VICTOR/JVC M-2020

Commentary

A 2020 series stereo power amplifier.

In order to prevent dynamic interference distortion, a class A and class B independent two power supply system is adopted in which the power supply for the class A amplifier stage and the class B amplifier stage are independent.
In this method, the power supply for the class A amplifier stage is provided independently of the transformer itself to provide a constant voltage. This method prevents the voltage fluctuation of the class B amplifier stage from being directly transmitted to the class A amplifier stage and prevents dynamic interference distortion.
In addition, the power supply for the class B amplifier stage, in which dynamic interference distortion is hardly a problem in principle, is designed to reduce impedance by shortening the power supply wire, a large transformer, a large-capacity capacitor, and a power supply wire instead of constant voltage. In particular, a pair capacitor with excellent characteristics is adopted with an emphasis on the balance between the positive side and the negative side.
In addition, the casing of the transformer is filled with a compound in order to prevent the throbbing of the transformer, which is often a problem in a power supply with excellent fluctuation rate.

It is a DC amplifier configuration that does not have a low-frequency time constant in the signal path. The newly developed dual FET is used in the first stage circuit in order to improve stability. The dual FET contains two FETs with the same characteristics in a single package. It has a good thermal balance and minimizes DC drift caused by temperature change.
In addition, a constant current circuit is inserted into the power supply, and the next stage transistor and double differential circuit are constructed. Moreover, a stable circuit resistant to heat, noise, and voltage fluctuations is realized by using polypropylene capacitors with good temperature stability at important points.

The input circuit is a direct coupling without a condenser, but a subsonic input terminal is also provided so that the ultra-low frequency input including DC can be cut if necessary.

Equipped with a power meter and LED peak indicator.
The power meter is a logarithmic compression type and can read from 0 to 130W. The peak indicator has five levels from 2W to 130W. It captures the peak level of music and emits light with an attack time of 10 ms.

Equipped with 3 high sensitivity filling protection circuits.

Equipped with an inrush protector circuit to prevent excessive current when power is turned on.

Equipped with 2 types of speaker selector.

It has a headphone port.

Model Rating

Type	Stereo power amplifier
Circuit system	Signal Circuit : First stage dual FET full DC parallel push-pull OCL Power supply circuit : Class A and Class B independent 2 power supplies
Effective output (both channel drive)	75W + 75W (8 Ω, 20 Hz to 20 kHz)
Harmonic distortion factor (8 Ω, both channel drive)	Effective Output : 0.02% or Less (20 Hz to 20 kHz), 0.005% or Less (1 kHz) At 37W output : 0.02% or less (20 Hz to 20 kHz) 0.02% or Less (20 Hz to 20 kHz) at 1W output
Cross modulation distortion factor (50 Hz : 7 kHz = 4 : 1, 8 Ω, both channel drive)	Effective power : 0.02% or less At 37W output : 0.02% or less 0.02% or less at 1W output
Output Bandwidth (IHF, both channel drives)	5 Hz ~ 50 kHz (THD 0.05%)
Frequency response (at 1W output)	Direct Input : DC ~ 100 khz + 0 -1dB Subsonic input : 18 Hz to 300 kHz + 0 -3dB
Input Sensitivity / Impedance	1V/50k Ω (Effective Output)
Signal-to-noise ratio	110 dB or more (IHF-A network, input short)
Damping factor	50 or More (8 Ω, 20 Hz to 20 kHz)
Output terminal	Speaker System 1or2 : 4 Ω ~ 16 Ω Speaker System 1 + 2 : 8 Ω ~ 16 Ω Phones : 8 Ω ~ 1,000 Ω
Meter	0W ~ 130W
Peak indicator	5 Points (2W, 15W, 40W, 80W, 130W)
Power supply voltage	100 VAC, 50Hz/60Hz
Power consumption	182W (Electrical Appliance and Material Control Law Standard) 455W (4 Ω, effective output)
External dimensions	Width 480x Height 161x Depth 402 mm
Weight	14.2kg