Do It Yourself
Other
80W x 2 RMS Stereo DC Audio Power Amplifier
This is a 80Wx2 stereo DC audio power amplifier. I built it to my friend Eric VR2ZXN since 1992. Although it is ten years ago, it still work quite good today. This amplifier has a DC coupling with a pair of JFET differential amplifier for high input impedance at the input terminal. It can response a 0Hz signal, produce magnificent bass and wide sound field. But a speaker protection circuit should be series at the output of this amplifier for prevent unwanted DC current to damage the speaker.
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| Front view |
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| Power transformer and transistors |
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| Ripple filtering unit |
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Amplifier and protection unit |
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Schematic Diagram for the
amplifier unit in JPG
format
Schematic Diagram for the power supply unit in JPG
format
Schematic Diagram for the speaker protection unit in JPG
format
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Specifications and Details :
| a) | Output power | : | 80W x 2 RMS at 8ohms |
| b) | Total harmonic distortion | : | < 0.05% at 1kHz |
| c) | Frequency response | : | DC to 25kHz +0dB -3dB |
| d) | DC supply voltage | : | +/- 42V dual voltage |
| e) | Loading impedance | : | 4 to 8 ohms |
| f) | Input impedance | : | 100kohms |
| g) | Input sensitivity | : | 1Vrms for full output |