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I am looking to design a high power amplifier that can amplify a 500 Hz, 20V signal to 80 V and power a 4 ohm load.

I have 2 ways of approaching this (using op amps):

  1. Design 1 inverting buffer, and 2 inverting power amps, and have a differential output.

  2. Design 1 inverting power op amp, and 1 non-inverting power op amp and have a differential output

See image for better explanation. Any help is appreciated.

Thanks.enter image description here

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  • \$\begingroup\$ You should explain what is preventing you from moving forward to a design. If you are unable to design an audio amplifier then consider buying one. Are you talking about RMS voltages? \$\endgroup\$
    – Andy aka
    Commented Feb 3, 2023 at 15:21
  • \$\begingroup\$ I am talking peak to peak voltages. I am just looking to get some thoughts before I begin designing... \$\endgroup\$ Commented Feb 3, 2023 at 15:30
  • \$\begingroup\$ What is your load and why are you inverting? If driving a speaker or resistive load, the two opposite polarity outputs will cancel and no current will flow. \$\endgroup\$ Commented Feb 3, 2023 at 15:31
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    \$\begingroup\$ Typically, you have 1 amp, that has a "phase splitter", followed by two drive sections. \$\endgroup\$ Commented Feb 3, 2023 at 15:35
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    \$\begingroup\$ If driving a speaker or resistive load, the two opposite polarity outputs will cancel and no current will flow. -- No. The two out-of-phase outputs will increase the load power by 4x over that of either output individually. This is called BTL - Bridge-Tied Load. \$\endgroup\$
    – AnalogKid
    Commented Feb 3, 2023 at 17:21

2 Answers 2

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It is always easier to use two identical power amplifiers.

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I would go with two identical power amps. A low-level inverting stage is very simple, and two identical power stages means that if something needs to be changed/updated/tweaked, the change is identical in both.

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