Abstract: A vacuum tube amplification system includes: a first power circuit electrically connected to utility power alternating voltage to transform it into a first DC voltage; a first vacuum tube amplification load circuit having a first grounding end, the first vacuum tube amplification load circuit using the first DC voltage as operating voltage; a second power circuit electrically connected to the utility power alternating voltage to transform it into a second DC voltage and output the second DC voltage; and a second vacuum tube amplification load circuit having a second grounding end, the second vacuum tube amplification load circuit using the second DC voltage as operating voltage. The first grounding end is not directly electrically connected to the second grounding end, the first grounding end and the second grounding end are each electrically connected to a compliance ground of the utility power alternating voltage through a jumper-wire zero-ohm resistor.

Abstract: A vacuum tube subwoofer extraction circuit system includes: a front-end circuit; and a vacuum tube subwoofer extraction circuit connected to the front-end circuit, the vacuum tube subwoofer extraction circuit including: a small signal amplification vacuum tube for receiving an input signal from the front-end circuit and outputting an audio signal; and a passive filtering circuit connected to the small signal amplification vacuum tube and adapted to perform a filtering process on the audio signal so as to output a filtered signal, wherein the front-end circuit includes a switch power circuit for providing low voltage to the vacuum tube subwoofer extraction circuit, wherein the small signal amplification vacuum tube does not have gain effect on the input signal.

Abstract: A three-piece extensible movable soundbox includes: a host portion; a first soundbox portion, wherein the host portion is extensibly connected to the first soundbox portion by a first connection line device; and a second soundbox portion, wherein the host portion is extensibly connected to the second soundbox portion by a second connection line device.

Abstract: An audio system with sound-field-type nature sound effect includes: a first primary channel playing device for playing a primary audio signal generated according to a left channel audio signal and/or a right channel audio signal; a first secondary signal circuit for generating a first secondary audio signal according to the left channel audio signal and the right channel audio signal; and a first sound field control playing device connected to the first secondary signal circuit and adapted to play the first secondary audio signal; wherein a first playing delay period exists between the playing of the first secondary audio signal and the playing of the primary audio signal; wherein the first secondary audio signal played by the first sound field control playing device does not undergo audio mixing with the primary audio signal by a first audio mixing circuit.

Abstract: The present invention provides a device with rear-mounted vacuum tubes, comprising a protective cover with a plurality of heat dissipating holes, a rear panel with a panel opening, and at least one vacuum tube, wherein the vacuum tubes are arranged in a containing space of the protective cover through the panel opening and inserted to a connection circuit board for coupling to a printed circuit board. In addition, the protective cover, the rear panel, and the vacuum tubes are placed in parallel with the printed circuit board, so that heat dissipation for the device is improved and replacement and maintenance of the vacuum tubes are easier. In particular, a vacuum tube audio amplifier apparatus having the device with rear-mounted vacuum tubes as disclosed herein can be stacked.

Abstract: A vacuum tube and transistor amplifier natural sound field tone dividing system includes: a front-end circuit for receiving and processing an input signal to thereby generate an audio signal; a transistor power amplifying circuit connected to the front-end circuit and adapted to process a low-frequency signal in the audio signal and play the low-frequency signal with a first player; and a vacuum tube power amplifying circuit connected to the front-end circuit and adapted to process a medium-frequency signal and a high-frequency signal in the audio signal, play the medium-frequency signal with a second player, and play the high-frequency signal with a third player, wherein the transistor power amplifying circuit and the vacuum tube power amplifying circuit are independent of each other.

Abstract: The present invention provides a vacuum tube audio amplifier which includes an audio pre-amplifying portion and an audio output transforming portion. The audio pre-amplifying portion includes an equalizer for enhanced sound quality and amplifies an audio signal, which is subsequently transmitted to the audio output transforming portion. Furthermore, the audio output transforming portion includes an audio output transformer which includes a plurality of stacked E-shaped silicon steel sheets and a plurality of stacked I-shaped silicon steel sheets, wherein the stacked E-shaped silicon steel sheets and the stacked I-shaped silicon steel sheets have a same height which is smaller than or equal to 48 mm.

Abstract: The invention provides a grounding structure and a grounding method for a vacuum tube audio amplifier, the grounding structure and the grounding method including: with respect to a power source, utilizing a power circuit without a choke, an anti-coupling circuit, and a filament voltage regulator circuit; and with respect to the grounding method, utilizing an negative output terminal of an audio output transforming circuit or a negative terminal of a filter capacitor in the power circuit as a single ground terminal of the vacuum tube audio amplifier, and not arranging a grounding metal bottom plate therein, in order to achieve a compact, lightweight desktop model of a vacuum tube audio amplifier.

Abstract: The present invention provides an apparatus for controlling an electronic stop watch. The apparatus comprises a controller and a transmission media. The controller includes a keyboard for inputting a datum and an output port outputting the datum to the electronic stopwatch. The transmission media connects the electronic stopwatch with the controller, through one of a wire connection and a wireless connection.

Abstract: A manufacturing method for a signal transmitting belt of a heart rate monitor is provided. The steps includes: (a) providing an injection molding assembly, a conductive chest belt, and a first shaft body; (b) placing the first shaft body and the conductive chest belt inside the injection molding assembly and injecting a molding material into the injection molding assembly to form an insulating chest belt; (c) removing the first shaft body; (d) providing a main body; and (e) mounting a second shaft body at a same position of the first shaft body for connecting the insulating chest belt and the main body so as to accomplish the signal transmitting belt.

Abstract: A signal transmitting belt for transmitting a heartbeat signal to a heart rate monitor is provided, which shows a cardiorespiratory information. The signal transmitting belt includes: a main body comprising a signal transmitter for transmitting the heartbeat signal, an insulating chest belt, a connecting element connecting the main body and the insulating chest belt for sustaining a tension therebetween, and a conductive chest belt mounted on the insulating chest belt for contacting a chest of a user so as to detect the heartbeat signal and then transmit the heartbeat signal to the signal transmitter.

Abstract: An electronic trip meter for a bicycle is provided. The electronic trip meter for a bicycle includes a signal generator and a main unit. The signal generator is used for generating a signal each time the bicycle travels over a specific distance, and the main unit is used for receiving the signal, evaluating and displaying the riding data, and generating an alert signal to remind the rider to execute a maintenance operation when the riding distance or the riding time exceeds a preset riding distance or a preset riding time.

Abstract: A device for demonstrating and testing electronic meters for bicycles including a body portion having a slot, a rod mounted on the body portion, a plurality of seats mounted on the rod, a first magnet fitted on the body portion, a handwheel partially pivotally fitted in the slot of the body portion, a second magnet fitted on a the handwheel, and an electronic testing device disposed within the body portion and operatively connected with the seats, whereby the device can be used for demonstrating as well as testing electronic meters for bicycles.