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The XQ50 is being marketed by Xduoo as a bluetooth receiver for upgrading older gear to be Bluetooth ready, but it has a hidden talent as well that may make it more interesting to many in a different capacity. I have had a couple weeks now to use it in various configurations so feel confident that I have wrung all the details out of it at this point.
Unboxing / Packaging
The XQ50 comes in a cardboard box with a white slipcover over it. The front shows the unit in near real size along with the model name and Xduoo logo while the rear of the slipcover has the details printed in English and Chinese.
Inside the box, the unit itself is well padded with the USB-C cable and antenna in a separate compartment. A warranty card and instruction manual complete the kit.
It isn’t fancy, but remember this is a sub 60USD unit so we shouldn’t expect some of the add-ons that come with higher priced components and it does have everything it needs to use it out of the box with the exception of a power connector for the USB cable if using the unit as a stand-alone.
The XQ50 is a small aluminum box with a single button and two LEDs on the front and the required ports on the rear.
Left to right, the rear panel has a pair of RCA outputs, a coaxial output, an optical output, a USB-C input, and the antenna connector which uses a standard sma connector type.
This facilitates using a larger antenna or moving the antenna to another location with an extender if the unit is to be placed inside a closet or cabinet. The unit is very light as it houses only a single PCB and does not have an internal battery. The unit is heavy enough that cable weight didn’t slide it around, but it is light enough if the cable is yanked it will pull the whole unit off the desk rather than unplugging the USB from the rear of the unit so caution is advised when placing the device to avoid traffic areas.
Removing the 4 screws at the corners of the face-plates on the front and rear allows for removal of the board if you are interested in the internals.
All chips are on the top of the board with only the traces being visible from the underside. When using Bluetooth input, the first chip in the path is the Qualcomm QCC3008.
The 3008 is an entry level chip designed specifically for use in bluetooth audio devices with bluetooth 5.0, aptX, and Qualcomm cVc noise cancelling technology. Outputs of the 3008 are I2S, spdif, and USB.
For digital output, the I2s output feeds a Cirrus Logic 8406 that handles conversion from I2S to optical or Coaxial output.
For analog output to the RCAs, the I2s signal is passed to a ESS9018K2M DAC chip that handles the conversion. The 9018 itself supports up to 32/384 and DSD256 but is limited by what bluetooth and USB inputs allow. Yep, you read that right but more on that later.
Finally the last stop on the output chain before reaching the RCA jacks is a 5532 dual op-amp that handles amplification to line level. The op-amp is socketed to the board so allows for changing out as the user sees fit, and has ample space in the case for use of a Stacatto, Spark-OS, or Burson discrete as well as any of the standard IC op-amps.
The XQ50 is easy to setup and get going.
A USB-C cable for power, a pair of RCAs , a coax cable, or an optical cable for output and you are in business.
Once connected, press the button on the front of the unit to pair it with your source. The Xduoo unit immediately showed up on multiple tablets (both android and ios) and phones (again of both varieties) and paired quickly and without issue in all cases.
I also tried it from several PCs of various varieties (mac included) and again found no issues connecting between any of them. Once connected, the connections were very stable as long as no physical barriers were present between source and destination.
A single layer of drywall didn’t cause signal interruption, but multiple layers did so moving the source to another room is not recommended. I did find I could hide the unit behind the receiver and there was enough bounced signal to keep the connection active, but it was more likely to drop out during movement in the room or source obstruction.
And now for the other use of the XQ50, that I think may be more interesting to many than the Bluetooth receiver.
The XQ50 will function as a USB DAC but support is limited to 16/48 due to its use of the bluetooth chip for USB input rather than having a distinct USB controller.
I am sure this saves costs, but seems a shame to take a DAC capable of 32/384 PCM and 256 DSD and limit it to PCM only at 16/48 tops. The unit functions well as a USB DAC, but with the previously mentioned limit few will want to invest in it purely for that functionality.
It does make an interesting platform to test op-amps in as it is very minimal and any change is easily distinguished. I spent an afternoon trying different ones out and while I think Xduoo did reasonably well with the 5532 as the stock op-amp, I did find the OPA2134 was a bit more energetic and lifelike at roughly the same price point and the Muses02 was a substantial improvement, but at nearly the cost of the box, this is of debatable value.
I found the XQ50 to deliver a slightly bright sound which I think is due to the DAC being slightly thin and clinical sounding and the limited power input to the op-amp that is inherent to the use of USB power (5V max).
So in reality, the sound is probably more realistically defined as slightly bass light rather than bright as I think the low end is recessed a touch. This is not to say that it lacks bass, just that it does not have quite the authority that the treble can.
While I found some op-amps made the sound a bit darker, none were able to deliver a signature that completely removed that bright top end. This is easy enough to adjust out with EQ or even the bass/treble adjustment on the receiver itself and probably won’t be an issue to most as the little unit is not really designed for the audiophile market when looking to add bluetooth to aging gear. (Most of us audio nuts have long since added a streamer to our collections).
Ok so with all the other options on the market for adding Bluetooth input to your existing stereo, does the little XQ50 represent good value?
Lets take a look by comparing to some of its competitors and see what it offers, what it lacks, and where it fits on the price spectrum.
Mixcder TR-008 VS xDuoo XQ-50
At the bottom end of the scale, we have the Mixcder TR-008 which retails for $25 when it can be found. Of late, it is has be perpetually out of stock.
The TR-008 is considerably smaller and offers battery power, but lacks the Coaxial output, and had problems with source cut outs at a lesser distance than the XQ50 did. Build quality also favors the XQ with it’s metal case vs the all plastic housing of the TR008. The TR008 does offer transmit as well as receive as do several in our comparisons while the XQ is purely a receiver.
Next up with have the Aventree Oasis Plus.
This unit retails for $70 so reasonably close to the asking price of the Xduoo unit.
When placed side by side, the first thing you notice is the difference in build quality.
The XQ50 is all metal while the Aventree is all plastic.
The Xduoo is quicker to setup while the Oasis+ offers both transmit and receive and takes a bit more fiddling to get it configured.
Once setup, both performed similarly with the aventree having a slight advantage in distance from source to antenna, but not as large as Aventree’s claims would make one expect.
Even with the Oasis+ advertising AptX-HD as compared to the Apt-X of the XQ50, I found the latency slightly lower on the XQ50.
The next step up the price scale is the Auris BluMe HD at $120 retail.
This time the comparison is more even.
Construction is similar, Outputs are RCA/Optical on both with Coax on the XQ50 unit and both are receivers only. Again the BluMe lists Apt-X HD but again any practical difference wasn’t noticeable in my testing.
Both units performed well, but with the Auris unit costing nearly double the XQ50, one has to wonder what was gained for the spend.
And finally, at the top end the AudioEngine B1 at $189 retail.
Here again, quality construction on both units, both are USB powered. Both offer optical and RCA outputs with the XQ50 offering Coaxial as well. Both offer very simple operation, and both function as receivers only.
Here the Apt-X HD did seem to pay off for the B1 as its latency was a bit lower than the XQ50 at times, but other than that small detail, connections were solid on both units and distances from source to antenna were roughly comparable.
At nearly 4 times the price of the XQ50, the B1 is at best a pretty minor upgrade and at worst a way to pay a lot more for the same end result.
Thoughts / Conclusion
The Xduoo XQ50 is a well built unit with all metal construction, a single circuit board design, and more connection options than several of its higher priced competitors.
Setup is very straight forward with nothing to scare off the less technical among us, and once setup connections are solid and sound quality is very respectable. Those who like to tinker have the option of exchanging op-amps as the XQ50 uses a dual op-amp in a dip-8 socket for easy exchange.
As a secondary use case, it also can be used as a USB dac and required no drivers for Windows, OsX, or Linux, so those looking for an inexpensive way to setup a computer to stereo connection will find it useful as well.
The only caveats regarding the unit are no RCA, optical, or coax cables are provided and while a USB-c cable is provided, no charger is. These items do come with some of the competitors products, but usually at enough higher cost to more than account for the difference.
For those reasons, the XQ50 earns my recommendation and should be on the short list for anyone looking for a Bluetooth receiver to upgrade an aging stereo. As for me, I am investigating how to waterproof one for outdoor use next summer by the pool.