Technics SE-A5000

Commentary

This is a stereo power amplifier that integrates Technics circuit technologies such as the classAA amplifier with VC-4 amplifier configuration.

The circuit configuration is based on the classAA method. A voltage control amplifier and a current drive amplifier are mounted on the left and right channels. The VC-4 amplifier is composed of a total of four amplifiers.
The voltage control, which determines audio characteristics, is a Darlington A-class amplifier with a differential amplifier input stage using one chip dual FET and a Pc150Wx2ch output transistor, realizing low distortion close to the limit of measuring instruments.
The current drive amplifier consists of a high-speed amplitude amplifier stage with a feed-forward bootstrap power supply and a Pc450Wx2ch 4-stage Darlington output stage using 3-parallel output transistors, with FET differential inputs. This amplifier supplies the current required for powerful power at a high speed of 50A / μ s.

The power supply section is equipped with three transformers : two power transformers for the current drive amplifier for the left and right channels, and one transformer for the voltage control amplifier for the left and right channels. The power supply section is fully symmetrical with no interference between the left and right channels, and is equipped with a large-capacity electrolytic capacitor with a total capacity of 89,400 μ F.
All power transformers use oxygen-free copper wires and are highly regulated by applying high-density and high-efficiency technology through the perfectly aligned winding method. In addition, this power transformer is sealed with special resin in a total of three layers of magnetic shield case. Coupled with the use of an attached power block, this power transformer enables regeneration with extremely low mechanical vibration and electrical noise.

It employs a unique concentrated power block that integrates the output stage and power supply with a ingenious structure, eliminating high-frequency distortion caused by electromagnetic induction.

It uses a 3 mm thick and 2.3 kg top plate, a 2 mm thick highly rigid chassis, and a 2 mm thick insulator rubber on the bottom of the transformer to suppress magnetic radiation and mechanical vibration. In addition, a punching net with a high opening ratio is used for the top plate and bottom plate, and along with a unique high-efficiency radiator and a 20 mm high and φ 60 mm large insulator, a high heat radiation effect is obtained.

Oxygen-free copper bus bars of 2 mm thick and 10 mm wide are used for the earth line, and low-frequency resolution is enhanced together with LC-OFC and OCC codes used for wiring materials.

Uses an electronic speaker selector.
The switching relay uses gold-clad contacts for quick operation and high reliability. The power supply after turning off also has the last one memory function to retain the selector contents.

Equipped with a large power meter that can read directly from 0.0001W to 300W.
The front is made of 10 mm thick bronze glass.

Equipped with a VC-4 indicator to check the operation of the voltage control amplifier and current drive amplifier.

Gold-plated DC / normal input terminal is used.

A 37-core OCC power cord is used for the power cable.

Model Rating

Type	Stereo power amplifier
Rated output	240W + 240W (4 ω, 20 Hz-20 kHz, 0.002%) 200W + 200W (6 ohm, 20 Hz-20 kHz, 0.001%)
Total harmonic distortion factor	0.0007% or Less (20 Hz to 20 kHz, -3dB, 8 Ω)
Output bandwidth	5 Hz to 100 kHz (cpo-3dB, 0.01%, 8 Ω)
Frequency characteristic	0.8 Hz ~ 150 kHz + 0 -3dB 20 Hz to 20 kHz + 0 dB -0.1 dB
S/N ratio (IFF66)	120dB
Damping factor	120 (8 Ω)
Input Sensitivity / Impedance	1.2V/47k Ω
Meter indication accuracy	± 3 dB (-40dB or more) ± 5 dB (less than -40dB)
Pwer	100 VAC, 50Hz/60Hz
Power consumption	400W
External dimensions	Width 484x Height 207x Depth 475 mm
Weight	34.0kg