Patented Inventions

Introduction

Vacuum tubes have excellent linear output characteristics, so a conventional vacuum tube audio amplifier that uses vacuum tubes for processing audio signals can provide superior sound quality. A conventional vacuum tube audio amplifier has the following circuit structure, a conventional vacuum tube audio amplifier receives an audio signal input and then outputs the signal to a loudspeaker. Moreover, the conventional vacuum tube audio amplifier includes a power circuit, a vacuum tube amplifying circuit, an audio output transforming circuit, and a grounding metal bottom plate, wherein the power circuit is utilized to receive a mains electricity input and provide power to the vacuum tube amplifying circuit and the audio output transforming circuit. The grounding metal bottom plate is employed to provide grounding shield to the power circuit, the vacuum tube amplifying circuit, and the audio output transforming circuit.

In the circuit diagram of a conventional vacuum tube audio amplifier, wherein with respect to power source, the mains electricity input is transformed and rectified through the power circuit, filtered by a choke (CHK) and then provided to the vacuum tube amplifying circuit and the audio output transforming circuit. Audio signal input is amplified by the vacuum tube amplifying circuit, transformed by the audio output transforming circuit and then transmitted to the loudspeaker. With respect to grounding, point A in the power circuit, or the negative terminal (point B) of the input terminal signal of the vacuum tube amplifying circuit is used as the only ground terminal in a conventional vacuum tube audio amplifier to be coupled with a single ground terminal with the grounding metal bottom plate to provide grounding shield to the conventional vacuum tube audio amplifier.

However, even though the grounding metal bottom plate of a conventional vacuum tube audio amplifier may provide grounding shield, it cannot eliminate the residual AC noise and impulse noise, resulting in that the user could hear clearly the residual hum and impulse hum in the sound played by the loudspeaker at a short distance (within about a meter). Also, the choke in the power circuit would be coupled with high-frequency noise and further aggravate the problem of humming. Moreover, the grounding metal bottom plate results in huge volume of the amplifier and expensive cost, and as the grounding metal bottom plate 6 is mostly designed integrally with the casing, which further leads to leakage in a conventional vacuum tube audio amplifier. Even though the conventional vacuum tube audio amplifier has superior sound quality, due to bulky volume and the problem of humming within a short distance, a desktop model cannot be developed nor do such vacuum tube audio amplifiers fit in ordinary households.

In order to solve the above shortcomings and develop an All-In-One vacuum tube music player that is affordable, and can be placed on the table or on the audio rack, the Echowell audio team has been continuously developing and verifying for many years, has successively designed many innovative solutions, and filed four patent applications in many countries, some of which have patented from many countries, and some are under review. The names of the four patents and the numbers of the patent certificates that have been patented in various countries are as follows.

1. Grounding Structure and Grounding Method of Vacuum Tube Audio Amplifier
Taiwan, ROC: Innovation Patent No.I650934
USA: US 10,135,402 B1
Russia: Patent for Invention No. 2695048
Australia: Patent number: 2018222961
Korea: Patent No. 10-2077092

2. Vacuum Tube Audio Amplifier
Taiwan R.O.C.: Innovation patent no.I703815
USA: US 10,218,320 B1

3. Vacuum Tube Rear Device

4. Vacuum tube amplification system capable of reducing residual noise and a grounding method thereof