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Knowing that the AKGs operate at speaker level, one could readily extrapolate from their described performance to loudspeakers. That would indeed be quite accurate. However, normal headphone listening moves in a quite different direction - into the famed sweet spot were nothing is as linear and low distortion as a superior direct-heated triode. This means operating it at a fraction of its full output, i.e. either on a very high-sensitivity loudspeaker 105dB plus ... or a headphone. Instead of gentle, laid-back and a bit pipe ' n' slippers gemütlich, the gestalt morphs into full-contact immersion. Colors get deeper, dynamics go up, bass goes down (lower and louder). It's like being in the midst of a touristy summer postcard of Switzerland. The tall mountains reflect in a lake, the colors are nearly preternaturally crisp and pristine and the sheer landscape is heart-stoppingly beautiful - but you're actually there and not looking at a postcard. You just feel as though you're somehow inside a postcard because everything is nearly too perfect.

Or invoke steroids. While over speakers and the K1000s, the Woo amp is somewhat on the polite, pretty, relaxed 'n' soft side particularly in the bass and not as direct and unfettered as my Emission Labs solid-plate 45s across the band, with headphones like my audio-technicas, you're suddenly on 'roids. It's a quite uncanny transformation and one I think could be duplicated readily with any decent SET if the latter's noise floor was low enough (a very big if indeed). Let's face it, building a full-blown speaker 300B amp only to dedicate it to headphone drive for that overkill fraction-of-a-first-watt glory where the tube is at its finest with headroom to spare... well, it is an extreme application of resources and nearly wasteful. But unlike that elite single woman with the V8 4x4 doing grocery shopping for one where everything speaks against her car -- puny European parking slots, narrow streets, high fuel consumption, insane insurance premiums, roads that are black-topped and smooth and inner seating for 7 -- the overkill element of the Woo Model 5 is in fact squarely at the service of hard-core performance. It's not just a silly status symbol but actually delivers the goods.

That said, my Yamamoto HA-02 is a quarter the price, 1/6th the size and on the W1000s, its attenuator sits no higher than the Woo's even though it only runs two comparatively minuscule Western Electric 408A/6028s in feedback-less pentode mode. Is the Woo amp guilty of conspicuous consumption then? Or does it bring something to the party on such headphones -- disregarding for a moment the obvious speaker and (discontinued) AKG K-1000 drive option -- which the Japanese amp does not? If the Yamamoto is the perfectly scaled tool for the job, is the Woo unnecessarily big and expensive even though it gets the same job done brilliantly? After all, the Yamamoto is top-shelf brilliant already.


The comparison saw both amps connected to the APL Hifi NWO 3.0-GO via two identical leads of Stealth Indra through a hard-metal splitter. To load the Woo while listening to the Yamamoto, I switched it to the connected K1000s. The Yamamoto got switched to its unused second input when the W-1000s swapped over into the Woo. Power cables were Crystal Cable Ultras fed from a Furutech RTP-6 passive power distribution box for all three components.

This became a meeting of equals which differed modestly as a matter of preference rather than one being categorically better than the other. The pentodes were more focused, crisper around the edges, with more pronounced articulated bass, a powerful center image and excellent depth. The triodes were a bit fuzzier around the edges, laterally more expansive but not as deep and a bit softer on top which wasn't necessarily less extension but a rounder quality with diminished energy on transients.


For tone color and image density, both amps are at the top of the game. The Yamamoto seems denser in the middle and a little less illuminated toward the sides of the headstage while the Woo's texture appears to be consistent across the stage but with less edge articulation or image lock. However, these distinctions over my headphones were flavor differences, minor enough to not dramatically shift the overall gestalt but obvious enough to be perceptible. Hence the opening statement of being essentially equals.

The general voicing of the Woo amplifier as first encountered over the AKGs and speakers thus translated intact to 1/4"-jack'd cans but shrunk significantly in scope or magnitude. Incidentally, the stock Shuguang 300B-98s moved things a little more towards the 408As, the Western Electric 300Bs in the opposite direction - but less than the high-level distinctions between these triode variants over speakers or AKGs. The conclusion is quite obvious. For these audio-technicas, the Woo is complete and utter overkill. That takes nothing away from it. It simply puts it in the luxury leagues where, if you have to ask anything other than "when can you deliver?", you're badly stretched beyond your means and appropriate station. Mind you, the majority of head-fiers will already consider the grand which the Yamamoto demands steep. Whether that says more about it or the Woo how they perform so squarely on the level I'll leave for you to decide*.

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* One unpleasant Wooism is the loud transient whenever you switch the output selector. Do not work that control with the phones already on your head. Your ears will thank you. And obviously, do not ruin the output transformers by running signal without an attached hi-level load (K1000s or speakers) when one of those two outputs is selected.

The real question, in my mind, is where in the pantheon of world-class 300B SETs the Woo belongs to drive speakers. Depending on how that question is answered, the Woo could be a top-ranking traditional SET that so happens to also be a brilliant headphone amp on the rarefied level of the Yamamoto. Or it could be a rather expensive headphone amp that doubles for speaker duty, emphasis on the former. With Yamamoto's A-09S, Trafomatic's Reference monos and Raysonic's SE-20 MkII already committed to and inbound from their respective first production runs, I'll reserve that assessment for a grand four-way duel which will link each of those reviews to the same -- massively paralleled -- sidebar. I'll go on record already with a

Sidebar I: 300B amps squared up and squared again - four amplifiers from Raysonic, Trafomatic, Woo and Yamamoto demonstrate similarities and differences - continue
suspicion that the 6SN7s utilized by the Woo men is not the most ideal driver for the famous 300B. I say that because compared to my 2-watt Yamamoto 45 SET, the Woo seems to be just a mite shy on spunk and grip over speakers. And those are qualities I associate with current and - well, drive. Put differently, my love affair with the EML 45 continues unabated as the direct-heated triode which, to my ears and in the systems I have assembled, is the mostest and baddest - more extended, more transparent , more incisive and dynamic than 300Bs and 2A3s, with tone just as rich but textures that are more linear and less specific to the midrange. Alas, I'm prepared to be proven wrong, to declare defeat at the hands of whichever of these incoming amps will steal my heart. After all, having 8 - 15 watts on hand (the Yamamoto can take hi-current KR/EML glass to exceed the usual single-tube 8 watt ceiling; the Trafomatix parallel their output tubes for double power) would be quite the deal in these micro power leagues. Keep your bias steady for the final installment...
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