It was at one bookstore when Akira Nagai experienced one of the most significant moments in his life,

who had been developing precision metrology instruments in Kumamoto, Japan during 1980s. The book that he picked up contained endless arguments between a philosopher and a musician on the topic of “Time” of music and “Ksana” (刹那) from Eastern philosophy.

The concept of “How short of a time can a human sense?” did not leave Akira Nagai’s mind, as he was well aware that this question also applies to audio circuits by means of excessive time distortion, reaction delay and time-related inaccuracy. Still, conventional audio designs hardly have solutions for such problems.

 

 

 

 

 

 

 

 

 

 

After endless research and perseverance in his work, it was during a boat trip back from Nagasaki that Akira Nagai discovered the solution to his dilemma. Enlightened by this discovery, he developed a circuit that is completely new and revolutionary. The circuit then transitioned into the very first D/A converter and amplifier which brought about huge sensation, receiving countless accolades from audio enthusiasts and professionals throughout Japan.

This was the beginning of the SATRI Circuit, and the introduction of a revolutionary new audio technology. Through such innovative approaches, Bakoon was and is able to exceed the limits of conventional audio technologies.

The “SATRI” (さとり, Enlightenment) circuit is our proprietary audio technology. The term SATRI also means major technology innovation that results in artistic elevation.

 

 

 

 

 

 

 

The SATRI Circuit,

 

represents a total solution for overcoming limitations of conventional circuits.

Amplifiers that play recorded sound existed since the Edison’s “Phonograph”. Such amplifying technology is already in our everyday lives, and the so called high-end audio is still produced based on the same technology. However, those made with the conventional amplifying technology possess several limits in playing back the sound source exactly, which is the fundamental function of the audio. In order to overcome such limits, the SATRI Circuit was developed by Bakoon Products through several decades of research and development.

The SATRI Circuit initially began with the current input & current output amplifying circuit in late 1980s. Through continuous developments, the development range has been broadened, and the SATRI Circuit now includes the overall circuit design methods to achieve the desired precision of audio circuits.

It is of utmost importance for high-end audio products to reproduce music as precise and as close to the natural, live musical performances. This is Bakoon Products’ one uncompromising goal, for which we have dedicated decades of experience and effort to.

 

The SATRI-IC is “The Heart of SATRI Circuit”

and is our own original discrete design that is composed of precision transistors and resistors. Since the first launch in 1998, it's gone through several version-up processes.

 

tech-1998

BPM-7110T

This is the very first version of SATRI-IC developed in 1998. Inside its epoxy molding, there are SMD dual transistors and carbon resistors. The spelling of the manufacturer is “Bakuun Products” but later on it is changed to “Bakoon Products”

tech-2000

BPM-7110S

In pursuit of low-noise level performance, the existing dual transistors were changed to specially-selected audio transistors in 2000. However, due to an honest mistake, “a” from Bakoon was missed and it became “Bkoon”

tech-2002

BPM-7110HS

In 2002, existing chip resisters were changed to 0.1 % precision metal film resistance and in mold, 1-component epoxy resin used to improve the stability and noise level further.

tech-2006

BPM-7120SP

This is the “Super Precision” SATRI-IC. 12 additional transistors were added and the circuit board was changed to 4 layers reducing the distortion rate to the 1/10 of existing value, improving the distortion rate and linearity level by a wide margin.

tech-2010

SATRI-IC-EX

Following the latest SATRI-IC-SP, the SATRI-IC-EX now employs a total of 48 micro-sized transistors, achieving even higher level of linearity and precision.

 

 

 

 

 

 

 

SATRI Circuit Concept

satri-circuit

 

Figure A shows the basic concept of the SATRI Circuit using the SATRI-IC.

Conventional amplifiers have high input impedance and low output impedance. This is mainly because it is more convenient to control the voltage signals in the circuit. However, the SATRI Circuit is completely opposite that the input impedance input of the SATRI Circuit is close to 0 Ohms, and the output impedance is above 100 M Ohms. With such behavior, the SATRI Circuit strictly works with the current signals of the circuit.

conventional circuit Conventional Amplifier Circuit

As can be seen above in the formula (Figure B), the input voltage signal (Ein) is converted to the input current signal (Iin) by the input resistor (R). As the input impedance of the SATRI-IC is close to 0 Ohms, the voltage signal is converted preciously into the current signal.

Summing up this procedure, the SATRI Circuit’s formula of the overall gain level can be just simplified to RL / R, meaning that the amplification involves two resistors only. As a result, the circuit is now perfectly linear without uses of any other complicated unnecessary circuits, which would only distort and introduce more noise source in the circuit.

Because of such simple and smart design, the SATRI Circuit yields superiority over any other available conventional designs, and this also explains why Bakoon Products produces the most precise and natural sounding products.

Then the input current signal (Iin) goes into the SATRI-IC, from which the output impedance of the signal is converted to above 100 M Ohms, while the current signal itself remains the same. As the output impedance is very high now, the output current signal goes into the output resistor (RL) without any loss. By this output resistor (RL), the current signal is converted back to the voltage signal.