High-end sound gets truly portable with the Woo WA11 headphone amp

The Woo WA11 Topaz is an amazingly compact, yet truly high-end headphone amplifier.

Steve Guttenberg
Ex-movie theater projectionist Steve Guttenberg has also worked as a high-end audio salesman, and as a record producer. Steve currently reviews audio products for CNET and works as a freelance writer for Stereophile.
Steve Guttenberg
3 min read
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The Woo Audio WA11 Topaz amp, with AKG K812 headphones

Steve Guttenberg/CNET

Woo Audio has been making exceptional tube electronics in New York CIty since 2004. So it came as a big surprise when I received the company's first solid-state WA11 Topaz headphone amplifier. Better yet, it's small enough to be truly portable -- Woo's taking high-end sound to the streets!

Even without the aid of tubes the WA11 ($1,400) sounds velvety-rich, powerful and refined. Instruments and vocals surely have a lot more body and substance than what I hear from my iPhone 6S' headphone jack.

The WA11's black anodized-aluminum chassis feels solid, and measuring just 6.1 by 3.3 by 1 inches, it's small enough to fit into a jacket pocket. The included Alcantara travel pouch protects the WA11 from scratches.

Upfront there's a machined metal volume control and two headphone jacks, a standard 6.3mm jack and a 4.4mm Pentaconn jack (for headphones fitted with balanced cables with Pentaconn connectors; only one headphone can be plugged in at a time). The amplifier circuitry is fully balanced from input to output.

Too bad Woo didn't also squeeze in a 3.5mm headphone jack, but space is limited. The amp's side panel has a high/low gain switch for compatibility with easy- and hard-to-drive headphones.

The rear-end hosts two USB Type-C ports, one for data, and one for charging (it's only USB 2.0 compliant) so you can listen to the WA11 and charge its lithium-ion battery simultaneously, or listen for up to six continuous hours of battery-only playtime. The WA11's built-in ESS Sabre Reference digital audio converter offers high resolution playback up to 24-bit/384kHz PCM files and up to DSD128 for DSD files.


The Woo Audio WA11 Topaz amp with Sony MDR Z1R headphones

Steve Guttenberg/CNET

At home, the WA11 can serve as a dandy desktop USB digital audio converter/headphone amp. It's compatible with PC, Mac, Android and iOS devices. I had good results on my desktop with my Mac Mini and also with my iPhone 6S.

There's one other bit of connectivity, a 4.4mm Pentaconn stereo analog balanced audio input, but no analog outputs so the WA11 cannot be used as a preamp. Maximum power output is specified at 1.2 watts per channel for 30-ohm headphones.

Wowed by the Woo's sound

I paired the amp with a wide range of headphones, starting with something truly special, the Audeze LCDi4 in-ear headphones . Wow! The sound was lush, clear, and very low in distortion. I've always loved these 'phones, but they never sounded this organically rich before.

The Sennheiser IE800 in-ears, one of my long-term references, were also very appreciative of the WA11's talents. I play the IE800 with my iPhone 6S all the time, but here with the WA11, the sound filled out with no loss of clarity.

I was eager to try the WA11 with the extraordinary Abyss Diana Phi on-ear headphones (review to come). The purity of the sound took my breath away, but this wasn't the sort of uber-transparency that highlights the faults of everyday recordings. The sound was sweet as can be, and stereo imaging was expansive.

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The Woo Audio WA11 Topaz amp

Woo Audio

The WA11 did stumble with the Diana Phi when I played the Isle of Dogs soundtrack album really loud. These are power-hungry 'phones after all, and battery-powered amps struggle to keep up with the score's big bass drums. With less challenging music, the WA11 sounded great via the Phi, while the Hifiman HE1000v2 headphones excelled with the WA11 on the Isle of Dogs massive drum thwacks.

I also tried my AKG K812 over-the-ears, which are among the most open sounding headphones I own. The K812 can sound a bit lean, but the WA11 brought more warmth to their sound, a welcome change.  

To finish, I hooked up my Schiit Yggdrasil digital converter to the WA11's Pentaconn analog input. But as good as the Schiit converter is, I preferred listening with the WA11's built-in converter! Which is how I suspect most WA11 buyers will use the amp.

The Woo Audio WA11 Topaz demonstrates extreme high-end sound in a portable size is possible. At least for audiophiles who've already invested in top-quality headphones they would like to enjoy on-the-go, at home or office. Wherever you go, the WA11 will bring out the best in your headphones.