Headphone AmpOverreview

xDuoo TA-26S

A $319 tube amp built like a tank for 300-ohm Sennheisers — warm to most ears, neutral to some, and only as quiet as your wall socket.

71/ 100
Review score
24 sourcesUpdated
$319Typical US price

Score aggregates reviewer opinions across topics.

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xDuoo TA-26S

The short version

What to know.

A $319 OTL tube headphone amp and preamp. Sources agree on its job: it drives 300- and 600-ohm dynamic headphones — the Sennheiser HD 600/650/800 family and high-impedance Beyerdynamics above all — with plenty of headroom, and it is a poor match for low-impedance headphones, planars and IEMs because of its roughly 90-ohm output impedance. They also agree it is simple to the point of spartan — one RCA input, a volume-controlled RCA preamp output, no gain switch, and a 4.4mm socket that is wired single-ended — and that it is heavy, solid and very good value. The splits: about 60% of the weighted opinion hears warm, smooth tube colour, while the rest hears a surprisingly neutral amp. Noise divides by setup — quiet in a clean system, but mains hum, ground-loop buzz, computer and modem interference and a buzzing transformer turn up often. A minority of units arrive with a dead tube or weak output. Most owners say the stock tubes are the first thing to replace.

About this product

The 2023 revision of the TA-26: essentially the same OTL tube circuit, with a 4.4mm socket added and the power switch moved to the back. The 4.4mm output is single-ended, not a balanced amp.

xDuoo's TA-26S is a two-tube, output-transformerless headphone amp in a heavy aluminium box: a 6N8P driver and a 6N5P power tube, the same 6SN7/6AS7 recipe as the long-running Darkvoice 336SE and close kin to the Bottlehead Crack, sold ready-built for $319. It is the 2023 revision of the 2021 TA-26 — the circuit is unchanged, but a 4.4mm socket took the front power switch's place.

Like every OTL amp, it has a high output impedance, so it is made for 300- and 600-ohm dynamic headphones and very little else. For owners of Sennheiser's HD 600 family it became one of the default first tube amps, and one of the easiest to roll tubes in. The arguments are about how much tube colour it really adds, and about hum.

A good fit for

  • Owners of Sennheiser HD 600/650/6XX/800 or 250–600-ohm Beyerdynamics who want a first tube amp
  • Tube rollers — 6SN7 and 6AS7/6080 tubes are plentiful and cheap
  • Anyone wanting a ready-built alternative to a Bottlehead Crack kit

Think twice if

  • Your headphones are below about 100–150 ohms, planar, or IEMs
  • You want one amp for everything, balanced output or a gain switch
  • Your desk shares power and grounding with a gaming PC or router and you can't tolerate troubleshooting hum
  • You want a front power switch

The reviewer consensus

Agreement &
disagreement.

4 / 7topics divide opinion
featuresvalueergonomicspowernoisetransparencybuild
2 Strong agreement1 Mostly agree4 Divided opinions

Common ground4

  • Built for 300–600-ohm dynamic headphones — the HD 600/650/800 family above all — and drives them with plenty of headroom
  • A poor match for low-impedance headphones, planars and sensitive IEMs
  • Spartan I/O: one RCA input, a preamp output, no gain switch, and a 4.4mm socket that is single-ended

Points of contention4

  • Tube colour: a warm, smooth, classic tube sound vs a surprisingly neutral one — largely down to the headphone and the tubes
  • Noise: quiet in a clean setup vs mains hum, ground-loop buzz, PC and modem interference and transformer hum
  • Build: a solid, heavy chassis vs a minority of units with dead tubes, a dead channel or a buzzing transformer

A closer listen.

7 topics · 4 divided
Left: criticalRight: positiveTighter lines: more agreement

Power

Leans positiveDivided opinions
Reviewer sentiment9 supporting sources
CriticalNeutralPositive

Band: opinion spread · Dot: weighted average

Sources split, though mostly over individual units. Most reviewers find ample drive for the headphones it is built for: an HD 650 reaches very loud levels with little rotation, 600-ohm Beyerdynamics are comfortable, and one owner calls it a nuclear power plant. The dissent is unit-level: one TA-26S owner measured only 50 V on the high-voltage rail, and an Amazon owner's unit had so little output it sounded like a laptop jack. Everyone agrees on the limit: below about 100–150 ohms, and with low-impedance planars, it runs short and distorts.

Measured

Passion for Sound measured the output impedance of the same-circuit TA-26 at roughly 90 ohms. Audiofool measured a 169 V B+ rail on a TA-26; a Head-Fi owner measured about 50 V on his TA-26S's high-voltage rail. xDuoo rates 500 mW into 300 or 600 ohms.

vs. listeners — The 90-ohm output impedance explains the agreed limit — below roughly 100–150 ohms the amp loses efficiency and control. The rail readings suggest the weak-output reports are unit variation rather than the design.

Where it splits
plenty of drive for 300–600-ohm dynamics77%

“The TA-26 was barely breaking a sweat, requiring minimal volume to drive the HD650 to ear splitting volume.”

Ryan Soo · Everyday Listening
some units come up weak23%

“The HV rail voltage is surprisingly low, only 50V.”

AudioCats · Head-Fi
Link to this topic

The hardware

Specifications.

Checked

Design

Form factor
Desktop
Amplifier
Tube · Pure-tube signal path: 6N8P preamp tube and 6N5P buffer tube

Output

Signal-to-noise
110 dB

Connection

Analog inputs
RCA
Line outputs
RCAvariable (preamp)
Preamp output
Yes
Power
Mains (internal PSU)

Physical

Weight
3,900 g

xDuoo rates output at 500 mW into 300 or 600 ohms and suits it to 60–600-ohm headphones. Manufacturer-published figures, not measurements · from xduoo.net, shenzhenaudio.com.

Follow the evidence

Sources 24

1–6 of 24 sources

Read with context

Limitations & method.

As of

What to keep in mind 5

  1. A read of where the reviews land as of September 2026. Most of the in-depth reviews cover the original TA-26 (2021); the TA-26S uses the same circuit, and reviewers who compared them heard no difference.

  2. As of September 2026 the TA-26S is hard to find new: several major retailers list it as sold out, and some owners report being told it is discontinued.

Where to buy Product & retailer links