Woo Audio WA7 Fireflies Tube Headphone Amplifier with DAC

A Tube DAC/Amp That's Now a True One-Box System

The Woo Audio WA7 Fireflies Generation 3 is a tube headphone amplifier and DAC in one compact glass-topped enclosure. Two 5963/12AU7 tubes do the amplifying. They run in a self-biasing circuit, seated in PTFE sockets. Woo chose those sockets so you can swap the tubes yourself, or upgrade them later.

This third generation adds a built-in linear power supply, replacing the external supply earlier WA7 models relied on. That turns the WA7 into a true one-box unit. There is nothing else to find room for on the desk.

Generation 3 also adds preamp outputs. The WA7 can now drive powered speakers directly, not just headphones. The case is anodized aluminum, in midnight black or silver, and the tubes show through a glass top.

That glass top isn't just a design flourish. It keeps the tubes on show. It also shields them from dust, and from knocks on a crowded desk. Woo has used this look across the WA7 line since the first model, and this one carries it forward.

An ESS Sabre DAC, Now With Speaker Outputs

An ESS Sabre DAC chip handles digital decoding up to 24-bit/384kHz PCM and DSD256 at 11.2MHz. Frequency response spans 10Hz to 46kHz within -3dB. Signal-to-noise ratio is rated at 100dB.

The balanced 4.4mm Pentaconn headphone output delivers over 1.5 watts per channel into 4 ohms. A 6.3mm unbalanced jack sits alongside it for headphones without a balanced cable. Both outputs draw on the same tube circuit.

New preamp outputs round out the back panel: a balanced 4.4mm output at -3.4V, and an unbalanced 3.5mm output at -1.7V. Either one can feed a power amplifier or a pair of active speakers.

Digital comes in on one high-retention USB socket. An RCA input takes other line-level sources. The linear supply runs on 115 to 230 volts. It measures 5.25 by 4.8 by 6 inches with the glass top on, and weighs 8.5 pounds.

Who Is This Amplifier Best For?

• Listeners who want genuine tube sound without extra boxes. A built-in linear power supply means no external brick cluttering your desk.
• Anyone who wants a headphone amp that can also run speakers. New balanced and unbalanced preamp outputs let the WA7 feed powered speakers or a power amplifier directly.
• Owners of headphones with a balanced cable. The 4.4mm Pentaconn output delivers over 1.5 watts per channel into 4 ohms, so power-hungry planars stop sounding flat.
• Listeners who value upgradeable tubes. PTFE sockets keep the 5963/12AU7 tubes easy to swap as they age or as your taste changes.
• The desk is where you listen — an internal power supply and a glass-topped tube stage make it a fixture, not something you carry. See our headphones.

How Does It Connect to Your System?

Connect a computer to the USB input, or run a cable from another source into the RCA analog input. Plug headphones into the 4.4mm balanced or 6.3mm unbalanced jack, whichever matches your cable.

To use the WA7 as a preamp, run its balanced or unbalanced pre-out into a power amplifier or a pair of active speakers. Give the tubes a few minutes to warm up before critical listening.

Pairs Well With

Building your system? Here are some great companions for the Woo Audio WA7 Fireflies Generation 3:

• Headphones with a 4.4mm balanced or 6.3mm unbalanced cable
• Powered speakers to build a compact desktop system via its preamp outputs
• USB cables to connect a computer or digital source
• Interconnects: A clean run onward — see our Interconnect Cables.

Frequently Asked Questions

How is Generation 3 different from earlier WA7 models?

Generation 3 adds a built-in linear power supply, so it no longer needs an external supply. It also adds balanced and unbalanced preamp outputs, letting it drive speakers as well as headphones.

Can I use the WA7 as a preamplifier for speakers?

Yes. Its balanced 4.4mm or unbalanced 3.5mm pre-out can feed a power amplifier or a pair of active speakers directly, alongside its headphone outputs.

Are the tubes replaceable?

Yes. The 5963/12AU7 tubes sit in PTFE sockets designed for easy swapping, so you can replace them as they age or roll in different tubes to taste.

Do I still need an external power supply?

That's the main change in this generation. A linear supply built into the chassis replaces the external unit earlier WA7 models required, so setup is just a power cord and your source and headphone cables.

What's the warranty?

Woo Audio covers the WA7 Fireflies Generation 3 with a three-year limited warranty.

See It in Action

Watch this product-focused video:

Woo Audio examines this model:

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Learn More

Want to learn more about tube versus solid-state headphone amps, matching an amp to your headphones, or getting the most from your desktop setup? Visit our Learning Center for guides, tips, and expert advice.