12 v DC power supply used with car audio amp?

[MYX]

Howdy folks. I am starting to figure out my audio set up for my cab. I am planning on using a car audio amp and car speakers. My thought was to use a wall wart 12 v power supply to power the 12v needs for the amp, but I do not know what kind of abuse an amp will put the PS through. Has anyone tried this approach? I am trying to not tap the computer power supply for anything other than lighting. How much amperage does an audio amp need?
Amp
Speakers

Nothing major to freak out about, but I did want a real pair of speakers as opposed to computer speakers. I want the cabinet to act as... well a cabinet. With the volume of the cabinet, the low frequencies should become quite boomy with that much air space.

[BobA]

At 240 watts your amp will need at least 20 amps at peak power at 12 V.  The power rating of speakers is not used to determine the draw only the max out of your amp.   Your speakers can be rated 200W each but only 120W is going to get to each one from a 2 channel 240-W amp.   A wall wart will not supply this type of power.  A good pc power supply can be used.   Check the specs on various supplies.

I think we have discussed this a few times in the forum

[Luckydevil]

I assure you that amp is not putting out anywhere near 240 watts. I'd say it is easily less than 100 watts rms, and probably closer to 50 watts rms.

Any normal ATX PC power supply should be more than enough to power that amp.

[MYX]

Are you saying with, or without the PC connected? Get a second ATX PS?

[mccoy178]

MYX, this is no help, but I got kind of lucky in this department.  I have two arcade power supplies that have 12v and 5v that I plan on using in my cabinet.  (Actually one in the cabinet, but I was too lazy to correct that).  Anyways, when I originally found these, that was one of my first planned uses.

[Luckydevil]

Don't use the power supply in your pc for powering an external stereo.

Just buy a seperate PC power supply and use the yellow (+12v) and black (ground).

Here ya go... $20 and 25 amps on the +12v line.

http://www.newegg.com/Product/Product.asp?Item=N82E16817170010

Depending on what else you have in your cab (P360's, etc.), you can also use the +5v line if need be.

[MYX]

MYX, this is no help, but I got kind of lucky in this department.  I have two arcade power supplies that have 12v and 5v that I plan on using in my cabinet.  (Actually one in the cabinet, but I was too lazy to correct that).  Anyways, when I originally found these, that was one of my first planned uses.

I do have a switching PS I pulled from a Dynamo. It is a little hot on the +5 but I am not sure about the +12. What kind of amparage do they supply?

Don't use the power supply in your pc for powering an external stereo.

Just buy a seperate PC power supply and use the yellow (+12v) and black (ground).

Here ya go... $25 and 25 amps on the +12v line.

No, I had no intention of sharing the Power supply. I was just trying to see what you meant. I have a PS in a PC down stairs that the PC is not working(would not take a new OS). I went round and round on a previous thread trying to get it working. It was to be my MAME computer. I can pull that PS. So great, I went from no PSs to 2 in one thread. This is great.

[M3talhead]

Do like these guys said. Get an additional computer power supply to provide juice to your amp. You need to test it though, some P.S. manufacturers build a "signal check" into the unit that requires a small draw to come from the green wire in a 20-pin mobo connector before electricity will flow to the rest of the connectors. If you end up testing yours and determining that it has this kind of circuit built in, you can short the green wire in the 20-pin connector to any black wire (like the one next to it) and force the unit to function as "always on".

[MYX]

Good to know. Thanks Guys!!!

[fatfingers]

Do like these guys said. Get an additional computer power supply to provide juice to your amp. You need to test it though, some P.S. manufacturers build a "signal check" into the unit that requires a small draw to come from the green wire in a 20-pin mobo connector before electricity will flow to the rest of the connectors. If you end up testing yours and determining that it has this kind of circuit built in, you can short the green wire in the 20-pin connector to any black wire (like the one next to it) and force the unit to function as "always on".

I found that cutting a small paperclip to The Right Size^TM and then inserting it into the green and black "holes" on the power supply connector worked well.  That way if you ever want to use that power supply for something else you still have a working connector on the power supply.

[Cornchip]

If your still looking for a capable power supply for your audio system you could try a Pyramid power supply (matches your components). The Ham radio guys use them a lot. I have a PS-15KX (13.8V @10A constant)  in my CAB for powering a 12V motor that rotates my monitor. I am somewhere below 3 amps at start up. I actually considered a car audio system since I had plenty of reserve power. Several of the Army surplus stores carry them here in Canada. I think I paid 60 for mine.

Cornchip.

[Luckydevil]

I did a lot of searching and for the money ($53), these are the best deal...

35amps on the +12v line. They do need to be modified slightly by grouping all of the +12v (yellow) and ground (black) wires together.

Rosewill RE502

http://www.newegg.com/Product/Product.asp?Item=N82E16817182002