Design of PC Speaker

[smartsarath2003]

Hello,
I want to design a simple PC speaker, probably less than 5W. The only building blocks I have in mind is a basic pre-amplifier with op-amp and a ClassAB power amplifier that will drive a 8ohm,6W speaker.
But My problem is where should I have the volume control. Is it during the pre-amplifier stage by varying gain of op-amp? Also  If want to add a small tweeter, what will be the simple and best way to separate high, low frequency components?  ???

Can anyone help me here please....
As this is my first audio amplifiersrelated project I appreciate any sort of help  :

Thanks
Smartsarath2003

 

[izach]

usually the  volume control is in the pre-amp section varying the gain of the first amplifier. the most simplest way to get rid of the loe frequency's is to put a cap of 1uF in series with the tweeter.  plse note this is the meanest and simplest way.

 

[smartsarath2003]

Do you mean connect the tweeter,1uf cap in parallel with the main speaker

 

[Shahriar]

Dear smartsarath2003

A PC speaker is just a power amplifier. if you want to build a good one, look for a good Power Amplifier IC which you can find it in your area. there are two many kinds of these ICs. then download the datasheet and the rest is easy. your sound card acts as a good preamplifier so you do not need a preAmplifier. connect the volume to the Sound card and conect the output from the Volume to your power amplifier. there are some sort of these ICs which have Digital volume which are used in Televisions. If you buy one of them then you can increase or decrease the volume with two push buttons instead of a volume....

P.S. Just be carefull about shorting the sound card. because most of them do not have a short circuit protection.


HTH - Shahriar

 

[Alun]

Try using the TDA1905 amplifier IC, if you want stereo then use two of them.

 

[izach]

if you take one wire from the normal speaker and connect it to one side of a 1uF electrolyic cap then take the other side of the cap and connect it to the tweeter then take the remainig lead of the tweeter to the remaing lead of the normal speaker

experiment with different values and you will see how itr makes a difference.

 

[audioguru2]

Hi Izach,
A 1uF capacitor is much too low a value to feed an 8 ohm tweeter. It would cut frequencies below 20,000Hz. A 4.7uF capacitor would have a 4255Hz cutoff frequency.

 

[izach]

yes you are right sorry for the wrong info but i did state that smartsarah2003 should expriment with different values