Main > Audio/Jukebox/MP3 Forum

Best/Cheapest way to power 6x9 speaker from PC line out ?

<< < (5/6) > >>

RedSquirrel:
i opened up an old pair of pc speakers today, and made it so that it connected to some old car speakers i had lieing around. worked fine =) I wanna see if my 6x9's work with it, and whether or not ill need another pair of pc speakers to hack as these ones are only 3w rms.

edit..

i think perhaps it will be fine. they are quite loud even if they are 3w wrms. (the amp).

OSCAR:
I seem to remember a similar discussion on RGVAC a while back...  Someone was going to build a very small amp that could be installed right into a jamma harness, probably based on a LM386 chip.  IIRC, the general consensus was that a 1W amp would be sufficient to drive a single cab speaker at normal gaming volume, but I don't know for sure.

If you search some electronics projects websites, I'm sure you can find plans for a very simple amp that can be built from readily available components from Radio Shack.

Here's a few cheap kits, anyway:

http://www.electronics123.com/amazon/catalogue/c3-3-1.htm

RandyT:
Or take a look at the ones on this page.

Not kits.  Looks like at least one of them should work.

RandyT

grafixmonkey:
If you think it'd be fun to try building one, this might be a good circuit to try.  You see a (?) ohms resistor because it's there in diagrams I look up, but I don't know why, and its value depends on the value of the other two.  Here's the equation, assuming the top left resistor is 100 ohms:

resistance = 1 / ( 1/100 + 1/(100*A) )

the thing is, A has a range of values, so I'd just make it about 80 to 90 ohms (about 80 to 90 percent of the top-left resistor's value.)

Now, about the A...  the A is the number that multiplies the input voltage.  If you have 1 volt going in, you will have -A volts going out.  This is where the potentiometer is.  I'm not sure what the voltage of an audio out jack is, but work out 'A' so that that voltage multiplied by A is the right voltage to send to your speaker.  

Say the speaker is 8 ohms, 10 watts...  then the maximum voltage you send to it should match (V^2 / 8) < 10,

and your potentiometer's max resistance R should match  100 * A = R, so that (max input voltage * A) < V.

The connections P+ and P- in the drawing are the power supply to your amplifier.  (they connect to the op amp.)  For safety, you could make these match the maximum voltage your speaker can stand, and then the op amp will not be able to burn out your speaker.

Or, you could just throw some stuff together, and see if anything starts smoking.    ;D   That's what I do!!

However, unless you wanna build it for fun to see if it works, getting one of those pre-made amps RandyT posted would be a better solution by far.

EDIT:  forgot to attach the drawing!   ::)

alank2:
Yeah, I found two of them -- which one is recommended?  These come assembled with a volume control on them for about $14 plus $6 for shipping.

UK153 - 5W Audio Amplifier (Assembled)
http://www.canakit.com/Contents/Items/UK153.asp

UK193 - 20W Bridged Power Amplifier (Assembled)
http://www.canakit.com/Contents/Items/UK193.asp

I plan on using a 30 watt 6x9 8 ohm shielded speaker (from mikesarcade!) and I am leaning towards the 20W UK193.  The doc says that it can output 12W RMS @ 8 ohm at 18V input.  I plan to tap a PC power supply 12V instead of 18V, so I'm guessing that will drop my output to about 8W RMS @ 8 Ohm.

I'm guessing the UK153 is probably about 3.5W RMS @ 4Ohm, so maybe around 2-2.5W @ 8 Ohm.  I'm not sure this would be enough, but you tell me!

Thanks,

Alan

Navigation

[0] Message Index

[#] Next page

[*] Previous page