disclaimer: The Xa-10 was provided for the purpose of this review by XDuoo. If you have an interest in purchasing any of the Xduoo amplifiers I have recently written about, I suggest you check out Xduoo’s website and follow them on facebook for more information. I have no financial interest in Xduoo, nor did I receive any compensation beyond the product itself for reviewing it.
Unboxing / Packaging:
The Xa-10 is a fairly light unit but is well packaged for travel all the same. The outer box is a heavy cardboard shipping container with a lighter display packaging appropriate to a resale resting inside. The packaging is fairly non-descript, but highly functional with all components packed neatly and kept from rattling around in transit. The kit contains the main unit, Bluetooth antenna, USB cable, and power cord . No interconnects are provided so you’ll want to make sure you have the necessities.
First off, if you’ve seen pictures online you probably have an idea of the size of the Xa-10 and if you are like me, you are probably wrong. I was surprised by the size of the Xa-10 when I got it out of the box. At four (4) inches tall, three (3) inches wide, and just under nine (9) inches deep, the unit is very compact. The unit is light as well as because it uses a switching power supply (external) and uses an output buffer it has no heavy transformers inside the case. Build quality is good as the unit uses a heavy gauge aluminum shell with an even heavier front plate. All of the surfaces are gun-metal gray anodized and the familiar X pattern of ports for venting is cut into the sides of the units housing. In keeping with other recent models, the large volume knob is also anodized aluminum in a deep red. The volume knob is pretty cool as the display is centered in the middle and stays stationary while the outer ring turns. Beneath the volume knob are (from left to right) a 6.3mm single ended headphone port, a 4 pin XLR balanced port, and a 4.4mm pentaconn balanced port. Controls for the display are on the right side of the unit with 3 buttons for input selection, menu items, and Bluetooth. On the rear of the unit, we find RCA input and outputs at top left and bluetooth antenna connector top right. Beneath the RCA jacks are the coax, optical, and usb inputs on the left and power switch and 12V DC power input on the right.
We expect the internals on the Xa-10 to be fairly high end with it being the co-flagship of the Xduoo line and it doesn’t disappoint. Inputs are handled by Xmos (Xu216) for USB, The Qualcomm CSR8675 handles Bluetooth, while a Cirrus Logic CS8422 handles Optical and Coaxial inputs. Next in sequence is a CPLD (complex programmable logic device) that is fed all inputs and handles jitter correction via two clocks (44/48) before feeding the signal to dual AKM4493 DAC chips. The filters on the dacs are exposed to the end user via the front controls and give the option to tune the sound. (more on this under controls). The Amplifier stage is composed of a quartet of OPA1612 followed by a Class A buffer. This combination of op-amp and buffer gives a higher output power than would be possible with either by itself and helps prevent droop when large power demands do occur. Finally, before exit, the signal passes through a digital volume control and protection circuit that keeps power on noises from being heard in the attached headphone. This is a smart feature as anything with nearly 4 watts of output power is capable of destroying headphones if an aberrant spike were to occur. Remember it is always wise to plug the headphone in before powering on the amp, but this does give a margin of safety as well.
File support includes up to and including 32bit/768kHz PCM, DSD64-512, DXD 24-32, and full MQA support (32/384 max). Optical and coaxial inputs are limited to 24/192 PCM and DSD64. Bluetooth supports ,AAC, AptX HD, and LDAC in addition to the base SBC and AptX protocols giving plenty of input options. Output power is up to 3Watts (with a 32Ω load) in single-ended and up to 4 Watts in balanced (also assuming a 32Ω load). I found this had plenty of power for everything in my collection although the He6 does have more headroom on the Ta-30 so for those really hard to drive headphones, audition the Xa-10 before purchase may be wise. Still with 600Ω Beyerdynamic and AKG models, I had enough headroom to listen at volumes entirely louder than recommended or safe.
Is it Balanced?
Let’s deal with the elephant in the room, some have called models that have the same power output on both single ended and balanced connections “Fake Balanced”. This is due to ignorance as balanced does not define output power and it is entirely possible to be balanced without increasing output power. The term balanced signaling means simply that conductors have equal impedance to ground. Single ended (R+,L+, Gc) is not balanced because of the combined return. Since each signal has to compete with the other on the return side, the impedance will vary. If instead the system is wired where left and right have separate grounds (R+ Rg and L+ Lg) as is the case with the Xa-10 (and the Sp200 as well) then the connection is balanced as the routes to and from the transducers have equal impedance to ground.
The confusion comes from the fact that balanced connections are often differential connections as well. Differential implies that the two conductors carry the same signal in opposite polarity and while differential does not require a separate ground, we often see a 3rd wire used for it. Almost all XLR interconnects are both balanced and differential as they are wired +,-,ground and only carry a single channel per connection. The separate ground helps with eliminating voltage potential between components while the differential connectors increase signal strength and help improve signal to noise ratio which is of high importance on the low power signals often traveling between components. Differential amplification gives twice the voltage swing as single-ended as the swing is from positive to negative rather than positive to zero.
With many XLR connections being both balanced and differential, the two terms have been used interchangeably and some have lost sight of the fact that it is not necessary to be differential in order to be balanced. Differential amps are usually more expensive as you have to have 4 amplifiers instead of 2 to create the positive and negative signals. For this reason budget gear opts for balanced, but not differential.
So yes, the Xa-10 is balanced, no, it is not differential. One can test this fairly simply by using the negative connection for one channel or the other of the XLR connector and connecting the other to ground to test using an ammeter. If voltage is present between the negative and ground, in equal and opposite amount to the reading from the positive to ground, the circuit is differential. If positive to ground yields a voltage reading but negative to ground sits at zero it is balanced using a ground per channel (the negative connector) and is not differential. remember to use bare metal for the return as anodizing acts as an insulator. I did my tests with the case removed so I had access to the internal ground.
There are 3 buttons immediately behind the face on the right hand side of the unit. The top is input select and clicking it cycles through the various input options available. Remember when using the usb, there is a windows driver that is required to support full resolution although the Xa-10 will work as a 24/192 DAC without use of a windows driver on recent builds of windows 10. The second button is the menu which exposes the gain and filter options. turning the dial switches between gain and filter and clicking the menu button again opens a list of choices for each. Gain has only two options low or high, but filter offers eight (8) total options, six for PCM and 2 for DSD. On Screen, these are listed as FIR1-8 at middle left. The first six are the PCM filters with 1 = sharp roll-off , 2 = Slow roll-off, 3 = Short Delay Sharp, 4 = Short Delay Slow, 5 = Super slow, and 6 = Low Dispersion Short Delay. Options 7 and 8 are DSD filters with 7 offering low and 8 high. The bottom most button is the bluetooth pairing button and leads us into our next section.
To pair the Xa-10, first make sure the input is set to Bluetooth using the input select button. This should make the display flash the Bluetooth symbol and display the word unpair. The unit should automatically go into pairing mode if not already paired and once connected the symbol will change and say connected. Once paired, the unit will search for existing pairings at each startup (when in BT mode), so to switch devices connected, one needs to press and hold the bluetooth button (bottom button on side) for 3 seconds to force the unit back into pairing mode. I found connection strength to be fairly good (although best with LDAC or AptX HD) and one can move around inside and not lose signal unless several layers of drywall are present. (I used the pre-amp function to test BT as none of my headphones have a long enough cable to test this). Average distance in open air before break up is roughly 25 feet.
Sound is tough to discuss on any DAC/Amp as it often is more a matter of source material and headphones that influence what we hear. I tested the Xa-10 with a few select headphones and iems that I am intimately familiar with to avoid attributing characteristics of the headphones to the Xa-10.
The Xa-10 had plenty of power for all but the most demanding of headphones and even then, it has enough power to run the He6, it just doesn’t have the headroom of the Ta-30 for driving the beasts. the Xa-10 was great with the T50rp which also has a reputation of being something that needs a ton of power to do well. The down side to all that power is even on low gain, the Xa-10 produces some hiss on things like the Magaosi K5 and other extremely high sensitivity in-ears. I think the fact that the 3 jacks on front are 6.3, 4.4, and XLR probably hint at the idea that it wasn’t really designed with extremely sensitive in ears in mind.
The Xa-10 has good linearity and enough power to deliver big hits when called upon without an attendant droop and recovery like some lesser amps. Even when running 600Ω Beyer and AKG models, the Xa-10 had more than enough power to keep big bass hits coming with good speed and clarity and no loss of definition in repeat strikes. Overall the Xa-10 does a good job of presenting what the source sends it with no coloration and very little smoothing. (I’m happy to see this as AKM can trade a bit of detail for smooth delivery).
The Xa-10 delivers here in spades, great detail, good transient speed, and no coloration. Vocals are tight and are not markedly lifted (at least by the Xa-10) which lets the tuning of the headphone attached really shine through. Very clean, controlled, and detailed mid-range.
The Xa-10 has good extension and clarity at the top with enough energy to again let the headphones tuning really show through. Very similar to the mids in detail level and clarity, but here we do see the AKM smoothing a little more than in the lower registers as tracks that are sibilant are slightly less abrasive and strident when played back on the Xa-10 when compared to something a bit less forgiving like the RME ADI-2.
Soundstage / Imaging:
I have always thought the job of a good amplifier was to stay out of the way and let the headphone deliver. For that reason I test stage with the Hifiman Ananda and Sennheiser HD800 which both have a reputation for massive stage. I can’t say that the Xa-10 expands the stage, but I can say it does not do anything to detract from it either.
Xduoo Ta-30 – The Xa-10 and Ta-30 arguably hold co-flagship positions in the Xduoo line-up with the Ta-30 being a tube hybrid using an ESS dac and being more amp focused while the Xa-10 uses dual AKM dacs and is arguably a bit more of an overall package rather than a tube amp that happens to have a dac internally. Having said that, the Ta-30 is a solid DAC/amp and for many offers more flexibility with the ability to roll both rectifier and pre-amp tubes. In addition the Ta-30 is also a bit more potent delivering a full 4 watts into its single ended connection. The Ta-30 doesn’t have any balanced outputs though and can’t match the SNR, or THD numbers of the Xa-10. The Xa-10 also adds MQA support which the Ta-30 does not have so for those who are using Tidal or other MQA capable streamers, the Xa-10 has a clear advantage. I love my tubes, but if I had to choose for an office desk, the Xa gets the nod, smaller, more capable, and less breakable has its advantages.
Topping D50s/A50s – The closest comparison to Topping’s line is their D50s/A50s that was recently released. Topping has focused on match separates rather than building an all-in-one device at this price point but at $249 for the dac and $219 for the amp, the price for the total package is roughly the same. The topping uses a pair of ESS 9038Q2m chips vs the AKM4493 pair in the Xduoo so this is pretty much a wash as these two are pretty evenly matched. Both Dacs offer optical, coax, usb, and Bluetooth inputs, so here again, no huge winners or losers, unless you use Tidal and then the Xa-10’s support for MQA outshines the Topping. The amps do differentiate a bit more. TheXa-10 is more potent at 3 Watts in single-ended vs the A50s at 1.4 Watts. And the Xa-10 offers both 4.4 and XLR jacks vs the 4.4 only of the A50s. Both have disgustingly low THD and incredibly good SNR but here the A50s shows off. The Xa-10 is listed as 120 dB SNR and <.0008 THD vs the A50s with its <.00007 THD and nearly 140dB SNR. Purists will opt for the A50s, while realists will realize both of these models are good enough that any difference is inaudible. This one will come down to MQA/Tidal use for many as both are very good, but the Xa-10 offers more capability while the topping may be slightly more flexible.
SMSL M500 – Here we have SMSL’s entry into the $500 market space. The M500 utilizes the 9038Pro chip so is a step up from the 9038q2m mobile chip in the Topping as it is the 8 DAC chip and uses 4 dacs summed per audio channel which helps reduce noise and improves resolution by reducing errors. Arguably the M500 is more dac than amp with balanced outputs for connecting to another amplifier but no balanced headphone output. It has less power than the others as well with only 600mW compared to the 1+ watt of the other two in the round up. Still, it has enough power to be a solid headphone amp for office use, does support MQA, is roughly the same form factor as the Xa-10, and again sports THD and SNR numbers that mean differences in the 3 should be inaudible. SMSL does not get the respect that either Topping or Xduoo have earned due to some early hit or miss QC issues, but of late, SMSL products have been improving and the M500 is worth a look, particularly if you intend to use IEMs where the lower power output may be a plus. For full sized headphones, the Xa-10 offers a better fit.
Thoughts / Conclusion:
Man you couldn’t have hit me more solidly wrong with this one. I’m a tube guy, everyone knows that, I’m not a huge fan of wireless as I have never had a problem wearing wired headphones, and I’m a file library guy who grudgingly uses Tidal and Quboz to test with. So what am I doing testing a solid-state, Bluetooth, MQA DAC amp? Well, I’m enjoying it, a lot. No it doesn’t fit with my usual preferences, and yes, I’d still prefer a little tube flavor in the sound at times, but this thing is really good. Once we get past the “Fake balanced” garbage of recent internet posts and realize that balanced does not have to be differential, we understand the power output numbers for the Xa-10, and the other specs are really amazingly good for a product that costs less than $500 out the door. On low gain it worked well with all but super sensitive iems (this is not the amp for Magaosi K5 or Campfire Andromeda that tend to hiss). On high gain it has more than enough power for 600Ω Beyer and AKGs and even enough to run the vaunted He6 (although not with as much headroom as the Ta-30). On top of impressive specs and power, its small enough to fit under my Dell monitor at work and all but disappear when not in use. As a desktop companion, it’s hard to imagine much better. Well worth your time to audition and on my short list of desktop recommendations.
Pros: great build quality, very clean sound, good power, lots of input options.
Cons: Price, hiss with high sensitivity iems