Current drawn by an amp?

[DannyHaddon]

Hi,

Im goin to put together a 400w amp and 400w sub, but I needed to know what would the current draw be at 12v? pls help if anyone has any ideas.
Thanx

[Mannyb18b]

it would help to know what exact amp it is.

[bumpinstang77]

if its 400 watts rms then somewhere between 30(very efficient) and 60(not ver efficient). if its 400 watts peak power then cut those numbers in half.

[DannyHaddon]

30 to 60 ma or amps? how would i be able to find a power supply for 30 amps?

[sr20de4evr]

30 to 60 amps

and why do you need a power supply? that's what the alternator is

[DannyHaddon]

oh sorry i didnt mention that its for home use,

[sr20de4evr]

you could buy a power inverter from somewhere like partsexpress.com or radio shack, but it's going to be expensive. Actually it would probably end up being about the same price to get a power inverter to run that amp as it would be for a brand new 400rms plate amp that you could use in its stead.

The power inverter you could use in the future to test other amps or whatever

The plate amp would probably look cleaner and actually work better, and let you use that other 400rms amp elsewhere

If you plan on benching or otherwise testing 12v accessories in your home (headunits, various amps, etc) then go for the power inverter. If you just want something to run this amp and don't plan on using it to test other things in the future, then just get a plate amp instead and use the amp you already have for something else.

[DannyHaddon]

plate amp? im in the uk and there isnt many about, couldnt i just get a transformer capable of 60A? bit hard to find though

[sr20de4evr]

you could build your own, but it's going to take a lot more than a transformer, you'll need some kind of high-current bridge rectifier and a large capacitor as well. The cost will still end up being close to $100 or more.

A plate amp is simply a sub amp that works off of AC power from your home instead of 12V DC from the car, like this.

[DannyHaddon]

oh right thanx, if i was to get a invertor is there a certain wattage that id need

[sr20de4evr]

you would go by current capability, and for your amp to reach max output you would need close to 50 amps, so you would need something like this

[DannyHaddon]

Thats alot of money though realy, i might aswell buy a car battery and keep charging it up when its flat, If i had a 300w sub and about 20w going into the sub would it be the full 20w of wouldnt i get much out of it compared to a 50w sub?

[sr20de4evr]

Well a 50 watt sub would generally be more efficient than a 300 watt sub, so on 20 watts it would probably get louder, though if you were to send it ~100 watts it would probably hit its limits but the 300 watt sub would keep going.

Power supplies are expensive, which is why I recommended you go with a plate amp instead. A car battery could work, but you have to keep in mind that it would only last for about an hour or 2 tops before you had to recharge it, and running it dead would destroy the battery unless it was a deep cycle, AND it would have to be a sealed battery or the fumes it emits would be dangerous.

[PaulD]

why do guys wanna use car stereo stuff in the house ? Just buying home stereo stuff is FAR more efficient