Electronics Overview

Opamp ST 4558C


These opamps are very common in the audio design community as they have a high bandwidth and fast slew rate of 2.2 V/uSec and THD - 0.008%. These opamps are featured in many audio devices and on many soundcards, such as the Creative X-fi X-Music and others. They are considered medium grade audio devices and on a brief examination of the circuit theses amps are for initial amplification and signal conditioning for the power stage. These amps are a great choice as they help keep the sound quality reasonably high and considering the price of this system, lesser amps could have been used for this circuit position.

ST 4558 Spec Sheet


Opamp TDA 7379


The TDA7379 IC is used in this circuit as a power amplifier section for all the drivers. The amplifier is in a multi-watt package and is mechanically connected to an internal heat-sink to help keep the internal amplifier temperatures down. This amplifier unit is a Class AB amplifier that can run in bridged mode and drive two speakers or run in quad mode. In this circuit the amplifier unit is set for quad mode and is driving the two satellites and the subwoofer.

TDA 7379 Spec Sheet


Modding Options

The best modding candidates for this system are the amplification stages and possibly the filtering stage. You can install a DIP8 socket and this would allow you to try out different opamps such as the Burr-Brown OPA2134’s, OPA2227, OPA2107’s or the highly recommended LM4562 to see which sound the best to you. You could also replace some of the filtering caps with better quality Black Gates or others. Modding should only be performed by experienced users as you can easily damage your speaker system and will certainly VOID your warranty.