A very simple power amplifier circuit built with 741, 2N3053, 2N4037, 2N3055 and MJ2955 which deliver up to 50W on a 8Ω speaker.
If you want to amplify lower frequencies increase the 4.7uF capacitor from the audio input or decrease it if you want to favour higher frequencies.
Use a 3A symmetric power supply for mono application and a 5A for stereo power amplifiers. Please take good precaution when use this audio amplifier : do not shortcircuit the output or not connect speakers ! Always check twice ! continue reading…

There are power ratings on every car stereo amplifier made. Learn tips from our stereo expert on how to read the true power rating on a car stereo amplifier rather than the one stated in this free video clip on stereo systems.

This is a medium power guitar amplifier is recommended especially for portable amplifier. The amplifier is a combination between a simple integrated audio driver, LM391-80 and a stage of output power designed contratemps with bipolar transistors.
Thermistor NTC, which is in temperature contact with output power transistors, allows to separate AO LM391 power stage when it heats too much. continue reading…

The LM386 circuit is a audio amplifier designed for use in low voltage consumer applications. The gain is internally set to 20 to keep external part count low, but the addition of an external resistor and capacitor between pins 1 and 8 will increase the gain to any value from 20 to 200.
The inputs are ground referenced while the output automatically biases to one-half the supply voltage. The quiescent power drain is only 24 milliwatts when operating from a 6 volt supply, making the LM386 ideal for battery operation. continue reading…