AMP-13R

This review first appeared in February 2019 on HifiKnights.com. By request of the manufacturer and permission of the author, it is hereby syndicated to reach a broader audience. All images contained in this piece are the property of Dawid Grzyb or Bakoon – Ed.

Reviewer: Dawid Grzyb
Sources: LampizatOr Pacific, AMR DP-777SE, fidata HFAS-S10U
Amplifiers: Kinki Audio EX-M1, NuForce STA200
Speakers: Boenicke Audio W8, Boenicke Audio W5, soundkaos Libération [on review]
Interconnects: Audiomica Laboratory Erys Excellence
Speaker cables: Forza AudioWorks Noir Concept, Audiomica Laboratory Celes Excellence, LessLoss C-MARC
Power components: Gigawatt PF-2 + Gigawatt LC-2 MK2 + Forza AudioWorks Noir Concept/Audiomica Laboratory Ness Excellence/LessLoss C-MARC
Rack: Franc Audio Accesories Wood Block Rack
Music: NativeDSD
Retail price of reviewed components in EU (ex. VAT): €5'800

In the summer of 2014, I met the Bakoon HPA-21 headphone amplifier which quickly became the very best-sounding machine for the notorious Sennheiser HD 800 I had at the time. I recognized that Bakoon were no ordinary operation and have been watching them closely ever since. When Martin Gateley of soundkaos offered me his big dipole Libération along with Bakoon's latest AMP-13R integrated amp for review, I happily accepted.

For Bakoon, it all started in the late '80s. Back then Japanese engineer Akira Nagai witnessed how the market shifted from analogue to digital. As a vinyl enthusiast, he found the new order dull by comparison. But because some music he enjoyed was available only on CD, Nagai's mind set upon improving their domain. He was already aware how essential to sound quality timing and accuracy were. Extra mass in turntables became lower jitter in digital devices to achieve similar results. So he built a machine with clock jitter as low as 100ps but most importantly, this experience gave him something to think about beyond the digital realm.

As a true valve aficionado, Akira Nagai had gathered thousands of tubes over the years. At some point he started wondering whether hardware powered by glass could be as accurate as his newly developed DAC. He soon concluded 'no'. That's when he abandoned valves and instead turned to the far smaller quicker semiconductors for his future projects, albeit with a twist. Despite the measurable benefits of widely popular negative feedback, he found the inherent time delay counter to his notions. To design a circuit free of time and THD distortion, Nagai-san then came up with the idea of amplifying his signal in the current not voltage domain. His solution alters the amplification factor with input and output resistors. It is very linear, of wide bandwidth, fast and inverts the usual impedance positions with an input impedance close to zero and an output impedance in excess of 100MΩ respectively. That's how the first iteration of the now patented SATRI circuitry was born to establish Bakoon Products Co., Ltd. Japan shortly after.

Interestingly, measuring instruments and industrial control systems had been Nagai's day job for years. Once SATRI and Bakoon Products Co., Ltd. were in place, he transitioned to audio full time. The full story is told in this interesting interview but there's more. Japan is filled with domestic audio houses known only to local enthusiasts. Nagai's operation too  flew under the worldwide radar for many years. Constant improvement of the SATRI circuit remained his top priority to let happy customers do all the marketing by word of mouth. Busy with ongoing R&D and keeping up with demand, Bakoon didn't pursue recognition outside Nippon for decades.