Audio Database

B-2301
Commentary

This high-grade stereo power amplifier was developed through analysis and technical challenges from a new point of view based on the technology and results accumulated in the pre-main amplifier.

The output stage adopts a newly developed four parallel configuration diamond power stage using eight Pc200W power transistors per channel, and the pre-drive stage adopts a cascode-connected push-pull configuration with improved high-frequency characteristics.

The power supply section is equipped with a large toroidal transformer of 178x173x120mm.
This transformer weighs as much as 12 kg and has a capacity of 1.3 kva. In addition, we have incorporated unprecedented know-how into the coil winding method and have taken into consideration the sound quality even with fillers.
The power supply consists of a 60000 μ F pure focus capacitor for the power stage and a 40000 μ F pure focus capacitor for the prethe pre-drive stage with the transformer as the core. It is a six power supply system with independent stages and independent left and right channels. This supports high power with plenty of room and completely eliminates IHM, which is extremely harmful to sound quality.

The chassis structure uses a sub-chassis made of pure copper to provide electromagnetic and electromagnetic shielding and vibration isolation through moderate internal loss. In addition, the chassis uses a case made of pure copper and a robust aluminum chassis to provide shielding and vibration suppression from the material.
In addition, the power transistor is sandwiched between a special aluminum block and a pure copper plate to prevent vibration, which is firmly fixed to a large heat sink to prevent electromagnetic radiation while significantly reducing vibration levels.

In addition to the newly developed pure focus capacitor used for the power supply, the signal system uses a copper foil styrene capacitor that has been carefully examined in terms of sound quality and a butyl capacitor with damping material that prevents vibration. The power transistor uses the best product that eliminates resonance phenomena. In addition, we use extremely high-quality carbon resistance and lambda resistance. We carefully select the best parts that can be expected at that time.

The printed pattern drawn on the printed circuit board has a thickness of 140 μ m, which is four times the normal thickness, and the impedance is extremely low in direct current and alternating current.

A LCD power meter is used for the display.
This is a logarithmic compression type meter that can read up to -60dB and can reliably monitor output even from a remote location. It is also possible to switch between peak indication and peak hold indication (3 sec).
In addition, in the event of DC leakage, the protective circuit operates and the DC Leak lights up, while the Protector lights up when oscillation occurs due to incorrect connection or when the load is short-circuited, and the Over Swing lights up when excessive input is applied. This is an easy-to-see indicator linked to the protective circuit.

The input terminal is plated with gold 3 μ m thick, 5 to 6 times thicker than the conventional one. In addition, the balance input type Canon terminal is mounted, and normal / balance can be changed with one touch by the input selector.
An attenuator type is used for the input level setting.

Uses a power cord with polarity display.

Model Rating
Type Stereo power amplifier
Rated output 300W + 300W (8 Ω, 20 Hz to 20 kHz)
550W + 550W (4 ω, 1 kHz)
Total harmonic distortion factor 0.003% or Less (10 Hz to 20 kHz at Rated Output)
Cross modulation distortion factor 0.003% or Less (60 Hz : 7 kHz = 4 : 1)
Frequency characteristic DC ~ 300 khz + 0 -3dB
Input Sensitivity / Impedance Normal : 1V/15k Ω
Balanced : 2V/10k Ω
Slew rate ± 300 V / μ sec
Rise time 0.5 μ sec
Signal-to-noise ratio 120dB
TIME distortion Measurement limit value or less
Envelope distortion Measurement limit value or less
Power consumption 630W (rating, according to Electrical Appliance and Material Control Law)
External dimensions Width 474x Height 215x Depth 490 mm
Weight 37kg