This review page is supported in part by the sponsors whose ad banners are displayed below
You know the triplets mantra of commercial real estate brokers: location, location, location. The equivalent amplifier charm might be power supply to the third power. And Woo goes a lot farther than that. Its power supply is scaled for 8 watts of loudspeaker drive - and we might assume that even for that purpose, it wasn't neglected but rather, slightly goosed. 1/10th power makes 0.8 watts. That's a lot more than most all normal headphones will realistically consume. Hence the power supply driving them must be called disproportionately, brutishly overbuilt - by a factor of at least 10. A broker for audiophile properties would hurl the word 'location' at your face in an endless monotone until you punched her sorrily obnoxious lights out. 'phone listeners meanwhile would see the light come on. Big time. You see, power supply greed is good. Very good. Lo-ca-tion!
The inherent challenge most beautifully aced by the Woo is
of course noise. A circuit appropriate for speakers could be unacceptably noisy over headphones. Obviously, the ¼" headphone socket here does not tap directly into the speaker outputs. It benefits instead from a downscaled circuit that's been optimized for the intended use and to come on song at a milli fraction of that infamous first watt. Still, what precedes that circuit is a monstrously overbuilt power supply. Another way of thinking about that is as an active preamp in a chain where it's technically superfluous - with variable-output sources that could drive an amplifier directly. Nearly invariably, the signal conditioning of the extra power boost and current injection from the active preamp (despite attenuation even below unity gain) create extra body, tone color and image density. A juicy booty call in other words.

From the above and if you know 300Bs, you could nearly write the review on regular headphone listening yourself. Radically overspec'd power supply + superior S/N ratio = sonic excellence. That takes no clairvoyance. It's utterly predictable and based on solid engineering. Here it's further massaged by a $1000 baksheesh for trick parts and a total outlay of four grand. To drive $480 audio-technica W-1000s with. We're back to that 1:10 ratio. It should sound bloody brilliant. And it does. Ditto for the K1000 output. Being a discontinued headphone with highly unusual drive requirements, the Model 5's special Neutrik socket is necessarily a feature of extremely limited appeal. Smartly then, the company also makes the Model 5 LE version above. That shaves off $600 from the base price. As you can see, the LE replaces the 4-pin K socket with a second ¼" plug for a total of 2. One is dedicated for low, one for high-Ω 'phones. That also does away with the output selector. If you've kept up your math, it comes as no surprise that the LE version does not sport speaker outputs. Scaling up the Model 5 circuit to power K-1000s was essentially the same as making it fit for speaker loads. Or vice versa. AKG's winged earspeakers were always delivered with speaker level terminations. And the stern demand for a minimum of 5 to 6 watts. That's SET 300B turf. Voilà, the circle is squared. But wait, there's more.


Our squared circle even includes triangulation. To make this circuit quiet enough for headphone use -- even the K-1000s elicit nothing -- also benefits the highly efficient speakers best suited to such an amplifier. As you will have, I've repeatedly come across not only noisy tube amplifiers but public statements outright condoning them. Such opinionators claim that the best specimens always are "a bit" noisy, i.e. display power supply hum through connected speakers. Are we to infer that to be an excellent-sounding tube amp means it must be noisy? I've always found that to be a highly disingenuous argument to excuse inferior circuit design. Cockamamie in other words.


With direct-heated triodes, there are endless arguments about AC vs. DC heating, tight power supply regulation vs. none as to not "strangulate and dry out the sound". In my book, there is no excuse for amplifier self noise in high-end audio. Yes, it's quite possible that the designer of a particularly good-sounding but noisy tube circuit didn't know how to make it quieter without hurting sonics. That merely means he's not 100% competent. One cannot claim high resolution and accept audible noise in the same breath. The entire notion is as peculiar as the acceptance of no bass in certain single-driver speakers as though their other virtues could somehow disguise or offset that fatal shortcoming. On that wobbly line, the Woo Audio Model is real high-end and a straight shooter. It's as quiet over by my 98 and 101dB Rethm Saadhana and loaner Zu Presence as it is over my two headphones. In short, while the Model 5 circuit may not scream innovation by way of rare pentode drivers or NOS rectifiers, interstage transformer coupling or other exotic wrinkles, its circuit represents a serious implementation that asks that no quarter be given for silly excuses. I for one find this to be eminently refreshing. Cheers.

I've always kept the faith with AKG's K1000s while accepting and admitting that they're somewhat of a Lowther of headphones - supernaturally transparent and fast as lightning yet also plagued by an energetic presence region that needs to be dealt with. Hence I had mine rewired from the voice coils up with the Stefan AudioArt upgrade harness (thanks to Vinnie Rossi of RedWine Audio for replacing/rewiring the one driver I bollixed up attempting this surgery myself). Two amps I've particularly enjoyed with my 'declawed' K1000s are the First Watt F1 with preceding tube amp (ultra articulate, stunning bass, recording monitor-style listening); and the Red Wine Audio Signature 30.2 (more relaxed, warmer and meatier than the F1, not as incisive on transients, not as preternaturally resolved). The Woo, hard as that may be to believe, has more top-end extension than the 30.2 for that inner life of cymbals such as the Todd Gustavsen Trio presents on The Ground. Mind you, my new wire harness also has redone spades, sadly of the hi-mass kind. This could be a barrier of sorts on the T-amp compared to the Neutrik connector jacking into the Woo.


After long stretches of wee-hour listening without any fatigue -- that's a biggie with these cans as only those who own 'em will fully appreciate -- I can squarely say that the Woo right off cleared the biggest hurdle any K amp has to clear before I'd even consider going further. That's no more of a backhanded compliment than my standard response to Lowther-equipped speaker solicitations these days is less than realistic. I always ask how they have modified their driver. If they reply that theirs is stock -- I'm talking about the DX55 -- I automatically turn them down. Having heard different iterations of DX-55 Rethms and finally arrived at the solution which involves a new phase plug with perforated skirt, a special compression chamber rear cone and rear-wave felt absorber threaded around the basket stems, I know what's wrong with the stock driver. I no longer believe that its failings can be successfully addressed by cabinet design alone.


My rewired Ks on their own aren't as 'defanged' as Jacob George's Lowthers are now. Without meaning to, just by personal inclination, it's led to me listening nearly exclusively to my W-1000s over the Yamamoto HA-02. I hadn't officially given up on the AKGs. I simply had something else in my crib that worked even better. In many ways then, my birthday acquisition of the Woo became the wooing of an old flame, all the old woes forgotten and transcended as it turned out. Rediscovering a former love can be glorious. The soundstaging of the AKGs with their wings semi splayed for the best balance of acoustic cross-feed and bass is legendary. Reliving this discovery fully justified the long road it took to get here, make up and say yes, I do.

What the Woo does very well over these earspeakers is harmonic nuance without slowing anything down. I'm terribly smitten with the trio performance of Aytaç Doğan, Hüsnü Şenlendirici and Ismail Tunçbilek on their first Taksim Trio installation on DoubleMoon (here's to many happy returns!). It combines the Turkish kanun zither with clarinet, duduk and acoustic and electric baglama, the long-necked Turkish lute. As with all relatively simple but well-executed music, the deeper you listen, the more you discover since nothing is obscured by mass and complexity. Here it is the harmonic finesse, the crisply plucked kanun flavor intersecting with the more watery baglama and the even softer clarinet. Upper harmonics live on air you might say. And air is something the Woo/AKG combo aces. It allows you to sink into the zone and surf the decay trails into oblivion.
Unlike over the Zu Presence where desired bass weight demanded a few extra clicks on their bass attenuators, the bass over the K1000s, while not as stupendous and obviously impressive as with the F1, was just fine (being open-backed + off-the-ear designs, the Ks cannot produce the kind of slamming brain lock of the best sealed headphones no matter what). But it's equally true to say that the gestalt of the presentation shifted from pure adrenaline to something dreamier less concerned with impact and jump factor and more romanced by space, decays and tonal beauty. For heart attacks and slicked-back hair, I go to my big rig and crank it when that mood strikes. No headphone can deliver the physicality of big air movements speakers produce. For me, headphone listening is far more intimate -
gentler if you will. That's exactly where the Woo fitted with current-production Western Electrics parked the K1000s. For my needs, that's progress as well as greater pleasure - which really are one and the same especially with earphones.


Put differently, the transient-led angular character of the AKGs is perfectly complimented by the rounder, more relaxed nature of the Woo to end up somewhere in the middle rather than being skewed to the side. Even though it goes about it in polar opposition, the end result is very much like my Lowthers on the Woo. They are 98dB efficient to do great on 2 watts, i.e. consume very little to fill a whole room from wall to wall. The K-1000s meanwhile consume monstrous power to merely energize the sphere between their panels and your ears. In fact, the volume control with the Ks sits higher on the dial than for my speakers - for lesser SPLs. Still, the subjective impression of boundless staging, extreme transparency and unfettered speed between these presentations are directly related. Naturally, none of this matters to anyone but existing K owners. And all of those already own amps they're happy with. Hence I won't say more on this topic except that the Woo is simply perfect for them and allows for even high levels without any onset of sizzle or ringiness. (And I can't fail to add the obvious postscript - that unlike the AKGs which stopped production in 2006, the Woo Audio Model 5 is very much current. Insert evil cackle while I sow the seeds of perennial discontent as all reviewers are wont to.)...