The Woo Audio WA8 Eclipse is big for a portable amp, but incredibly tiny for an all-tube headphone amplifier. The WA8 was in development for three years with a goal of shrinking the size to the minimum and optimizing sound quality. True, there are other portable, battery-powered tube amps, but they're hybrid tube/solid-state designs -- the WA8's audio circuitry is pure tube, with two 6S31B tubes, and one 6021 tube. Like all true tube amplifiers, the WA8 uses output transformers, and in this case the transformers were designed by Woo Audio specifically for the WA8.

Enlarge Image Steve Guttenberg/CNET

I don't think pictures fully convey the beauty of the WA8. It feels like a precision machine, without a single plastic bit in sight. It is very much a high-end component, designed and built to the highest standards in Queens, New York.

The milled aluminum chassis measures 6.7 by 3.6 by 1.7 inches (170 by 92 by 43mm), and it's available in anodized black, gray, and gold (the gold finish is very subtle). The WA8 weighs 2.4 pounds, (1.09 kg). So while it may be battery powered, Woo Audio isn't suggesting the WA8 will fit in anyone's shirt pocket, but I imagine some of you might listen to the WA8 on planes or at work on your desktop. The amp is supplied with a water-resistant, foam-lined Pelican carrying case to provide maximum travel protection. Woo also offers a handsome real leather case as an option for the WA8.

With fully charged batteries the WA8 plays three to four hours, which might rule out use during long plane flights, but you could take the WA8 on trips and play it in your hotel room, or at work running off its AC power supply for extended listening sessions.

Enlarge Image Steve Guttenberg/CNET

Connectivity is limited to one USB (Type B) jack and one 3.5mm analog input, along with 3.5- and 6.3-mm headphone jacks. The built-in digital converter handles up to ultrahigh-resolution 384-kHz/24-bit files.

Listening to high-res files with my Sennheiser IE800 in-ear headphones, the sound was pure and clean. Tube noise might be a concern with other tube headphone amps, but not with this one. I almost always listen to the IE800s on the go, but here with the WA8, the headphones' transparency was above and beyond what I've heard from them before.

The WA8 also sounded great with my hard-to-drive, high-impedance (600 ohm) Beyerdynamic T 1 full-size headphones; the amp sweetened and warmed up the sound. I next played my low-impedance (32 ohm) Grado RS-1 headphones with the WA8, and compared it with an Aurender Flow portable digital converter/headphone amp ($1,295/AU$1,799). The solid-state Flow was a touch more laid-back and mellow; the WA8 more transparent, low-level detailing and spatial cues were more vividly presented. While you might expect the tube amp would be more "tubey," the solid-state Flow softened details more than the WA8. I also compared the two amps again with an Oppo PM-1 headphone, and heard similar differences. Both amps are excellent, but the WA8 extracted more detail from the music.

Beyond its look and feel and even its sound quality, the Woo Audio WA8 Eclipse ($1,799. AU$2,799) exemplifies what separates the best high-end products from mainstream offerings. The WA8 is the sort of design that you'd be proud to own for decades -- it's that good.