Top-notch Master Integrated Amplifier RA280

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 analogue 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 externalising 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 aluminium 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.

Class AD Amplifier with Next-Generation GaN FET

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 utilise 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 (HD). 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 analogue while maintaining the efficiency and power amplification of existing Class D amplifiers.

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 analogue amplifier.

Balance Control for Bass and Treble

The default output trend of the RA280 is flat and equipped with a tone control function, allowing for ‡15 dB adjustment of bass (100 Hz) and treble (10 kHz). The tone control circuit is equipped with a high-fidelity active EQ (OP-AMP: 12 dB slope) instead of passive (CR), with a gentle 6 dB slope.

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 Q and 8 0) for the left and right amplifiers respectively, outputting 500 W on a stereo channel. The RA280 applies two-stage analogue 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 kiz and -3 d attenuation in the 85 kIz 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.

High-Efficiency Power Supply

The RA280 actively utilises 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 minimising 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.

Phono Amplifier that Supports Moving Magnet

The RA280 supports moving magnet input with a simple switch selection. The RA280 amplifies the very weak audio signal captured by the cartridge, processes it without distortion, and uses high-precision compensation circuitry developed by HiFi ROSE to deliver sound as close to the original sound as possible. The RA280's phono amplifier supports moving magnet cartridge input, which can be activated with a simple switch selection. The activated phono amplifier amplifies the very weak audio signals captured by the cartridge with precision and processes them without distortion. Additionally, it utilises a high-precision correction circuit independently developed by HiFi ROSE to deliver audio signals as close to the original sound as possible. In essence, it offers the best sound quality without compromising the fine details of the audio signal and the original impression of the music. The RA280's phono amplifier perfectly provides the essential elements for high-quality music playback, taking the performance of your audio system to the next level and allowing you to enjoy richer, more vivid sound.