Hi-fi-expander-with-de-emphasis

Description: The expander designed to complement the compressor is illustrated. An external operational amplifier is utilized for high slew rate performance. Both the compressor and expander maintain a unity gain level of 0 dB. Trim networks are provided for adjusting distortion (Total Harmonic Distortion - THD) and de-shift. The distortion trim should be performed first, using an input of 0 dB at 10 kHz. The de-shift adjustment should be made to achieve minimum envelope bounce during tone bursts. When implemented in consumer tape recorders, the subjective performance of this system is excellent.

The expander circuit operates in conjunction with a compressor to enhance dynamic range and audio fidelity. The external operational amplifier is selected for its high slew rate, which is critical in handling rapid changes in audio signals without introducing distortion. The unity gain configuration of both devices ensures that the audio signal is neither amplified nor attenuated, maintaining the integrity of the original sound.

The trim networks for distortion adjustment allow for precise calibration of the system, ensuring that the Total Harmonic Distortion (THD) remains within acceptable limits. This is particularly important in audio applications where clarity and fidelity are paramount. The initial distortion trim should be conducted with a 0 dB input signal at a frequency of 10 kHz, as this frequency is often critical in audio processing.

Following the distortion adjustment, the de-shift parameter must be fine-tuned to minimize envelope bounce. This adjustment is crucial when working with tone bursts, as it helps to stabilize the output and prevent unwanted fluctuations that can degrade sound quality.

In practical applications, such as in consumer tape recorders, this expander-compressor system has been noted for its excellent subjective performance, providing a rich and dynamic audio experience. The careful design and calibration of the circuit elements contribute to its effectiveness in real-world scenarios, making it a valuable addition to audio processing equipment.The expander to complement the compressor is shown. An external op amp is used for high slew rate. Both the compressor and expander have unity gain levels of 0 dB. Trim networks are shown for distortion (THD) and de shift. The distortion trim should be done first, with an input of 0 dB at 10 kHz. The de shift should be adjusted for minimum envelope bounce with tone bursts. When applied to consumer tape recorders, the subjective performance oi this system is excellent.