Abstract: A vacuum tube includes a filament and two pairs of a grid and an anode. The filament is tensioned linearly and emits thermoelectrons. Both of the anodes are formed on a same face on a planar substrate. The filament is arranged parallel to the planar substrate at a position facing both of the anodes. Each of the grids is arranged, such that the grid faces the anode of a same pair at a first predetermined distance from the anode and has a second predetermined distance from the filament, between the anode and the filament. The vacuum tube further includes an intermediate filament fixing part fixing the filament at a position corresponding to an intermediate point between the anodes of the two pairs.

Abstract: A vacuum tube includes a filament and two pairs of a grid and an anode. The filament is tensioned linearly and emits thermoelectrons. Both of the anodes are formed on a same face on a planar substrate. The filament is arranged parallel to the planar substrate at a position facing both of the anodes. Each of the grids is arranged, such that the grid faces the anode of a same pair at a first predetermined distance from the anode and has a second predetermined distance from the filament, between the anode and the filament. The vacuum tube further includes an intermediate filament fixing part fixing the filament at a position corresponding to an intermediate point between the anodes of the two pairs.

Abstract: The vacuum tube subject to the present invention comprises a filament and two pairs of a grid and an anode. The filament is tensioned linearly and emitting thermoelectrons. Both of the anodes are formed on the same face on a planar substrate. The filament is arranged parallel to the planar substrate at a position facing both of the anodes. Each of the grids is arranged, such that the grid faces the anode in the same pair at a first predetermined distance from the anode and has a second predetermined distance from the filament, between the anode and the filament. The vacuum tube comprises an intermediate filament fixing part fixing the filament at a position corresponding to an intermediate point between the anodes of the two pairs.

Abstract: The vacuum tube subject to the present invention comprises a filament and two pairs of a grid and an anode. The filament is tensioned linearly and emitting thermoelectrons. Both of the anodes are formed on the same face on a planar substrate. The filament is arranged parallel to the planar substrate at a position facing both of the anodes. Each of the grids is arranged, such that the grid faces the anode in the same pair at a first predetermined distance from the anode and has a second predetermined distance from the filament, between the anode and the filament. The vacuum tube comprises an intermediate filament fixing part fixing the filament at a position corresponding to an intermediate point between the anodes of the two pairs.

Abstract: A vacuum tube circuit is capable of amplifying an input signal with use of a low source voltage. Ordinarily, the amount of electrons released from a cathode which is heated by a heater is small since a voltage supplied to the heater is low. In the vacuum tube circuit disclosed here, a positive voltage is supplied to a grid terminal, which more effectively attracts the emitted electrons, thereby increasing the amount of electrons arriving at the plate terminal passing through the grid. As a result, a grid current and a plate current flow in the vacuum tube circuit, which achieves an operation for amplifying an input signal from a signal source.

Abstract: A vacuum tube circuit is capable of amplifying an input signal with use of a low source voltage. Ordinarily, the amount of electrons released from a cathode which is heated by a heater is small since a voltage supplied to the heater is low. In the vacuum tube circuit disclosed here, a positive voltage is supplied to a grid terminal, which more effectively attracts the emitted electrons, thereby increasing the amount of electrons arriving at the plate terminal passing through the grid. As a result, a grid current and a plate current flow in the vacuum tube circuit, which achieves an operation for amplifying an input signal from a signal source.

Abstract: Provides a one-terminal effector having an input terminal and an output terminal structured as one terminal by providing a circuit that makes input and output of the effector common. The one-terminal effector can avoid complex cable wiring, and can prevent degradation of sound quality. The one-terminal effector includes one input/output terminal, and an effector circuit that executes a predetermined processing on an analog audio signal that is input from the input/output terminal, and outputs the processed analog audio signal from the input/output terminal. The one-terminal effector further includes an input/output signal conversion circuit that converts the input signal and the output signal into mutually different signal forms of voltage signals or current signals.

Abstract: A pressure point detector has a simple structure and is capable of detecting which location of a two-dimensional surface such as a circle a pressure is applied can be detected. The pressure point detector includes a flexible insulation member in a predetermined shape, a resistance film formed on one side of the flexible insulation member, a conductive member made of conductive material and established to face the insulation member with a with a predetermined gap therebetween, and a pair of electrodes established on the resistance film in a parallel fashion to produce voltage distribution. The pressure point detector produces an output voltage from the conductive member indicative of a location of the pressure applied to the insulation member.

Abstract: A vacuum tube amplifier is formed of a vacuum tube having a cathode, a plate, a grid, and a heater to radiate electrons from the cathode. An input signal is supplied to the plate, an output signal is obtained at the grid, and a predetermined low voltage is supplied to the heater. The voltage supplied to the heater can be low, thereby significantly decreasing an overall consumption of electric power for the vacuum tube amplifier.

Abstract: A vacuum tube amplifier is formed of a vacuum tube having a cathode, a plate, a grid, and a heater to radiate electrons from the cathode. An input signal is supplied to the plate, an output signal is obtained at the grid, and a predetermined low voltage is supplied to the heater. The voltage supplied to the heater can be low, thereby significantly decreasing an overall consumption of electric power for the vacuum tube amplifier.

Abstract: A pressure point detector has a simple structure and is capable of detecting which location of a two-dimensional surface such as a circle a pressure is applied can be detected. The pressure point detector is comprised of a flexible insulation member in a predetermined shape, a resistance film formed on one side of the flexible insulation member, a conductive member made of conductive material and established to face the insulation member with a with a predetermined gap therebetween, and a pair of electrodes established on said resistance film in a parallel fashion to produce voltage distribution, thereby producing an output voltage from said conductive member indicative of a location of the pressure applied to the insulation member.

Abstract: Provides a one-terminal effector having an input terminal and an output terminal structured as one terminal by providing a circuit that makes input and output of the effector common. The one-terminal effector can avoid complex cable wiring, and can prevent degradation of sound quality. The one-terminal effector includes one input/output terminal, and an effector circuit that executes a predetermined processing on an analog audio signal that is input from the input/output terminal, and outputs the processed analog audio signal from the input/output terminal. The one-terminal effector further includes an input/output signal conversion circuit that converts the input signal and the output signal into mutually different signal forms of voltage signals or current signals.

Abstract: The output signal converter for a tube amplifier includes semiconductor devices for amplifying or attenuating an output signal of the tube amplifier while maintaining the output properties of the tube amplifier. The output signal converter according to one embodiment has an output transformer (TR) having an input terminal (TRa); a first circuit branch (C1) connected between the input terminal (TRa) and an output terminal of the tube amplifier and a second circuit branch (C2) connected to the input terminal (TRa) of the output transformer (TR) and in parallel to the first circuit branch and including components that produce an electric current proportional to a current level in the first circuit branch. The first and second circuit branches are located between the tube amplifier and the output transformer (TR) and include semiconductor devices so that the output signal from the tube amplifier is amplified while maintaining the output properties of the tube amplifier.

Abstract: The output signal converter for a tube amplifier includes semiconductor devices for amplifying or attenuating an output signal of the tube amplifier while maintaining output properties of the tube amplifier. The output signal converter in preferred embodiments has an output transformer (1) connected to the tube amplifier, a current amplifier and a voltage amplifier serially connected with each other via a node, and a speaker (4). The current amplification factor (Ac) of the current amplifier (2) and the voltage amplification factor (Av) of the voltage amplifier (3) are related according to the following equation: Ac*Av=−k, wherein k is a constant.

Abstract: An electronic keyboard instrument generates signals of frequencies respectively corresponding to keys by depressing the keys of a keyboard from a signal source, and reproduces a musical note corresponding to the generated signal. The frequency spectrum of an external signal is detected and used to control the frequency spectrum of the generated signal to cause the frequency spectrum of the generated signal to approximate that of the external signal.