A real new-generation class-D amplifier
with latest highly accurate PWM switching devices
By employing the latest developed class-D amplifier devices, power MOS-FET achieves ideal highly accurate current switching in the power stage, and high-voltage gate driver IC with excellent time-axis control maximizes the ultimate PWM switching. The exceptional performance of the class-D devices ensures ultimate real-sound with quality damping in the mid to low ranges even when driving low-efficiency speakers. Furthermore, the sweet and rich tonal character in the mid to high ranges of the amplifier is almost like the tone of the best triode tube amplifiers.
Superb power source of RSA-F33EX / RSA-M3EX / RSA-V1EX ensures the real musical sound
In order to maximize the potential of the unprecedented high performance of this amplifier (power utilization in the power stage at maximum output; 96%), we daringly employed a classical and very simple plus/minus power source composed of minimal numbers of high quality components, such as only transformers, bridge-diodes and capacitors.
Specially selected parts of low-pass filter contribute to the Real-Sound
The sound of this class-D amplifier owes a lot to the individual parts of low-pass filter in the final stage of the amplifier. The capacitor and the coil employed for the low-pass filter were custom-ordered after careful listening tests and guarantee the excellent musical sound of RSA-F33EX / RSA-M3EX / RSA-V1EX. Above all, many custom hermetic seal paper-oil filled capacitors are employed in the low-pass filter and snubber circuit of RSA-F33EX because of the natural and vivid character of the sound only those old type capacitors have. These paper-oil filed capacitors have been supplied to the aerospace industry for the past half century and made to meet the strict MIL standards for getting the highest reliability.
Wooden base-chassis and insulators to realize rich and beautiful instrument-like sound
In an unusual endeavor for an audio amplifier, natural wood was used for the base chassis and insulators.
Base-chassis of RSA-F33EX: A solid laminated panel of European spruce from Austria was used for the under-base. Spruce has long been used for the top plate of stringed instruments and the soundboard of pianos, and is known as a material with excellent sound quality that provides quick vibration trans-mission and moderate damping.
The combination of this material with the rigid steel chassis produces a rich pleasant sound.
Insulators of RSA-F33:Three insulators combine pure painted maple from Hokkaido, Japan and hickory from North America. Maple has excellent strength and is used in combination with spruce for the sides and backs of stringed instruments. Hickory is a hard material that absorbs impact well and is used for drumsticks for example. The maple and hickory insulators moderate the vibrancy of the spruce material and help provide rich musicality.