For those not familiar with Woo Audio’s offerings, the USA-based company has been making high performance loudspeaker and headphone amplifiers for several years out of New York. Owner Jack Woo has successfully piloted the company and built a substantial reputation for quality-made tube stage amplifiers. While the full product rundown includes loudspeaker implementations, most of Woo’s foothold in the marketplace comes directly from its large, perfectly incremental headphone amplifier product line. From their entry level single-ended OTL WA3 amp ($599) to the behemoth WA234 monoblocks ($15,900) Jack and the team have a little bit of something for everyone interested in analog listening. Keeping up with the times requires a bit more than just creating price touch points across a scale. The newest version of the WA7 Fireflies firmly addresses these changes in technology while also tapping into that elusive harmony which happens when the digital and analog realms collide. The two-part package starts at a cool $999 for the WA7 with a solid-state power supply by itself, with the WA7 tube power block costing an additional $749. Bundled together however, you will be able to save a little bit of scratch as the full tube package purchased at the same time will cost a mere $1,599.
Both the solid state brick and matching tube cube attach themselves to the back of the main WA7 unit via a DC input port located on the back panel. A further inspection of this rear faceplate reveals why this new product is the interception of new and old. One of the first Woo products with an internal digital section, the new WA7 also receives USB input up to 24/384kHz. A pair of single ended RCAs can be found in close proximity to the digital port, and cleverly doubles as both an analog input and as an analog output for the USB connection. A three-way switch allows you to toggle between the USB/RCA inputs and analog outs. There is a two level low/high gain switch as well as a power toggle, however, if you purchase the WA7 the mirrored round knob on the front of the power supply also acts as an on/off switch when pressed in, but lacks a function for its rotational capabilities. When activated, the WA7 presents itself with a very satisfying glow from the four tubes that sit on top of the cubes. The main amplification of this desktop digital combo is pure tube class-A topology (with no semiconductors in the amplification path) and comes stock with a pair of matched Sovtek 6C45 glass for the main amp and RCA 5963 NOS for the tube power supply. Woo also sells additional tube upgrades direct from their site, and the amplifier is of course susceptible to all matter of tube rolling options that add an additional layer of customization to the hobby. The Sovtek 6C45 triode assumes both driver and power tube responsibilities.
Perhaps one of the most eye-catching features of this combination amp/DAC is the solid block of glass that sits atop both boxes that allows the tubes to remain delightfully visible while providing a protective shell of sorts against random collisions for the tubes. The fully transparent block is striking and adds to the overall design in a very interesting way. It is important to note that the block does indeed rest on the unit and is not secured to the surface in any manner. It didn’t prove to be an issue during use, as general care is very much recommended whenever hot external tubes are employed in the design of an amplifier. The glass blocks did manage to do a significant job in dispersing the heat generated from the tubes. The lower section warms up a little as expected, but the top of the glass remains relatively cool to the touch. The WA7 comes together with an appearance that resembles a perfect cube, which proves to be a very pleasant design element to its overall cosmetic appeal. Its art-ish sensibilities do a great job of bringing something more visually to the desktop, without overdoing it. Like all things Woo, it is quite heavy for the size and feels durable against the elements of time. Even the little rubber feet on the bottom of each unit feel secure, while still responsive enough to absorb vibrations in proper form.
There are two single ended headphone connections located on the lower right corner of the main amplifier unit. While the ¼” output may act like your typical full size audiophile headphone jack, the 3.5mm does not. Woo provided some more light on the subject: “The 3.5mm is designed for extremely sensitive IEMs, specifically made to deliver an ultra-low noise floor for these type of earphones. The 1/4” output is for all other headphones (8-600 Ohms).” In execution the 3.5mm did complement a pair of JH Audio Layla IEMs very well by allowing for a more even volume sweep with a reduced chance for low-level channel imbalance. The jump from no volume to ear bleeding can be frighteningly thin when it comes to sensitive IEMs plugged into full size amplifiers. The extra layer of security here was a welcome one in this scenario.
So what makes this new version of the WA7 different than the previous iteration? According to Woo there have been several updates, including a new “high-resolution audiophile-grade DAC, improvements to the voltage regulator and the DAC is now powered by a linear PSU for better performance. There is also a new OP amp output stage, improved analog circuit, Teflon tube sockets, high-retention USB connector (orange color) and enhanced tube glow.” Specifics on the new choice of silicon boiled down to the SABRE ESS 9018M for digital signal management. “We tested many DAC chips, USB controllers and circuit designs. The ESS 9018M with XMOS controller sounded most musical. The new DAC supports Hi-Res up to 24/384kHz and is iOS/Android compatible with appropriate adapter, previously it was 32/192kHz.” The digital section indeed feels very 9018. While the chipset can vary quite a bit upon implementation, there is a mild consistency to the sound, if it is done correctly. Some high priced standalone DACs have been known to push the 9018 series even further, but its commonality in portable amp/DAC combinations as of late raises its frequency in the wild to near “everyday” values which help push the new benchmark for performance even higher than it was just a few years ago. The same holds true with the WA7, it is well executed and clean. No significant missteps in the transfer and no driver needed for connecting to my Macbook Air. Utilizing Audirvana Plus it was easy to select the DAC as the preferred audio device from the preferences menu. The digital connection showed up as “xCORE-AUDIO Hi-Res 2” and played succinctly without any further issue. The USB input comes off detailed and accurate with the tube section of amplifier rounding out the sound in an agreeable fashion. Comparisons to the more premium priced Auralic VEGA ($3,499) from the unbalanced inputs highlighted the organic and natural presentation the VEGA is known for, but put up a good fight in terms information retrieval and firmness. Overall the digital section feels accurate and on point for any 9018 in this price range. Given the output capabilities (which are surprisingly rare with these type of all-in-one units) additional value is piled on top of an already solid digital conversion story.
The house sound of Woo has always managed to avoid a Goldilocks scenario with regards to “how much” tuby-ness it seeks to employ. The bed it chooses to lie in always supplies the right amount of warmth without leaving the mids too loose or allowing the low end to get destroyed in a grand wave of slushy softness. The “sweet” sound is there with the WA7, but it’s not in your face waving its hand wildly for attention. The subtlety of it all drives your music with a pleasant demeanor, one that can often counter-balance the directness of the room-less headphone listening experience. Listening to the 24/96 version of Jason Mraz’s Everything is Sound provided a very open representation of the fairly dynamic and varied track. The vocals to the introductory verse sounded robust and textured with a pleasing timbre. As the first signs of the backing band appear in the track, it was easy to pick out the left and right stereo location of the keyboard (right), organ (left), guitar and sax as they jumped around in the sound field. As the bass enters the scene the overall appeal leans to a more smooth presentation that is very easy to listen to. It is equal parts relaxed inspiration and dynamic stability that provide much of the allure to the analog-inspired sonic portrait of the WA7. Vocals arrive in a balanced contribution to the picture, falling neither back nor too far forward against the rest of the spectrum. Bass response is clear and never overcooked and the treble doesn’t take on any additional screech or sibilance during the amplification process. The extension upward feels natural and airy. Cymbals don’t sizzle or crackle at loud intersections but rather communicate a more buttery aggregation of high-end sonics during energetic passages.
From end to end the 9018 provides a nice platform that complements the traditional Woo prowess of amplifier construction. In/out rights from the analog RCAs maximize the feature set while keeping real estate to a minimum. The external design of the WA7 looks like a thousand bucks, which is convenient considering the going rate for the solid state option falls closely in line with the sentiment. Its easy to say that any design elements that deviate from the norm cause the populace to pick sides, but in the case of this Woo unit most will likely agree that its break from the masses is one for the better. Talk piece combined with audiophile analog traits make the all-in-one unit a fine complement to any upscale desktop or the top shelf of your audio gear rack. If you are a fan of Woo gear already then trust this newest addition to the family puts a fine digital foundation behind the house sound of the company. It appears that a lot of thought has gone into implementing the proper combination of in/outs/features for Woo’s resurging everything-in-a-box. Certainly one of the highlights is the forward thinking dual headphone output, carefully prepared for the headphone that is most likely to utilize the jack size. The overall size of the WA7 is big enough to be taken seriously, but not so much that seriously takes up space. Tonality from the device is a reasonable extension of company’s origins but picks up the latest updates to stay current with market trends. Its packed with enough power to drive all the latest headphones to sufficient levels without a hint of strain, but yet is also capable of delivering music that is free of hard edges while remaining significantly true to the original source material. The WA7 Fireflies is a tight package on many fronts.
- Product - Woo Audio WA7 Fireflies
- Price - $1,599
- Product Page - Link
Source: MacBook Air
DAC: Auralic VEGA
Amplifier: Questyle CMA 800R
Headphones: Audeze LCD-4, HiFiMAN HE-560, JH Audio Layla (Custom), Beyerdynamic AK T5p
Playback Software: Audirvana Plus
Cables: Zu Mission RCA Mk.II-B
About The Author
I’m a recovering musician turned audio reviewer. I currently manage and write reviews for Audio-Head.com and freelance with several other publications. I love tech and the tools of music, especially the ones involved in reproduction. After I finished my undergrad degree in business I went to the local community college and got one in photography, which was way more fun. I like it when people have unbridled enthusiasm for something and I have the utmost respect for individuals who try to create, even more for those who are good at it.