The "Improved HiB" (IHiB) output transformers are used in the Oto Phono SE Signature integrated amplifier, are custom designed and manufactured by Audio Note (UK) specifically for the Oto Phono SE Signature, and "allow the Oto SE Signature to produce impressively extended and controlled bass."
In case you are not familiar with transformer nomenclature, let me tell you what "HiB" refers to, as you will see it repeated extensively in the Audio Note (UK) white paper on transformers should you choose to read it (HERE).
The National Research Council (U.S.), Committee on Magnetic Materials, National Academies, 1985, report says, "Within the last ten years, improved grades of grain-oriented silicon steel have been introduced by various steelmakers, starting in Japan. These are often referred to by the trade name HiB steel; they have better texture, larger grain size, and lower losses at high working flux densities than conventional oriented steel."
The above National Academies report was published in 1985, but since then there has been a lot of progress in HiB steel development.
Audio Note (UK) says, in "… collaboration with our suppliers in Sweden/South Korea/Japan/USA we developed from 2009 onwards three greatly improved versions of the standard HiB material that we have been using in our basic C-core transformers since the late 1990s, a material which has also benefitted from our research into heat treatment, so even the basic HiB C-cores are now better than ever!"
There are three grades of HiB transformer cores that Audio Note (UK) currently uses depending upon the application, the Improved HiB (used in the Oto Phono SE Signature integrated amplifier), the Super HiB, and the Ultra HiB.
In case you are wondering, a "C-core transformer" refers to a transformer that is made on a core that is wound with a single wire, and in the case of the Oto Phono SE Signature integrated amplifier, the transformer core is made from the aforementioned IHiB, and is wound with copper wire.
Audio Note (UK) says, "What is important to point out is that where "normal" core materials are normally judged by their saturation behavior, our C-cores are designed to optimize the low level behavior which is where an audio signal starts, for us it is not all that interesting whether a material is linear well up its magnetization curve, as in our book the way it treats a signal when it starts is far more relevant as this has a direct impact on its low level signal linearity, which in audio is what matters to retain signal integrity."
The Audio Note (UK) C-core output transformers all utilize solid copper frames. For single-ended applications the output transformers "… are generally over specified by at least 100% …".
Once the transformers are completed, they are then "… specially impregnated and coated," as Andy has said.
As an aside, with those massive transformers used in the Oto Phono SE Signature integrated amplifier, it is heavy. The literature says it weighs about 40 pounds, but with its compact size it feels even heavier than that.
On the Audio Note (UK) web page for the Oto Phono SE Signature integrated amplifier it says, "Audio Note (UK) Tantalum resistors used in the most critical areas."
Audio Note (UK) refers to their tantalum resistors as "the Tone King" of resistors, saying, "We at Audio Note (UK) have always been passionate about component quality, and our continuing use of the finest sounding tantalum resistors for our higher-level products is testament to this passion. We have gone to great lengths to ensure a continuing supply of these wonderful, tone-full components, even to extent of convincing the manufacturer to continue production, purely to supply our requirements."
On the Audio Note (UK) web page for the Oto Phono SE Signature integrated amplifier it says, "Audio Note (UK) Copper foil capacitors used in the most critical areas."
Audio Note (UK) now makes their own copper foil signal capacitors. The Audio Note (UK) copper foil capacitors are a mylar in oil design that are encased in copper.
As Andy alluded to in his description of the Oto Phono SE Signature integrated amplifier, KAISE electrolytic capacitors are also used in the design, and the KAISEI electrolytic capacitors are a near copy of the highly regarded Rubycon Black Gate capacitors.
On the Audio Note (UK) website it says about the KAISEI, "… use all of the same materials as these supreme components (the same special electrolyte, foil and construction quality) apart from the hyper expensive and extremely difficult to produce Graphite impregnated paper, so the only difference between the KAISEI capacitors and the forthcoming Black Gate replacements is that the paper is not graphite impregnated in the KAISEI, otherwise they are the same."
Audio Note (UK) Research & Development – Andy Grove
While visiting Audio Note (UK) I had told Andy that in my day job as a physical scientist (now retired), I reviewed and oversaw research projects and programs for the USA's Office of Science National Laboratories.
Many fundamental science research projects were structured to include three research components: collecting experimental data for a given research project, comparing the collected data to data that theory would predict for the research project, and the use of supercomputers for computational modeling and data intensive computing to gain new insights on how the experimental data and theoretical data might relate.
The coupling of experimental research, theory, and computational methods provides scientists a powerful way of advancing the sciences to meet the needs of today's world.
In the photo above, you can see me as part of a review committee for an annual review at the Argonne Leadership Computing Facility some years back. There's a lot of exciting and important science that is enabled by cutting edge supercomputing capabilities. In the photo we were standing in front of Mira, a 10-petaflops IBM Blue Gene/Q system, which at the time was considered a leadership class machine.
I knew from conversations with Andy that he takes his research & development activities just as seriously as any scientist in a national laboratory does, and I asked Andy if he would be willing to share with us a little more about his thoughts on research & development in audio.
Here's what Andy told me:
"There are those research & development topics that (1) fit the accepted audio theoretical or scientific framework, (2) or are theoretically or scientifically plausible, but which aren't easily substantiated, (3) or those things that work to make an audible difference, but we have little or no idea why, and (4) those things that are utter nonsense (which I'll talk about at some other time).
Reformulating, we can see that 1, 2 and 3 aren't strictly exclusive, and, in general, are something like three nested sets:
C is the set of that which fully fits the accepted framework.
P is the set of that which works, and does so within the realms of accepted theory, even if substantiation is difficult or impossible.
W is the set of that which works or makes an audible difference, even if we don't know how.
C is a subset of P is a subset of W.
C ⊂ P ⊂ W
Much of conventional audio engineering and its measurement regime, exists within set C, even though we aren't exactly sure about how to interpret these measurements in relation to their impact on the listening experience. It's more a case of trusting that a change in the magnitude (more or less) of some parameter will result in better reproduction. Of course, 'standard' audio measurements are extremely important, so audio tends to be an expensive hobby by way of test equipment.
However, let's perform a semi-scientific thought experiment: Take two identical guitars, one fitted with bronze strings, the other steel (or go finer grained, and use pure nickel vs steel). The experiment is to take measurements, double blind, and using only a continuous sine stimulus and an audio test instrument. After the fact, the experimenter, who is a non-musician so as not to cause bias, must define the differences between the two guitars, how they are relevant to the guitar's tone, and why a musician may choose one over the other.
You can imagine it would be difficult, if not impossible, for our experimenter to define what's going on, especially as a non-musician, and, he may well conclude that there is no appreciable difference between the two guitars: They are both tuned to the same intonation, therefore they must sound the same, because (dogma says) the human ear cannot detect such subtle differences.
Unfortunately, we live in a society which is verging on fundamental materialism, and, from that, stems the sentiment that information is more valid if it is arrived at by an axiomatic, sequential process. Of course, let's not forget that science, and the scientific method have brought humans many benefits. However, what I am leading to here is the formation of a 'mental policy' from a high-school level of understanding of the subject in question, often not actually gained in high-school, but simply acquired as second hand, perceived wisdom.
Therefore, our skilled experimenter, not being a musician, is very likely to conclude there is no difference between the two guitars, because he or she has no experience when it comes to understanding that subtleties might be important. Those laymen reading the test report will most likely extrapolate that this means no-one can tell any difference between the guitars, and, unfortunately, further postulate that to claim any difference is delusional.
I guess we can sleep sound in our beds that there is always music out there which is played on second-rate instruments, so no need to feel a sense of being ripped off by deluded musicians playing Martin guitars, Stradivarius violins, or such preposterous machines as Bosendorfer or Fazioli pianos. Waiter, take this old wine away and get me some new stuff immediately!
Yet, luckily for us, it's rarely called into question that a musician can tell the difference between two different types, or even brands of strings, because it is deemed feasible that he or she may be able to hear a difference, due to, for example, a difference in material density and/or Young's modulus. This is what I mean by set P.
Set W, the superset, is much more difficult to define with any kind of technical language, because it contains elements of 'I don't fully understand why or how it works, but it does, and it doesn't hurt anything else, so I use it.' It's pretty normal, arriving at useful information empirically. We are humans, with a limited time here, and it's impossible, and undesirable, to rigorously justify everything we do, especially when it's to do with the enjoyment of music, rather than analyzing it.
As I mentioned above, such information arrived at empirically, by inspiration, or simply by fumbling around in the dark, is regarded as being less valid, which is incorrect; truth is truth regardless of the path trodden to obtain it. And, it's interesting to note that we are talking about information here which is gained first-hand, while those criticizing it are often observing a kind of faith, quoting from what may as well be a religious text as far as their own depth of actual experience with the subject really is.
I would like to mention here that those actually involved in science and mathematics know that plain inspiration plays a very big part in both problem solving and discovery; the idea comes first, and the proof of it afterwards. Furthermore, our accepted theory of the world relies on mathematical shims such as Renormalization and Perturbation Theory to work, it's not all neat formulae and spotless lab coats like a 1950s Sci-Fi movie.
Looking at this from a different perspective; we are all familiar with waiting in a railway station for a loved one to arrive. Over the din, first you hear their footsteps, then their voice as they call out to you. Our ear/brain system not only separates some complex waveforms from a crazy 3D sound field, but meaning from it too. We can hear our friend is wearing a new pair of shoes, and sounds a bit pissed at you arriving late for the pickup.
Studying that sound-field on a scope or FFT will tell you very little, and will certainly reveal nothing of actual meaning, not in a human sense.
What I am waving my hands at here is, although subject to subjectivity, the ear/brain system is incredibly sensitive and has incredible resolving power of complex sound fields, like an orchestra in a concert hall. And, it seems very likely that even our best test equipment isn't capable of resolving everything that is happening in an audio device, or, at least we don't have a method of displaying resolved information visually in a such a way that we can sensibly interpret or understand it.
This situation is a little strange because it's well appreciated that, even though our eyes aren't really all that good optically, we can recognize a face in a crowd and drive a car, and, there is considerable research taking place in these areas. Our sense of taste and smell is another interesting area of perception, especially as combinations of chemicals can evoke the image of a fruit, or a place or person from the distant past, yet, we are to believe that an FFT of a 1kHz sine wave is all we need to know about the entire audio chain, from the consciousness of the musician to that of the listener?
What's particularly disappointing is the fundamentalist vehemence with which some people feel the need to attack the type of research & development we do. Audio is a sizable industry, and there are many very clever people working within it, as well spending money on finished products and components for home builds of recording, reproduction, and instrument electronics.
It seems like in high-performance audio we've been on the receiving end of flak, ridicule and insults for too long. The reality is that when doing research & development in audio to advance the state of the audio arts it is necessary to investigate all those things that are important to understanding what is going on from both theoretical and subjective perspectives.
We must investigate those things that fall into the accepted audio theoretical or scientific framework, those things that are theoretically or scientifically plausible, but which aren't easily substantiated, and those things that work to make an audible difference, but we have little or no idea why. That's all necessary in order to advance the state of art in music reproduction."
Many thanks to Andy Grove for explaining his philosophy and methods for doing research & development for audio.
While discussing research & development at Audio Note (UK) with Andy, I was impressed with the level of rigor and discipline employed, which was truly representative of the same sort of level of rigor in research & development that you see in the USA's cutting-edge National Laboratories, like for example, with the first-of-its-kind imaging Time-Of-Propagation counter (iTOP) that the project team I was the Federal Project Director for built and installed into the Belle II detector at the SuperKEKB accelerator complex at KEK in Japan.
Andy collects experimental data from measurements and listening trials, evaluates how it fits in with accepted theory, and also uses computational modeling to gain a greater understanding as to what is occurring, just as a scientist in a USA National Laboratory would do.
However, in Andy's research & development, there's an additional highly specialized supercomputer he uses to validate results, that of the human brain and auditory system.
Long time readers of mine know of my interest in research into the neurobiology of music, a field that is growing, and revealing fascinating insights into what aspects of musicality and sonics are key to the reproduction of music in the home (you can read more on this topic HERE).
I think it is impressive how Andy and his Audio Note (UK) colleagues go about doing research & development to advance the audio arts.
Oto Phono SE Signature Integrated Amplifier – Amy Tweed's Amplifier Build!
One of the things that I observed—and very much appreciated—about Audio Note (UK) while I was visiting was that it is very much a family-oriented business, with Peter Qvortrup, Lesley Fennell (Peter's wife), Emily Qvortrup (Peter's eldest daughter), and Daniel Qvortrup (Peter's son) all being involved in the day-to-day business activities.
Not only is Peter's family heavily involved in Audio Note (UK), but that same family-like atmosphere permeates through the staff as well. I was impressed to note as I walked around Audio Note UK headquarters how happy people were while doing their work, and how gracious and thoughtful they were towards each other, and it was obvious to me that they care about each other.
The staff of Audio Note (UK) reminded me of being more like an extended family than employees who just come in and then go home after a day's work.
Take for example, Amy Tweed (above), the engineer who assembled the beautiful Oto Phono SE Signature Integrated Amplifier you see in the accompanying photos.
"Amy has been with Audio Note UK for years", her colleague Micky Seaton told me, who made it a point to tell me what a fine assembly engineer Amy is, "Amy is at the forefront of build and quality, she knows how to build components that create beautiful music," as well as how Amy took it upon herself to make the best possible version of the Oto Phono SE Signature Integrated Amplifier for yours truly.
I'm impressed that Micky made it a point to tell me about Amy (Micky and Amy are in the photo below), and I'm impressed with Amy's level of expertise, care, and consideration in building the Audio Note (UK) Oto Phono SE Signature integrated amplifier for me to write about for all of you. It makes me feel cared for too, and Amy's amplifier build is a work of art!
You rarely see that kind of dedication and care in today's world, and it impresses me, and that's why this section of this article is titled "Oto Phono SE Signature Integrated Amplifier – Amy's Amplifier!"
That's my way of saying, "Thank you, Amy, I appreciate you, your talent and knowledge, your care and dedication, and your fine craftsmanship in creating this Audio Note (UK) Oto Phono SE Signature integrated amplifier just for me."
I might add that when you place an order for any product from Audio Note (UK), each product is built just for you after you order it, and that same dedication, skills, and tender loving care that Amy put into building the Audio Note (UK) Oto Phono SE Signature integrated amplifier for me, goes into each and every Audio Note (UK) product they build for you. I find that to be very impressive and refreshing indeed!
The Review System
Initially I installed the Audio Note UK Oto Phono SE Signature integrated amplifier into my vintage Altec 832A Corona loudspeakers based system—more HERE—to get some run-in time accumulated on it while finishing up another feature article for Positive Feedback.
After run-in was nearly complete I installed the Audio Note UK Oto Phono SE Signature integrated amplifier into my vintage "Stokowski" Altec loudspeakers-based system.
In the above photo you can see the Acoustic Revive RAF-48H Air Floating Board isolation device that the Oto was placed upon for the review.
The "Stokowski" Altec's were custom built for conductor Leopold Stokowski in the early 1960s, and Frederik Carøe (Duelund Coherent Audio) and I teamed to build state-of-art Duelund CAST tinned-copper crossovers for them that I described in the Positive Feedback feature article "The Duelund-Altec Project – Dare to Dream!" (which you can read HERE).
The "Stokowski" Altec's with their Duelund CAST tinned-copper crossovers are the highest performing loudspeakers I have ever encountered for what I value in the reproduction of music, and they seem to get the very best performance out of every amplification component I have tried with them, and their high-sensitivity makes them a perfect match to the Oto Phono SE Signature integrated amplifier's 10 watts of power.
Speaker cables from the "Stokowski" Altec's to the Audio Note UK Oto Phono SE Signature integrated amplifier were the Duelund DCA16GA tinned-copper cables with a baked oil-soaked cotton dielectric. Wire ends for the speaker cables were unterminated, because I think they sound better that way.
An Acoustic Revive Absolute power cable connected the Audio Note UK Oto Phono SE Signature integrated amplifier to an Acoustic Revive RPT-6 Absolute NCF Power Distributor, which in turned was connected to wall AC with another Acoustic Revive Absolute power cable.
The wall outlets used in this review system were fitted with Acoustic Revive customized Oyaide R-1 outlets, Acoustic Revive CB-1DB Receptacle Base Plates, and CFRP-1F Carbon Fiber Outlet Plates.
