Woo Audio TUBE mini Balanced Headphone Amplifier and DAC - Red

A Tube Amplifier That Fits in a Pocket

The Woo Audio TUBE mini is what it sounds like: a vacuum tube headphone amplifier and converter small enough to carry. It is 107mm long and weighs 49 grams, and there are two real tubes inside it, one for each channel, visible through a window in the front.

Woo has been building full-size tube amplifiers in New York since 2004, and the TUBE mini is designed and assembled there too. It arrived in July 2023 as the company's answer to a question most people assumed had no answer.

A MOSFET Does the Heavy Work

Each tube takes one channel, paired with MOSFET output parts in a balanced layout. That is why a thing this size puts out as much as 1 watt into 8 ohms. It will drive full-size headphones that normally want a desk amp behind them.

Two Outputs, and One Rule About Them

The 4.4mm Pentaconn socket is the balanced one. The 3.5mm is not. An ESS Sabre chip does the converting, taking PCM up to 24-bit and 384kHz, and DSD up to DSD256. Response runs from 20Hz to 46kHz, and signal-to-noise sits at 100dB.

No Driver, No Battery, No Fuss

It takes its power from the USB cable, so there is no battery to charge and no driver to install. It works with Windows 10 and 11, with every version of macOS, and with Apple and certified Android devices, over USB, USB-C or Thunderbolt 3.

The case is anodized aluminum, in black, silver, blue or red, and the warranty runs three years. On something you carry in a bag each day, both of those count for more than they would on a box that never moves off its shelf.

What Reviewers Are Saying

Major HiFi found the TUBE mini pulls off "the very impressive feat of being a tube amp that's as affordable as it is portable." Its verdict: "Better still: it's not a gimmick, as it actually sounds fantastic."

The review credited Woo with widening the audience for tubes. "Props to Woo Audio for bringing high quality tubes down to a price point that the mid-fi crowd can afford, and to a size that the HiFi crowd can take with them."

Who Is This Headphone Amp Best For?

• You want to hear tubes without owning furniture — two real valves, one per channel, in something that goes in a coat pocket rather than on a shelf.
• Your headphones are hard to drive — a maximum of 1 watt means full-size pairs that normally need a desktop amplifier will play properly away from the desk.
• You move between devices — bus power and no drivers mean it works on a phone, a tablet, a Mac and a PC without setup on any of them.
• You keep your gear a long time — an anodized aluminum chassis, assembly in New York, and a three-year warranty on a portable device.
• The 4.4mm output is balanced, and only balanced — Woo warns never to connect an unbalanced cable or adapter to it, as that can damage the amplifier. Use the 3.5mm jack instead, or fit a proper balanced cable from our headphone cables.

How Does It Connect to Your System?

Connect it to a phone, tablet, laptop or desktop over USB, USB-C or Thunderbolt 3. There is no driver to install and no battery to charge, because the amplifier runs on power from the same cable that carries the music.

Headphones with a balanced cable go into the 4.4mm Pentaconn socket. Anything with an ordinary unbalanced cable uses the 3.5mm output. Never adapt one to the other, whichever direction you are tempted to try it.

Pairs Well With

Building your system? Here are some great companions:

• Headphones: Full-size pairs are what this was built for — see our Headphones.
• Headphone Cables: A 4.4mm balanced cable unlocks the balanced output — browse our Headphone Cables.
• Desktop Amplifier: For when you are at a desk instead — see our Headphone Amplifiers.
• DAC: If the system grows around it — browse our DACs.

Frequently Asked Questions

How much power does it deliver?

A maximum of 1 watt into 8 ohms, which is enough for most full-size headphones.

Does it need a battery or a charger?

Neither. It is USB bus-powered, drawing what it needs from the device it is plugged into.

What resolution does it handle?

PCM up to 24-bit and 384kHz, and DSD up to DSD256, through its ESS Sabre converter.

Can I use an adapter on the 4.4mm output?

Woo advises against it. The balanced output must only see a balanced cable, and an adapter can damage the amplifier. Use the 3.5mm jack for unbalanced headphones.

Which devices does it work with?

Windows 10 and 11, all versions of macOS, Apple iOS and certified Android devices, over USB, USB-C or Thunderbolt 3.

What warranty does it carry?

Three years, limited, on a chassis designed and assembled in New York.

See It in Action

The Headphone Show puts a tube amp in a pocket to the test:

And Joshua Valour finds out how much it can drive:

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Learn More

Want to learn more about headphone amplifiers, tube audio, or portable DACs? Visit our Learning Center for guides, tips, and expert advice.