Preamplifier section
The Ai500's solid-state circuitry includes high-speed, low-noise
transistors, and direct coupling throughout. Meticulous ground isolation
techniques insure superb signal-to-noise ratio. Much care has been taken
in the selection of components and the layout of circuitry for low
noise, fast response time, and linear frequency response. We are
confident that the Ai500 is among the very best preamplifiers on the
market, at any price. Small-signal capacitors, where needed, are all 1%
tolerance Wima brand resistors.
Power amplifier Stello Ai500's output stage employs matched
Hitachi MOSFET power transistors in Class AB push-pull configuration.
Class AB offers the best trade-off between high performance and high
efficiency. Input circuitry, gain stage, drive stage and bias net are
April Music's unique proprietary circuitry, with optimum signal transfer
and minimum phase shift.
D/A Converter
Digital signals received via COAX and OPTIC inputs are processed by the
digital input receiving circuit. Likewise, the USB signal from a PC
enters the USB DAC through the digital input receiving circuit.
Power supply
Separate power supplies deliver super-stable DC voltages to the
preamplifier and DAC circuits. The power amp's supply has tremendous
current reserves for lifelike dynamics. With an overlarge 800VA toroidal transformer, fast-recovery rectifiers, and
an enormous capacitor bank (90,000uF), the Ai500 will never "run
out of breath" even with the most demanding music and the most
difficult loudspeaker loads.
Connectors
Ai500 features Neutrik balanced connectors,
gold-plated RCA jacks, and gold-plated speaker terminal binding posts.
Specifications
Output Power
150 Watts/CH @ 8 Ohms, 300
Watts/CH @ 4 Ohms
Output Stage
Quad Para Push-Pull Hitachi
MOSFET Power Transistors, Class AB
Power Supply
Custom Made 800 VA Toroidal
Transformer 90,000 uF Capacitor Bank
Frequency response
20~45 kHz
THD + N
< 0.05 %
Volume control
Cirrus logic CS3310 digital
volume control
Analog inputs
3 unbalanced analog line inputs
1 balanced analog line input
1 BYPASS input
