Pros: A Perfect Amp
Cons: Poor Quality Control and Customer Service
The stock tubes the amp ships with are a disservice. That's not entirely the company's fault: short of raising the base price of the amp by several hundred dollars, the WA2 needs to ship with inexpensive tubes--and cheap tubes means comparatively mediocre sound. But the tubes should, at the very least, work. Many WA2 owners have complained that the stock tubes were defective. I myself received defective tubes, which took about $200, 15 hours, and some slow, casual indifference from Woo Audio to diagnose (I had to rule out a ground loop to prove the tubes were at fault). Woo Audio, almost comically unapologetic for the expense and inconvenience, did the absolute minimum to address the matter--i.e., by sending cheap reimbursement tubes after I had already bought and installed replacement tubes to correct the problem. A company with better customer service would have sent better tube replacements (even if not top-tier NOS tubes) as a token apology. Sadly, the forums demonstrate that customers after me--after Woo Audio claimed to have addressed the matter--experienced the same problem. Exactly why a $1200 amp--arguably, the company's flagship, even if not its most expensive, product--is being shipped to customers without first having its stock tubes tested in the amp is an uncomfortable mystery. Certainly, though, I've never had to work so hard to spend so much money. If it were any other product, I would have returned it--but perfection is worth some pains.
If you buy the amp, you should be prepared immediately to buy tube upgrades. The WA2 with stock tubes is merely enjoyable. With upgraded tubes, the WA2 is absolutely enchanting, and puts other amps at similar prices to shame: upgrade the power and driver tubes first, as they affect the sound the most. Upgrade the rectifiers last, as their effect on the sound is comparatively small (though ultimately important). I'd advise against buying those upgraded tubes through Woo Audio, however, since the company consistently charges a significant premium on NOS tubes compared to market prices.
You should also be prepared to supply your own power cord since the WA2, much to the surprise and chagrin of some customers, ships without one. Personally, I think the amp's sound benefits greatly from an audiophile-grade power cord, but a $3 power cable will get you started, and may be all you ever need.
My interactions with Woo Audio have been consistently off, often odd, and occasionally rude. However, I don't think these rudenesses were intentional so much as the result of distraction and misunderstanding. I got the sense, perhaps mistakenly, that Woo Audio's staff was simply overworked--the result of a company's infrastructure lagging behind its own success. I never once, in my interactions with Woo Audio, felt like a valued or respected customer so much as a hurried duty. In fairness, many customers find their interactions with the company perfectly affable and helpful.
The WA2 is, for the price, about as close to perfection as one can find in this world--that, at least, is the humble opinion of this former professional classical musician. The amp, with proper NOS tube upgrades, offers a vast soundstage and, without aggrandizement, breathtakingly gorgeous timbre and divine imaging, subtle and layered. There's something magical about the amp, something pure in its presentation: it makes sense of complicated musical passages that, on lesser--even if more expensive--amplifiers, are just confused convolutions. To call this amp awe-inspiring is simply to state fact: I have whiled away untold hours listening in awe. I'm genuinely distraught that I can't give the amp the five-star rating it so justly deserves. But the company's faults--its quality assurance and customer service--tarnish the amp's perfection.