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SATRI CONNECTION

Akira Nagai Interview

Bakoon Products (short for Bakoon hereinafter) is well known and considered to be the "best" to selected audio enthusiasts by their SATRI Circuit and the excellent performance resulting from it. One key thing to note is that this fame is not generated by any marketing or advertisement, but only through sound quality and the talk of audio enthusiasts brought Bakoon up to where it is today.

 

Akira Nagai, President of Bakoon Products Co., Ltd. Japan, is the man who developed the SATRI Circuit 25 years ago. The first impression of him showed his pride and perseverance as an engineer and an audio enthusiast. The following interview was from last may when Mr. Nagai visited Korea for the hi-fi audio show.

 

 

Interviewed by Hi Fi Club

 

Q: Welcome to Korea! What brought you here today?

 

Our partner, Bakoon Products International, held a hi-fi audio show event in Seoul, so I came here to support and give a few seminars to attendees.

 

 

 

Q: How was the show?

 

It was fabulous. A lot of people came, and I was truly happy about the interests that people showed us. I also have to mention about all the fun I had with friends and organizers during and after the show.

 

Q: Bakoon amplifiers have amazing sound quality but it seems like not a lot of people know about your company and products. I personally think it will be much more popular if Bakoon puts a bit more effort into marketing and go to more audio shows and such.

 

My favorite work is designing and developing electronics. As for the marketing activities you mentioned, it needs quite a lot of investments and resources. Rather than using our resources on such activities, I prefer to concentrate more into our R&D process. I think this attitude helped us to make better products eventually.

 

 

Q: What is the desired sound quality of Bakoon?

 

What we strive for is the precise recreation of the live or recorded music. We don't just try to sound "good" because a "good sound" is very subjective and it is different for everybody. This is why we try to achieve the precision or accuracy of the live playback in the recordings, rather than trying to make products that sound "good".

 

In general, musicians at live concerts cannot play their music all over again if they make mistakes. But, when they produce recordings, they can take as many recordings as they want, in order to achieve their best take. So theoretically, musicians can try to bring out the best in their recordings, and I think it's truly disrespectful to these musicians who try really hard to create their best recordings, if I just make the products that merely sound "good" to play those. Therefore we only focus on bringing out the best of musicians as accurate as we can through our products.

 

Q: Well, your products still sound "really good" as well regardless of your philosophy.

 

When I first developed SATRI Circuit, some people told me that I was cheating. It was a bit of a violent expression saying that "Audio can't sound this good". There are still people out there, and usually they have never experienced our products, saying that SATRI Circuit is a lie. Figuratively speaking, if conventional audio circuits are airplanes, then SATRI Circuit is a rocket. It is far more advanced and more improved circuit.

 

 

Q: When and how was the SATRI Circuit developed?

 

I started developing SATRI Circuit about 25 years ago. Back then, I was just an audio enthusiast, especially for the analogue playbacks. But most of the audio sources were shifting from analogue to digital, so that I could get some of my favorite music only in digital format.

 

However, the CD sound quality could never be compared with the sound quality of the analogue records. In fact, I could not stand the dull sound of CD then. I wanted so much to fix the sound quality of CDs, and from this idea, I thought of developing my own D/A converter. I wanted to fix the process where digital signals change to analogue signals. Starting from that D/A converter, I started to think about developing the SATRI Circuit.

 

Q: It is very interesting to know that your D/A converter was made 25 years ago in Bakoon. Back then, some audio enthusiasts even got rid of all of analogue records because some of them preferred the sound quality of CD. How was Bakoon's D/A converter comprised of?

 

I was thinking of applying the advantages of analogue playbacks into the D/A converter. For example, it was a trend to make the inertia mass bigger in turntable designs, and some turntables weighed much more than a hundred kilograms.

 

So I thought, "why does the sound quality of analogue record get better when the inertia mass of turntables get bigger?". I came to a conclusion that it has to be the accuracy of the turntable's rotation speed. If there was even a tiny change in the speed of turntables, time error occurred and the sound quality was worsened.

 

 

Q: So, this is quite similar to jitter in digital, right?

 

Yes. I wanted to apply the idea from turntables to the digital circuit. In digital circuits, frequency of oscillator changes which sets the time and this results in jitter. Reducing this problem was similar to increasing the inertia mass of the turntables and it resulted in better and more natural sound.

 

Therefore, I mainly focused my very first D/A converter on reducing jitter through various methods, and as a result, the completed D/A converter's jitter was only 100 ps. During this time, the standard jitter level of CD was only about 30 ns (or 30,000 ps) and below, so it was quite an improvement, for about 300 times better.

 

Q: It is amazing. This jitter level is still quite hard to reach with modern products. Truly amazing! So, how was SATRI Circuit developed from the D/A converter?

 

Back then, I just loved vacuum tube amplifiers. I collected more than 2,000 vacuum tubes and my favorites were from Western Electric such as 300B, 350B, 310A and 310B. But I started to wonder if these vacuum tube amplifiers could have the same time accuracy like my D/A converter, which had the time accuracy of 100 pS.

 

I came to a conclusion that the time accuracy of 100 pS is just simply impossible considering the time that electrons travel in vacuum tubes. Rather, this could only be realized through using semiconductors, which is physically smaller than vacuum tubes, thus resulting much shorter travel distance and quicker response. So I've decided to develop transistor based amplifiers only, and started comparing sound coming from them to actual live music.

 

Q: So, you were trying to fix problems of vacuum tubes by working with semiconductors. How did that go?

 

Unfortunately, I could not make the circuits that satisfied me. But from that, the next question came upon me. It was quite natural to use negative feedback in all amplifying circuits both vacuum tube and transistor designs. But can the negative feedback really sustain the time accuracy?

 

Negative feedback compensates outputs with inputs, and through this, we can achieve low distortion, low noise, and high damping factor. But to output a signal that was put in, there results a delay of over a few microseconds. It then tries to compensate this delay with the input signal, and this results a even bigger problem, because some of the signal gets lost!

 

 

Q: High-end audio manufacturers nowadays are avoiding negative feedback technology. It seems like Bakoon already knew this problem.

 

To avoid this problem, there are only two ways. We could either eliminate the time delay from the beginning or abandon the negative feedback circuits. But, there is no such amplification device without time delay and using negative feedback was a common sense so I thought it was really impossible to develop an amplifier that meets my then time accuracy goal. From that moment, I abandoned all of my previous knowledge about circuit designs and went back to the very bottom of the problem, "what is amplification?"

 

Q: So the conclusion is that as long as people use the existing technology to build amplifiers, it is impossible to design an amplifier without distortion that does not use negative feedback. Right?

 

Yes. All amplifying device behaves in a nonlinear way and it has a distortion unique to each amplification device. The best way to reduce this distortion was to use negative feedback, and without this negative feedback, it was believed to be impossible to develop an amplifier without distortion. From this, I decided to control signals using current not voltage, which is exactly the opposite of conventional amplifying designs. I concentrated all of my study on controlling the current signals and developed a completely new circuit design. This resulted in a simple, yet high performance circuit that never existed before. This circuit was also free from all of the negative feedback problems.

 

Q: This kind of circuit never existed before, so I believe the products made from the circuit also made sound that never existed before. How was the actual product?

 

I brought the new amplifier to an audio enthusiasts meeting in Tokyo, which was held by a PC communication online audio club. I was the one who came farthest from Tokyo and the show started with mine. That place became completely quiet and there was no one who even said any word about testing their products.

 

I answered everybody's question and I told them how it was developed. At that place, one member told me "that's an enlightenment right there!". Japanese word for enlightenment is "satori", and that's where the name "SATRI" came from and this was beginning of the very first SATRI amplifier.

 

Q: So that was how the amplifier with SATRI Circuit was developed in a first place. Did the circuit improve after that?

 

From the first amplifier, Bakoon Products was also started. We stopped making measuring instruments and industrial control system and became a full-time audio manufacturer. With every technology we had then, we started making more advanced SATRI Circuits.

 

Q: More advanced SATRI Circuits? What are they? I also want to know about improvement history of SATRI Circuits.

 

From the very first circuit, we kept researching and we realized that in order to accurately amplify a musical source:

 

We have to avoid distortion or delay in time. So we do not use negative feedback. Second, let the ratio of resistors take care amplification to secure the linearity of amplification source. Third, accurately fix the bias current. Lastly, eliminate the interference between input part and output part.

 

These components are the core parts of SATRI Circuits developed onwards. Based on the research so far, I think we have developed the necessary circuits for accurate playback, but we will try harder to evolve the circuits so that they can be perfected further.

 

 

Q: I would like to know about your plans for new products.

 

We finished developing the flagship amplifier incorporating the circuit that was developed just now and we are currently developing source devices like flagship D/A converter and pre-amplifier. I also think that even though the performances of playback devices improve, there is no point if recording devices do not catch up to that level. So, I am planning to develop recording devices using SATRI Circuits such as mixers and microphones.

 

Q: What is the relationship between your two offices in Japan and in Korea? What are the goals for each company?

 

We at Bakoon Products Japan are currently working on developing new circuits and products, Bakoon Products International in Korea is introducing products based on these circuits to the world. We both share the technology and know-how and work together very closely. After all, we have a same goal: let more people know about us, so that we could help them enjoy listening to music more through our products.

 

 

Throughout the whole interview, Mr. Akira talked persistently with a serious, sometimes humorous attitude. We felt the master craftsman's pride and an intensely devoted individual whose goal is to study and make the best audio products. We are sure that his devotion has made Bakoon Products we know today, and will make them even more successful later on.

 

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