Power supply question

[ryan256]

I'm drawing up plans for a digital jukebox I'm wanting to build. One of my plans is to use an old Kenwood 100watt car amp and an unused pair of 6x9s for the audio system. I'm going to have the power supply power the amp as well. The system will be a meager one which could be easily handled by a 250watt PSU. I'm planning to get a 500 watt PSU and guessing I'll want one with dual 12 volt rails.
Questions are:
How do I make sure the system functions on one of the rails and the amp on the other?
Which 12v wire do I splice into to run the power to the amp?

 

[Zepper]

The wires from the different channels should be marked differently. One should be plain yellow and the other rail(s) have some color(s) of stripe(s) on the yellow. And you certainly don't NEED to use a split rail PSU for your project. The split (or more) rail PSU was yet another stupid idea from Intel that should never have made an inroad into the market - and wouldn't have if the buying public was more technically literate... :roll:

.bh.

 

[Operandi]

Just match up the max 12v power draw of the 12v amp 12v rating of whatever PSU you intend to use.

And as Zepper mentioned no, you don' want a dual rail PSU. More to the point if you are going out of your way to buy something new there is probably a better choice to run an amp then a switching power supply.

 

[thecoolnessrune]

Are not most car amps designed in mind for a car battery environment? And dont those batteries tend to run around 14.4V rather than 12? Looking into a Meanwell 15V PSU might be a better idea. I wouldn't know that much about it though.

 

[Aluvus]

Originally posted by: thecoolnessrune
Are not most car amps designed in mind for a car battery environment? And dont those batteries tend to run around 14.4V rather than 12? Looking into a Meanwell 15V PSU might be a better idea. I wouldn't know that much about it though.

The batteries are normally 12 V; the alternator generally puts out something like 13.2 V, in order to be able to charge the battery. So when the car is running, the supply voltage is above 12 V.

If the amp could be run in a car on battery power only (that is, the alternator is not turning, the motor is not running) then it should be fine with 12 V. I would expect it to simply regulate down any higher input voltage anyway, though I'm by no means a car audio expert.

 

[aigomorla]

i think someone already tried this. They said unless you use a powerful PSU, the draw from the sub and amp will be too great for a single PSU.

Link

Basically he had to merge 2 PSU's to get that little tiny sub to hit right. Anyhow might be worth reading b4 you attempt.

 

[herm0016]

switching powersupplies are very noisy!. you will have to put filter capacitors on the fan and will have a nice hum if the filtering in your amp is not very very good. you should look for a toroidal transformer to step line voltage down to 12v and then use 2 sets of rectifiers to turn the ac into dc power. kinda like this: http://www.adireaudio.com/Files/UcDPowerSupply.pdf

 

[Howard]

What class is that amp?