xDuoo TA-20 Plus

A gorgeous hybrid tube headphone amp that provides wants you to stare at it for hours

The TA-20 Plus is xDuoo’s update to their popular TA-20 desktop tube amplifier. Despite the “tube amp” billing it is really a hybrid: a 12AU7 tube voltage stage feeds a Class A transistor buffer output, with a fully balanced signal path from input to output. The headline additions over the original are a 5Z4P rectifier tube, higher balanced output power, a true preamp output, and a mechanical VU meter on the front.

At $499 it sits in the mid-tier of desktop tube amps, aimed at people who want some tube character without giving up the power to drive demanding planars and high-impedance dynamics. It is a pure analogue amplifier — there is no DAC inside — so it expects a separate source feeding its RCA, XLR or 4.4mm inputs.

I have used the TA-20 Plus on my desk as the amplifier in a separates chain, fed from an external DAC. The standout impression is that it manages to sound like a tube amp — a little warmth, a slightly relaxed presentation — while still having the muscle to drive headphones that usually need a serious desktop amp. But before the unboxing, it is worth saying who I think this amplifier is really for.

Unboxing and Packaging

The TA-20 Plus is a heavy unit at 4.3kg, and the packaging reflects that — a sturdy box with thick foam cradling the amp and its tubes:

The documentation and manuals cover setup and the tube installation:

Removing the TA-20 plus from this protective cover, you finally see it in all its retro tube glory:

There is foam cut out to protect the tubes in transit: |

And finally, in the box you get the cables:

Design and Build Quality

This is a substantial, traditional-looking desktop amp. The front panel is clean — a large volume knob and input/gain controls — and the mechanical VU meter is the visual centrepiece:

The VU meter is not just decoration — it bounces with the music and is genuinely part of the appeal of a tube amp like this. Here it is in motion:

Features and Connectivity

The rear panel is where the TA-20 Plus shows its flexibility. Inputs include two RCA pairs, a balanced XLR pair and a 4.4mm balanced input, and there is an RCA line-out that acts as a volume-attenuated preamp output — a genuine addition over the original TA-20, whose RCA out was a fixed passthrough:

That preamp function makes it more useful in a wider system — you can run it as the hub of a desktop setup and feed active speakers or a power amp from the pre-out. The input selection lets you compare sources easily:

The signal path is fully balanced from input to output. The tube stage uses a matched pair of 12AU7s with a 5Z4P rectifier, feeding a Class A transistor buffer — a hybrid topology rather than a pure tube (OTL) design, which is what gives it the power to drive harder loads. xDuoo’s own architecture diagram lays this out:

The tubes are rollable, so the dual 12AU7s can be swapped for other compatible types if you want to tune the character — a common reason people choose a tube amp like this.

Tubes, solid state, and where the TA-20 Plus fits

My honest view is that the TA-20 Plus is a fantastic audiophile bargain — specifically for people who like the idea of tubes and are getting into the hobby. To explain why, it helps to lay out the two ends of the spectrum it sits between.

Solid-state amplifiers have fewer issues with impedance matching, and they mostly deliver the music exactly as the artist intended — a clean, honest sound. Their only real sin is that they tend to look a bit boring. At the other end, true OTL tube amplifiers are more expensive and promise — though not all of them deliver — a sweet, harmonically rich sound, and of course they look fantastic with their warm, glowing tubes. My genuine advice is that most audiophiles should stay on the solid-state side for a good while, and get to know their music with as clean a sound as possible before they start adding flavour to it.

But once you have done that and you feel the pull to dip a toe in the tube water, the TA-20 Plus is one of those products that makes perfect pragmatic sense. You are not paying a lot, and you get maybe 90% of the tube experience. Crucially, xDuoo’s tube-buffer approach here is exactly the right amount of intervention: it changes the sound in subtle ways — just enough to be tube-flavoured — while still mostly delivering the “correct” sound, albeit with measurably worse numbers than a clean solid-state amp. That sprinkling of tube character, in an amplifier that also looks lovely and has real power behind it, is enough to tell most people whether they actually want to disappear down the tube rabbit hole.

And here is the part I keep coming back to: I suspect most people in this hobby want precisely what the TA-20 Plus delivers, and that for a lot of them this is the perfect place to stop. It sounds great, it looks great, and honestly, that combination is most of what an audiophile should be looking for in a device.

Sound and Synergy

I used the TA-20 Plus as the amplifier in a separates chain with an external DAC, listening through both balanced and single-ended outputs. The character is mild-tube rather than thick-tube: there is a touch of warmth and a slightly rounded, easygoing presentation, but it does not smear detail or roll off the treble in the way a heavier OTL design might.

The most useful trait is its drive. The balanced output is rated at 2600mW into 32Ω, and with that on tap it had no trouble bringing demanding planars and higher-impedance dynamics up to volume with headroom to spare — this is not a polite low-power tube box. On “Angel” by Massive Attack the low end stayed controlled and weighty even at higher levels, with the tube stage adding a little body rather than softening the grip.

Through the midrange the tube character is most audible: voices gain a small amount of warmth and note weight, which suits acoustic and vocal material. On “Fast Car” by Tracy Chapman the vocal has a pleasant, slightly fuller presentation without losing clarity. The treble stays clean and extended thanks to the transistor buffer, so cymbals keep their energy rather than being dulled. Tube rolling the 12AU7s is the obvious way to nudge the balance further toward or away from warmth if you want to fine-tune the pairing.

Comparison: against a simpler tube amp

It is worth seeing the TA-20 Plus next to some other tube amplifiers:

Here it is alongside a smaller, simpler tube buffer from Fosi Audio:

The contrast sums up why I like the xDuoo. The little Fosi exposes a pair of tubes and adds a faint glow, but next to the TA-20 Plus it feels like a token gesture: the tube effect is slight, the build is plain, and it is just not that impressive. The TA-20 Plus, by comparison, delivers what I would call the full retro experience — the substantial caged-tube chassis you want to stare at, genuine power behind the outputs, and a tube-buffer judged just right. If you are dipping a toe into tubes, that is the difference between a device that merely gestures at the idea and one that actually delivers it.

Specifications

A note on the figures: xDuoo publish power into 32Ω only, so I have not listed 300Ω or 600Ω power numbers. The TA-20 Plus has no USB input and no built-in DAC — it is an analogue amplifier that needs a separate source.

Rating Explanation

The Pragmatic Rating of 4 reflects a tube amp that delivers the experience people want from the category — visible tubes, a bouncing VU meter, a little warmth — without the usual compromise of weak output. The fully balanced path, the trio of headphone outputs, the added preamp function and the rollable 12AU7s make it genuinely flexible, and the build quality matches the price.

The limitations are worth being clear about. There is no DAC, so you need a separate source, which adds to the real cost of a system. The tube character is mild rather than dramatic, so listeners specifically chasing a thick, syrupy tube sound may find it more neutral than expected — though that is arguably the right call for an amp meant to drive a range of headphones. And at $499 it is a considered purchase rather than an impulse buy.

This one is for the desktop listener who wants a balanced, good-looking tube amplifier with enough power for demanding headphones, already has a DAC they are happy with, and likes the idea of tube rolling to tune the sound.

Conclusion

The TA-20 Plus is a sensible, well-built update to a popular tube amp. The additions that matter — the 5Z4P rectifier, the higher balanced power, the preamp output and the VU meter — all push it toward being a more capable and more flexible centrepiece for a desktop system, while keeping the tube character that draws people to this kind of amp in the first place.

If you want an all-in-one with a built-in DAC this is not it, and if you want an extreme tube flavour you may want something more coloured. But as a balanced hybrid amp that looks the part and has the power to drive almost anything you put in front of it, the TA-20 Plus makes a strong case at $499.