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Main => Main Forum => Topic started by: Hoagie_one on January 27, 2009, 04:43:06 pm

Title: How do you reduce voltage from 12 volt to 9 volt?
Post by: Hoagie_one on January 27, 2009, 04:43:06 pm

I have a set of powered PC speakers, but do not have the power brick.  It says it requires 9v AC in, and since I'm just going to use the amp inside to power my original cab speakers, I want to just power it directly from my PC's internal power.  What do I have to solder in to reduce the voltage?

Also, does internal PC power run AC or DC?

Thanks

Title: Re: How do you reduce voltage from 12 volt to 9 volt?
Post by: csa3d on January 27, 2009, 04:56:22 pm

Pc power supplies serve out DC voltages.  It would probably be easier to go to RadioShack and pick up a Walwart (plug that fits yours which is rated 9v) and then use a SmartStrip power supply.  The smart strip will turn on and off with the power of your computer.  This setup will prove to be the easiest, and probably only set you back about 30$ total.

-csa

Title: Re: How do you reduce voltage from 12 volt to 9 volt?
Post by: SirPeale on January 27, 2009, 05:20:23 pm

Actually, you don't want to run it from your PC power supply.  It will place additional work on the PS and eventually fail because of that.

Title: Re: How do you reduce voltage from 12 volt to 9 volt?
Post by: Hoagie_one on January 27, 2009, 05:30:20 pm

Whats funny is the price for a new AC adapter is generally more than a whole new set of generic PC speakers.

Any other alternatives?

Title: Re: How do you reduce voltage from 12 volt to 9 volt?
Post by: Malenko on January 27, 2009, 06:27:17 pm

Quote from: Hoagie_one on January 27, 2009, 05:30:20 pm

Whats funny is the price for a new AC adapter is generally more than a whole new set of generic PC speakers.

Any other alternatives?

buy a new set of generic PC speakers

Title: Re: How do you reduce voltage from 12 volt to 9 volt?
Post by: Hoagie_one on January 27, 2009, 06:36:35 pm

lol, yeah

Title: Re: How do you reduce voltage from 12 volt to 9 volt?
Post by: ghettodish on January 27, 2009, 10:41:48 pm

edit...was off topic

Title: Re: How do you reduce voltage from 12 volt to 9 volt?
Post by: Thenasty on January 27, 2009, 10:53:22 pm

Quote from: Hoagie_one on January 27, 2009, 05:30:20 pm

Whats funny is the price for a new AC adapter is generally more than a whole new set of generic PC speakers.

Any other alternatives?

Use 9V batteries  :dunno

Title: Re: How do you reduce voltage from 12 volt to 9 volt?
Post by: BobA on January 27, 2009, 11:24:50 pm

The power requirement for is PC speakers was 9V AC.    A 9V AC wall wart looks like the only way to go.

Title: Re: How do you reduce voltage from 12 volt to 9 volt?
Post by: leapinlew on January 27, 2009, 11:53:15 pm

Tell the 12Volts it has to pay taxes still. That should get it to about 9Volts.

Title: Re: How do you reduce voltage from 12 volt to 9 volt?
Post by: Blanka on January 28, 2009, 02:17:35 am

Use a 7809 voltage regulator with a heatsink. It can handle 1 or 1.5 ampere, depending on the model.
http://nl.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=5164812

Oops: READ, it says AC

BUT,
9 V AC is often regulated to 12V DC. Amplifiers always run on DC. Make a picture of the circuitboard.