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Jem666 11-11-2019 11:44 AM

Bruno Putzeys...He did it again
“42”...“The Answer to the Ultimate Question of Life, the Universe, and Everything” supplied by the supercomputer Deep Thought after 7.5 million years of, ahem, deep thought. But what was the Ultimate Question again? To find out you need to read “The Restaurant at the End of the Universe” by Douglas Adams. If there is one thing “The Hitchhiker’s Guide to the Galaxy”, by the same pen, imprints on our collective memory is that satisfying answers deserve, dare I say demand, the “right questions”.

Asking the “right questions” is what the good folk at Purifi are all about.

How apt than that the “About” section of the Purifi Audio website would reveal the coming together of some of Audio Industry’s greatest minds and accomplished entrepreneurs. Their mission is bold as is their ambition boundless. It would be easy to dismiss out of hand Purifi's claims of grandeur as just another feeble exercise in marketing smoke and mirrors. But when you learn that Bruno Putzeys and Lars Risbo are Co-Founders, one takes note; this is big, like really BIG.

Lars Risbo is the man behind the technology residing in the TacT Millennium amp, by many considered to be the first High-End PWM Amplifier worthy of the moniker Audiophile.

Bruno Putzeys is the mastermind/inventor of UcD and Ncore Class-D amplifiers. Products by Grimm, Mola-Mola and Kii have his fingerprints all over them. When Bruno has something to say, one tends to listen.

And listen we did. Bart and I had the good fortune of spending the better part of a day with Bruno Putzeys at the Gydotron Show held on the 2nd and 3rd of November. On active display: the exquisite Mola-Mola Tambaqui DAC Roon Endpoint, the 1ET400A Eigentakt amplifier modules and the PTT6.5W04-01A Long Stroke Transducer mounted in two way bookshelf speaker cabinets accompanied by AMT tweeters.

That looks can be deceiving is a given, but the irony is that the significance of the Eigentakt amplifier and Purifi 6.5 inch Woofer was probably lost on the majority of visitors, courtesy of the kit like home build appearance of the setup (Bart will post pictures in his show report). Regardless, external crossovers laid bare on the ground do have their charm.

Make no mistake though, the Eigentakt amplifier and 6.5 inch Woofer are significant, as with them we enter a realm of “Beyond this point there be Dragons”. These first physical manifestations of the combined brain power of the Purifi team unlock new territories in technological achievement as well as business opportunities. Whether it will be all roses all the way remains to be seen, but more on that later.

I deliberately mentioned physical manifestations as both products took root in completely fleshed out mathematical models first. It is all about asking the right questions you see. In particular the Eigentakt module is a marvel of applied "Control Theory". I can only imagine the orgy of partial differential equations needed to predict the behaviour of such a non linear device. But Bruno Putzeys succeeded in taming the beast allowing him to push performance to a level where even his prior creations cannot go.

For those who want to delve into the technical details I recommend visiting the Purifi Audio website, but here are some takeaway observations.

The Eigentakt module is ridiculously small considering its power output of 400 Watt into 4 Ohm. Conveniently, thermal management can be demoted to a mere afterthought. Eigentakt really doesn’t care about the impedance curve of the connected loudspeaker as long as the impedance doesn’t flirt with anything short of 2 Ohm. Within its operating window this self-oscillating amplifier is extremely stable and the robustness of the circuit makes component tolerances less of an issue. No special virtues are required of the power supply, a decent SMPS will do.

This evolution of Ncore tech is far removed from the Pulse Width Modulation amplifiers from days of yore, requiring clocks and barely wrangling the nasty gremlins into submission that rear their ugly heads when massive amounts of feedback are applied.

The 6.5 inch Long Stroke Woofer with its unorthodox Neutral Surround geometry is another example of applied mathematics that challenges many established paradigms of pistonic drivers to date. It basically enables one to design and build a 2 way speaker that equals or bests a 3 way design by virtue of marrying excellent midrange reproduction with extended bass capability. If the Eigentakt is an evolution, this Long Stroke Woofer is a revolution. However, whenever established certainties are challenged, resistance is bound to surface.

“But how did it sound?” I hear you asking.

Right off the bat, just like with the Kii, one needs to let go of any assumptions or preconceptions. Taking into account the size of the room, the performance of this diminutive setup was arresting. I have no doubt it could stand shoulder to shoulder with systems many times its price, even eclipse them.

Bruno Putzeys was kind enough to let me play two tracks I know very well and use as reference to gauge the performance of any system. First track is “The Package” by A Perfect Circle. It starts quietly and has an explosive bridge. During the song the tone of the Bass changes and many systems simply do not pick up on this. The other track “In My Room” by avant-garde guitarist Fennesz is a shimmering wall of sound sparsely revealing layers of tonality fighting their way through an onslaught of distortion. Fennesz’s music is an acquired taste. For me, if ever there was a sonic analog for the space-time continuum, his music would be it. A lesser system would not reveal all the subtle layering within his monumental and uncompromising soundscapes. Sometimes in chaos and noise, beauty is to be found.

Both tracks played flawlessly. Quiet or loud, tonal balance was natural and consistent. The cymbals on the APC track sounded a bit unusual to my ears, but I attribute that to my unfamiliarity with AMT tweeters used in the speaker. No hint of grit or grain, no euphonic artefacts, a very neutral presentation with excellent imaging and resolving power. It does what it says on the tin “Building a Straight Wire to the Soul of Music”.

Bart’s selection of Jazz and Classical Organ tracks did not phase this system one bit and especially the potential of the Purifi Woofer, performing bass and midrange duties, became abundantly clear. One simply does not expect this kind of well controlled and articulate bass from a 6.5 inch woofer.

The Eigentakt amplifier module and Long Stroke Woofer are primarily OEM products although they will be sold to the enthusiast who wishes to build his/her own system. For those DIY people the acronym to remember is TINA...There Is No Alternative. For the price of purchase the performance of both products is simply off the scale...sometimes life is simple.

Undoubtedly some manufacturers will package the Eigentakt modules in beautiful albeit expensive cases prompting high MSRP’s which is perfectly fine. But they will not be able to change or tweak anything on the actual circuit. By its very design, being extremely stable within very delineated boundaries, performance will be the same irrespective of housing and power supply.

The Eigentakt proposition, which offers outstanding performance in a compact form factor, kind of upsets established notions of price versus performance balance. For some applications, when every cent counts, it will still be too expensive regardless of merit. For High End applications the performance is up there with the best; but added value will have to be found in other parts of the offering, like chassis or brand.

The Long Stroke woofer; now that is a whole different ball game. It would be a perfect fit for bespoke multichannel rooms, possibly with Purifi Woofer/Eigentakt combo's built in wall. For established speaker manufacturers the puzzle becomes more complicated as the performance/cost ratio will most likely challenge products in their existing portfolio. A balancing act for sure. I do hope some OEM starts building line arrays with these transducers as those promise to be epic. Whatever transpires, it will be interesting to see what kind of footing this driver will find in the market.

As I drove home, I pondered what I just experienced. He did it again. To be fair he did not do it alone but for Bruno Putzeys and Lars Risbo to find each other, start a new venture, pushing the envelope, writing new Chapters in the Book of Audio and setting new standards for others to aspire to is simply amazing. Life, the Universe, and Everything; sometimes they conspire to make great things happen.

In Belgium we have a word, understood by Flemish and Walloons alike, that transcends its Google translation and carries deeper meaning. That word is “Incontournable” and it can be used with reverence for things, events as well as persons. It means “cannot be dismissed, a force to be reckoned with”.

With its first two offerings, Purifi has become just that, Incontournable.

bart 11-11-2019 05:32 PM

Jacques, very well written, with your usual wit.

Dear AA friends, my audio buddy doesn't exaggerate: Purifi delivers and then some!
We'll remember in a couple of decades, if we have the luck to be still alive by then, the moment we heard this, as you all will quite soon.

I'll post my impressions with photographic evidence the moment I find a couple of hours.

bart 11-23-2019 08:01 AM

I finally found the time to add my impressions.

This is Bruno, with his amp modules, and the XLR - speaker output module.

When I last saw Bruno, he was not in such good shape.
He lost quite some weight now, and looks really sharp without the (big) beard. :D

bart 11-23-2019 08:13 AM

Here are the 2 modules:

400W of (very) clean power.
I put a small coin next to it to put it into perspective.

Imagine what you can do with this kind of modules.
Like putting them in a multi-channel amp, top quality AV-receiver, of active speaker,...

Bruno put them for this demonstration in a small box. He just had to add a decent power supply.
Weight: less than 4 pounds.

bart 11-23-2019 08:23 AM

This is the 6" woofer/midrange module Bruno designed with his new company Purifi.

Material of the cone: paper.

Look at the special shape of the surround of the driver.
This reduces distortion, and allows for more supple movement of the driver.

bart 11-23-2019 08:27 AM

Bruno told us that a 4" driver is in the works as well as 8" and 10" ones.

In this demo, we listened to a cheap looking DIY small speaker with the new 6" driver + an AMT tweeter in it.

External crossover:

bart 11-23-2019 08:30 AM

DAC: the fantastic Mola Mola Tambaqui (of course, Bruno is involved in that company also):

I heard this DAC on different occasions so far.
It remains one of my favourite DACs on the market.

bart 11-23-2019 08:35 AM

This gives us the following set-up:

The Tambaqui is worth 10K, but the other components can be made cheaply.
The woofer/midrange will cost 200-300€, the amp modules the same.
This must be most worrying for many well established hifi companies!

bart 11-23-2019 08:49 AM

So, how did it sound?

We first listened to a couple of tracks that Bruno chose, like the 'Fanfare for the Common Man' from Copland.
I heard those tracks already when I listened to the Kii Three BXT speakers last month.

Wow, these little cardboard-like stand-mounts didn't sound like any other bookshelf speakers!
Bass was amazingly good for 6" drivers.
But also the midrange (cross-over at 3 kHz) was wonderful, detailed and delicate.

I asked for a track that I know very well, and have heard on dozens of systems.
Dave Brubeck's 'Take Five':


Again, the bass was terrific.
But what is even more important, the midrange was fantastic, the instruments had air around them, their placement was correct, and there was plenty of detail.
Scale was impressive for such a small speaker.

bart 11-23-2019 09:02 AM

To test what these drivers are really capable of, I asked for a test track that those who follow my threads are already familiar with.
Pachelbel's Ciacona in D minor from this album:

When it doesn't shake and rattle your place, look for other speakers!
We listened to the whole 5'25".
It did pressurise the room!
Unlike some floorstanders like the Boenicke W11 I heard earlier this year.

The drivers gently roll off under 35 Hz says Bruno.
Well, it can reach depths that go much lower, I can assure you.

I can only imagine what his 8" and 10" drivers will do, and I fully understand there will never be any need for a 12" unit.

This cheap DIY speaker easily beats stand mounts from popular brands as B&W (their 805D3), Sonus Faber (up to their highest line), Focal and the likes.

Jacques and I were greatly astonished.

We're really looking forward to what these Purifi modules will do when (more) properly implemented in a speaker with their own tweeter, which is also in the pipeline.

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