Gain by ratio
Two resistors set the amplification. No global feedback loop is needed to correct the stage, so there is no loop delay to smear the leading edge.
Kumamoto, Japan · Since 1974
The first microsecond is where the music lives.
The shortest path from recording to room. Zero global feedback. Zero input attenuation. A signal delay of one ten-millionth of a second. Built one at a time in Kumamoto, Japan, for fifty years.
- Circuit delay
- 1/10,000,000s
- Global feedback
- 0loops
- Same workshop
- 50years
01
The principle
Every stage you add is a decision the music didn't ask for.
Most amplifiers are born with an error and spend the rest of the circuit correcting it. Negative feedback compares the output to the input, then feeds the difference back. It lowers distortion on paper. It also bends time: the correction arrives after the note.
SATRI starts somewhere else. Gain is set by the ratio of two resistors. The output device is asked to be accurate at the first attempt, so it never has to apologise for the first attempt. The signal travels forward; the timing stays intact.
The leading edge, the breath before the bow, the room after the last chord. All of it arrives when it should.
SCL
SATRI V9.3 / HBK(I) second generation
In continuous development since 1989
In continuous development since 1989
Current is a language
SATRI-LINK carries the signal as current over BNC. Preamplifier and power amplifier speak directly, with no voltage conversion in between.
Fast enough to disappear
The SATRI circuit's delay is about one ten-millionth of a second. The CAP-1001M reaches 600 kHz and stays flat to 100 kHz.
Both inputs, one circuit
HBK(I), now in its second generation, accepts voltage or current at the input without a buffer stage. Your source chooses the language.
02
The circuit
Proof, published.
The shortest path is also the easiest to verify. These are published figures for the CAP-1001M, a 13-watt monoblock with a 0.6Ω output impedance and no global feedback.
- Circuit delay
- ~0.1µs
- Global feedback
- None
- Frequency range
- 1 Hz – 600 kHz
- THD at 1W
- 0.024% 20 Hz
- Damping factor
- 13.1–13.3 0.1–10W
- Input impedance
- 100kΩ
Published CAP-1001M specifications. THD at 20 Hz, 8Ω, 1W. Damping factor stays effectively flat across output level because there is no feedback loop to vary.
Read the SATRI technical papers
03
The range
Four ways in.
Each one necessary.
A deliberately small range, because every extra model is a compromise somewhere. Choose the power, the topology, and the inputs your system needs. Each model earns its place.
The flagship
AMP-5522
AMP-5522
Digital-control power amplifier
The most complete expression of the SATRI generation in a single chassis. Digital control of gain and bias, the surface-mount generation, and the same commitment to getting it right at the first attempt.
¥820,000 incl. tax
Discover the flagship
CAP-1001M
MonoblockThe reference, distilled.
- Output
- 13W max / 11W clean
- Bandwidth
- 1 Hz – 600 kHz
¥160,000 incl. tax
↗
SCA-7511 MK4
Stereo / monoThe compact reference.
- Output
- 15W + 15W / 8Ω
- Inputs
- Voltage + current
¥442,800 incl. tax
↗
PRE-7610 Mk4
PreamplifierControl, in current.
- Inputs
- 3 RCA + 2 SATRI-LINK
- Circuit
- SATRI-IC UL + HIBIKI
¥478,400 incl. tax
↗
HDA-8210
HeadphoneTwo ways to drive a headphone.
- Outputs
- Voltage + current
- THD
- 0.006% / 600Ω · 1mW
¥140,000 incl. tax
↗
Prices include Japanese consumption tax. International shipping and import duties are calculated separately. See the full SATRI Shop range ↗
04
The craft
Still a workshop.
On purpose.
Bakoon Products was founded in Kumamoto in 1974. Fifty years later, the company is still deliberately small: one bench, one small team, and a designer who works in the same room where the amplifiers are assembled, measured, and heard.
We stay small because it is the only way to hear the last five percent. Small is what we protect. A factory optimises for the average unit. A workshop can hear the difference between this one and the last one.
- 01One factory, in Kumamoto.
- 02One line, one bench.
- 03Every unit heard before it ships.
Most of what we make leaves Japan. If a fault appears in the first year, it goes back to the same bench that built it.
1974
Founded in Kumamoto
50+
Years, one workshop
89%
Sales outside Japan
1
Bench, one line, one team
05
The record
Heritage, and
state of the art.
The SATRI circuit has been revised, measured, and rebuilt for thirty-seven years. Every generation removed something: a capacitor, a conversion, a correction. The latest HBK(I) is in its second generation, in current production. This is the record.
-
1974
Bakoon Products is founded
Audio manufacturing begins in Kumamoto, Japan.
-
1989
SATRI V1.0
The first SATRI amplifier, MORPHEUS. Gain set by two resistors; no global feedback.
-
1998
The first SATRI-IC
BPM-7110T hybrid IC. Super-SATRI output stages follow in the AMP-5520 series.
-
2007
SATRI V9.0
A new ultra-precision current mirror cuts distortion to one tenth. SATRI-IC-SP enters production.
-
2011
SATRI V9.3
Base-current error is corrected. SATRI-IC-EX and the higher-precision UL follow.
-
2013
Best Sound, HIGH END Munich
The circuit is recognised on the international stage.
-
2014
AMP-5521
A fully surface-mount amplifier, and a new generation of circuits built around it.
-
2016
AMP-KUMAMOTO
A limited model made in the wake of the Kumamoto earthquakes.
-
2019
MJ Technology of the Year
CAP-1001 and CAP-1004 both take awards from MJ Wireless & Experiment.
-
2026
HBK(I), second generation
CAP-1001M introduces the latest input topology. SATRI V12 appears in the CAP-1005 DAC.
The SATRI principle
The amplifier steps aside.SCL · 1974
The music arrives.
06
Listen
Hear it in person.
The range is deliberately small. Tell us about the room and the music, and we will tell you which amplifier fits. Write to us, or visit the workshop in Kumamoto.
Workshop
Kumamoto, Japan
By appointment
Direct
SATRI Shop inquiry form ↗
Shipped from Kumamoto
Dealers in Korea and Australia