Alpine F#1 Status CDA 7990R User Manual page 5

Unprecedented "wide dynamic range" Persistent pursuit of
energetic and enjoyable "high-speed sound"
Resonant DC-DC converter for stable power supply
Whereas the general DC-DC converters send rectangular waves to the step-up transformer, the
resonant DC-DC converter, with a simple design integrating capacitors in its Taylor circuit, sends sine
waves to the step-up transformer. Consequently, the high frequency components inherent to the
normal switching power supply units are significantly reduced and high frequency noise and spike
noises are extremely small. The right solution for a clean power supply.
A large capacity power supply circuit allows instantaneous supply of a large amount
of electrical current, four times as large as the maximum current consumption. It's as
powerful as those used in desktop audio units.
An audio-use large capacity power supply is employed. The dual line independent power cables and
independent shield structures for the respective circuit blocks allow the separation of the power for the
audio signal circuits from those of the operation display systems, remarkably reducing mutual
interference (noise or voltage fluctuation effects). These designs achieve both a listener feel of wide
dynamic range and lower noise level, while ensuring sufficient power supply capacity. More than
enough dynamic range is constantly available.
High-Voltage I/V converter eliminates the necessity of a final stage booster circuit
which amplifies noise.
Inside the DAC, the digital bits are translated into electric currents. An I/V (current, I to voltage, V)
converter transforms those currents into output voltage. To achieve high output voltage, a commonly
available booster IC typically amplifies the I/V converter output. Unfortunately this amplifies noise as
well. Instead of following this standard path, Alpine specially engineered a Direct High Voltage I/V
converter. The output from the I/V converter is already high voltage, so no additional noise amplifica-
tion occurs.
Large-diameter power cable improves the power supply capacity
The power cables, from the battery to the black box, are all OFC (Oxygen Free Copper) 14AWG
2
equivalents (2 mm
reduction, ensuring not only satisfactory anti-noise performance but also top-level capacity for
instantaneous power supply.
Custom large-capacity electrolytic capacitors provide extremely clear and crisp sound
These capacitors, with their improved capacity for instantaneous current supply, are remarkably
effective in sound reproduction stability including powerful bass expression and quick sound
generation. CDA-7990 uses eight times the total capacity of compared to normal systems.
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). The carefully selected cable size and material (OFC) contribute to impedance