Woo Audio WA5 LE Headphone Amplifier - Silver

The Legendary 300B, Devoted to Headphones

Ask a tube devotee to name the greatest power tube ever made. The answer is usually the 300B. This directly heated triode has been prized since the 1930s. People buy it for a rich midrange and a natural way with voices. The Woo Audio WA5-LE is built around a pair of them.

It is a single-ended triode, Class-A, all-tube design, made for headphones alone. Nothing in it is asked to drive a speaker, and the output stage is the better for it.

Two 6SN7 driver tubes feed the 300Bs. Dual 5U4G rectifiers handle the power supply. The result is up to 8 watts, a huge reserve for a headphone amp, from both the 4-pin XLR and the quarter-inch outputs. High and low switches cover power, impedance and level. They match that reserve to anything from a sensitive in-ear to a 600-ohm dynamic.

Frequency response runs 10Hz to 60kHz (-2dB). Signal-to-noise ratio is 95dB or better, and distortion is 0.08% or less. Those numbers hold across the whole output range, not just at a convenient level.

Two Chassis, One Purpose

The WA5-LE is a two-piece design. The power supply lives in its own chassis, which keeps transformer noise away from the signal circuit. Each chassis measures 9 inches wide by 17 deep. Together they weigh over 70 pounds.

Like every Woo Audio amplifier, it's handcrafted in New York with point-to-point wiring rather than circuit boards, gold-plated inputs, and an ALPS volume control. The design is self-biasing, so swapping tubes needs no adjustments.

The 300B is one of the most rewarding tubes to roll, with options from cheap current production to sought-after vintage glass. It takes global voltage from 100 to 240 volts, and the anodized aluminum chassis comes in black or silver.

What Reviewers Are Saying

Dubstep Girl of Headphone Guru, reviewing the second-generation WA5-LE on April 12, 2016, wrote that "the amplifier is transparent and has tons of spatial details with an ethereal presence and air around every note," adding that it's "dynamic and focused across the entire frequency range" with "significantly more energy behind every note" than the version it replaced, and "tight and punchy" bass.

Who Is This Amplifier Best For?

• You want to hear the legendary 300B tube — this is one of the most accessible ways to own a true 300B amplifier from a major builder.
• You own hard-to-drive headphones — 8 watts of Class-A power handles demanding planars and 600-ohm dynamics with ease.
• You want one amp for every headphone you own — selectable power, impedance, and level settings match it to sensitive and demanding loads alike.
• You plan to explore tube rolling — the 300B, 6SN7, and rectifier families offer decades of options, and the self-biasing design makes swaps simple.
• Desk space is tight, or you want something you just switch on — this is a 70-pound amplifier in two chassis, and a single-box design from our headphone amplifiers fits a small room far more easily.

How Does It Connect to Your System?

Connect up to three sources: one balanced XLR pair and two RCA pairs. Headphones plug into the 4-pin XLR or 1/4" jack, and the three high/low switches let you dial in the right power, impedance, and level for your specific pair.

Plan your rack around the two-chassis layout, each piece is 9" wide and 17" deep, and give the tubes generous ventilation. Let them warm up for a few minutes before serious listening.

Pairs Well With

Building your system? Here are some great companions for the WA5-LE:

• Headphones: An amp this capable deserves a reference headphone — see our Headphones.
• DAC: A balanced source makes the most of the XLR input — see our Digital-to-Analog Converters.
• Cables: Quality interconnects matter at this level — see our Interconnect Cables.
• Audio Rack: Two chassis need a sturdy, ventilated home — see our Audio Racks.

Frequently Asked Questions

What makes the 300B tube special?

It's a directly heated triode dating to the 1930s, prized for a rich, natural midrange. It remains one of the most sought-after power tubes in high-end audio.

How powerful is it?

Up to 8 watts, from both the 4-pin XLR and 1/4" outputs, with selectable high/low power, impedance, and level settings for headphones from 8 to 600 ohms.

What tubes does it use?

Two 6SN7 drivers, two 300B power tubes, and two 5U4G rectifiers. The self-biasing design makes tube rolling simple.

Why two chassis?

The power supply lives in its own enclosure, keeping transformer noise physically separated from the audio circuit.

Can it drive speakers?

Headphones are its job. Its sibling, the WA5, adds speaker outputs.

What's the warranty?

Woo Audio covers the WA5-LE with a 3-year limited warranty.

See It in Action

Woo Audio walks through the WA5 platform this amplifier is built on (the WA5-LE is the headphone-only version of the amp shown):

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Learn More

Want to learn more about headphone amplifiers, tube audio, or building a reference headphone system? Visit our Learning Center for guides, tips, and expert advice.