Hybrid thermionic valve and solid state audio amplifier
OwnerErick M. Cookinventor
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Abstract
A hybrid thermionic valve and solid state audio amplifier. A complete tube amplifier is scaled to produce a relatively low power yet also retain its small and large signal distortion characteristics. The output of the scaled amplifier is amplified by a relatively linear solid state amplifier. In one embodiment of the invention, a plurality of tube amplifiers are coupled in parallel and input to a mixing circuit for selectably mixing the outputs of the tube amplifiers and providing the mixed outputs to the solid state amplifier.
Claims19
A hybrid audio amplifier for amplifying an electrical audio input signal, comprising:
- a first audio amplifier section having an input for receiving the audio signal and a power amplification stage having an output, said first audio amplifier being adapted to amplify the audio signal to produce a corresponding first amplified audio signal at said output, said power amplification stage employing at least one thermionic valve to produce said first amplified audio signal and an output transformer for providing said output, said thermionic valve and said output transformer providing a desired characteristic distortion;
- and
- a second audio amplifier section coupled in cascade relationship to said first audio amplifier section and having an input for receiving said first amplified audio signal, said second audio amplifier section being adapted to amplify said first amplified audio signal to produce a corresponding second amplified audio signal at a power that is at least sufficient to drive a loudspeaker at ordinary room listening levels, said second audio amplifier section employing solid state circuitry for amplifying relatively linearly said first amplified audio signal to produce said second amplified audio signal.
A method for constructing an amplifier having the advantages of solid state circuitry that emulates the sonic characteristics of a tube amplifier using as a model a tube amplifier having an input for receiving the audio signal and a power amplification stage having an output, the power amplification stage being adapted to amplify the audio signal to produce a corresponding first amplified signal at the output at a power that is at least sufficient to drive a loudspeaker at ordinary room listening levels, the power amplification stage employing at least one thermionic valve for amplifying the audio signal to produce the first amplified signal, the method comprising:
- providing a tube amplifier section having an output by scaling the power amplification stage of the tube amplifier, wherein said scaling adapts the architecture of the tube amplifier to produce a second amplified signal that has substantially the sonic characteristics of the tube amplifier at a power that is limited to being substantially less than sufficient to drive the loudspeaker at the ordinary room listening levels;
- providing a solid state amplifier section having an input for receiving said second amplified signal, said solid state amplifier section being adapted to amplify said second amplified audio signal to produce a corresponding third amplified audio signal at a power that is at least sufficient to drive the loudspeaker at the ordinary room listening levels, said solid state amplifier section employing solid state circuitry for amplifying said second amplified signal to produce said third amplified audio signal;
- and
- coupling said output of said tube amplifier section to said input of said solid state amplifier section.
A method for mixing the characteristics of a plurality of tube amplifiers, comprising:
- providing a first audio amplifier having an input for receiving the audio signal and a power amplification stage having an output, said first audio amplifier being adapted to amplify the audio signal to produce a corresponding first amplified audio signal at said output at a power that is limited to being substantially less than a desired power for driving a loudspeaker at ordinary room listening levels, said power amplification stage employing at least one thermionic valve to produce said first amplified audio signal;
- providing a second audio amplifier having an input for receiving the audio signal and a power amplification stage having an output, said second audio amplifier being adapted to amplify the audio signal to produce a corresponding second amplified audio signal at said output of said second audio amplifier at a power that is limited to being substantially less than said desired power, said power amplification stage of said second audio amplifier employing at least one thermionic valve to produce said second amplified audio signal;
- selectably mixing said first amplified audio signal and said second amplified audio signal to produce a mixed audio signal;
- and
- providing a third audio amplifier having an input for receiving said mixed audio signal and a power amplification stage, said power amplification stage of said third audio amplifier employing solid state circuitry for amplifying relatively linearly said mixed audio signal to a power at least about equal to said desired power.
Dependencies are inferred from the claim text.