Manufacturer: SPEC CORPORATION
here is not too many people like Mr Shirokazu Yazaki. I was tempted to write something like: are extremely rare, but I managed to hold myself back. He is an engineer with impressive education and immense practical experience with both, analogue and digital devices. He created such a remarkable devices like TEAC A-7300 reel-to-reel, high quality cassette recorders including Pioneer CT-95, he is also behind the best multi-format DVD-Audio/SACD Player, Pioneer V-AX10. What's more, he's also a brilliant manager who lead large teams and large companies for years as he did for 17 years for Pioneer Corporation where he was in charge as a group leader or a manager in the engineering department of mainly cassette tape recorder, and later as the general manager of DVD engineering department. He shared the story of his life with „High Fidelity” Readers in the article My private history of audio. And on top of all that Mr Yazaki is a music “addict”.
Want more? - No problem: in his private life Shirokazu-san is a great fan of tubes, SET amplifiers and horn speakers. To share his experience about the wonderful sound of extremely rare tubes with a wider group of music lovers he decided to build, together with his friend Honda-san, class D amplifiers that would sound like the best tube ones. Let me remind you that both gentlemen worked together for Pioneer, but beginning 20th century Honda-san left with his family for USA, where he took up the job in International Rectifier, a manufacturer of semi-conductors. He developed a class D amplifier for this company. Soon after a third engineer joined these two - Banno-san, today a chief engineer of SPEC Corporation, they found proper oil coupling capacitors and finally designed and manufactured the class D Real-Sound Amplifier.
I was lucky to reviewed the first unit that came to Europe and ever since I couldn't shake the memory of this immensely dense, rich sound and how wonderful music sounded when played via this amp. It was the first time when I saw something more in the “switching-mode ” amplifier – its sonic signature truly offered a resemblance to very expensive tube amplifiers, thus realizing the main goal formulated by its designers. Today company offers three integrated amplifiers: RSA-F33EX, RSA-M3EX, RSA-V1EX and the latest, RSA-717EX, phonostage RSQ-S1EX, and a fascinating turntable GMP-8000. So one could build almost a complete system with SPEC devices. SPEC does not offer their own loudspeakers. They use (I dare to take some credit here) Kaiser Acoustics http://www.kaiser-acoustics.com and Amphion ones.
The line-up is completed with oil and mica capacitors of the MC-DA line which is quite unusual for a manufacturer of very modern components. But once we realize that Shirokazu-san loves tube amplifiers all become clear. As he told me finding right capacitors was a key to realizing his concept of Class D amplifiers sounding like best tube ones. He chose oil caps, once produced by WEST-CAP, and presently offered by Arizona Capacitors.
These capacitors became sort of a central element of the whole design of a new product, I haven't even mentioned yet - Real-Sound Processor. I was the first non-Japanese who had a chance to try this product out in his own system and it took me quite some time to realize what this small box did for the sound. Falling in love with it was in fact only a matter of time. RSP-101 http://www.highfidelity.pl/@numer--40&lang= is a small, wonderfully made wooden box with a pair of speakers posts. And that's it. One connects it with loudspeakers posts in parallel with speaker cables. Once I did it, what I heard took me by surprise and forced me to give it a serious thought. I repeated this experiment again some time later, when I received a newer version, model RSP-501EX. I was truly honored by a fact that I received the first pair ever produced, with serial numbers 0001/0002. And again – impact on sound was even greater.
Mr Shirokazu Yazaki describes Real-Sound Processor as „Impedance Compensator” that works in a similar way as loudspeaker's crossover. But unlike them it is a more versatile product, as it might work well with many different speakers and amplifiers. In theory it should do a good job for all solid-state amplifiers, including those in Class D and loudspeakers with “difficult” impedance curve. But experience shows that it always works. As my reference power amplifier I use Soulution 710 that offers uniquely high damping factor and a very fast signal risetime. M40.1 loudspeakers, my personal favorite, offer relatively (at least in theory) friendly impedance curve. And yet the RSP-501EX, that I've been using for quite some time now, turned out to be a fantastic, natural partner for this duo. More about this “magical box” in its latest incarnation called RSP-901EX directly from Mr Shirokazu Yazaki.
In the photo: Mr Shirokazu Yazaki (second from the left), Mr Banno (in the back) and people from International Rectifier, listening to SPEC amplifier.
I’m so happy to have the chance for talking about the latest Real-Sound Processor, RSP-901EX, because that it is not only our new product but also might be the ultimate improved model I have ever developed and I hope it would be a good news for all of music lovers live in overseas.
The operating principle of “Real-Sound Processor” had been made in public on the Japanese specialized magazine named MJ, “AUDIO TECCHNOLOGY” by Mr Yasui throughout 1971. He just drought out this concept as “ Impedance Correction” for speaker. Yasui-san was a senior amateur researcher and a person of authority of semiconductor linear amplifier. At that time he got into the conclusion that only the pursuit of improving the static characteristic of power amplifier could never bring the superior sound. And also he set up the importance of amplifier’s dynamic characteristic including the actual movement of speaker to get musical sound. But still right now, after more than 40 years passed I regard his view point as an excellent insight and much further a relevant challenge for the present “audio-technology”. Sorry to say, I should recognize we only know the improving the dynamic characteristic of the system consisted of amplifier and speaker might be an extremely important factor for getting superior sound quality.
For that matter, we are not able to reach at an effective measuring method to be fixed the dynamic behaviors and also expose the real relations between the characteristic and our hearing. I suppose, so many reasons might exist. But one of the major difficulties of analysis of the dynamic characteristic would be speaker itself. Needless to say, speaker is the transducer which converts some electric energy to kinetic motion. But if I were to say frankly, this transducer would be a collective of imperfect characteristic for being driven by amplifier. How fluctuant the impedance frequency characteristic is, you know. Yes it might be quite simply the hard load of amplifier. But also you should remind one more thing, “Counter-electromotive Force” of speaker. The motion of speaker is started in the magnetic circuit or voice-coil of the unit by the current be flowed from amplifier on Fleming's left-hand rule and at the same time this motion raises up counter-electromotive force in the voice-coil by Fleming's right-hand rule. It is true that amplifier drives speaker, but would be the fact that speaker affects amplifier by this counter-electromotive force. And this counter-electromotive current returns to the amp via the speaker cord, making it difficult to drive speaker in accordance with the input signal. And this current causes negative effect especially on the traditional semiconductor linear amplifier. .
Since the transfer function of semiconductor is poor in linearity compared to tube, this type of amplifier inevitably needs correct the static characteristic by performing negative feedback circuitry. But this negative feedback makes the amplifier stage vulnerable to the counteraction, counter-electromotive current from speaker, causing complicated phase delays inside of amplifying stage. Needless to say, this physical phenomenon hurts the sound quality of the audio system including amplifier and speaker.
Because again, our “Real-Sound Processor” has two major functions, one is making an improvement to reduce the fluctuations of speaker’s impedance frequency characteristic. The other is absorbing that counter-electromotive current from speaker including network composed of some inductors. Accordingly, the processor makes amplifier possible to drive the speaker more faithfully for sound source, improving the sound resolution and the start-up, also reproduces natural resonances. Above all you could find out the deep, rich and fascinating tonal characters you have never experienced before and also agree how amplifier could drive speaker easily!!
I had tried so long time to seek out improving the sound quality of “Real-Sound Processor” and learned that only the tonal or the sound quality of the parts, resistor and capacitor decide the sound itself. You should recognize that the perfect characteristic resistor and capacitor has never existed at all ages and countries. For example, capacitor is consisted of mainly capacitance, small quantity of resistance and inductance. Also we should remind the matter of material’s physicality. Sometimes when I make hearing tests for capacitor, I feel the unique tonal character of dielectric material or electrode itself.
By the way, language above all Japanese is far away from European language.
As well, please pay attention to the appearance of RSP-901EX. It’s like a jewelry box made of real spruce from north America with string instrument’s color. And 901EX’s box is produced by famous “Shirakawa Co., Ltd” at Hida-Takayama, beautiful historic town. You will see also woodworking is the Japanese traditional handicrafts. I believe firmly that RSP-901EX could bring out the full potential of your system and you could fully enjoy the “Real-Musicality” through “Real-Sound” of 901EX!!
Test was performed as an A/B/A comparison, with A and B known. There were few stages of this test. First I compared RSP-901EX with two previous versions: RSP-101 (No 0029/0030) and RSP-501EX (No 0001/0002). Then I listened to my system with and without RSP-901EX. The boxes were connected with speakers using short (around 60cm) runs of Oyaide Tunami speaker cable and were placed on Harbeth M40.1 bases. To even better decouple them from the ground I placed them on small Acoustic Revive TB-38H platforms; I use one of these under my power strip – it really works! For the test I used following power amplifiers: Soulution 710, Accuphase E-470, Accuphase A-70, SoulNote SA730, Chord SPM 1200 MkII and Audio Research Galileo GS150.
Recording used for this test (a selection)
No matter how “crazy” or “snake-oil-like” such products might look like to skeptics, they are usually based on a solid scientific knowledge and measurements. Especially when it come to Japanese products. Over the years I learned that Japanese manage to combine solid facts, modern technologies with things that, at least at the first sight, seem to belong to the world of magic. An example? How about Mr Ken Ishiguro, chief of Acoustic Revive, who made a quartz crystal one of key elements of his products. And as one can easily check, all his products are supported with serious scientific research and measurement's results.
Despite the facts lots of hardheaded engineers treat such products as snake-oil that won't help, nor harm any audio system(more HERE). But they are simply wrong! Knowledge gained through experiments plays a great role in audio. Which is obvious once one starts to use such a fantastic product as RSP-901EX. Product created by such an unusual person as Mr Shirokazu Yazaki. No matter what one thinks about such product one has no ground to doubt competency of Mr Yazaki as a skilled, experienced engineer.
„Real-Sound Processor” introduced to the sound depth and serenity. Smoothness and richness. These changes I mentioned are not limited only to tonality, or dynamics, or resolution of the presentation (although how much more resolving presentation becomes might be easiest to recognize). In fact it introduces deep, structural changes to the sound, reconstructing its very fabric from inside. All these superficial differences, I mentioned, very easy to notice. But I think that these changes are different from what other amplifier, source or loudspeakers introduce to the system. It reminded me of what a complex approach to the problem of vibration in the system, by using high quality anti-vibration rack, placing each component on a platform and so on, can give user in terms of system's performance.
The impact on sound of the first version of RSP, model „101”, I perceived as the sound getting darker. Each time a newer model replaced older, so when I changed „101” to „501”, and now „501” to „901”, this effect was getting stronger. I noted this aspect in particular because it shows how complex system our hearing is, and how insufficient, how simple is our vocabulary when it comes to describing it. Why would I say that? Because the easiest way to describe Mr Shirokazu's “correctors” would be to say that they change frequency range by limiting the top extreme, the treble. That's what subjectively listener feels like at the beginning. But the more experienced one, given it some time, would realize soon that there is in fact more information in the top end, not less. With „901” much more!.
It is an extraordinary experience – comparing sound of my system with and without „101” I could easily recognize that the level of background noise was lower and thus there was more information in the sound. „501” worked in the same way and the results were even better. „901” is another step in the same direction, or maybe even a huge leap which makes it sound like a totally different product and not just an enhanced version.
It results in a much better differentiation of events on the soundstage. Everything happening deeper into the stage becomes more clear, more distinct. Drum sticks hitting drums echoed somewhere in the back of the hall on Milt Jackson's album, which became much clearer with “901” in the system. Thelonious Monk's piano seemed even bigger, more three-dimensional than usually because of a more audible response of the surrounding environment. The Solo Monk album seems to be recorded in a very direct way, with microphones placed almost inside piano's body. And maybe that's how it actually was recorded, but with „901” presentation included also more information from outside the body. In the Welcome To My World opening Depeche Mode's album Delta Machine there is some short reverb added to Dave Gahan's voice. One can hear it even without Japanese boxes but when one lets them do their job one finally realizes why this reverb was added – it was done to create sort of a “buffer” around the voice – this way voice didn't have to be loud to be well heard. Without SPEC device vocal was placed deeper in the mix and it wasn't so well defined.
The latest version of RSP enriches the sound, makes it deeper. Listener has an impression of much, much more controlled presentation. But, to be fair, sound without RSP seems more direct, with more powerful attack phase. Once we connect RSP-901EX to our speakers we quickly realize that without it presentation is “simplified”, not to use the term “ordinary”.
Exactly on the day when I took photos for this text and wrote the summary we had a partial (3/4) Sun eclipse in Poland. In Cracow it started at 9.44 A.M., the maximum eclipse was at 10.53, and it ended at 12.04. Photos I took are time-stamped at 11.00 and there is my daughter on one of them looking at the Sun through an X-ray photo. There is something mystical about how drown we all are to the star that gives us life. Already the Ancients knew that and today we know it even better as we know much more about how it all works. If today such an ordinary (in a cosmic scale) event initiates such a huge, almost primal emotions, how powerful these had to be for our ancestors?!
It works in a similar way with accessories like RSP-901EX: we know how they work, what's the scientific background, and yet hearing them work still comes as a surprise. It's even more so because they change an already good performance into even better, more refined, more dynamic, smoother and yet offering even more information in the top end and lower bass. Each version of a Real-Sound Processor works very well, but each one delivers even better performance then its predecessor. Now I don't have a problem with selling „101” and „501” and let them serve other music fans. I am going to keep „901” for myself because it is simply the best one in what it does.
Mr Shirokazu Yazaki is a flesh&blood engineer who is not afraid of the newest inventions, solutions and technologies, who even participates in creating them. He does it though, in his own way using what he knows to be good. Only by being aware of the past we might build the future, so to speak. His choice of cables for his own, private audio system with tube amplifier with unique tubes and horn speakers complements this particular setup. He uses Belden 8402 IC and NOS Western Electric WE16GA speaker cable (more HERE). I received both as a gift from Mr Yazaki, who asked me to share my impressions with him on these products.
So it is not a universal rule that every „vintage” product sound better than those from current production. If I understood Mr Yazaki correctly he did not claim that these were the best cables he knew, but rather that with these two he found sound features he was after. So apart from comparing their sound with the sound of cables from current production, I wanted to find out what it was exactly they offered, that made them one of the kind for Mr Yazaki.
We live immersed in music. Due to the second wave of digital revolution in audio that happened initially thanks to mp3 files and later was carried forward by portable Apple players, the access to the music is so much more common then ever. The third stage of this revolution is streaming – official reports state that sales of music on physical medium decreases, but, which is surely surprising, also incomes from selling music over Internet systematically decreases. The sector that is growing rapidly though, is streaming of music.
An easy, common access to information, and that's what music is after all, has it's “Dark” side – it eliminated “central” sources of information on music – specialized magazines played hat role once. Today there are thousands of different websites about music to be found on the web, most of them really useless, some with interesting information, but it makes it difficult to find reliable info on music that interests us. There is a bright side of things – a “bigger”, more differentiated views spectrum, on the other hand – that means a lower “average” level of available information.
I think that we might be facing another “age” of „gurus” and specialists. People left in a vast space sooner or later, after initial euphoria, realize that they actually are left alone. So a natural reaction is to look for some sources of knowledge. My sources are paper magazines, radio, concerts and friends. Most information about music comes from radio and my friends. Without a friend in Japan I would probably never get to know the music of Japanese progressive group called Yonin Bayashi. I received two albums of this group from Mr Mark M. Suzuki, the chief engineer of Accuphase. It all started with him noticing a photo of Accuphase E-470 amplifier (in my review), with the Kameleon Records release of Skaldowie on top of it.
As already mentioned, Yonin Bayashi play progressive music. "Yonin" actually means „four people”, "Bayashi" are musicians playing traditional Japanese music. Their first album, Isshoku-Sokuhatsu, was released in 1974, which means something like: “a scary crisis”. Text is sang in Japanese and music reminded me a bit of Emerson, Lake & Palmer. Golden Picnicks is their second album, released in 1976. Suzuki-san told me that his wife loved the last piece of this album, a beautiful, instrumental A song for lady Violetta. Also on this album all texts are in Japanese. Music on this album seems to foretell what only three years later (in 1979) Pink Floyd proposed on their famous album, The Wall. Interestingly on the cover of Golden Picnicks one might find a date: 1979…
Sound quality of both albums is really good, I would say that quality of Isshoku-Sokuhatsu is very good, and of Golden Picnicks extremely good. I also truly enjoyed this purely progressive music. At the beginning the Japanese language got me bit confused but later it became inextricable part of this music. I'd recommend these albums to any true music fan who appreciates good music. These digital re-issues were created for Japanese market but I'm sure that one might find a way to acquire them. And if you do – please remember that credit for the discovery of this music goes to Mr! I thank him by sending him new remasters of progressive albums of Niemen and Skaldowie from 1969, recently released by Kameleon Records. I hope he will like them…
- Turntable: AVID HIFI Acutus SP [Custom Version]
- Cartridges: Miyajima Laboratory KANSUI, review HERE | Miyajima Laboratory SHILABE, review HERE | Miyajima Laboratory ZERO (mono) | Denon DL-103SA, review HERE
- Phono stage: RCM Audio Sensor Prelude IC, review HERE
- Compact Disc Player: Ancient Audio AIR V-edition, review HERE
- Multiformat Player: Cambridge Audio Azur 752BD
- Line Preamplifier: Polaris III [Custom Version] + AC Regenerator, regular version review (in Polish) HERE
- Power amplifier: Soulution 710
- Integrated Amplifier: Leben CS300XS Custom Version, review HERE
- Stand mount Loudspeakers: Harbeth M40.1 Domestic, review HERE
- Stands for Harbeths: Acoustic Revive Custom Series Loudspeaker Stands
- Real-Sound Processor: SPEC RSP-101/GL
- Integrated Amplifier/Headphone amplifier: Leben CS300XS Custom Version, review HERE
- Headphones: HIFIMAN HE-6, review HERE | HIFIMAN HE-500, review HERE | HIFIMAN HE-300, review HERE | Sennheiser HD800 | AKG K701, review (in Polish) HERE | Ultrasone PROLine 2500, Beyerdynamic DT-990 Pro, version 600 - reviews (in Polish): HERE, HERE, HERE
- Headphone Stands: Klutz Design CanCans (x 3), review (in Polish) HERE
- Headphone Cables: Entreq Konstantin 2010/Sennheiser HD800/HIFIMAN HE-500, review HERE
- Portable Player: HIFIMAN HM-801
- USB Cables: Acoustic Revive USB-1.0SP (1 m) | Acoustic Revive USB-5.0PL (5 m), review HERE
- LAN Cables: Acoustic Revive LAN-1.0 PA (kable ) | RLI-1 (filtry), review HERE
- Router: Liksys WAG320N
- NAS: Synology DS410j/8 TB
- Interconnects: Acrolink Mexcel 7N-DA6300, review HERE | preamplifier-power amplifier: Acrolink 8N-A2080III Evo, review HERE
- Loudspeaker Cables: Tara Labs Omega Onyx, review (in Polish) HERE
- Interconnects: Acoustic Revive RCA-1.0PA | XLR-1.0PA II
- Loudspeaker Cables: Acoustic Revive SPC-PA
- Power Cables: Acrolink Mexcel 7N-PC9300, all system, review HERE
- Power Distributor: Acoustic Revive RTP-4eu Ultimate, review HERE
- Power Line: fuse – power cable Oyaide Tunami Nigo (6m) – wall sockets 3 x Furutech FT-SWS (R)
- Power Cables: Harmonix X-DC350M2R Improved-Version, review (in Polish) HERE | Oyaide GPX-R (x 4 ), review HERE
- Power Distributor: Oyaide MTS-4e, review HERE
- Stolik: SolidBase IV Custom, read HERE/all system
- Anti-vibration Platforms: Acoustic Revive RAF-48H, review HERE/digital sources | Pro Audio Bono [Custom Version]/headphone amplifier/integrated amplifier, review HERE | Acoustic Revive RST-38H/loudspeakers under review/stands for loudspeakers under review
- Anti-vibration Feets: Franc Audio Accessories Ceramic Disc/ CD Player/Ayon Polaris II Power Supply /products under review, review HERE | Finite Elemente CeraPuc/ products under review, review HERE | Audio Replas OPT-30HG-SC/PL HR Quartz, review HERE
- Anti-vibration accsories: Audio Replas CNS-7000SZ/power cable, review HERE
- Quartz Isolators: Acoustic Revive RIQ-5010/CP-4
- FM Radio: Tivoli Audio Model One