AMXEKR FV-2020 High-Fidelity Hi-Fi Preamplifier with Tone Adjustment, Aluminum Panel, and Gold-Plated Terminals.

 The FV-2020 machine is an improvement and upgrade based on the F1 preamplifier circuit in my store. Originally, this machine has sold thousands of units in my store, and the user satisfaction is relatively high. Now it is newly designed and produced according to the aesthetic vision of modern users. The layout and materials of this machine have been changed on the basis of the original machine. The two channels are independently powered and amplified to minimize the influence of mutual crosstalk. Ensure that the sound is purer and the restoration is more accurate. This machine is powered by a Class A power supply, which can ensure that the original design of the warm tone is fully utilized.

The standard op amp of this machine is 4 single op amps (two single op amps are used for each channel)

Dual transformer power supply, left and right channels are completely independent

FV-2020/2024 both use ALPS 16-type volume potentiometer and B-type tone-specific potentiometer

The following is the introduction of FV-2024:

FV-2024 uses Sanyo's thick-film encapsulated STK3048 as the preamplifier. It has a dual op amp structure inside and the maximum voltage can reach ±50V, which can significantly improve the dynamic range of music and have minimal harmonic distortion. The actual test comparison shows that the treble is more transparent and delicate than the ordinary op amp, and the hard bass becomes more elastic, which sounds very comfortable, which is not an effect that ordinary op amp circuits can achieve.

STK3048 is a dual-channel single-in-line thick film package with two stages inside. The input stage is a protected differential amplifier. Its collector's resistor-capacitor series phase compensation network can prevent the input stage from transient distortion due to sudden signals. A set of mirror current sources is connected between the two collectors. The main voltage amplification stage is a common-base cascode circuit. The upper tube amplifies the signal in a broadband manner and provides impedance matching for the direct coupling between the input and output stages. The lower tube linearly outputs the amplification current of the upper tube to reduce the opening of the stage. loop distortion and provide larger excitation power to the subsequent stage. The two-stage amplifier tubes are supplemented by a constant current source as a load, which has strong suppression of power supply ripples..

The famous sealed green cube transformer has high efficiency, small magnetic leakage and good output characteristics.

The red heat sink bottom is the STK3048 module, and the periphery is equipped with ELNA, Siemens and other audio capacitors

All are made of solid aluminum knobs, full of texture

Customized real gold plated RCA terminal blocks