E-650 Integrated Amplifier

Innovative engineering and top-grade parts and materials come together in the E-650, featuring the superb Balanced AAVA type volume control and a triple parallel arrangement of power MOS-FETs in the output stage.

The power amplifier section employs the latest instrumentation amplifier configuration for balanced signal transmission, resulting in an integrated amplifier with fully balanced configuration from the inputs right through to the output. The massive power supply and low-impedance output circuitry deliver 150 watts per channel (into 1 ohm, with music signal) and a damping factor of 800.

• First integrated amplifier featuring Balanced AAVA volume control
• Pure Class A operation (30 watts into 8 ohms)
• Guaranteed linear power: 120 watts into 2 ohms, 60 watts into 4 ohms, 30 watts into 8 ohms
• Output stage with power MOS-FETs in triple parallel push-pull configuration
• Instrumentation amplifier principle in power amplifier for fully balanced signal transmission, complemented by MCS+ topology and current feedback amplification circuitry
• Strong power supply with massive high-efficiency transformer and large filtering capacitors
• Preamplifier and power amplifier sections can be used separately
• Numeric indication of volume level

Balanced AAVA type volume control
As a first in an integrated amplifier, the E-650 features the sophisticated Balanced AAVA type volume control incorporated in Accuphase’s top-of-the-line preamplifier model C-3850. Balanced AAVA uses two AAVA circuits driven in a fully balanced configuration. This completely cancels out any external noise and results in unsurpassed S/N ratio.

High-accuracy, high-rigidity volume sensor construction
AAVA uses a volume control knob that looks similar to conventional controls. However, Accuphase also paid careful attention to volume sensor construction. The rotary mechanism is assembled with high accuracy and mounted to a highly rigid frame extruded from a single aluminium block. The solid brass shaft has a diameter of 8 mm and gives a pleasingly massive yet responsive operation feel to the volume knob. Floating suspension technology developed by Accuphase for its SA-CD/CD players is used to mount the volume sensor mechanism to the main chassis.

Furthermore, utterly smooth and quiet operation is assured also when adjusting the volume with the remote commander, thanks to insulators that dampen any vibrations of the drive motor.

Formidable power amplification stage
Triple parallel push-pull output stage with power MOS-FETs and power amplifier stage mounted on a large heat sink. Two identical units are arranged on the left and right sides of the chassis.

Class A operation (30 watts into 8 ohms). Guaranteed linear power of 120 watts into 2 ohms, 60 watts into 4 ohms, 30 watts into 8 ohms per channel.

Strong power supply with massive high-efficiency toroidal transformer and large filtering capacitors. The E-650 uses a massive power transformer with high output
capability. Highly effective filtering is realized with two custom-made aluminium electrolytic capacitors, each with a large 50,000 µF rating.

Advanced features

• Power amplifier stage features instrumentation amplifier configuration for balanced signal transmission.
• MCS+ topology and current feedback principle in amplification circuitry assure excellent phase characteristics in high range.
• Semiconductor (MOS-FET) switches used for protection circuitry prevent contact problems and ensure long-term reliability. Eliminating mechanical contacts
  from the path of the music signal also further enhances sound quality.
• Logic-controlled relays for signal switching assure high sound quality and long-term reliability.
• MAIN IN switch and preamplifier output and power amplifier input connectors allow independent use of both sections. Both line level and balanced connectors are provided.
• Tone controls with balanced circuit configuration and summing active filters for optimum sound quality.
• Versatile array of inputs with two balanced inputs to shut out external noise interference.
• Individual phase setting supported for each input position.
• Dedicated headphone amplifier constructed with discrete components.
• Two option board installation slots on the rear panel provide further versatility. With the AD-50, AD-30, or AD-20 board, MC/MM switching is performed on the
  front panel.
• The DAC input selector button allows the user to select the desired input when using the Digital Input Board DAC-50 or DAC-40 With USB Port. Display of the sampling frequency of the locked digital signal is also possible. (This is not supported with the DAC-30, DAC-20, or DAC-10.)
• LED-based bar graph power meters with improved sensitivity and readability.
• Two sets of large speaker terminals that also accept spade connectors or banana plugs.
• Supplied Remote – Commander RC-220 allows volume adjustment and input source switching.

Option Boards
Rear panel expansion slots allow use of three types of option boards (DAC-50, AD-50, LINE-10). Up to two boards can be inserted, according to requirements.

Analog Disc Input Board AD-50 features a high-performance phono equalizer for playback of analogue records.

• Supports MC and MM cartridges
• Load impedance selector button (for MC only)
• Subsonic filter