A unique 30-W RMS stereo amplifier

The frequency response required for the tone controls and frequency shaping networks in a hi-fidelity stereo amplifier is obtained by feedback techniques using integrated circuit operational amplifiers. The basic amplifier is discussed and the equations for the networks used to implement the bass and treble controls and RIAA phono compensation are derived. A practical design is shown for a 30-W rms stereo amplifier with a bandpass of 0.7 Hz to 50 kHz and 100 dB of excess gain at midrange frequencies. Test results are used to verify the performance of the technique described. Special considerations in the design and compensation of feedback amplifiers are discussed throughout the paper.