For my sound impressions, I am feeding the XDuoo TA-20 from the Topping DX7 Pro XLR output, set to -00.0db, which is full volume.
The TA-20 is beautifully clear and clean, with superb airiness and detail. It has a touch of warmth to it, but not as much as you might expect, given the tubes. Compared to the XLR Phone Out on the Topping, the XDuoo possesses only a hint of lushness, conveying a smoother, more euphonic tone. But only very slightly. They honestly don’t sound all that different. The DX7Pro has more bite, revealing micro-details a little better. But the TA-20 is what you might call musical, issuing a silkier and more organic voice.
When I switch between the TA-20 and the Cayin iHA-6, in some ways there’s bigger change, and in others, it’s about the same. The iHA-6 is utterly colorless, so the tone is identical to that of the Topping DAC. All the tonal changes I mentioned in the paragraph above are true here, as well. And yet, the Cayin amp makes a significant difference. It is around twice the price of the XDuoo and possesses significantly more power. Notes strike with more authority, and the bass is both tighter and harder-hitting, displaying more texture. I couldn’t really hear a change in soundstage between Topping and XDuoo, but Cayin does sound a little wider and deeper.
The HIFIMAN Sundara ($349, Review HERE) is what I used for my sound impressions, as it is fabulously neutral and the best I own for telling the naked truth of a source. Sundara picks up on the tube coloration, revealing the smoothness and harmonic overtones. Because of its neutrality, there is a tendency for these headphones to lean dry, and the TA-20 helps wet things up a bit. Indeed, Sundara is a more enjoyable listen from an amp like this.
Now, my favorite headphones are the Audeze LCD-3 Fazor ($2,000), and they don’t need help with things like lushness and warmth. These qualities are inherent in them. Unlike some warm cans, however, the LCD-3 never lacks in clarity and airiness, so the XDuoo’s vacuum tubes don’t push the tuning too far. Thanks to the TA-20’s impressive transparency, all it seems to do is bolster the LCD-3’s strengths, without causing any harm. Oh yes, I’ve got to say, this is a sweet pairing.
Probably my least favorite headphones, but ones I have great respect for, are the Sennheiser HD800 ($1,299). I like them a lot, but I don’t enjoy them much, if that is even possible. When I listen to the HD800, I am in awe of the soundstage and detail, but anything other than classical or acoustic become grating after only a short session. The XDuoo helps a little, but it would have to be seriously colored to make a big enough difference, for my tastes. Still, I found myself relaxing to Pink Floyd’s Division Bells, thanks to the band’s ultra smooth style.
For those looking for something simple and light to stick in your ears, but still gives you that headphone-like sound, I recommend the Venture Electronics Zen 2.0 ($144, Review HERE). It’s a 300Ω earphone, with the note weight, soundstage, and authority of a full-size headphone. Its voice is warm but textured, with richness and detail walking hand-in-hand. Zen has so much bite to it, I find a smoother source really helps. The Zen’s dynamic driver vibes very well indeed with the TA-20 tubes.
F**k! It’s been many months since last I listened to the Sennheiser HD6xx ($199), and I’ve never before heard it from a tube amp. These things are made for tubes! I wish I had a balanced cable, but I never got around to making or buying one, since these cans were never a priority. Fortunately, this gives us the opportunity to test the XDuoo’s 1/4” single-ended output. Listening to my DSD64 copy of Dark Side of the Moon, the HD6xx is nice and loud at only 70/100 on the volume pot. And how does it sound? Well, it’s the very definition of lush. So rich, so smooth. It’s terribly addictive.
Another important test for any amp is what sort of noise/hiss do sensitive IEMs pick up? For this, I chose the Noble Audio Encore ($1,890, Review HERE). I classify it as super sensitive, with impedance in the single digits. If there’s hiss, Encore knows about it. And indeed, there is some low-level background noise from the XDuoo. However, it’s not bad. It’s difficult to hear when the volume is up. Still, it is there. IF you are concerned about it, there is always the iFi iEMatch, to quiet things up.
There is also audible background noise on the Meze 99 Classics ($309, Review HERE). Of course, the 99C is made for mobile devices, so they are unusually sensitive. The noise is low-level, like with Encore, and does little to distract from how good Meze sounds with a tube amp of this quality. The 99 Classics are famous for how beautifully they vibe with warm gear. Vocals get smoother and fuller, yet retain all the detail afforded by the slight treble emphasis.
ZMF Headphones Atticus ($1,099, Review HERE) is a set of cans that LOVES tubes! These headphones are expertly balanced to deliver warmth and sparkle, mid-bass impact and vitality in the presence region. Good lord do they respond to the power and musicality of the TA-20. Together, they become one of the best-sounding systems I’ve ever heard. Between the soundstage and resolution, the treble twinkle, and the depth and warmth, it tickles my bias like few things can. I want to throw everything else away and just listen to this, forever.