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US 5,498,997 AGranted
Transformerless audio amplifier
OwnerCristopher F. Schieboldinventor
Life of this patent
Estimating the term…
Abstract
A transformerless solid state audio amplifier which exhibits the superior linearity and saturation characteristics of a triode vacuum tube amplifier, and which has an output impedance which nominally matches the impedance of a speaker is disclosed in which the gate of a low impedance transistor having triode-like current-voltage I-V characteristics is electrically coupled to an audio input source, the drain is electrically coupled to a supply voltage, a choke is connected in series between the drain and the supply voltage, and a speaker is coupled to the drain lead in parallel with the choke. Alternatively, a high impedance current source can be used instead of the choke.
Claims12
An audio amplifier, comprising:
- (a) a transistor, said transistor having gate, drain and source terminals, said transistor having an output impedance between approximately two and sixteen ohms;
- (b) a signal input terminal electrically connected to said gate terminal;
- (c) a DC voltage source terminal electrically connected to said drain terminal;
- (d) a choke electrically connected in series with said DC voltage source terminal and said drain terminal;
- and
- (e) a first speaker output terminal electrically connected to said drain terminal and a second speaker output terminal electrically connected to said DC voltage source terminal;
- (f) wherein said amplifier has an output impedance as measured across said speaker output terminals between approximately two and sixteen ohms, and wherein said output impedance matches the drive impedance of a high fidelity speaker without the need for an impedance matching transformer.
4 more elements
A transformerless amplifier, comprising:
- (a) a transistor, said transistor having gate, drain and source terminals, said transistor having triode current-voltage characteristics and an output impedance between approximately two and sixteen ohms;
- (b) a signal input terminal electrically connected to said gate terminal;
- (c) a DC voltage source terminal electrically connected to said drain terminal;
- (d) a choke electrically connected in series with said DC voltage source and said drain terminal, said choke having a low impedance to direct current and a high impedance to alternating current audio frequencies;
- and
- (e) a first speaker output terminal electrically connected to said drain terminal and a second speaker output terminal electrically connected to said DC voltage source terminal and in parallel with said choke;
- (f) wherein said amplifier has an output impedance as measured across said speaker output terminals between approximately two and sixteen ohms, and wherein said output impedance matches the drive impedance of a high fidelity speaker without the need for an impedance matching transformer.
4 more elements
An impedance matched amplifier, comprising:
- (a) a transistor, said transistor having gate, drain and source terminals, said transistor having an output impedance ranging from approximately two ohms to sixteen ohms, said transistor having triode current-voltage characteristics;
- (b) a signal input terminal electrically connected to said gate terminal;
- (c) a DC voltage source terminal electrically connected to said drain terminal;
- (d) a choke electrically connected in series with said DC voltage source and said drain terminal, said choke having a low impedance to direct current and a high impedance to alternating current audio frequencies;
- and
- (e) speaker output terminals electrically connected in parallel with said choke;
- (f) wherein said amplifier has an output impedance as measured across said speaker output terminals between approximately two and sixteen ohms, and wherein said output impedance matches the drive impedance of a high fidelity speaker without the need for an impedance matching transformer.
4 more elements
An audio amplifier, comprising:
- (a) a transistor, said transistor having gate, drain and source terminals, said transistor having an output impedance between approximately two ohms and sixteen ohms;
- (b) a signal input terminal electrically connected to said gate terminal;
- (c) a DC voltage source terminal electrically connected to said drain terminal;
- (d) a high impedance current source electrically connected in series with said DC voltage source terminal and said drain terminal;
- and
- (e) a speaker output terminal electrically coupled to said drain terminal;
- (f) wherein said amplifier has an output impedance between approximately two and sixteen ohms, and wherein said output impedance matches the drive impedance of a high fidelity speaker without the need for an impedance matching transformer.
4 more elements
A transformerless amplifier, comprising:
- (a) a transistor, said transistor having gate, drain and source terminals, said transistor having triode current-voltage characteristics and an output impedance between approximately two ohms and sixteen ohms;
- (b) a signal input terminal electrically connected to said gate terminal;
- (c) a DC voltage source terminal electrically connected to said drain terminal;
- (d) a high impedance current source electrically connected in series with said DC voltage source terminal and said drain terminal;
- and
- (e) a speaker output terminal electrically coupled to said drain terminal;
- (f) wherein said amplifier has an output impedance between approximately two and sixteen ohms, and wherein said output impedance matches the drive impedance of a high fidelity speaker without the need for an impedance matching transformer.
4 more elements
An impedance matched amplifier, comprising:
- (a) a transistor, said transistor having gate, drain and source terminals, said transistor having an output impedance ranging from approximately two ohms to sixteen ohms, said transistor having triode current-voltage characteristics;
- (b) a signal input terminal electrically connected to said gate terminal;
- (c) a DC voltage source terminal electrically connected to said drain terminal;
- (d) a high impedance current source electrically connected in series with said DC voltage source terminal and said drain terminal;
- and
- (e) a speaker output terminal electrically coupled to said drain terminal;
- (f) wherein said amplifier has an output impedance between approximately two and sixteen ohms, and wherein said output impedance matches the drive impedance of a high fidelity speaker without the need for an impedance matching transformer.
4 more elements
Dependencies are inferred from the claim text.