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This year April Music will take the brand upmarket with new Stello Ai500. Featuring cool contemporary modrn styling, extensive connectivity, and advanced performance, Stello Ai 500 will bring storied April Music technology to an entirely new population of music fans - those who seek the ultimate blend of high style, reliability, technical excellence, and extreme musicality.

The Ai500 combines state-of-the-art analog and digital circuitry with features sure to please the most demanding music lovers.

With power output reaching 300 Watts/channel @ 4 Ohms, the Ai500 is compatible with virtually all loudspeakers. The Ai500 features an oversize power supply, a Cirrus logic CS3310 digital volume control for precise sound level adjustment, four pairs of analog line inputs, a "bypass" pair of inputs for direct feed of the output stage, and digital inputs for every source: disc player, PC, iPod, and cable TV receiver.

Unique contemporary styling takes the Ai500 into the realm of functional art. A full-function remote control makes it a joy to use from anywhere in the room!


  • 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.


  • 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
  • 2 Analog Outputs: Pre-out, REC
  • 4 Digital inputs: COAX, OPTIC, PC USB Link, iPod
  • Front Panel: POWER, BALANCED, CD, TUNER, AUX, DIGITAL, BYPASS, MUTE, Rotary Volume Encoder
  • Full Function Remote Control    
  • Dimension: 460 (W) X 86 (H) X 400 (D) mm
  • Weight: 16 Kg (35lbs)



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