US3700811A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tone and volume control for a multi-channel audio amplifier system
Assignee: Motorola Solutions Inc
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Filing: 1970-07-20
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Granted: 1972-10-24
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Expires: 1990-07-20
Abstract
Abstract A tone control circuit for an audio amplifier system whereby the bass tones are enhanced by increasing the total gain or volume of the audio system, the treble tones are shunted to ground potential by a variable impedance network, and the bass and treble controls are effected by the DC control of discrete current control devices.
Inventors
- 👤 John R Davidson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:56
CPC Classifications
H; H03; H03G; H03G5/00; H03G5/02; H03G5/04; H03G5/10
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
361 words
A control circuit for a multi-channel audio amplifier system comprising a direct current power source and a signal translating path for each channel, including in combination, volume control means connected between the direct current power source and a reference potential, said volume control means including circuit means for varying the direct current therethrough for simultaneously controlling the amplitude of the signals being translated through each of the channels, a variable resistance element having terminal contact means at the ends of said resistance element and a movable contact selectively adjustable between the ends of said resistance element; separate reactance means connected in shunt relation with each of said signal translating paths for selectively shunting a portion of the high frequency audio signals; a separate treble control device connected in circuit with each of said separate reactance means and having load electrodes and a control electrode, each of said load electrodes being connected in series with said respective reactance means and a reference potential, and each said control electrode being connected to one end of said variable resistance elements; a current control device having load electrodes connected between the direct current source and the reference potential and in shunt with said volume control means of the audio amplifier system, and a control electrode connected to the end of said variable resistance element other than said end connected to each of said treble control devices; and means applying a control voltage to the movable contact of said variable resistance element so that movement of said contact in one direction on said resistance element will increase the conduction of each of said treble control devices and decrease the conduction of said current control device in shunt with said volume control means thereby reducing the frequency of the high frequency cutoff and increasing the gain of the lower frequencies and movement of said contact in the other direction on said resistance element will increase the conductioN of said current control device in shunt with said volume control means and decrease the conduction of each of said treble control devices thereby increasing the frequency of the high frequency cutoff and decreasing the gain of the lower frequencies.
Claim 2
Dependent Claim
361 words
A control circuit for a multi-channel audio amplifier system comprising a direct current power source and a signal translating path for each channel, including in combination, volume control means connected between the direct current power source and a reference potential, said volume control means including circuit means for varying the direct current therethrough for simultaneously controlling the amplitude of the signals being translated through each of the channels, a variable resistance element having terminal contact means at the ends of said resistance element and a movable contact selectively adjustable between the ends of said resistance element; separate reactance means connected in shunt relation with each of said signal translating paths for selectively shunting a portion of the high frequency audio signals; a separate treble control device connected in circuit with each of said separate reactance means and having load electrodes and a control electrode, each of said load electrodes being connected in series with said respective reactance means and a reference potential, and each said control electrode being connected to one end of said variable resistance elements; a current control device having load electrodes connected between the direct current source and the reference potential and in shunt with said volume control means of the audio amplifier system, and a control electrode connected to the end of said variable resistance element other than said end connected to each of said treble control devices; and means applying a control voltage to the movable contact of said variable resistance element so that movement of said contact in one direction on said resistance element will increase the conduction of each of said treble control devices and decrease the conduction of said current control device in shunt with said volume control means thereby reducing the frequency of the high frequency cutoff and increasing the gain of the lower frequencies and movement of said contact in the other direction on said resistance element will increase the conductioN of said current control device in shunt with said volume control means and decrease the conduction of each of said treble control devices thereby increasing the frequency of the high frequency cutoff and decreasing the gain of the lower frequencies.
Claim 3
Dependent Claim
20 words
The control circuit of claim 1 wherein said treble control device and said current control device comprise field effect transistors.
Claim 4
Dependent Claim
31 words
The control circuit of claim 1 including a resistance and said load electrodes of said current control device connected in parallel with said volume control means of the audio amplifier circuit.
Claim 5
Dependent Claim
88 words
The control circuit according to claim 1 wherein said volume control means comprises a current control device for each of said channels, each of said devices having load and control electrodes, said load electrodes being coupled in circuit with a respective channel and the reference potential, a DC power source, a variable resistance element coupled between said DC power source and the reference potential and having its variable output voltage terminal coupled to each of said control electrodes of said current control devices of said volume control means.
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) | 1975-10-24 | 1976-04-24 | 1976-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-24 | 1980-04-24 | 1980-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-24 | 1984-04-24 | 1984-10-24 | $7700.00 | Window Closed / Lapsed |