Anyone listen to Zu Audio's Definition Mk3?

>>...more than 200 watts which he ran successfully on his Def. IV speakers. On paper this seems like overkill or even a mismatch? Can someone perhaps shed some light on this?<<

Putting aside all the usual reasons why a Zu speaker sounds good and performs well -- crossoverless full-range driver, high efficiency, etc. -- what makes it just about in a class by itself is the main driver's combination of high 101db/w/m efficiency with high power handling. Last I heard, no customer has ever blown a Zu driver in the field. It's remarkable enough that Zu rates their speakers for amps from 2w - 300w, but frankly you can put 1200w McIntosh MC1.2kW monoblocks on them. The advantage of using high power with an efficient speaker that can handle the power is freedom from dynamic restriction in any practical sense. Or put another way, the sense of dynamic ease and effortlessness with the perceived ceiling on peak clarity removed improves the clarity of even single notes from a piano or a close-miked guitar or cello, for example.

Now, this is only worth so much. Most high power amplifiers don't sound as authentic in the essentials of tonal fidelity, spatial representation, event precision and octave-to-octave balance as a truly well designed low power amp, but there are high power contenders. So if you find a powerful amp in which you like the proverbial first watt, and the rest of the watts retain that clarity and beauty, then a Zu speaker will show you the added benefit of dynamic ease. However, if the powerful amp isn't listenable for you, then no perception of dynamic ease will draw you to it over a better, smaller amp.

The big Mac autoformer-output amps work well with Zu. The Dartzheel makes sense. I prefer and recommend 25w 845 SET amps over 2w triodes. On the other hand the best solid state sound I've heard so far comes from 10w First Watt SIT-1 monoblocks biased hot and I have not heard great sound from big 200+w push-pull tetrode and pentode amps by any brand. So you should sometime have the experience of hearing a great amp on Zu that happens to be powerful, and you can rank-order the relative benefits for your space. And your music preferences. If you listen to a lot of EDM or electronica, you may have a different view of the value of high power than someone listening to indie rock and jazz, for example.

Most high efficiency speakers don't even give you the option of finding out.

Phil

Thank you, 213Cobra. That puts it nicely into perspective.

Well, the Def4s have arrived, and I'm still taking stock of them, so my considered response will take the form of a few postings. I thought I'd leave a few initial impressions. First aesthetics; I'm SSSOOOO glad my girlfriend made me go for Cosmic Carbon, it's such a good match with the Aluminium driver rings and tweeter lens, and fits my loft decor perfectly. This finish never seems to work in photos but is to-die-for in the flesh.
So, the sound. Yes, it is a cliche, but it really sounds like a different speaker, but the same. In a nutshell, it shares all the DNA of my previous Def2s with a definite increase in sophistication common to spkrs much further up the price scale.
This is most noticeable in a quantum leap improvement in transparency. There is a real "hear thru" quality to the sound, but maintaining the Zu tonal density. But now, instead of a concentration of musical energy into a sort of wall of sound, there is a more layered quality to the presentation. It's the same, but very different. This increased transparency really allows music to breath more easily than the old Def2s, which seem coarse by comparison. This is the only area where I disagree with Roy Gregory in his Audio Beat review, IMHO there is no "harmonic leaness" (about the least accurate criticism to be levelled against Zu).
But don't be fooled if my words make you think that we now have a polite, twee sound. No , nothing of the sort, and I'll explain more at my next post...

Ok, time for the second part of the early listening experience with my new Def4s. At present I'm only listening to cd, and as an analogue fan, any extra enjoyment when listening to the necessary evil that is digital is a massive plus.
I previously referred to the more sophisticated sound of the 4s compared to the 2s, summarised by a massive increase in transparency and delicacy, no doubt a direct result of the improved full range nano drivers. Initially this appeared to be at the expense of tonal weight, but on further analysis I just wasn't used to the massive speed of these drivers. The old drivers in the 2s sound earthbound on reflection.
The great thing is that once adjusted to this extra speed, you realise the delicious full bodied balance of the 2s is maintained into the 4s, and the ante is really upped by this lightning fast transient response. So now we can have tonally dense, the trademark Zu sound, in combination with a lot of what electrostatics have to offer. I'm not sure I've heard such a magic combination even in uber spkrs like Wilsons and Magicos. I was really fearful the Zu sound might be "tamed" in the 4s, but this extra transparency really has just enhanced all that the 2s had to offer.
So, that's a summary of 90% of what these marvels have to offer. Next I'll discuss the bass, and fear not, there'll be LOTS to discuss here...

"Initially this appeared to be at the expense of tonal weight, but on further analysis I just wasn't used to the massive speed of these drivers. The old drivers in the 2s sound earthbound on reflection."

I had the same concerns at first with the nanotech drivers, but as I grew more acclimated and juggled a few tubes to compensate for the new signature, I arrived at the same conclusion as you. The weight and body is there--the speed and nimbleness is just initially misleading.