Hi, I have 3 questions which I need answers for as part of my project in implementing an audio amplifier system. The system is made up of 3 sub-components, namely the Voltage Control Unit, Power Amplifier and Volume Meter. I have the attached the schematic of the system here.

1) When testing your audio amplifier system, did you encounter the overheating problem of power amplifier (PA) or Volume Control Amplifier (VCA) ? What reasons do you think that lead to this issue? Please suggest possible approaches to address the overheating problem.

2) The chip of voltage control amplifier (VCA) SSM2018T is an old-fashioned production. Suppose now we want to replace or upgrade the hardware, please try to find a commercial chip to replace SSM2018T while maintaining the operation of our volume control system (you can make corresponding adjustments on overall circuit design and show this in report).

3) The whole circuit includes two amplifier subsystems, the voltage controlled amplifier (VCA) and the power amplifier (PA). Why do we need two amplifiers? What are the purposes of using VCA and PA respectively? Can the two amplifier subsystems be replaced by one subsystem?

 

Homework is it??

 

Homework is it??

These are additional qns in my project work which I have to answer.

 

2) The chip of voltage control amplifier (VCA) SSM2018T is an old-fashioned production. Suppose now we want to replace or upgrade the hardware, please try to find a commercial chip to replace SSM2018T while maintaining the operation of our volume control system (you can make corresponding adjustments on overall circuit design and show this in report).

A more modern VCA is the M5283P dual channel VCA chip. It was used in the Yamaha EL25 Organ.
No. I am not going to make the adj and show it in your report. That's your job. See the datasheet here and the attached.

3) The whole circuit includes two amplifier subsystems, the voltage controlled amplifier (VCA) and the power amplifier (PA). Why do we need two amplifiers? What are the purposes of using VCA and PA respectively? Can the two amplifier subsystems be replaced by one subsystem?

Perhaps you're making a Stereo amplifier. One Amp for the Left and one for the right.
PA = power amplifier implies that it is used for driving the low ohmic speaker.
VCA = Voltage controlled amplifier is used for controlling the volume of sound.

Allen