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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.
Extensive Protection
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.
Manufacturing:
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.
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