xDuoo TA-03S USB DAC/headphone amplifier
+ Extremely sweet and capable amp stage; expansive soundstage; it’s cheap; warm tube-y sound is preferred by some; drives any sensibly hard-to-drive headphones without no problem; DSD support.
– Average DAC section bottlenecks performance; line out doesn’t pass through tubes and non-variable.
Sound: 7.5/10 (amp section: 9/10)
IT not often that I get my hands on a tube headphone amp, so when the opportunity came in the form of the China-made xDuoo TA-03S, I jumped at it. The TA-03 (without S) was originally released around mid-2016 and was updated recently to the TA-03S.
The desktop unit is unassumingly small and compact, weighing 2.6kg and measuring 22 x 12.5 x 9.5cm, slightly shorter than a Subway foot-long sandwich and of similar girth. The TA-03S only comes in flat black, basically just like every other equipment ever made by everyone. On the front panel, there isn’t much going on, just a volume knob, a quarter-inch jack and a blue indicator light.
Business is at the back – USB-C input (upgraded from the five-pin mini-USB on the previous iteration), a pair of RCA jacks functioning as both line in and out, and an IEC inlet allowing you to choose your own flavour of power cable. What it does not have is a gain switch but the excellent volume control and output transformer remove the need for it. My IEMs and sensitive headphones showed no signs of hiss while the harder-to-drive HD525 got loud at 9 o’clock – I think one would be hard pressed to find any headphones this amp can’t drive.
The elephant in the room here are those three tubes in front of the power transformer. The TA-03S uses a single 12AU7 tube for voltage amplification at the preamp stage, feeding a pair of 6C19 tubes at the current amplification power stage.
Of course, as a headphone amplifier, these tubes do not run as hot as tube amps made to drive speakers. That being said, the tubes still glow bright, especially the 6C19s, and if you choose to touch them after an hour or so of operation, you need to rethink your life choices.
On the inside, almost everything that counts has been upgraded from the previous version. The TA-03S now uses an XMOS U8 USB chip and a pair of CS4398 DAC chips compared with the already great XMOS USB chip and dual WM8470 DAC chips before. With the XMOS U8 upgrade, the TA-03S also ups the supported format to 32-bit/192kHz PCM and DSD128. Perhaps the biggest change topology-wise would be the addition of output transformers as opposed to the previous transformer-less (OTL) output stage.
Going back to the RCA jacks, the function is relay controlled, depending on the USB connection. They work as non-variable line outs when USB is connected and as analogue in when disconnected. What’s surprising is the USB DAC section is self-powered. This means you can use it as a USB DAC without plugging in the power or turning the unit on. This also means using the TA-03S as a DAC into an external amp will bypass its tube section.
Seeing how the amp is serving at least three different duties, this review will be slightly more comprehensive than the usual.
With my Windows 10 machine, the TA-03S showed up immediately as a USB audio device. Despite the murmur of it only supporting Windows 8 and earlier, it worked fine throughout testing. For DSD playback, it requires an XMOS driver which is available for download from the website.
The unit gets hot and the area around the tubes easily reaches 50° Celcius. I would recommend against stacking anything one it – and god forbid stacking anything over it – unless conflagration is on your checklist.
Listening was done with the supplied stock tubes, and USB and power cables.
As a DAC/headphone amp, the TA-03S does nothing wrong at all – in fact, it does a lot of things right. The opening bass line in Space Oddity from the Secret Life of Walter Mitty soundtrack was rendered with convincingly real decay. While there was accentuation in the lower registers that I could attribute to the 6C19 power tubes, it was a welcomed coloration.
As is, the TA-03S feels a lot like enjoying your favourite cup of flat white in a local cafe mid-afternoon. The presentation is relaxed and laidback, so oftentimes, instead of trying hard to detect what’s wrong with it, you get lost in what’s right. It is satisfying listening to the TA-03S as its warmth envelopes every track you play like a blanket of honey.
The unit is not the last word in resolution as some of the warmth bleeds into the upper mids and treble, veiling the whole presentation – which is only the case if you try to look for it. Just as how the body doesn’t need to constantly remind itself to breathe, the veil goes away once your mind wanders off.
As a pure DAC, it is resolving enough without having excessive flavour. Upon switching its analogue output to my Lovely Cube Premium class A solid-state headphone amp, it’s immediately apparent how average the DAC section on this unit is. The TA-03S resolves macro details well but micro details such as the scratch from calloused fingers rubbing against guitar string gets lost in translation and blends into the background. To that I say, who cares? You’re listening to music, not trying to count the number of people clapping in the front seat at the end of Track 3 of Adele’s Live at the Royal Albert Hall album.
As a pure headphone amp, the TA-03S does so many things right. I would even go as far as to say the performance is bottlenecked by the mediocre DAC stage. Mids are smooth and intimate with no hint of sibilance or graininess. Through the Gen 1 Chord Hugo, switching from my solid state amp to this unit expanded the soundstage abruptly.
The beautiful blanket of warmth was now back, sweeter than saccharine. And while cream goes with coffee and salt goes with stew, the TA-03S definitely “goes” with Hugo. The subtle brightness of the Hugo FPGA DAC balances out the warmth of the TA-03S and in return, the TA-03S replicates the music fed by Hugo with brutal honesty.
Now I found myself playing – and replaying – my library of DSD tracks while trailing off well into the night with this combination. Though the tone is still slightly tilted towards the warmer side of things, and while tubes aren’t the best devices for linear audio reproduction, the TA-03S sounded natural and correct.
THE LAST WORD
Anyone who knows me knows that I am a low level listener. The xDuoo TA-03S has the capability and subtlety to push me to turn the volume knob just a little higher than usual. While the DAC section serves as a good upgrade from your onboard devices, the amp section shines brighter than it should at this price point.
The TA-03S will serve as a very good gateway drug to tube amps for those who want to start from scratch, and will be just as good for those who want to look for an alternative to their solid-state setups. Either way, it is hard to be disappointed with the xDuoo TA-03S. Just watch out for pets or toddlers enchanted with the glowing hot tubes. This is a definite buy if you’re planning to get a more resolving DAC/headamp.
Sources: Acer Aspire V5 573PG, Vivo X21, Tidal Master, Spotify Premium, Telefunken S-500 turntable / DAC: Matrix Mini-i, Chord Hugo V1 / Amp: Lovely Cube Premium / Headphones: Sennheiser HD525, Final Audio Pandora Hope VI
Malaysian price: RM1,200
Malaysian distributor: TechX Malaysia (+6014 2511062)