circuit ideas for boosting loudspeaker output

[geoff2004]

Hi i need to boost the sound output from a circuit powerd by a 9v bettery ac. ive thought about using op-amps but i dont know which basic op-amp circuit to use inverting, non inverting etc ? or using a number a transistors to boost it. My understanding of electronics is not brillant and any help would be very helpful.

Many thanks Geoff b

 

[Nigel Goodwin]

Hi i need to boost the sound output from a circuit powerd by a 9v bettery ac. ive thought about using op-amps but i dont know which basic op-amp circuit to use inverting, non inverting etc ? or using a number a transistors to boost it. My understanding of electronics is not brillant and any help would be very helpful.

You need to post more details?. What is the existing device?, and why do you want it louder?.

You can only get a certain amount (fairly small - about 1W into 8 ohms), off a 9V supply - if you're already getting that you would probably need to increase your supply to make it louder (using a larger amplifier and speaker). If the existing system isn't being driven enough, you could add a pre-amplifier to drive the amplifier harder - but this will still only achieve fairly low power off 9V.

But please give more details.

 

[stevez]

Battery life is another thing to consider - more power out requires more power in. Another consideration - there is a limit to the amount of current (amps) you can draw from a given battery even if short life is acceptable. Keeping efficiency up will help with battery life.

 

[geoff2004]

audio boost

its directly from an output tone circuit which im am also constructing. i need the circuit just to give enough sound output to be heard around 600-800 HZ. i might also use cut filters.

thanks for any help

Geoff b

 

[stevez]

A rather common IC for low power audio applications here in the US is an LM386. Sometimes they are preceeded by a 741 op amp. The National Semiconductor datasheet for the LM386 has some good application notes.