[SOLVED] OpAmp help me with a simple audio amplifier.

[zerodegreec]

For the life of me I cannot get a simple OpAmp circuit to work. To be honest I am trying to learn the analog side of things and this one is killing me.
I have a pile of OpAmps on my bench: KA741, MC1458N, LM307N, LF351N and a few more but you get the point.

SO what I have is a simple audio signal I am using (audio out from an iPod). I have an amp I made with a basic NTE123AP but the output is crap and I was hoping for something better. The only requirements I have is that it run off of a 9v battery.

I have tried a few "online calculators" but I cant get this to work. Someone please help and or be willing to school me. (I am self taught with electronics and thus have some "gray" areas in my knowledge). I would like to learn the process of the design as well as make a working amp to play with.

Thanks.

 

[tpetar]

TDA2004 stereo bridge audio amplifier

Most of the lovers, especially in audio electronics, it will never escape from this one component of the IC TDA2004. Because these components are very easy to get and the price is also quite cheap. Amplfiier audio series was also quite easy to make because the circuit is not too complicated, and one ic also already has 2 outputs and inputs.

Not only that, the audio is processed from the IC is also well qualified, many power power branded car, using it as an amplifier ic. Nothing mistake this ic tried to make an audio amplifier. For the circuit scheme can be seen below.

with this amplifier circuit you can easily enhance your audio levels, from your stereo walkman, Ipod, tuner, MP3 player or MP4, the portable receiver, laptops or PCs

 

[zerodegreec]

I actually need a Mono amp but thats easy (only use one side). but this amp requires 18v power supply... I need it to run off of a 9v.

 

[tpetar]

I actually need a Mono amp but thats easy (only use one side). but this amp requires 18v power supply... I need it to run off of a 9v.

Not True!!!

18V is absolute maximum value for voltage!

Minimal Voltage is 8V!

Check datasheets ;-)



Additional as second simple amplifier You can use this with TDA1554Q 2x22W

The 22 watt amp is easy to build, and very inexpensive. The circuit can be used as a booster in a car audio system, an amp for satellite speakers in a surround sound or home theater system, or as an amp for computer speakers. The circuit is quite compact and uses only about 60 watts. Also works on 9V.




Dont even think to run this things on 9V battery!

 

[Raza]

Hi zerodegreec,
Here is a circuit for you even, works even half the voltage (9volts) easy to build, too.

These circuits work from 6 volts to 12 volts.




These circuits can work between 6 volts to 12 volts. R1 and R2 can be of any value from 1K to 100K (good for your experiment, change the value and see the result)

 

[BradtheRad]

I recall one of my first projects: an audio amp using a TDA 2002 (or TD2002, LM383).

The Radio Shack databooks made it look easy to use. It contained a power op amp, used a single supply, had 5 pins, and needed a scant few additional components.

Years later I made another amp using TDA2003's. I recommend this family of op amps for powering audio speakers.

The LM386 is another popular series. Designed to be easy to use for audio amplification. It's a good choice to step up to when you find that low-cost op amps (of the 500mW variety) fail to provide sufficient power in headphones or small speakers..

Normally using op amps is easier when the supply is two 9 volt batteries in bipolar arrangement. Ground is in the middle.

However I like the economy of using a single supply. This requires lifting the non-inverting input to V divided by 2. (A resistor network is used in most cases.) Then a capacitor goes at the output to block the V/2 DC component from going to the speaker.

The TDA 2002/2003 series do not need the additional resistor network at the inputs. They have it built in.