US3683293A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tone control circuit
Assignee: Nippon Gakki Co Ltd
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Filing: 1970-06-15
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Granted: 1972-08-08
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Expires: 1990-06-15
Abstract
Abstract A tone control circuit used in a stereo amplifier, guitar amplifier, or the like, comprising an amplifier having a first terminal and a second terminal for delivering outputs in an opposite phase relation, a plurality of circuit branches connected across the first and the second terminals for controlling tone level in the corresponding frequency ranges, and variable elements included in said plurality of circuit branches and each having a movable contact terminal connected to the ground, so that the ratio between the load impedances connected to the first and the second output terminals of the amplifier can be varied by varying the position of the movable contact terminal on either one of the variable elements, whereby the gain of the amplifier can be controlled by varying the impedance ratio in a desired frequency range.
Inventors
- 👤 Teruyoshi Matsui
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 06:08
CPC Classifications
H; H03; H03G; H03G5/00; H03G5/02; H03G5/04; H03G5/10
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
287 words
A tone control circuit comprising an amplifier circuit having a first output terminal and a second output terminal for delivering outputs in opposing phase relation, a plurality of circuit branches connected across the first and the second output terminals for controlling the tone level in the corresponding frequency ranges, and variable impedance elements included respectively in said plurality of circuit branches and each of the variable impedance elements having a movable contact terminal connected to ground, so that the ratio between the load impedances connected to the first and the second output terminals of the amplifier circuit can be varied by varying the position of the movable contact terminal on either one of the variable impedance elements included in the plurality of the circuit branches, whereby the gain of the amplifier circuit is allowed to be controlled in accordance with the variation of the impedance ratio in either of the frequency ranges; said amplifier being in the form of a transistor amplifier having a first output terminal at the collector side and a second output terminal at the emitter side; said plurality of circuit branches connected across the first and the second output terminals for controlling the tone level are made into two circuit branches one being a treble control circuit branch and the other being a bass control circuit branch; said bass control circuit branch comprising a first resistor, a variable resistor having a movable contact terminal, and a second resistor, all connected in series across the first output terminal and the second output terminal of said transistor amplifier, and a conductive circuit connected in parallel across the fixed terminals at the opposite ends of said variable resistor, said conductive circuit including at least one capacitor.
Claim 2
Dependent Claim
287 words
A tone control circuit comprising an amplifier circuit having a first output terminal and a second output terminal for delivering outputs in opposing phase relation, a plurality of circuit branches connected across the first and the second output terminals for controlling the tone level in the corresponding frequency ranges, and variable impedance elements included respectively in said plurality of circuit branches and each of the variable impedance elements having a movable contact terminal connected to ground, so that the ratio between the load impedances connected to the first and the second output terminals of the amplifier circuit can be varied by varying the position of the movable contact terminal on either one of the variable impedance elements included in the plurality of the circuit branches, whereby the gain of the amplifier circuit is allowed to be controlled in accordance with the variation of the impedance ratio in either of the frequency ranges; said amplifier being in the form of a transistor amplifier having a first output terminal at the collector side and a second output terminal at the emitter side; said plurality of circuit branches connected across the first and the second output terminals for controlling the tone level are made into two circuit branches one being a treble control circuit branch and the other being a bass control circuit branch; said bass control circuit branch comprising a first resistor, a variable resistor having a movable contact terminal, and a second resistor, all connected in series across the first output terminal and the second output terminal of said transistor amplifier, and a conductive circuit connected in parallel across the fixed terminals at the opposite ends of said variable resistor, said conductive circuit including at least one capacitor.
Claim 3
Dependent Claim
48 words
A tone control circuit as defined in claim 1 wherein the ratio of said first and second resistors, at the time the movable contact terminal on said variable resistor element is placed at the mechanical neutral position, is selected to be a value which is greater than 1.
Claim 4
Dependent Claim
66 words
A tone control circuit as defined in claim 1 wherein said treble control circuit branch comprises two capacitors and a variable resistance element having a sliding contact terminal, all connected in series across the first output terminal at the collector side and the second output terminal at the emitter side, and a resistor connected between the slidable contact terminal of the variable resistance element and ground.
Claim 5
Dependent Claim
69 words
A tone control circuit as defined in claim 1 wherein said treble control circuit branch comprises a variable resistance element having a sliding contact terminal, said variable resistance element connected across the first output terminal at the collector side and the second output terminal at the emitter side and a resistor and a capacitor connected in series between the variable contact terminal of the variable resistance element and ground.
Claim 6
Dependent Claim
154 words
A tone control circuit comprising an amplifier having a first output terminal and a second output terminal for delivering outputs in opposing phase relation; a treble control circuit branch inclUding a variable resistor having a sliding terminal and two fixed terminals and at least one capacitor and one resistor, said sliding terminal being grounded, said fixed terminals being connected respectively to said first and second output terminals, and said at least one capacitor and one resistor being inserted in series between said first output terminal and ground; and a bass control circuit branch including a second variable resistor having a sliding terminal and two fixed terminals, two resistors and at least one capacitor, said sliding terminal being grounded, said fixed terminals being connected respectively through each of said resistors to said first and second output terminals, and said at least one capacitor being connected across the two fixed terminals of said second variable resistor.
Claim 7
Dependent Claim
154 words
A tone control circuit comprising an amplifier having a first output terminal and a second output terminal for delivering outputs in opposing phase relation; a treble control circuit branch inclUding a variable resistor having a sliding terminal and two fixed terminals and at least one capacitor and one resistor, said sliding terminal being grounded, said fixed terminals being connected respectively to said first and second output terminals, and said at least one capacitor and one resistor being inserted in series between said first output terminal and ground; and a bass control circuit branch including a second variable resistor having a sliding terminal and two fixed terminals, two resistors and at least one capacitor, said sliding terminal being grounded, said fixed terminals being connected respectively through each of said resistors to said first and second output terminals, and said at least one capacitor being connected across the two fixed terminals of said second variable resistor.
Claim 8
Dependent Claim
55 words
A tone control circuit as defined in claim 5 wherein said treble control circuit branch includes a second capacitor and a second resistor, said sliding terminal being grounded directly, the remaining one of said fixed terminals being connected to said second output terminal through a series path comprising said second capacitor and said second resistor.
Claim 9
Dependent Claim
50 words
A tone control circuit as defined in claim 5 wherein said bass control circuit branch includes a second capacitor connected in series with said one capacitor with said series path extending across said two fixed terminals of said second variable resistor, and the juncture of said two capacitors being grounded.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-08 | 1976-02-07 | 1976-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-08 | 1980-02-07 | 1980-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-08 | 1984-02-07 | 1984-08-08 | $7700.00 | Window Closed / Lapsed |