Output signals given from a tube amplifier (5) are amplified by a small number of vacuum tubes with maintaining the output property of the output signals. A second circuit (C2) is arranged in parallel to a first circuit (C1) wherein the output signals given from a vacuum tube (VA1) is flowing, and a node of the first circuit (C1) and the second circuit (C2) is connected to an input terminal of an output transformer (TR(1)). Since electric current proportioned to current level flowing in the first circuit (C1) flows into the second circuit (C2), current which amplified the output signals given from the vacuum tube (VA1) flows into the primary side of the output transformer (TR(1)). Consequently, by using the tube amplifier containing the small number of vacuum tubes, it is possible to obtain high output power as if it is obtainable by using a large number of vacuum tubes.

An output signal converter for tube amplifiers, being constituted by using semiconductor devices and either amplifying or attenuating output signals given from the tube amplifier having the output terminal to be supplied to the speaker while maintaining the output property of the tube amplifier comprising:

an output transformer (1) connected to an output terminal of a tube amplifier and provided with two output terminals; a first voltage amplifier (11) connected to a site locating between said output terminals; a first impedance circuit (Z3); a second voltage amplifier (12);

a series connecting circuit with a coefficient multiplier (13); and a second impedance circuit (Zi) connected in parallel to the first voltage amplifier, wherein a speaker is arranged in parallel to the second voltage amplifier (12).

Verstärker in symmetrischer Gegentaktausführung mit jeweils einem Vorverstärkerblock (N1B, N2B) und einem Endverstärker (M1, M2) in den beiden Signalzweigen, wobei eine extern anzuschließende Last (RL) direkt ohne Trennkondensatoren oder Übertrager an den ersten und zweiten Endverstärker (M1, M2) anschließbar ist. Der erste und zweite Vorverstärkerblock (N1B, N2B) wird jeweils von einer massebezogenen Spannungsversorgungseinrichtung (V3, V4) und der erste und zweite Endverstärker (M1, M2) jeweils von einer schwimmenden Spannungsquelle (V1, V2) gespeist. Durch einen ersten und zweiten Potentialdifferenzerzeuger (4, 5) in Verbindung mit einer Ruhestromeinstelleinrichtung (Ix) werden die erforderlichen Ruhepegel und Ruheströme für die Endverstärker (M1, M2) eingestellt. Die Schaltungsarchitektur des Gegentaktverstärkers ist bezüglich der Auswahl aktiver Verstärkungsbausteine flexibel und erlaubt eine vollständige DC-Kopplung in den beiden Signalzweigen.

Output signals given from a tube amplifier (5) are amplified by a small number of vacuum tubes with maintaining the output property of the output signals. A second circuit (C2) is arranged in parallel to a first circuit (C1) wherein the output signals given from a vacuum tube (VA1) is flowing, and a node of the first circuit (C1) and the second circuit (C2) is connected to an input terminal of an output transformer (TR(1)). Since electric current proportioned to current level flowing in the first circuit (C1) flows into the second circuit (C2), current which amplified the output signals given from the vacuum tube (VA1) flows into the primary side of the output transformer (TR(1)).

Consequently, by using the tube amplifier containing the small number of vacuum tubes, it is possible to obtain high output power as if it is obtainable by using a large number of vacuum tubes.

Output signals given from a tube amplifier (5) are amplified by a small number of vacuum tubes with maintaining the output property of the output signals. A second circuit (C2) is arranged in parallel to a first circuit (C1) wherein the output signals given from a vacuum tube (VA1) is flowing, and a node of the first circuit (C1) and the second circuit (C2) is connected to an input terminal of an output transformer (TR(1)). Since electric current proportioned to current level flowing in the first circuit (C1) flows into the second circuit (C2), current which amplified the output signals given from the vacuum tube (VA1) flows into the primary side of the output transformer (TR(1)). Consequently, by using the tube amplifier containing the small number of vacuum tubes, it is possible to obtain high output power as if it is obtainable by using a large number of vacuum tubes.

The present invention is the electronic system of a hybrid amplifier, especially electroacoustic hybrid amplifier comprising a tube voltage amplifier, a tube isolating repeater, a power repeater, and a power repeater power supply, a voltage amplifier power supply, and an isolating repeater power supply.

An electronic device includes an amplifier which is configured to amplify a sound signal and includes a vacuum tube including a heater configured to heat the vacuum tube; a voltage supply which is configured to supply a first voltage and a second voltage which is higher than the first voltage; and a controller which is configured to control the voltage supply to supply the second voltage to the heater in response to supply of a drive voltage to the amplifier being started and to supply the first voltage to the heater if the vacuum tube reaches a predetermined temperature.

A sound output device is provided. The sound output device includes a vacuum tube for amplifying an audio signal; a power supply that supplies power to the vacuum tube; a first switch circuit that selectively connects the power supply to the vacuum tube; and a controller that controls the first switch circuit according to whether the vacuum tube is in use. When the vacuum tube is not in use, it is bypassed by the audio signal.

Output signals given from a tube amplifier (5) are amplified by a small number of vacuum tubes with maintaining the output property of the output signals. A second circuit (C2) is arranged in parallel to a first circuit (C1) wherein the output signals given from a vacuum tube (VA1) is flowing, and a node of the first circuit (C1) and the second circuit (C2) is connected to an input terminal of an output transformer (TR(1)). Since electric current proportioned to current level flowing in the first circuit (C1) flows into the second circuit (C2), current which amplified the output signals given from the vacuum tube (VA1) flows into the primary side of the output transformer (TR(1)).

Consequently, by using the tube amplifier containing the small number of vacuum tubes, it is possible to obtain high output power as if it is obtainable by using a large number of vacuum tubes.