Speakers: 12V TO 9V/6V

[bassmasta]

I have some speakers that run on 6V with 4 1.5A AA's wired in series/parallel, but the wall adapter puts out 9V with plus polarity (but doesn't work when I plug it in). I need to run them off a 12V line.

So,
1) Should I run them at 6V or 9V?
2) What should I use to step down the voltage? Resistor, regulator, or modulator?

[bassmasta]

bump! I need this for a project I need to finish soon.

[timmeh87]

Check inside, its possible that it just has a 7805 in it or something... or else an opamp chip that can use a wide supply voltage range. It might take 12v already.

(If it only has 4 batteries then there isn't any parallel connection...?)

You cant just use a resistor to step down voltage. Id say use a 7806 or something.

[bassmasta]

Check inside, its possible that it just has a 7805 in it or something... or else an opamp chip that can use a wide supply voltage range. It might take 12v already.

(If it only has 4 batteries then there isn't any parallel connection...?)

You cant just use a resistor to step down voltage. Id say use a 7806 or something.

I'll check monday when I crack it open to see if there's a chip.

I meant series, I forgot which one voltage adds in.

Do I need to heatsink a 7806? And I'll probably also need to put it in a circuit-would this be suitable?

Thanks.

[timmeh87]

yeah, but you dont need the rectifier if its DC

[bassmasta]

Here's the board-tell me if there is an opamp chip or the like (yes that is my crappy cell phone camera).
.

Also, I was at Fry's the other day and grabbed an NTE962 (datasheet). I'm assuming this would work the same as a 7806. So assuming I'll have to run it off of 6V:
1) Would this circuit work?

2) I don't know what capacitors to use, but I got some .01uF ceramic capacitors at Radioshack-would these work?
3)They are 3W speakers-so 3W/6V=500mA. I'll have to heatsink it, right?
4) For a heatsink, would something like this work? How would I attach it?

[timmeh87]

0.01uF is too small, the vaules it wants are in the datasheet.

And if you get the number off that black chip, that would help a lot.

[marshallh]

Looks like a National simple switcher to me

[timmeh87]

actually come to think of it... you arent wrong. Im even pretty sure I see a doide beside it.

sooo... where does the audio get amplified then? Whats on the other side of the board? What are those two connectors for?

You can probably just run it off 12v.

[bassmasta]

Black Chip:
YD
2576B
A D J
VC.3.J

All the connectors are header receptacles. The two on the right go to each speaker, and the three on the bottom are the power LED, on off switch, and power.

Also, on the other side of the board, it says A-2209 amp REV:1.0. I could take a picture of the bottom of the board if you want. Picture of bottom of board

[timmeh87]

Simple switcher, put in any voltage you want

http://www.national.com/ds/LM/LM2576.pdf" onclick="window.open(this.href);return false;