The iron-and-tube ethos

Woo Audio's 20th Anniversary WA24 headphone amplifier comes ina distinctive, low-slung chassis that welcomes the eye with gentle angular volumes and bright, frosty-surfaced, copper-toned controls.

- BY HERB REICHERT

In the always-crowded Woo-JPS Labs-Stax room at CanJam 2025,¹ Woo's new $12,999 flagship caught everybody's eye, sitting on a table next to its similar-looking stablemate, the $8999 WA23 LUNA, a tube-rectified single-ended amplifier that, unlike the new WA24, uses 2A3 tubes.

I asked Woo Audio founder Jack Wu how he came up with this design. He told me, "My brother, Zhidong Wu, designed it. He did all the original drawings. But after that, we worked together, slowly revising and refining those drawings. We started out with a 3D-printed model, then we had numerous revisions leading up to a metal sampling. It was a long process, during which I worked very closely with him. We are both pleased with the results."

What struck me most about the WA24's chassis was that no matter how fabulous it looked with the lights on—no matter how bright and golden that Woo Audio 20th Anniversary badge looked—I thought the amplifier looked more appealing in the dark, where all you see is the halo of orange light surrounding the volume knob, matching perfectly the hue of fire from the 3A/109E tubes’ filament cathodes. That's a nice touch, and the kind of intangible that gives its keeper pleasure every day.

With the lights on, I could see that the WA24’s four slender tubes were of a type I'dnever seen before. A closer look revealed their Stradi brand logos (screened in Western Electric yellow) on Bakelite bases. Under the Stradi logo, the tube identified itself as 3A/109E, a type I'd never heard of. Under that, it said “Made for Woo Audio.”