The R20 beside others in its design offers the following highlights:
No Switch Distortion Amplifier Design
A truly balanced input topology eliminates the need for an input buffer amplification stage, allowing the first stage differential amplifier to be driven directly by the source. Matched impedances are presented to the source and both signals travel through identical circuit paths. Switch distortion does not exist at all.
With DUSSUN's adaptive bias technology, the R20 power amplifiers keep class A output even if the speakers' impedance goes down largely and due to that output power increased several times. This prevents from the traditional pure class A amplifiers' inevitable regret of returning to class B when the speaker load impedance drops down, and so is much close to the ideal class A amplifier.
Massive Power Supply
The R20's feature a 1200VA (1600VA at short time) low-noise toroidal transformer in a fully balanced power supply for both the amplifiers inverting and non-inverting halves. In addition, twelve 10,000UF low ESR capacitors are used.
Copper bus bars enhance the efficiency of power distribution within the amplifier and eliminate variances introduced by the wiring harnesses, etc. more commonly found even in high performance amplifiers.
High frequency power supply bypass is accomplished on individual boards by a total of 26 components of several film types. The resulting uniformly low power supply impedance seen by the various circuits within the R20 lays the foundation for both the massive power and the extraordinary finesse that characterizes this machine.
Fully Balanced Design
A truly balanced input topology eliminates the need for an input buffer amplification stage, allowing the first stage differential amplifier to be driven directly by the source. Matched impedances are presented to the source and both signals travel through identical circuit paths.
Meticulous attention to the layout of the amplifier, including careful mirror-imaging of circuits to cancel magnetic fields, essentially minimized magnetic field distortions that can occur with such a massive power delivery system. The input signal remains balanced, and rejection of common made noise and distortion is achieved in the loudspeaker s voice coil.
True Voltage Source
The R20 operates like a true voltage source maintaining the appropriate voltage at a given time (based on signal demands) without particular regard for the current demands of the associated loudspeakers.
48 output transistors distributed throughout the four main heat sinks conduct and control the flow of power to the associated loudspeakers.
12 complementary pairs of output transistors are used in both the inverting and non-inverting output stages.
No known high-quality loudspeaker can continuously absorb the full power of the R20, but many loudspeakers require these extreme bursts of power on a short-term basis when reproducing music at realistic levels. The R20 provides these short bursts without creating power supply sag or altering sonic performance. Its imperturbable nature is reflected in the authority and control with which it reproduces musical signals.
Protection from internal or external component failure is an integral feature of the DUSSUN design philosophy. The R20 employs several forms of protection, both for its own self-preservation as well as the protection of loudspeakers and other components to which it is connected.
The surge buffer helps to prevent damage from an occasional or prolonged influx of surges and spikes.
Over-drive protection circuits are used to prevent high-energy, high-frequency ringing artifacts from reaching and damaging loudspeakers if the amplifier is over-driven.
When the amplifier is over-driven for prolonged periods, or if a loudspeaker cable or output device has shorted, an over-driving protection circuit switches the amplifier off.
DC servos are used to correct for potentially damaging DC-offset. As with other DUSSUN components, the correction range is +1V. If the problem exceeds the servo's range, the amplifier will be switched off.
Regardless of the technology used, numerous details have to match for fully realizing the potential of this design. They, such as quality of individual components, the care and craftsmanship with which they are assembled and the exhaustive inspection and testing employed help raise the value of this product greatly.