Technics SE-A7000 Ver.4.0

Commentary

This is a stereo power amplifier based on SE-A7000 and improved by examining each part individually.

It is equipped with a MOS class AA circuit that adopts a MOS FET as the amplifying element of the class AA circuit.
Class AA amplifiers provide high power and complete class A voltage control by using separate amplifiers for voltage amplification and current supply. In this circuit, all the current to the speakers is supplied from the current supply amplifier due to the class AA Bridge effect. As a result, the voltage control amplifier operates in an ideal full class A operation with an output of 0 and exhibits excellent element characteristics.
Therefore, in the SE-A7000ver4.0, the MOS FET, which is an amplifying element with extremely high input impedance and excellent linearity, is adopted for the class A operation voltage control amplifier to reproduce the sound signal faithful to the input source. In the current supply amplifier, the speaker drive power is improved by the strong current supply of the bipolar transistor, which is well known for its low loss and high output operation.

Newly developed electrolytic capacitors are used for smoothing power supply.
This condenser is equipped with a thick special sleeve, which is well-known as an anti-vibration measure, and a special separator with improved mechanical and electrical characteristics through improvements in aluminum foil and electrolyte solution. This reduces unnecessary incidental sounds and further enhances sound quality.

The power supply section is equipped with 10 anti-vibration capacitors with a total capacity of 93,600 μ F. The power supply is supplied by three transformers, two current supply amplifiers for the left and right sides, and one for voltage control.

As anti-vibration measures, a 3 mm thick heavyweight top plate, a highly rigid chassis, a large insulator, and a side wood with a real wood mirror finish are adopted.

Equipped with a balanced input terminal that is not easily affected by external magnetism.

Equipped with a high-precision large peak power meter that can read directly from 0.0001W to 300W.
This meter is equipped with a light ON/OFF switch.

The internal wiring uses OFC bus bars, LC-OFC, and 6N ESC-OCC.

The speaker selector is electronic and uses highly reliable gold-clad contacts.

It uses an aluminum base mount gold plated large speaker terminal that can be used with very thick cords.

Uses a very thick PC-OCC power cord with polarity display.

Model Rating

Type	Stereo power amplifier
Rated output	240W + 240W (20 Hz to 20 kHz, 0.005%, 4 Ω) 200W + 200W (20 Hz to 20 kHz, 0.005%, 6 Ω) 170W + 170W (20 Hz to 20 kHz, 0.005%, 8 Ω)
Frequency characteristic	20 Hz ~ 20 kHz + 0 -0.1 dB 0.8 Hz ~ 150 kHz + 0 -3dB
Signal-to-noise ratio	93dB(EIAJ) 120dB(IHF'66)
Input Sensitivity / Impedance	Normal / DC : 1.2V/47k Ω Balance : 1.2V/600 Ω
Meter indication range	0.0001W ~ 300W (8 Ω)
Pwer	100 VAC, 50Hz/60Hz
Power consumption	420W
External dimensions	Width 483x Height 208x Depth 476 mm
Weight	38kg