XDUOO TA-20 PLUS HEADPHONE AMPLIFIER REVIEW

Oscar Stewart reviews the £409 XDUOO TA-20 Plus Headphone Amplifier for HiFi PiG.

XDuoo has been around for several years and is a well-established name in the headphone scene. They make a few amplifiers, DACs, and portable audio products. In recent years they have ramped up their production of DACs, dongles, and headphone amplifiers from OTL to solid state and hybrid designs like this TA-20 Plus. 

My experiences with xDuoo date back to 2014 and they consistently make well-built and great-sounding products for a very reasonable price. This amp comes in at around £409.00 and has a few attractive features for the price – in this review, I will be using the Apos Ray 12AU7 valves that were supplied as an upgrade valve set for this amp. 

BUILD QUALITY AND FEATURES OF THE XDUOO TA-20 PLUS HEADPHONE AMPLIFIER

The TA-20 Plus uses a mostly aluminium chassis with steel surrounding the transformer, there is a cage included that protects the valves from curious fingers – however, I prefer the look of the amp without the cage. It uses 3 valves, a 5Z4P rectifier for added valve tonality, along with a pair of 12AU7 handling the input stage. There is then a full class-A solid state output stage that helps make this amp more suitable for a variety of headphones over an OTL design. The volume is controlled by a digitally controlled analogue chip which means that channel matching is perfect throughout the volume range and there is no imbalance that can sometimes happens at low volume with conventional potentiometers.

The amp is fully balanced from input to output, it features 2 pairs of RCA inputs, a 4.4mm balanced input and a pair of XLR balanced inputs. On the output side of things, you get the usual 6.3mm single-ended output alongside both 4.4mm and 4-pin XLR balanced outputs, there is a single pair of RCA outputs on the back if you wish to use this as a pre-amp. The volume knob also controls the input and there is a nice little VU meter on the front – it’s responsive, works well and looks great in my opinion. The LED volume indicator is subtle and the input LED is not too bright making this a very pleasing amp to use even at night. All the inputs and outputs feel great and the whole amp feels positively solid for its price.

There are warm orange LEDs under the valves to accentuate their glow and these are subtle and well implemented. There is a little bit of hum from the transformer that isn’t audible through the amp stage, but is audible with headphones off – this could be the mains in my home. The valves are socketed and you can easily swap them out for others, this allows you to tune the sound a little, but there is slightly less influence on the sound here compared to a full OTL or SET amplifier due to the solid-state output stage. 

XDuoo chose to use high-quality capacitors in this amplifier, with Panasonic filtering caps, Elna Silmic II’s as input coupling caps and metalized polyester film caps for output coupling – this kind of attention to detail helps when it comes to sound quality. The gain is quite high at +18dB, yet this amp works very well with most full-size headphones and I didn’t notice any background noise. This amp offers a maximum output power of 2600mw @32Ohms (balanced) meaning it can comfortably drive most headphones. 

Apos supplied their Ray 12AU7 new stock valves with the TA-20 Plus as an upgrade to the standard valves, these have a nice tight fit in the sockets and bring a nice little sonic boost to this amplifier – more on that next. 

SOUND QUALITY

Being a hybrid amplifier, the sound of the TA-20 Plus is well controlled with a slight colouring from the valve stage. Out of the box with the stock valves, this amp comes across as well balanced with a realistic tonality and good extension from top to bottom. It’s not hyper-resolving or clean, it carefully treads the line of being balanced with a hint of emotion, it’s pleasing and enjoyable rather than analytical, yet never sounds bloated. This is an amp that pairs well with neutral DACs (like the S.M.S.L D6s I am using) and happily drives a variety of headphones with plenty of power on tap.

Starting off with the Fiio FT3 I found myself listening between 17-25 on the volume display. The bass digs deep when called for and has good impact. This amp doesn’t seem to focus on having the biggest bass or massive slam, instead, it gives an enjoyable bass presentation that’s neither lacking – but nor does it excel in this area. The midrange seems to be the stand-out point of this amplifier with a believable sound and well-judged tonality, great separation, and layering. The treble is slightly relaxed yet still retains an airy nature to it and there is a sense that the edges of transients are softened by a small degree. Once again this isn’t a hugely coloured amp and there is less influence on the sound compared to an OTL valve amp, yet there is still a bit of flavour to the sound that is highly enjoyable with the right pairing – the FT3 being one of those. 

Next up I used the Meze 109 Pro and on came Thursday – Magnets Caught in a Metal Heart, the high hats have great definition being crisp yet not overbearing, the articulate bass line is prominent yet not overdone, ever-present without dominating the sound. Once again, this amp shines in the midrange where Geoff Rickley’s haunting vocals are pitch-perfect and the guitars circle around the edges with excellent placement, there is never any bleed between any part of the mix. Yes, there are cleaner sounding amplifiers for this price, and some excellent all-valves amps too, yet the TA-20 Plus takes the best of both worlds and blends them to great effect. You don’t quite get the full warmth of an OTL amp, or the pure analytical power of a reference-sounding solid-state amp, yet there is a sense of emotion and character to the sound that is ever so enjoyable to listen to whilst retaining a composed and detailed sound. 

One of the great benefits of having a hybrid design like this is that they don’t suffer from high output impedance like OTL amps do, this allows them to sound good with lower impedance headphones like the Meze 109 Pro. 

With an amp like this, pairing does come into play! For example, using a warmer headphone can lead to a slightly dull sound, the Fiio FT5 is one such pairing. This amp has no issues with driving the FT5, but due to the FT5’s slightly safe sound this amp tips them into the “boring” territory and there’s a slight lack of drive and dynamics to their sound. Biffy Clyro – Folding Stars fails to have any impact, everything is there it’s just not got the energy that it deserves, this amp isn’t guaranteed to pair sonically with any headphone but, get it right and it is an excellent sounding amp.

Lastly, I paired the TA-20 Plus with my Beyerdynamic DT880 (600 Ohm) headphones and this is another excellent pairing. This amp brings out a nice level of body to these headphones whilst rounding off the edges of notes making the sound slightly less sharp. This is not a night and day difference, but is noticeable. Red Hot Chili Peppers – I Could Die For sounds excellent with this setup, big and punchy with plenty of detail whilst retaining that slightly smooth valve realism. Audio is a funny one, we can have everything presented in a flat and neutral way yet, introducing valves tends to just make the sound more enjoyable to listen to. It’s one of those oxymorons whereby adding something objectively worse, makes the sound subjectively better. 

This amp sounds great out of the box, but one of the joys of valves is swapping them out, be it for some rare NOS ones or new production stock. Apos Audio provided a matched pair of their Ray 12AU7 valves with this amp and they are worth the investment, in my opinion. The sound opens up with these installed, there is more detail in the treble, the soundstage is bigger and there is better bass body and extension. The stock valves sound fine but, they are a little limited and sound a bit closed in and dull with the Apos Ray 12AU7 valves really bringing this amp up a notch and there is a clear sonic improvement to me. 

QUIBBLES

This amp won’t pair well with every headphone but, that’s often the case with valves.

CONCLUSION

Pair the xDuoo TA20 Plus with the right headphone and it is an incredibly enjoyable amp, combining both the technicalities and power of solid-state with the natural colouration of valves. It’s a combo that works well with a plethora of headphones and the midrange performance is simply stunning with the right setup. 

If you have a good solid-state amp and want something that sounds a little different to complement it, valves are worth considering and this is a great place to start. It gives you the flexibility to roll some valves of your liking without limiting you to using it with high-impedance dynamic headphones only, even if it does pair very well with those kinds of headphones. 

I am giving this five hearts as it sounds excellent with the right cans, but you do need to ensure a good partnership or it can be found wanting. However, at the asking price is would be churlish to mark this product down.

AT A GLANCE

Build Quality And Features: 

Solid build quality and it looks great

Good array of inputs and outputs

Sound Quality:

Well-balanced and controlled

Slight valve warmth and natural tonality, especially in the midrange

Value For Money:

Great value, combining the natural qualities of valves with the technicalities of solid-state amps

We Loved:

The sound is highly enjoyable with the right pairing

It looks lovely

Valve rolling capabilities

We Didn’t Love So Much:

Not the most resolving amplifier

The sonic colouration won’t pair well with all headphones

Elevator Pitch Review: If you are looking to add a valve amp to your collection but are worried about the compatibility between your headphones and OTL amps then a hybrid like this could well be the best option of you. Its ability to pair with low-impedance headphones whilst retaining some of the magic that valves bring to the listening experience makes this amp extremely versatile. While the stock valves sound ok, it is well worth investing in some alertnative valves to get a taste of their different sound signatures and bring this amp up a level. 

Price: Amp £409.00 / Apos valves $180.00

Oscar Stewart

SUPPLIED BY APOS AUDIO

SUPPLIED SPECIFICATION

• Power Source: AC 110V(100-120V)/220V(220-240V)
• Gain: +18dB
• 6.35mm Headphone Output Parameters:

Output Power: 2000mW(32Ω load)

Frequency Response:10Hz ~ 80kHz(+0.5dB)

Crosstalk:74dB

SNR:113dB

THD+N:0.05%

• 4.4mm/XLR balanced Headphone Output Parameters:

Output Power: 2600mW(32Ω load)

Frequency Response:10Hz ~ 80kHz(+0.5dB)

Crosstalk:95dB

SNR:113 dB

THD+N:0.05%

• Suitable Headphone Impedance: 16Ω -600Ω
• Size: 26×17.7×15.3cm
• Weight: 4.3KG