R20 was an monaural amplifier developed and
handcrafted elaborately to re-render
full music spirit and connotation,whose design
reference benchmark is state of the art counterpart
the top hi-end preamplifiers’
function, construction and fabrication.
adaptive bias technology, The R20 power amplifier
keep class A output even if the speakers’ impedance
went down largely and output power increased several
times. This prevented from the traditional pure
class A amplifiers’ inevitable regret of returning
to class B when the speaker load impedance went
down, and was much close to the ideal class A
The R20 features a 1200VA（1600VA
at short time）low-noise
toroidal transformer in a fully balanced power
for both the
amplifier’s inverting and non-inverting halves. In
low ESR capacitors are used in R20 amplifier.
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 amplifier.
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
attention to the layout of the amplifier, including
careful mirror-imaging of circuits to cancel
magnetic fields, was essential to minimize magnetic
field distortions that can occur with such a massive
power delivery system. The input signal remains
balanced, and rejection of common mode noise and
distortion is achieved in the loudspeaker’s voice
True Voltage Source
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.
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.
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
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 prevent damage from an occasional or prolonged
influx of surges and spikes.
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-driven
protection circuit switches the amplifier off.
are used to correct for potentially damaging DC-offset.As
with other Dussun components, the correction range
If the problem exceeds the servo's range, the
amplifier will be switched off.
Regardless of the technology used, numerous details
must be executed to fully realize the potential of a
Dussun design. The quality of individual components,
the care and craftsmanship with which they are
assembled and the exhaustive inspection and testing
we employ help raise the value of Dussun products.
The R20 is built to the same high construction
standards as all other Dussun products.
Rated Power Output:
300 watts at 8Ω,
600 watts at 4Ω
(All of the above power ratings measured
20Hz to 20kHz with no more than 0.1% THD)
dB from 20 Hz to 20 kHz
(300W/8Ω, 600W/4Ω, 20Hz～20KHz)
Signal to noise ratio:
better than 102 dB（20
Hz to 20 kHz）