Perreaux 200 MkII, Руководство пользователя

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Special Design Features
Rugged Build
Quality
Mechanical strength has been a hallmark of Perreaux products since the
company first started production back in 1974. The concept behind the physical
design and construction is that each structural member should contribute to both
rigidity and performance.
Ultra Stiff
Power Supply
The 200 MkII incorporates a massive custom designed, toroidal power
transformer, employing unusually heavy gauge wire that reduces copper losses
to a minimum. An electrostatic shield prevents AC line borne interference from
entering the signal path. The power supply filter capacitors, totaling 22,400µF
(11,200µF per channel), have exceptionally low inductance and internal
resistance. They charge and discharge in response to load demand far more
rapidly than conventional storage capacitors and are capable of delivering the
instantaneous current required by the output stages, providing optimum dynamic
range and transient response. The wiring from the power supplies to the output
boards is designed for unimpeded transmission of the required current and
voltage and utilizes heavy gauge, tinned copper wire cables. Since power supply
leads radiate at signal frequencies, all wiring is carefully loomed to minimise
this effect.
Hybrid Class
A/AB
The bi-polar signal transistors used in the 200 MkII are run in Class A mode.
This avoids the crossover notch distortion and the resulting odd-order harmonics
present, to some degree, in all other classes of operation. The output devices
used in the 200 MkII output stage are MOSFETs, which with high quiescent
current circuitry, are run in the equivalent of Class A to 10 watts. Beyond this
point the output class is technically Class AB (hence the hybrid nomenclature),
but with a major difference. The combination of MOSFET characteristics and
their application in this circuitry, result in crossover distortion so minimal that it
is virtually non-existent.
MOSFET
Output Stage
The 200 MkII output stage takes full advantage of the unique qualities of
MOSFET devices and in many ways they are superior to bi-polar transistors. A
major advantage is their tendency to draw less current over a large section of the
power bandwidth as their temperature rises (Negative Temperature Coefficient),
hence self stabilising thermally, whereas bi-polar transistors draw more current
as their temperature rises (Positive Temperature Coefficient) and protection
circuits become mandatory to prevent thermal runaway and eventual self
destruction. MOSFETs have the ability to swing fully across the amplifier’s
internal DC voltage and are therefore true "rail-to-rail" devices. Using
MOSFETs encourages the highest performance from the balance of the internal
amplifier circuitry.
Earthing
Perreaux engineers pay particular attention to designing the product to ensure
maximum separation between internal signal and power earths, only meeting at a
central starred point.