HiFi Rose RA180 GaNFET Power Amplifier

All Image Credit: HiFi Rose

Clearly Class D amplifiers are starting to take hold in the audiophile community. Power amplifiers have developed from Class A to B to AB and now Class D. Class D amplifiers have very high efficiencies so create little heat, often requiring no heatsinks and can have improved signal to noise ratios and distortion characteristics compared to Class A and AB amplifiers. Unfortunately the sound quality of the early Class D designs were inferior to A and AB designs due to the inherent limitations in those earlier designs and devices used.

Using the latest GaN (Gallium Nitride) FET semiconductors and improvements in Class D amplifier designs, HiFi Rose has introduced another class of amplifier that improves the original Class D sound quality issues.

HiFi Rose, a South Korean manufacturer, made a name for itself last year with the release of the RS201E streaming amplifier and RS250 streaming DAC. This year they have released the RA180 Class AD (Advanced Class D) integrated power amplifier. The RA180 uses GaN FET devices in its power output stages. These devices switch far faster than silicon FET devices resulting in very high power efficiency and very low distortion. Rose says that the improvements in switching linearity “goes beyond the Class D limits and produces an smooth and natural sound, like an analog amplifier“.

The RA180 contains four GaN FET based amplifier modules each capable of delivering 200 watts per channel into 8 and 4 ohms. The four amplifier modules allow for simple support for either bi-amping speakers or delivering up to 400 watts in two channel stereo. The very high switching speeds of GaN devices gives this amplifier an exceptionally broad frequency range of 20-100,000 Hz @ 0,-3dB (20-200KHz @ 0,-6dB) with a very low distortion of 0.005% THD and a high damping factor of 150.

Although human hearing only covers the range 20-20KHz some instruments can produce harmonics well beyond our hearing extending up to 100KHz. The extreme bandwidth and low distortion of the RA180 will allow these to be amplified should they be available from your source and you have a suitable pair of speakers. According to HiFi Rose: “Although this playability may be outside a person’s hearing range, it faithfully reproduces a wide frequency range, which contributes to expressing a deep and wide sound field with the original sound“. To this end the amplifier comes with an adjustable super-tweeter crossover selection between 600Hz to 6KHz supporting the high full power bandwidths that are available.

The purpose designed SMPS (switched mode power supply) uses 4th generation SiC (silicon carbide) technology that produces less heat, includes power factor correction technology and is said not be to impacted by sudden load fluctuations, providing over 1000watts and helping support the amplifier damping factors of at least 200.

The amplifier includes, support for both MM (5mV) and MC (0.5mV) phono cartridges (47K ohms – no loading options) with selectable turnover and roll-off EQ curves, defeatable bass and treble tone controls and defeatable 50Hz subsonic filter. Additional functionality includes; sub output, adjustable crossover frequency and gain, an HT bypass switch allowing the power amplifiers to be driven directly and cell phone remote Wi-Fi control.