[chesterqw]

hi guys, i need some help with my project.
i am going to drive 2x speakers which is 32 ohms and rated at 0.5 watts.
i bought a DIY kit at a local store and the quality of it was

so i am making one on my own.

are opamps alone capable of driving them?
i am using only one 9V cell.

i might change the speakers to others with a higher rating.
and i can use 2x 9V batteries if possible.

i also read about something about buffers but i am entirely sure what they do

thanks

 

[DKJones96]

Are you looking for a kit or are you wanting to go completely DIY and P2P or etch it?

There are some really nice kits and schematics available online.

 

[Billyk]

Chip Amp?

 

[DKJones96]

Link

Almost a steal at $45.

 

[Nemo de Monet]

There are a couple of pretty nice LM1875 amp kits on eBay, as well.

None of 'em are going to run off two 9V batteries, though, let alone one.

You might be able to get away with a little opamp, CMoy-like amp with a fairly high gain, powered off batteries, but it may or may not get loud enough to be useful.

Maybe use one of the low-power Tripath boards and a small 12V SLA instead?

 

[MASantos]

[rant]

Quote:

Originally Posted by DKJones96 /img/forum/go_quote.gif Link Almost a steal at $45.

If the OP's speakers are rated at 0.5W do you really think it needs 20W of amplification?

Do you have any expererience with this amp to recomend it?
The amp you posted is way to powerful for such speakers and can't be powered from a 9v battery.

Do your research before you post and if you don't have experience in the subject don't do it...

To the op:

please share some more information regarding the speakers and the purpose of this system.
Any particular reason behind the 9v battery?

 

[Nemo de Monet]

I forgot earlier about the venerable LM386, which isn't exactly hi-fi, but will work off batteries.

 

[DKJones96]

The LM1875 can run on as little as +- 8v. Two 9v batteries will supply it with +-9v and at those voltages the amp runs a maximum of 4 watts output. I haven't used that particular amp but I have used that chip plenty of times all the way to its minimum rated voltages.

What DIY amp did you purchase? Maybe you can modify the one you have.

 

[rembrant]

HeadBanger Headphone Amp Construction Kit

This will do what you want. LM386 is good for about 350mW into 32ohms. Mine has no problem running a set of Polk audio satellites that are 8ohm at acceptable volume levels. Cheap 2 dollar Walkman speakers are even louder.

You can buy every part at Radioshack and spend about $30.

 

[chesterqw]

hi guys, sorry for not replying earlier.
time difference + rarely online nowadays.

i found the lm386 available in my school's component store and when for it.
after the supervisor approve it i should play with them.
20 gain is what i am going to use, since it is much simpler then anything else.

i went for the 9V battery option as it is small and provide a high voltage

not planning on etching stuff, just putting them breadboard(is that why you call those you can solder on?) and connecting them with jumper wires and solder

thanks for the replies guys

 

[rembrant]

Trust me. Build the headbanger circuit. It has a gain of 12, 20 is too high IMO.

Steven Lafferty did a great job of hiding the faults of the LM386. If your feeling frisky you can try both the data sheet bare minimum and then the headbanger. You will be surprised.

 

[chesterqw]

sure thing. but i have to wait for approval first haha.