Audio Amplifier

[audioguru]

If I were to build a more powerful version, what IC amp would you suggest??

Your question can be answered may ways.
Here is one way:

 

[biggy238]

How about a schematic using an LM386? I looked at the specs on it a few minutes ago.

Also, what is the footprint on that amp you provided?

I need something small. The one I just finished fits inside a flashlight/lantern that ran on a 6V lantern battery.
The PCB and 3 AA batteries fit inside the old battery cavity and I mounted a speaker where the bulb and lense housing were before. The original on/off switch for the light powers the board, and I mounted the mp3 player externally with velcro.

It will need to be louder.

I either need a more powerful unit, or I need to up the voltage to the TDA2822. I think I damaged the first IC trying to solder a connection to the input. I believe I overheated it. After that I started asking questions here.

Do you think I can safely up the voltage to 6V from 4.5 without damaging anything currently being used? The 2822 is an 8 pin dual rail configured in a bridged mode.

This will allow me to use the lantern battery and have a much longer service life.

Kyle

 

[audioguru]

When the battery is brand new it will be 6V. The little TDA2822 has fairly high distortion so in the power output chart in its datasheet it is difficult to see at which power it clips. It looks like only 1.0W bridged into 8 ohms or 1.2W bridged into 4 ohms.

The voltage from a disposeable battery (alkaline) drops quickly to 1.2V per cell which is 4.8V. Then the amplifier max power is less.

If you double the power then it is only a little louder. 10 times as much power sounds twice as loud.

My clock radio has an output of 1W. My computer speakers have a total power of 6W. My home stereo has a total power of 250W. I can't remember how may hundreds of Watts is my car radio.

Your low battery voltage is what limits the power that you will have.

 

[biggy238]

I would only like %25 more volume or so.

Also, this lantern battery would have to have a much greater reserve capacity than the 3 AA batteries, correct?

Ultimately A stronger amplifier would be the solution though?

Is there an equation for computing db from wattage? I know it would need frequency and maybe some other variables.

So far i'm pleased.

Thank you,
Kyle

 

[audioguru]

Twice the power and the dBs increase 3dB which is a small increase in volume. Double the distance from the speaker and the dBs drop 6dB which is noticeable since the power drops to 1/4.

I have never looked at a lantern battery. If it is alkaline then it will last a lot longrer than AA cells.

A stronger amplifier needs to have a higher supply voltage or if it works with only 6V then its power will be the same as the TDA2822.

 

[biggy238]

**broken link removed**


Switching to 6V did what I wanted. I have it all packaged up now. My first try looks like A$$ but i'm going to build anotherone and refine it some.