US5148116A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Enhanced vacuum tube power amplifier
Assignee: Individual
•
Filing: 1991-09-04
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Granted: 1992-09-15
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Expires: 2011-09-04
Abstract
Abstract An audio power amplifier for general audio and sound reinforcement use, or musical amplification, stringed or otherwise, which combines the sonic properties of vacuum tube amplification with the modern technology of solid state electronics, with its attendant advantages.
Inventors
- 👤 John M. Robinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:59
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/30; H03F3/3069; H03F3/3076; H03F5/00
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
170 words
An improved audio power amplifier comprising: an audio input: A. A level control and an input buffer receiving said audio input and applying it to a vacuum tube voltage amplifier producing a signal equal in amplitude to the output signal; B. A dual complimentary buffer array which receives the voltage amplifier signal and produces the POS DRIVE and NEG DRIVE signals at the same amplitude but at a lower impedance level; C. A driver stage which again lowers the impedance of the above signals; D. A bi-polar power transistor output stage which supplies the actual current to the loudspeaker load; E. An offset servo stage which serves to compensate for inequalities within the amplifier circuitry, while preserving the average D.C. level of the input; F. A bias control stage to control thermal runaway, and to afford the benefits of Class B operation in the input stage while lowering crossover distortion to an acceptable level; G. Positive side and negative side overcurrent protection circuitry to protect against an output short condition.
Claim 2
Dependent Claim
170 words
An improved audio power amplifier comprising: an audio input: A. A level control and an input buffer receiving said audio input and applying it to a vacuum tube voltage amplifier producing a signal equal in amplitude to the output signal; B. A dual complimentary buffer array which receives the voltage amplifier signal and produces the POS DRIVE and NEG DRIVE signals at the same amplitude but at a lower impedance level; C. A driver stage which again lowers the impedance of the above signals; D. A bi-polar power transistor output stage which supplies the actual current to the loudspeaker load; E. An offset servo stage which serves to compensate for inequalities within the amplifier circuitry, while preserving the average D.C. level of the input; F. A bias control stage to control thermal runaway, and to afford the benefits of Class B operation in the input stage while lowering crossover distortion to an acceptable level; G. Positive side and negative side overcurrent protection circuitry to protect against an output short condition.
References Cited (Backward Citations)
US2773136A
Cited
US2979664A
Cited
US3253225A
Cited
US3325742A
Cited
US3995226A
Cited
US4163198A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-09-15 | 1996-03-16 | 1996-09-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-15 | 2000-03-16 | 2000-09-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-15 | 2004-03-16 | 2004-09-15 | $7700.00 | Window Closed / Lapsed |