WATATSUMI inherits the concept of the original TSURANAGI while aiming for improvements

WATATSUMI inherits the concept of the original TSURANAGI while aiming for improvements in every aspect. To achieve this, we completely redesigned the circuit from the ground up and adopted the low-noise BIS2.0 input stage used in FUGAKU.

The output amplifier has also been upgraded to BOS1.5, increasing the maximum output to 2000mW+2000mW at a 16Ω load—approximately three times higher than before.
The PCB layout was also fundamentally optimized by leveraging the expertise and knowledge we have accumulated over the years. The power supply circuit has been updated to BPS1.5, providing more stable voltage and significantly contributing to deeper and more grounded low-frequency reproduction.

In addition, the internal wiring uses pure silver wire with a greater conductor volume than SHIROGANE, and high quality sound processing has been applied to electronic components to ensure compatibility with a wide range of cables and players.

Next-generation reference model

Brise Audio WATATSUMI is a new portable amplifier created as a next-generation reference model. It was developed from scratch to meet modern requirements: high-impedance headphones require high power, and sensitive in-ear models require low noise. The amplifier is built on a new circuit design using technologies tested in the FUGAKU model , and inherits the TSURANAGI concept, but surpasses it in all key parameters.

The amplifier design

The amplifier design uses proprietary pure silver wiring with a larger cross-section than the SHIROGANE model, and a completely redesigned printed circuit board with six layers and thickened copper tracks. Thanks to this architecture, it was possible to achieve low trace resistance, improved transmission of low frequencies and reduced distortion even at high output power.

WATATSUMI is equipped with balanced inputs and outputs on 4.4 mm connectors, and also supports unbalanced inputs via 3.5 mm. The input signal can be automatically detected without switches. When using an unbalanced source, the amplifier converts the signal to a balanced one for the output. A high-quality electronic regulator MUSES72320 is responsible for volume control.

Maintains the purity of the signal throughout the path

The built-in BOS1.5 amplifier with current feedback and the BIS2.0 input stage provide high linearity and low distortion. Thanks to the implementation of DC servo control and bipolar power supply, the amplifier does not need decoupling capacitors and maintains the purity of the signal throughout the path.

Particular attention has been paid to the body: it is completely milled from an aluminum block, complemented by a decorative insert made of forged carbon and a base with Ultrasuede® to protect the surfaces. The volume button is made of titanium and is protected from accidental touching. The device maintains stable operation even with short-term temperature jumps, thanks to an effective heat sink, similar to that used in FUGAKU.

Attention to Chassis Design

In WATATSUMI, the amount of components was increased to achieve a significant improvement in sound quality.
To maintain a size comparable to previous models, the chassis is CNC-machined from a solid block of aluminum, allowing for a higher-density and more flexible internal layout.

Power Section: BPS1.5

The power supply, as with previous models, consists of a total of six independent rails for both left and right channels.
The major changes in the power supply circuit are the increased number of decoupling capacitors and the redesigned PCB layout.

The power supply and its corresponding amplifier circuit are grouped as independent sets. In the layout, each power “island” is paired with its corresponding amplifier “island” and connected through a broad copper pattern, resulting in low-impedance wiring.

Amplifier Section: BIS2.0, BOS1.5

Evolving Audio Performance

Pure silver wire with maximum conductor volume

While WATATSUMI uses pure silver wire internally, it shares the same role as TSURANAGI as an amplifier for evaluating connected cables. It is designed with a neutral sound signature to bring out the full potential of any connected cable or player.

Pure silver is said to have approximately 5% higher electrical conductivity than pure copper.

In current-carrying paths such as amplifier outputs, losses due to wiring resistance become more noticeable, making silver’s high conductivity a significant advantage.
In addition, by using pure silver wire with a greater conductor volume than SHIROGANE, output resistance has been minimized to the utmost limit.