Woo Audio WA22 Balanced Transformer Headphone Amplifier - Generation 2 - Black

All Tube, Fully Balanced, No Shortcuts

Some headphone amplifiers use tubes for flavor and transistors for the heavy lifting. The Woo Audio WA22 takes the harder road: an all-tube, fully balanced, Class-A design with no transistors anywhere in the signal path. Now in its second generation, the WA22 adds improved sound and a true preamp function to a design Woo Audio has refined since 2009.

Two 6SN7 driver tubes, two 6080 power tubes, and a 5U4G rectifier handle everything, delivering up to 1.5 watts per channel into 32 ohms. That's real power for planar and other hard-to-drive headphones, and a switchable high/low impedance setting matches the amp to anything from 8 to 600 ohms. Frequency response runs 8Hz to 50kHz (-3dB), with a signal-to-noise ratio of 92dB.

Because the outputs are transformer-coupled, your headphones stay isolated from the tubes' DC voltage, and the amp presents a consistent, controlled drive across that whole impedance range.

Hand-Built in Brooklyn, Point to Point

Every WA22 is assembled in Brooklyn, New York, wired point to point by hand rather than on a circuit board. An ALPS balanced volume control handles level, and the design is self-biasing, so you can swap tubes without measurements or adjustments. Tube rolling, trying different 6SN7, 6080-family, and rectifier tubes to fine-tune the sound, is a big part of what owners love about this amp.

The second generation also turns the WA22 into a genuine control center: balanced XLR preamp outputs (under 50 ohms) let it drive a power amp or powered speakers, so one volume knob can run both your headphone and speaker systems.

The chassis is anodized aluminum, available in black or silver, measuring 12.5" wide, 12" deep, and 8.5" tall with tubes, at a substantial 26 pounds.

Who Is This Amplifier Best For?

• You own demanding, high-end headphones — 1.5 watts per channel and an 8-600 ohm range drive hard loads that leave smaller amps strained.
• You want a true balanced setup — balanced XLR input, dual 3-pin and 4-pin XLR headphone outputs, and a fully balanced circuit from end to end.
• You want tubes without the maintenance headaches — the self-biasing design means tube swaps need no adjustment or test gear.
• You want one volume control for headphones and speakers — the balanced preamp output runs a power amp or powered monitors.
• If you mostly listen to sensitive IEMs or want a compact desktop amp, the WA22's size and power are more than you need — a smaller solid-state or hybrid amp fits better.

How Does It Connect to Your System?

Connect a source two ways: balanced XLR from a DAC or other balanced component, or standard RCA, which the WA22's phase splitter converts for its balanced circuit. Headphones connect through a 4-pin XLR, dual 3-pin XLRs, or a 1/4" jack, and the high/low impedance switch matches the output to your specific headphones.

To use it as a preamplifier, run the balanced XLR outputs to a power amplifier or powered speakers. Give the tubes a few minutes to warm up, and leave room above the amp for ventilation, as a Class-A tube design runs warm by nature.

Pairs Well With

Building your system? Here are some great companions for the WA22:

• Headphones: This amp deserves a reference-level headphone to match — see our Headphones.
• DAC: A balanced DAC feeding the XLR input completes a fully balanced chain — see our Digital-to-Analog Converters.
• Cables: Quality balanced interconnects matter in a system at this level — see our Interconnect Cables.
• Audio Rack: Give this 26-pound amp a stable, ventilated home — see our Audio Racks.

Frequently Asked Questions

What's different about the second generation?

Woo Audio updated the WA22 in 2018 with improved sonic performance and added a balanced preamplifier output, so it can control a speaker system as well as headphones.

What tubes does it use?

Two 6SN7 driver tubes, two 6080 power tubes, and one 5U4G rectifier. The self-biasing design makes tube rolling simple.

Can it drive hard-to-drive headphones?

Yes. It delivers up to 1.5 watts per channel into 32 ohms and handles headphones from 8 to 600 ohms, with a high/low impedance switch for the best match.

Do I need a balanced source to use it?

No. Alongside the balanced XLR input, there's a standard RCA input, and an internal phase splitter converts that signal for the balanced circuit.

Can I use it as a preamp?

Yes. Balanced XLR preamp outputs let the WA22 drive a power amplifier or powered speakers.

What's the warranty?

Woo Audio covers the WA22 with a 3-year limited warranty.

See It in Action

Ryan Ho shares his listening impressions of the second-generation WA22:

The Source AV Design Group walks through the WA22 as both headphone amp and preamplifier:

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Learn More

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