I love this hobby. Not only do I get to test just about every pair of headphones and headphone amplifiers on the planet I’m also fortunate enough to be able to choose my test subjects selectively and, above all, at my leisure.
Many readers may have often wondered why my reviews tend to be mostly positive. Well, that’s precisely due to the aforementioned circumstance. If I had to review every device that came my way, it would exceed my capabilities.
Unfortunately, my day job usually only allows me to write on weekends. As a result, some devices that, in my opinion, don’t even survive the first listening test in my own home are usually promptly returned to the respective manufacturers and distributors. This is the fundamental advantage of financial independence.
After all, it’s understandably not much fun to spend countless hours of my already limited free time evaluating components that I don’t musically like in advance. It’s kind of understandable, after all. And entirely in keeping with my dear wife’s wishes: For a life beyond headphones.
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And why this little digression now? Well, a handful of headphones and headphone amplifiers sometimes only find their way to my home via a roundabout route because I simply want to test them out. This brings us to the actual topic. And my test object today – the WOO AUDIO WA8 ECLIPSE.
The New York-based manufacturer WOO AUDIO has been selling its almost legendary tube amplifiers primarily in the USA, Canada, Australia, and Asia since its founding in 2004. The product range also includes products such as DACs and CD players, headphones, and various accessories in the form of cables and NOS tube sets.
Unfortunately, WOO AUDIO’s multi-award-winning amplifiers, highly praised by the trade press, are not yet available in German-speaking countries. Therefore, anyone wishing to purchase a device from the American company must still place a binding order on the manufacturer’s website and then import it. Oops.
Don’t worry, this is actually quite straightforward, as I recently verified when I purchased two TUNG SOL 5998 NOS tubes from their own tube accessories. FedEx promptly sends the necessary documents for customs clearance, which simply need to be completed and returned. The package is then promptly delivered to the recipient.
But this approach may soon change. At this year’s HIGH-END trade fair in Munich, Jack Wu told me in a lengthy conversation that he could certainly envision direct distribution in Germany in the future.
And since I recently presented the prototype of the brand-new mobile headphone amplifier WA11 PASSPORT under Musicalhead/News and was already able to take a detailed acoustic look at it at home, it was of course not difficult to accept Jack’s tempting offer to send me another of his ingenious amplifiers directly from New York for a detailed sonic evaluation.
The final production version of the WA11 is still a while away. So, I ultimately opted for the WA8. This portable DAC/amp combination perfectly rounds off my “Summer Special” this year, thus perfectly completing this little mini-series.
The battery-powered WA8 ECLIPSE tube amplifier has been available in the US for some time but is still relatively unknown here. However, the WOO impressed me with its very airy and equally excellently balanced sound when used with the LB MYSPHERE 3.2 at the HIGH-END trade fair in Munich, and I therefore definitely recommended it for a future review.
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Furthermore, IMO, it also provides the interested buyer with a very good insight into the WOO AUDIO brand. I’d like to take this opportunity to sincerely thank Jack Wu for the quick and unbureaucratic delivery and provision of my review sample.
Processing & Equipment
WOO AUDIO products are always manufactured with extreme precision and care from high-quality materials. The plastic content is practically zero. This not only looks beautiful but also conveys a high level of tactile quality. Top-notch.
The WA8 is, of course, no exception. All components fit extremely precisely and also have perfect gaps. This isn’t always typical for American devices. Cleanly milled edges throughout, sockets and switches seamlessly integrated into the housing, and a smooth, smooth volume control further demonstrate the great attention to detail.
However, the solid aluminum housing and its elaborate internal components also contribute to the WA8’s relatively high weight (1.1 kg), which, in my opinion, limits its mobile use to mere transport from place to place. Since the tube amplifier naturally gets quite warm due to its operating principle, it’s hardly suitable for use on the go anyway.
The natural habitat of the WOO AUDIO amplifier is therefore more likely the garden or balcony at home, but the office or a hotel room on vacation also have a corresponding right to exist. Of course, the WA8 can also be used as a fully-fledged all-in-one solution within the four walls of your home. But more on that later in the sound test.
Furthermore, the equipment list of the small tube amplifier is more practical and well thought out than lavish.
The dark gray cardboard box with the manufacturer’s logo printed on it contains a tailor-made and waterproof Pelikan case for safe transport of the amp, a universal power supply for easy adjustment to the respective voltage requirements, a USB cable for connecting to appropriate data sources, and a quick-start guide, naturally in English.
Technology
In addition to the obligatory on/off switch on the input side, the WOO AUDIO WA8 ECLIPSE itself features a USB-A port for connecting to a suitable data source, such as a PC or Mac. By wisely foregoing the usual micro-USB solutions, I can draw on my fairly extensive collection of high-quality accessory cables from my magic box. Thanks for that.
On the other hand, the WOO can also be supplied with musical material from the line output of a corresponding music source, ideally with an output voltage of 2V, directly via a 3.5 mm jack socket, bypassing the DAC section.
Conveniently, the WA8 operates with an external power supply that exclusively supplies the batteries with the necessary power without negatively impacting the sound of the other parts of the DAC/KHV. In my opinion, this solution is much more sensible than using a single cable for both transport and charging.
This allows the WOO to remain plugged into the home mains power supply while still being ready for occasional sonic excursions into the garden. The integrated lithium-ion battery with a capacity of 3,400 mAh allows for 3-4 hours of standalone operation. While this isn’t particularly generous in my opinion, it should still be sufficient in most cases. A 5-level LED display shows the current charge level at all times.
The WA8’s three tubes, housed under glass, require a relatively high level of current, along with its transformer-coupled Class-A output stage circuitry. The WOO is therefore truly a pure tube amplifier and not a hybrid version like my ALO CONTINENTAL DUAL MONO, for example.
The WA8’s digital converter section uses a renowned ES9018K2M reference chipset, which isn’t necessarily the most up-to-date version – but IMO it’s still a very good choice, as will become apparent in the later sound test.
The WOO’s tube design harmonizes perfectly with the slightly analytical nature of the ESS-SABRE converter. The WA8’s DAC accepts data rates up to 24-bit/384 kHz and plays DSD files via DoP, even though the WOO doesn’t officially support DSD. It works.
The WA8 ECLIPSE’s amplification concept is still based on a 6021 driver tube and two 6S31B power tubes. The number of tubes can also be varied via a selector switch on the top of the amplifier. In 2-mode operation, the subminiature driver tube is deactivated, which, according to the manufacturer, is intended to optimize the woofer, especially for use with sensitive IEMs.
Jack Wu states that the miniature tubes have a lifespan of approximately 5,000 hours. Replacing the tubes yourself is possible, although it may require some manual skill, but IMO it’s not rocket science. WOO AUDIO will also supply a completely new module with the corresponding installation instructions upon request. So, it’s no problem at all.
On the output side, the single-ended headphone amplifier features a 3.5 mm jack, but also, commendably, a 6.3 mm jack. This eliminates the often unavoidable adapters, which usually unnecessarily increase the contact resistance in the signal chain. Symmetrical operation is, of course, not intended due to the aforementioned circuit layout. Nor is it absolutely necessary. See the sound test.
Preparation
Due to its fairly broad range of applications, I’m combining the WOO AUDIO WA8 ECLIPSE with a variety of audiophile components for the following sound test. My iMAC, optimized with AUDIRVANA+ software, serves as the source, feeding the WOO’s integrated USB converter with high-res data. I’m using an AUDIOQUEST CINNAMON as the data cable.
This experimental setup can, of course, also be carried out on the go using a suitable smartphone in this case, an iPhone X, which I adapted to the technical requirements using Apple’s Camera Connection Kit. Here, too, the sonically superior AUDIOQUEST cable is used.
To be able to evaluate the WA8 as a pure headphone amplifier, I subsequently used my ASTELL&KERN SE100 FUTURA as a sonically compatible companion, which feeds the WOO with music via its line output (set to 2V). An AUDIOQUEST BIG SUR serves as the RCA connection cable.
The tried and tested AKG812 PRO, the current AUDEZE LCD4 Z, as well as my beloved ABYSS DIANA act in conjunction with the tube amplifier as adequate partners from the over-ear faction, while the brand new CAMPFIRE ANDROMEDA S takes on the role of the unerring IEM noise detector.
You probably already know the usual suspects. As musical reference material, I’ll once again be using pieces from jazz, blues, classical, rock, and pop that I’m familiar with.
Sound test
And how does my silver-grey test subject sound now?
First of all, I’m quite amazed at how powerful the Bonsai amplifier is when paired with various over-ear headphones. This is especially true considering that WOO AUDIO specifies a maximum output of only 350 mW at 50 ohms. However, the tube amplifier never gives the impression that it can’t handle the resistive loads imposed on it.
So, regardless of whether the relatively undemanding AKG812 engages in an acoustic liaison with the WA8 ECLIPSE, or Lady DIANA invites it to a hot dance – the little WOO always maintains sovereign control over the musical events.
If I didn’t know better, I would never, ever guess a portable amplifier in a blind sound test. However, IMO, it’s recommended to keep the WA8 in 3-tube mode if possible.
If the WOO loses its 6021 driver tube, this is primarily noticeable through somewhat flatter spatial imaging and slightly compressed dynamics. I will, therefore leave the WA8 in my previously preferred switch position for the remainder of my review.
In my opinion, operation with only 2 tubes only makes sense in combination with very sensitive IEMs, although in both versions, the KHV basically operates against a pitch-black background and also has a sufficiently generous adjustment range regarding the desired listening volume.
This is especially evident in combination with the CAMPFIRE ANDROMEDA S. The brand-new, world-class IEM reacts remarkably sensitively, especially to tube-equipped sources, often underlining the sound with a light background noise. In the current setup, however, not the slightest disturbing noise is audible, even in extremely quiet passages of classical music. Simply superb.
However, anyone who expects the typical warm and powerful tube sound from WOO AUDIO will most likely be somewhat surprised by the sound signature of the WA8 ECLIPSE.
The WOO undoubtedly has all the fundamental advantages of tube amplifiers, such as the well-known high basic speed with a faithful reproduction of impulses, an excellent spatial expansion in depth and width, as well as wonderfully authentic timbres.
However, especially in conjunction with the meticulously analytical ESS converter section, the overall result is a predominantly neutral and finely balanced sound, not entirely dissimilar to a solid transistor amplifier concept. Naturally garnished with a delicate touch of tube mellow. And this should certainly be taken as a compliment.
In combination with the CAMPFIRE ANDROMEDA S, the reproduction of voices and instruments never seems too flowery or thick. I’m already noticing that the “S” on the WA8 is unusually airy and open for an IEM. Even a top-of-the-line DAP, like the new A&K SE100 FUTURA, is comparatively slightly more two-dimensional, with a more compact spatial imaging.
Since the WOO AUDIO WA8 ECLIPSE will likely be paired with circumaural headphones in practice, I quickly reach for my AKG812 PRO. And I’m quite surprised at first. In my opinion, the AKG definitely plays in a higher league of sound on this American.
Tightly contoured and well-balanced bass, a sculpted midrange, and rather uncharacteristically silky and finely structured highs – IMO, this acoustic magnifying glass is also suitable for long-term use. What more could you want?
And by the way, at no point do I miss the symmetrical operating mode in this harmonious interplay. The subtle and detailed performance of the WA8 in conjunction with the 812 PRO is virtually beyond criticism. All in all, a truly successful combination.
My next candidate, the ABYSS DIANA, has often proven to be a demanding little beast. Fortunately, it finds a suitable acoustic companion in the WOO. Here, too, the WA8 acts almost like the famous amplifying wire, albeit with a highly musical (tube) touch.
In any case, the mobile DAC/headphone amplifier perfectly showcases all of DIANA’s strengths: the extremely fast and completely seamless bass range, a magnificently vivid and emotionally moving reproduction of voices and instruments with completely natural-sounding transients, coupled with an extraordinary resolution in the high-frequency range.
The WOO delivers exceptionally finely tuned midrange dynamics combined with outstanding clarity and transparency. Only at exceptionally high levels do the amp and the woman in the engaging acoustic arrangement eventually run out of steam. No problem.
Finally, the final participant, when combined, actually manages to easily top the already very successful performance of the WA8 ECLIPSE. No wonder, because the new AUDEZE LCD4 Z is, in my opinion, the American company’s masterpiece to date in the field of over-ear headphones.
The LCD4’s already well-known sonic advantages experience a dramatic improvement in dynamic quality with the new 15 ohm model. It’s more than telling that I operate the AUDEZE flat panel speaker at almost the same volume control range as I did with the CAMPFIRE ANDROMEDA S.
The WA8 continues to be the ideal partner for the LCD4 Z and also has sufficient headroom to adequately challenge the magnetostatic headphones at any time. Or simply to explore my personal pain threshold.
Mercilessly powerful and at the same time impulse-accurate basses are flanked at the top by the brand-typical earthy fundamental tone of the LCD series, on which the timbrally rich and body-rich midrange of the AUDEZE headphones is built.
The resolution, especially in the high frequencies, has been successively improved in a constant evolution of the LCD model series, without, however, reaching the highest sonic ramifications, for example, those of the ABYSS DIANA.
Nevertheless, the LCD4 Z’s delicate detailing, acoustically driven almost perfectly by the WA8, represents the current pinnacle of AUDEZE’s sonic performance. The high-frequency range is naturally free of any harshness and continues to shine with a very relaxed reproduction of sibilants.
Reverberation tails now also linger somewhat longer than in previous versions, giving the Z the best spatial reproduction of any LCD over-ear to date. The WA8 naturally contributes significantly to this. The phenomenal spatial impression is accompanied by very precise localization of individual actors on the virtual soundstage. Combined with the latest version of the LCD4, this makes a congenial team.
The most fascinating aspect, however, remains the outstanding dynamics of this combination. To even get the original LCD4 to achieve comparable dynamic performance, it feels like at least five times the amplifier power is needed. The two partners in this performance once again impressively demonstrate how important uninhibited and uncompressed dynamics are for the authentic perception of music.
As expected, there are no significant sonic differences when choosing the respective data suppliers. Regardless of whether the WA8’s USB DAC gets its musical data from my iMAC or my iPhone via the CCK, it’s not audible, IMO. Assuming, of course, that the digital data material is in the same format.
Now, of course, one final question remains to be answered: To what extent does the sound of the WOO change when used purely as a headphone amplifier? And while the differences on the A&K SE100 FUTURA aren’t enormous, they are still noticeable.
The current ES9038 PRO, which is used in the SE100 FUTURA, impresses with its even greater resolution, literally making the ES9018K2M look a bit outdated in this area. Musical events are also defined a nuance more sharply than with the WA8’s truly impressive digital-to-analog converter.
Surprisingly, the older ESS chipset offers slight advantages in terms of a slightly more expansive, spatial impression. Furthermore, the musical reproduction seems more coherent and, in the best sense, a bit more analog. Where appropriate, the corresponding output stages of the KHV have also been adapted somewhat more sensitively to the WA8’s implemented DAC.
Be that as it may. Of course, all these differences are marginal at best. In all operating modes I tested, the WOO simply performs at a remarkably high audiophile level and, IMO, is in no way inferior to the sonic performance of a full-fledged stationary headphone amplifier.
Conclusion
So, is the WOO AUDIO WA8 ECLIPSE a jack-of-all-trades? A portable all-in-one combination without any weaknesses? No – of course not. But almost.
Firstly, the small tube amplifier certainly doesn’t qualify as a portable solution. At over 1 kg, the WA8 is far too heavy to be discreetly carried in a jacket pocket while on the go. Furthermore, the small WOO AUDIO gets far too hot for that. And, in my opinion, the device should only be used freestanding, if only to ensure adequate cooling.
Secondly, the WA8 cannot be operated symmetrically. While I personally never considered this a disadvantage during my review, I can certainly imagine that it could be a disqualifying factor for some potential buyers.
In such a case, I recommend trying out an ALO CONTINENTAL DUAL MONO, which, fortunately, masters both operating modes with a similar (tube) performance.
From a purely sonic point of view, however, there is currently virtually no way to beat the WOO AUDIO WA8 ECLIPSE.
The aforementioned ALO CDM, for example, has a slightly warmer timbre and, in symmetrical mode, also delivers slightly more powerful reproduction but doesn’t quite match the DAC qualities of the WOO. A CHORD HUGO2 perhaps resolves complex sound structures with a bit more finesse than the WA8, but, as a typical representative of the transistor faction, IMO squanders this advantage with its slightly digital character.
In sum, the WOO AUDIO DAC/amp combination is, for me, the uncrowned king of tubes in the portable sector. And my new benchmark in this segment.
The WOO AUDIO WA8 ECLIPSE is available in rose gold, silver gray, and black for $1,799 in the US. It will hopefully be available in German distribution soon.
Woo Audio WA8 Eclipse Specifications
| Category | Details |
|---|---|
| Amplifier Type | All-tube, Class-A, Single-Ended Triode (SET) |
| Tubes | 6S31B x2 (power), 6021 x1 (driver) |
| DAC Chip | ESS Sabre ES9018K2M (24-bit/384kHz, DSD128 via DoP) |
| USB Receiver | XMOS xCore |
| Output Power | 350mW @45Ω (3-tube mode) |
| Headphone Outputs | 6.3mm + 3.5mm (single-ended) |
| Inputs | USB-B (digital), 3.5mm (analog) |
| Battery | 3400mAh Li-ion (~4 hours) |
| Charging | 12.6V/3A external charger (included) |
| Dimensions | 170mm × 92mm × 43mm |
| Weight | 1.09kg |
| Included Accessories | Pelican case, USB cable, charger |
