TSURANAGI Portable amplifier.

The TSURANAGI portable amplifier was developed as an evaluation unit for the development of BriseAudio's high-end earphone cables and high-end portable line cables (mini-mini cables) in order to create an ideal portable audio environment. BriseAudio cables are used for internal wiring, and the electromagnetic wave absorbing shielding material and CNT (carbon nanotube) used in our high-end cables such as MURAKUMO and YATONO are installed on the board to further improve the sound quality.

Overview

Portable amplifier with analog input and output (for earphones and headphones)
◆Balanced input/output
◆Balanced output for unbalanced input signals
◆Pentaconn 4.4mm terminal mounted
◆Input: Balanced/unbalanced (5-pole 4.4mm + 3-pole 3.5mm)
◆Output: Balanced (5-pole 4.4mm + 4-pole 2.5mm)
◆High quality sound electronic volume IC MUSES72320 installed
◆Low noise differential line receiver for high input impedance & high common mode noise rejection
◆Low-noise all-differential operational amplifier for unbalanced-to-balanced conversion
◆Low distortion current feedback amplifier to drive headphones
◆Dual power supply and DC servo eliminates input/output coupling capacitors
◆Charging from USB Type C
◆Continuous playback time: approx. 8h (varies depending on the environment of use) 　

Product Concept

In response to the recent increase in the number of players with balanced LINE OUT and balanced drive of headphones and earphones, Brise Audio has developed a portable amplifier with ideal balanced input/output for the development of mini-mini cables and re-cables.
To allow connection to conventional players, an unbalanced 3.5mm 3-pole input is also provided, which is internally converted to a high-precision balanced signal before being output.
Both 5-pole 4.4mm and 4-pole 2.5mm output terminals are provided. The design is based on low distortion and low noise, with the theme of expressing all the information of the source.
Low performance of any of the circuits from input to output will result in poor overall performance, so low distortion and low noise circuits and components are used in all signal processing circuits.
The high input impedance of 1MΩ also minimizes distortion of the upstream player output.
The differential line receiver precisely unbalances the balanced signal once and eliminates extraneous noise, enabling clean playback even in noisy outdoor environments.
The key composite amplifier in this amplifier simultaneously performs unbalanced-to-balanced conversion and current amplification.
Distortion is further reduced by including a current feedback amplifier in the feedback loop of all differential operational amplifiers.
The power supply circuit uses ultra-low noise & ultra-high PSRR regulators and is supplied independently to each channel.
 A 6-layer board is used to eliminate common impedance and improve signal quality in terms of layout.

TSURANAGI, as with the development of our cables, has a high output, wide bandwidth, no sound distortion, low noise floor, and a low noise floor.
Furthermore, we design for sound quality and performance with the guideline of minimizing the effects of the external environment and extracting as much performance from the equipment as possible.
TSURANAGI is a reference for our cable development environment, and we aimed to create an amplifier that would not spoil the performance and sound quality of the cable.
Cables are also designed to avoid bottlenecks in the equipment, so the aim is to further improve them in-house.