simplest audio amp using opamps

[ibrar0]

Hi, i want to make simple audio amp by using opamp ic like Lm358 etc. i want to make it for my mp4 player, i want to attatch any small speakers, guide me please, with complete circuit diagram

 

[ibrar0]

if any prepaid project on this with fine quality,plz post i will change my parameters similar to that

 

[audioguru]

An opamp has a max output current of only 20mA.
An 8 ohm speaker needs a peak current of 250mA for a 1/4W sinewave. A 1/4W is a very low volume.

Philips and ST-Micro have hundreds of power amp ICs. Most are made for cars and have 14W per channel at low distortion into 4 ohm speakers or 20W when turned up too loud with 10% distortion.

National Semi have their LM386 little power amp IC that has an output of 450mW at low distortion into an 8 ohm speaker with a 9V supply. The output is 200mW with a 6V supply.

Decide how much power you need and what supply voltage is reasonable.

 

[ibrar0]

any circuit by using power amp ic which will easily availabel in markete.9v supply is preffered. i dont need high power audio amp.my requirement is to loud mp4 player audio(speech format) to room level.

 

[audioguru]

My computer speakers have an output of 4W each with low distortion. They play pretty loud in my computer room.

My sound system in my living room plays pretty loud at 70W per channel with very low distortion.

I don't know which "market" you shop at. I order electronic parts online.

 

[ibrar0]

4W is sufficient ok i will arrange the ic, ok refer me any circuit. and audioguru please also give some comments on my second post topic "voice echoing problem"

 

[Hero999]

Does it need to be battery operated?

Even 4W is too much for a tiney 9V battery, for that kind of power you need six AA cells.

 

[blueroomelectronics]

any circuit by using power amp ic which will easily availabel in markete.9v supply is preffered. i dont need high power audio amp.my requirement is to loud mp4 player audio(speech format) to room level.

What market?

 

[Krumlink]

Teh Black Market!!!

 

[ibrar0]

Even 4W is too much for a tiney 9V battery, for that kind of power you need six AA cells.

its ok i can arrange adapter or 6 cells or just i need is a circuit diagrame. i can change my some requirements according to that.

 

[audioguru]

6 alkaline cells makes 9V when they are new and average about 7.2V like rechargable Ni-Cad or Ni-MH cells.

Most audio amp ICs are made for cars and are powered from 13.8V. With a 12V supply then the output from a bridged amplifier like a TDA7240A IC into an 8 ohm speaker is 6.4W with low distortion. A pcb layout is in the datasheet.