound quality better than what can be provided by these newer protocols.
Most of the time these are noisy environments that don’t lend themselves to critical listening anyway.
My battery life argument still has me using a DAP for streaming instead of a phone, but even that is less of an issue than it used to be with current phones offering higher capacity batteries than previous models.
On top of that, Tidal has a deal for new users where for the next 5 months you can enjoy any of their plans for $5.
I jumped at it as a way to really compare what Tidal was all about to Qubuz, spotify, and files stored locally.
A dap like the Fiio M6 offers an inexpensive way to jump into streaming services and not drain the phones battery so I loaded it up with Tidal, Spotify, Qubuz, and a 512gb micro-sd card full of flac and mp3.
The M6 offers long battery life, an easy to use interface, small form factor, and a ton of features.
What it doesn’t offer is a ton of output power.
I paired the M6 to the 05bl Pro and now I have a rig that will run any of the Streaming services all day, or allow me to sift through my library for that one song I am after.
The M6 connects using AptX-HD and performed well enough that I haven’t checked to see if there is a way to force LDAC.
Without going into the full compare as that is certainly a discussion for another article, needless to say, I am slowly warming up to the idea of using a streaming service instead of locally sourced files.
If nothing else, it introduces you to a lot of new music you might not otherwise here.
For old favorites, I still think files have a place, but streaming certainly helps with the finding new favorites and the 05BL pro gives me one more way to deliver those favorites to the XD-05 and one that is now almost as good as any of the wired solutions and a bit easier to pocket than any of them.
I started out saying that I really liked the XD05 but couldn’t recommend the 05BL and now must change that statement to “while I can’t recommend the original 05BL, the Pro is well worth the spend and gives an already versatile device yet another input option”.