Headphones amplifiers — Woo Audio WA24 20th Anniversary Edition

The WA24 20th Anniversary Edition is a headphone amplifier from Woo Audio, built with a wide rated bandwidth typical of a tube-based design. Woo Audio has built two decades of history specifically around tube headphone amplification, and this anniversary edition presumably represents a refined or specially finished version of an established platform within that history rather than an entirely new design.

Key specs that matter

Rated bandwidth is 10 Hz to 40 kHz, a wide window extending comfortably beyond the audible range at the top end, typical of a well-executed tube design rather than one artificially rolled off at the edges of hearing. At 390 x 270 x 197 mm and 17 kg it is a substantial, heavy chassis consistent with a tube-based amplifier of this scale, the weight reflecting substantial output transformers and a robust power supply rather than a compact solid-state circuit board.

Sound and use context

Expect the open, harmonically rich character typical of a tube headphone amplifier at this scale and weight - the substantial build suggests genuine output transformer coupling rather than a lighter-duty output stage, generally associated with a fuller, more three-dimensional presentation than a typical transformerless tube design.

Pairing

Works with a wide range of headphone impedances typical of Woo Audio's tube amplifier range; the substantial chassis suggests ample power reserve, meaning even relatively demanding, lower-sensitivity headphones should be well within its capability.

Alternatives

Woo Audio's broader headphone amplifier range offers different power and feature tiers for various headphone types, worth exploring if a specific headphone's impedance or sensitivity calls for a different output configuration than this anniversary model provides. Anniversary editions of established amplifier platforms like this one often carry cosmetic or component-grade upgrades over the standard model - premium capacitors, upgraded tube sockets, or a special chassis finish - though the core circuit topology and voicing typically remain unchanged from the platform being celebrated. Given the substantial 17 kg weight, adequate ventilation and a sturdy equipment shelf both matter more here than with a typical solid-state headphone amplifier, since class A or low-feedback tube designs of this scale run considerably warmer in continuous use. Buyers considering this specific anniversary edition should confirm with a dealer exactly which component or cosmetic upgrades distinguish it from the standard WA24 before paying any premium.