The RA280 is an integrated amplifier that inherits the innovative technologies used in RA180. Enjoy pure natural sound as close to the original sound as you can get with the RA280: a near-perfect sound that transcends the boundaries between digital and analog technologies with excellent linearity achieved through strong power damping and short dead time. The RA280 offers a special listening experience that lets you feel the true essence of music.

Form follows Sound The design of the RA280 is differentiated by its inner purity. ROSE pursues a pure natural sound that is reflected in all parts based on our design philosophy of externalizing the internal parts. The RA280 provides high quality in terms of overall solid finish and functionality, while at the same time achieving harmony between the interior and exterior through a design that focuses on acoustic aspects. The sturdy aluminum chassis at the top, matte finish, and elaborate arrangement of grooves satisfy both functionality and progressive exterior design. Additionally, the front buttons and control panel embody vintage elegance and sophistication. The RA280 will make your space even more classy by adding the pure beauty of a perfectly blended interior and exterior design.

In the Hi-Fi audio field, amplifier technology has continued to evolve in the order of Class A, Class AB, and Class D. Class D amplifiers that utilize the latest technology are outstandingly superior in efficiency compared to Class A or AB amplifiers, and have achieved significant improvements in signal-to-noise ratio (S/N) and total harmonic distortion (THD). However, despite these advantages, evaluation shows a lack of sound quality compared to analog amplifiers due to the limitations of digital circuits. To overcome these limitations, HiFi ROSE independently developed Class AD amplifier technology using GaN (gallium nitride) FETs and applied this technology to the RA280. It achieved sound quality comparable to analog while maintaining the efficiency and power amplification of existing Class D amplifiers.

Class AD Amplifier with Next-Generation GaN FET
Class D amplifiers are known for their high efficiency, low total harmonic distortion rate, and theoretical topology of perfectly linear output. The speed and accuracy of switching operations are essential to achieve perfect Class D design theory. However, conventional products are lacking in linearity compared to Class A and AB amplifiers due to the limitations of silicon FETS (field effect transistors). It is clear that conventional products had limitations in providing smooth, natural sound quality. To improve on these problems, RA280 uses the innovative new material gallium nitride (GaN) to replace the previously used silicon FET (field effect transistor). This dramatically improves dead time to 1/10 of the previous level and implements linear output with a switching speed close to zero. This improvement in linearity is the result of pushing the limitations of Class D amplifiers, allowing smooth, natural reproduction of sound quality with the fluidity of an analog amplifier.

Two Completely Separated Mono Amplifier Modules The RA280 is designed with two separate amplifier modules that operate like a mono amplifier, supporting 250 W (4 and 8 ) for the left and right amplifiers respectively, outputting 500 W on a stereo channel. The RA280 applies two-stage analog filter technology designed by HiFi ROSE to achieve the best sound quality. HiFi ROSE's LC filter provides excellent frequency response by offering -1 dB attenuation in the frequency band up to 65 kHz and -3 dB attenuation in the 85 kHz range. This technology dramatically reduces carrier noise caused by the inherent switching of Class D amplifiers, providing clearer and cleaner sound quality in all bands. The spatial description and resolution have been greatly improved, creating an evolved sound with an analogue feel.

The RA280 actively utilizes the latest technology via a power supply circuit independently developed by HiFi ROSE. This circuit uses silicon carbide FET instead of silicon FET. Silicon carbide FET is a power semiconductor device with high voltage and high heat resistance. It has higher efficiency and generates less heat than silicon FET, enabling optimal power supply. Based on innovative design of the materials and structure, the RA280 stably provides high output while minimizing heat generation to deliver the best sound quality. In addition, RA280 applies a 2.5 kW power factor correction (PFC) circuit independently designed by HiFi ROSE and introduces a high-capacity condenser to maintain excellent performance even under rapid load situations This allows for a stronger response in terms of stability and reliability.