JP3662116B2 - Output signal amplifier for vacuum tube amplifier - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to amplifiers for electric and electronic musical instruments and audios, and in particular, installed on the rear side of a vacuum tube amplifier, amplifies or attenuates an output signal while maintaining the characteristics of the vacuum tube amplifier, and outputs a large output. The present invention relates to an output signal conversion apparatus capable of converting from a small output to a small output.
[0002]
[Prior art]
In recent years, with the advance of semiconductor technology, amplifiers used for electronic musical instruments and audio have been changed to vacuum tubes that have been mainly used conventionally, and those using semiconductor devices such as transistors have been used. However, amplifiers using vacuum tubes are still popular because of their unique output characteristics, and although few, tube amplifiers are manufactured and sold.
[0003]
However, as is well known, a vacuum tube has a short life and low reliability compared to a semiconductor device, and the components are heavy and large, so that the storage property is poor, the heat generation amount is large, the high voltage is required, the cost is high, and it is fragile. Therefore, even if there is a desire to use a vacuum tube amplifier, it is almost impossible to actually use it. Therefore, in order to solve such a problem, a number of devices that reproduce the output characteristics of a vacuum tube amplifier in a pseudo manner using a semiconductor device have been devised and used in practice. However, the sound of the vacuum tube amplifier is made by the bidirectional relationship that the magnetic saturation of the output transformer and the back electromotive force generated by the speaker affect the operation of the output tube located in the preceding stage. There are limits to imitating complex circuits using semiconductor devices. Therefore, in practice, it has been impossible to reproduce an amplifier having substantially the same characteristics as the output characteristics of a vacuum tube amplifier with a semiconductor device.
[0004]
[Problems to be solved by the invention]
As described above, many devices have been devised in the past to obtain output characteristics as if using a vacuum tube using a semiconductor device. However, magnetic saturation of the output transformer and back electromotive force of the speaker are generated. There is no one that obtains the output characteristics including the above characteristics, and there is no one that can faithfully reproduce the characteristics of the vacuum tube amplifier.
[0005]
The present invention has been made to solve such conventional problems, and the object of the present invention is to maintain the characteristics including the characteristics of the transformer and the speaker obtained by the vacuum tube amplifier while maintaining the characteristics. An object of the present invention is to provide an output signal amplifying apparatus capable of amplifying an output signal using a minimum necessary vacuum tube by amplifying the output signal using a semiconductor device.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 of the present application is an output signal amplifying apparatus configured using a semiconductor device and amplifying an output signal of a vacuum tube amplifier while maintaining the characteristics of the output signal. Te, is disposed between the output end of one of the input terminals and the vacuum tube output transformer connected to the load side, a first circuit is constituted by the series connection of the first resistor and the first transistor, A second circuit disposed between one input terminal of the output transformer and the ground, and configured by a series connection of a second resistor, a second transistor, and a third transistor; A base terminal of the first transistor is disposed between the second resistor and the second transistor, and is connected to a base terminal of the third transistor to form a current mirror circuit. Over scan terminals are connected, wherein the Rukoto between the output terminal of the first transistor and a vacuum tube.
[0008]
The invention according to claim 2 is an output signal amplifying device configured using a semiconductor device and amplifying the output signal of the vacuum tube amplifier while maintaining the characteristics of the output signal. The first amplifier circuit is a push-pull type composed of a second amplifier circuit configured in a mirror image type, and the first amplifier circuit and the second amplifier circuit are respectively connected to the load side. A first circuit disposed between an input terminal of the output transformer and an output end of the vacuum tube and configured by series connection of a first resistor and a first transistor; and an input terminal of the output transformer; A second circuit disposed between the first resistor and the second resistor, and a second circuit configured by connecting the second transistor and the third transistor in series. The base terminal of the first transistor is The second resistor and the second transistor Disposed between, so as to form a current mirror circuit is connected to the base terminal of the third transistor, the base terminal of the second transistor is connected between the output terminal of the first transistor and a vacuum tube The cathodes of the vacuum tubes of the first amplifier circuit and the second amplifier circuit are connected to each other, and this connection point is connected to the ground through a resistor.
[0009]
According to a third aspect of the invention, the pre-Symbol second resistor is a variable resistor, and adjusts the output level by operating the variable resistor.
[0010]
According to the first aspect of the present invention configured as described above, when the current amplified in the vacuum tube flows to the first circuit, a current proportional to the amplified current flows to the second circuit. Therefore, a current as if amplified by a plurality of vacuum tubes flows through the output transformer. This makes it possible to obtain output characteristics that are almost equivalent to the case where a large number of vacuum tubes are used with a small number of vacuum tubes, such as a short life, a large amount of heat generation, poor storage, and fragile. By using only a necessary minimum number of vacuum tubes, a tone similar to that of a vacuum tube amplifier can be obtained. In the invention according to claim 2, the same operation as described above can be obtained for the push-pull type amplifier using a vacuum tube. In addition, if a current mirror circuit is formed by the first transistor and the third transistor, the third transistor operates following the characteristic such as the temperature characteristic of the first transistor. It becomes possible to cause the second circuit to generate a current that reproduces the current flowing through the circuit very faithfully, thereby improving the reproducibility of the timbre of the vacuum tube.
[0012]
In the third aspect of the present invention, when the second resistor is a variable resistor and the resistance value is appropriately changed, the ratio of the current flowing through the first circuit to the current flowing through the second circuit is arbitrarily changed. Therefore, the output volume can be adjusted. At this time, since the current flowing through the first circuit, that is, the output current of the vacuum tube is kept substantially constant, the volume can be adjusted while maintaining the tone of the vacuum tube.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram showing a configuration of an embodiment of an output signal amplifying apparatus for a vacuum tube amplifier to which the present invention is applied. The output signal of a single vacuum tube V1 is amplified, as if a plurality of vacuum tubes are used. The output characteristics as described above are obtained.
[0014]
As shown in the figure, this amplifying device is installed between the plate terminal of the vacuum tube V1 and one input terminal TRa of the output transformer TR, and is connected in series with the first resistor R1 and the first transistor Q1. And a second circuit configured by connecting the second resistor R2 and the second transistor Q2 in series.
[0015]
That is, the connection to the terminal TRa is branched into two systems, and one of these systems (first circuit) is connected to the emitter of the first transistor Q1 via the first resistor R1, and this transistor Q1. Are connected to the plate terminal of the vacuum tube V1. The other system (second circuit) is connected to the emitter of the second transistor Q2 via the second resistor R2, and the collector of the transistor Q2 is connected to the ground. Further, the base of the first transistor Q1 is connected to the connection point between the second resistor R2 and the second transistor Q2, and the base of the second transistor Q2 is connected to the plate terminal of the vacuum tube V1. The input signal is supplied to the grid terminal of the vacuum tube V1, and the output signal of the output signal amplifying device is output to the transformer TR.
[0016]
Next, the operation of the present embodiment configured as described above will be described. Here, the current flowing to the input side of the transformer TR is IOUT, the current flowing to the first circuit (a series connection circuit of the resistor R1 and the transistor Q1) is IIN, and between the plate terminal of the vacuum tube V1 and the input terminal TRa of the transformer TR. the voltage V 0, ZOUT the impedance when viewing the load side from the transformer TR, ZIN the impedance when viewing the load side from the vacuum tube V1, the voltage generated by the plate terminal of the vacuum tube V1 and VIN.
[0017]
Then, the following equations (1) to (3) are established.
IOUT = VIN / (ZOUT + R1 // R2) (1)
Here, R1 // R2 represents a parallel combined resistance of the resistor R1 and the resistor R2.
V 0 = R1 // R2 * IOUT (2)
IIN = V 0 / R1 (3)
From equations (2) and (3), equation (4) is obtained.
IIN = {(R1 // R2) / R1} * IOUT (4)
[0018]
Further, since IIN = VIN / ZIN, if this is substituted into the equation (4) and further the equation (1) is substituted into (4), the following equation (5) is obtained.
VIN / ZIN = {(R1 // R2) / R1} * VIN / {ZOUT + (R1 // R2)} (5)
When the equation (5) is modified and R1 // R2 is expanded, the following equation (6) can be obtained.
ZIN = {(R1 + R2) / R2} * [ZOUT + {(R1 * R2) / (R1 + R2)}] (6)
In the equation (6), when R1 << ZOUT and R2 << ZOUT, the equation (7) is obtained.
ZIN≈ {(R1 + R2) / R2} * ZOUT (7)
From the equation (7), it can be understood that ZIN and ZOUT are determined by the ratio of the first resistance R1 and the second resistance R. For example, if R1 = R2,
ZOUT = (1/2) ZIN, and the impedance is halved. Therefore, the current output from the transformer TR is doubled, and the output signal of the vacuum tube V1 is amplified to a double current. At this time, since the current flowing through the second circuit (the circuit formed by the second resistor R and the second transistor Q2) is the same as the current flowing through the first circuit, IOUT is twice IIN. The output characteristics of the vacuum tube V1 are maintained, and as a result, an output signal as if using two vacuum tubes can be obtained with one vacuum tube.
[0019]
Further, the current amplification factor can be changed by appropriately changing the ratio between the first resistor R1 and the second resistor R2. For example, if R2 = 2 * R1, IOUT can be three times IIN, and if R2 = (1/2) * R1, IOUT can be 1.5 times IIN.
[0020]
In this way, in the output signal amplifying apparatus in the present embodiment, it is possible to obtain an output signal as if using one vacuum tube V1, as if using one or more vacuum tubes. It is possible to minimize the number of vacuum tubes with various problems such as high voltage, high voltage, high cost, short life, etc. Useful.
[0021]
Further, since the second resistor R2 is a variable resistor and the variable resistor is operated, the magnitude of the current IOUT can be adjusted, whereby the increase or decrease in the output volume can be adjusted appropriately. The volume adjustment is normally performed on the input side (that is, the stage before being input to the vacuum tube V1 in FIG. 1). However, if a method of changing the resistance value of the second resistor R2 is adopted, the vacuum tube V1 is adjusted. Since the volume can be adjusted while keeping the flowing current IIN substantially constant, the volume can be adjusted while maintaining the tone of the vacuum tube.
[0022]
FIG. 2 is a circuit diagram showing a configuration of an output signal amplifying apparatus for a vacuum tube amplifier according to the second embodiment of the present invention. As shown in the figure, the connection line to one input terminal TRa of the output transformer TR is branched into two systems, and one of these branches (first circuit) includes the first resistor R11, the first resistor The other branch (second circuit) is connected to the plate terminal of the vacuum tube V1 through the emitter and collector of the transistor Q11, and the second branch is connected to the second resistor R12 and the emitter and collector of the third transistor Q13. The second transistor Q12 is connected to the ground via the emitter and collector. The bases of the first transistor Q11 and the third transistor Q13 are connected to each other, and this connection point is also connected to the collector of the second transistor Q12 . That is, a current mirror circuit is configured by the first transistor Q11 and the third transistor Q13. The base of the second transistor Q12 is connected to the plate terminal of the vacuum tube V1 via the resistor R3, and the speaker SP is connected to the secondary side of the output transformer TR.
[0023]
According to the second embodiment configured as described above, the characteristics (temperature characteristics, etc.) of the first transistor Q11 are obtained by the current mirror circuit formed by the first transistor Q11 and the third transistor Q13. ) Directly flows in the second circuit, so that a more stable circuit operation can be achieved.
[0024]
If a slight deterioration in stability is allowed, as shown in FIG. 3, it is possible to use a diode D1 instead of the third transistor Q13 shown in FIG. According to such a configuration, an effect that the configuration can be simplified by using a diode instead of a transistor can be exhibited.
[0025]
4A and 4B are explanatory diagrams showing various waveforms. FIG. 4A shows a sine wave as an input signal, and FIG. 4B amplifies the sine wave signal by an amplifier configured using a semiconductor device. (C) is an output waveform diagram when amplified by a conventional vacuum tube amplifier, and (d) is a sinusoidal input waveform amplification using the circuit shown in FIG. The output waveform diagram at the time of doing is shown, respectively. As can be easily understood from FIG. 5B, an amplifier using a semiconductor device has an output waveform that substantially faithfully reproduces an input sine wave, whereas FIG. In the case of an amplifier using a vacuum tube as shown in Fig. 1, a waveform unique to the vacuum tube amplifier is obtained.
In the amplifying device to which the present invention is applied, as shown in FIG. 4D, the output waveform obtained from a conventional vacuum tube amplifier (amplifier composed entirely of vacuum tubes) is substantially the same as that of the vacuum tube. It can be understood that the output characteristics are faithfully reproduced.
[0026]
FIG. 5 is a circuit diagram showing a configuration of an output amplifying apparatus for a vacuum tube amplifier according to a third embodiment of the present invention. As shown in the figure, this output amplifying apparatus uses a push-pull that uses two vacuum tubes V11 and V12. Type amplifier. That is, although detailed description is omitted to avoid duplication, the amplifier circuits using the current mirror shown in FIG. 2 are arranged vertically symmetrically, and the cathode terminals (hot cathodes) of the two vacuum tubes V11 and V12 are connected to each other. This connection point is connected to the ground via a resistor R24.
[0027]
As is well known, the push-pull type power amplifier separates the audio signal obtained from the preamplifier into positive and negative signals by the phase inverter PI, and the positive signal among them is sent to the upper circuit equipped with the vacuum tube V11. The negative signal is amplified by the lower circuit provided with the vacuum tube V12, and these signals are synthesized by the transformer TR and output from the speaker SP. According to such a configuration, it is possible to obtain substantially the same amplification characteristics as a push-pull type vacuum tube amplifier using 4 to 6 vacuum tubes only by using two vacuum tubes V11 and V12.
[0028]
FIG. 6 is a waveform diagram showing output characteristics obtained by using the push-pull amplifier shown in FIG. 5. FIG. 6A shows a sine wave as an input signal, and FIG. ) Is an output waveform diagram when the sine wave is supplied to an amplifying device configured using four vacuum tubes (that is, a conventional push-pull type amplifying device to which the present invention is not applied), and FIG. FIG. 6 shows output waveform diagrams when a sine wave is supplied to the amplifying apparatus shown in FIG. 5. As can be easily understood from FIGS. 7B and 7C, when a conventional push-pull type amplifying apparatus using a vacuum tube is used (b) and when a necessary minimum vacuum tube is used ( Comparing c), substantially the same waveform was obtained, and it was confirmed that the amplification device of the present invention faithfully maintained the characteristics of the vacuum tube.
[0029]
【The invention's effect】
As described above, according to the output signal amplifying apparatus for a vacuum tube amplifier according to the present invention, since a small number of vacuum tubes are used and the output characteristics as if a large number of vacuum tubes are used can be obtained, a large amount of heat is generated. High voltage is required, high cost, short life, fragile vacuum tubes with various disadvantages can be minimized, and output signals equivalent to those using many vacuum tubes can be obtained Therefore, it is possible to realize a vacuum tube amplifier which has been popular as a guitar amplifier and an audio amplifier and is relatively simple and low cost.
[0030]
In addition, if a current mirror circuit is formed by the first transistor and the third transistor, the third transistor operates following the characteristic such as the temperature characteristic of the first transistor. It becomes possible to cause the second circuit to generate a current that reproduces the current flowing through the circuit very faithfully, thereby improving the reproducibility of the timbre of the vacuum tube. Further, it can be applied to a push-pull type amplifying device, and is normally composed of 4 to 6 vacuum tubes, and a push-pull type vacuum tube amplifying device is composed of two vacuum tubes which are the minimum necessary. can do.
[0031]
In addition, if the second resistor is a variable resistor and the output volume is adjusted by operating this variable resistor, the volume can be adjusted while maintaining the current value flowing through the vacuum tube substantially constant. The volume can be adjusted while maintaining the timbre, and its utility value is extremely high.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing a configuration of an output signal amplifying device of a vacuum tube amplifier according to a first embodiment of the present invention.
FIG. 2 is a circuit diagram showing a configuration of an output signal amplifying device of a vacuum tube amplifier according to a second embodiment of the present invention.
3 is a circuit diagram showing an example in which a diode is connected instead of the third transistor shown in FIG. 2;
4A is a waveform diagram of a sine wave serving as an input waveform, FIG. 4B is a waveform diagram illustrating an output signal when a sine wave is input to an amplifier using a semiconductor device, and FIG. 4C is a conventional vacuum tube; FIG. 4D is a waveform diagram showing an output signal when a sine wave is inputted to the amplifier, and FIG. 4D is a waveform diagram showing an output signal when the sine wave is inputted to the circuit shown in FIG.
FIG. 5 is a circuit diagram showing a configuration of an output signal amplifying device (push-pull type) of a vacuum tube amplifier according to a third embodiment of the present invention.
6A is a waveform diagram of a sine wave as an input waveform, FIG. 6B is an output waveform diagram when a push-pull amplifier is configured using four vacuum tubes, and FIG. FIG. 6 is an output waveform diagram obtained using the push-pull amplifier.
[Explanation of symbols]
R1, R11, R21, R25 First resistor R2, R12, R22, R26 Second resistor R3, R23, R24, R27 Resistor Q1, Q11, Q21, Q24 First transistor Q2, Q12, Q22, Q25 Second Transistors Q13, 23, Q26 Third transistors V1, V11, V12 Vacuum tube TR Output transformer D1 Diode SP Speaker PI Phase inverter

Claims (3)

An output signal amplifying apparatus configured using a semiconductor device and amplifying an output signal of a vacuum tube amplifier while maintaining the characteristics of the output signal,
Is disposed between the output end of one of the input terminals and the vacuum tube output transformer connected to the load side, a first circuit is constituted by the series connection of the first resistor and the first transistor,
A second circuit disposed between one input terminal of the output transformer and the ground, and configured by connecting a second resistor, a second transistor, and a third transistor in series;
The base terminal of the first transistor is disposed between the second resistor and the second transistor, is connected to the base terminal of the third transistor to form a current mirror circuit, and the second transistor connected to an output signal amplifier tube amp, wherein Rukoto between the base terminal and the output terminal of the first transistor and the vacuum tube. An output signal amplifying apparatus configured using a semiconductor device and amplifying an output signal of a vacuum tube amplifier while maintaining the characteristics of the output signal,
The first amplifier circuit and the first amplifier circuit are a push-pull type composed of a second amplifier circuit configured in a mirror image type, and the first amplifier circuit and the second amplifier circuit are respectively
A first circuit that is arranged between one input terminal of an output transformer connected to the load side and an output end of the vacuum tube, and is configured by a series connection of a first resistor and a first transistor;
A second circuit disposed between one input terminal of the output transformer and the ground, and configured by connecting a second resistor, a second transistor, and a third transistor in series;
The base terminal of the first transistor is disposed between the second resistor and the second transistor, is connected to the base terminal of the third transistor to form a current mirror circuit, and the second transistor A base terminal of the first transistor is connected between the first transistor and an output terminal of the vacuum tube ;
An output signal amplifying apparatus for a vacuum tube amplifier, wherein the cathodes of the vacuum tubes of the first amplifier circuit and the second amplifier circuit are connected to each other, and the connection point is connected to the ground through a resistor . 3. The output signal amplifying device for a vacuum tube amplifier according to claim 1, wherein the second resistor is a variable resistor, and an output level is adjusted by operating the variable resistor .

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