new guy on the block - 12V 200watt?

[dudio_me]

hey guys, totally new on here, and fairly new to this world, in short, i have been digging the internet and getting extremly confused...

i have this idea in my head that i want to try and build a 100 to 200watt rms amplifier, that will happily power a 400watt rms sub in my car, obviously it will need to run at 12/14vdc. is this at all possible or am i just mad?

also i am not very clued up on where to source parts, my knowledge does not exceed maplins.co.uk and ebay!

thanks for your time
scott

[lineup]

Hello
it is not an easy project to get 100s of Watt from 12VDC
because with normal 4 Ohms speakers you need to step up the voltage to get s much power

100 Watt into 4 Ohm needs a voltage swing of +- 28.3 VDC
add some 5 Volts drop and we see you need like +- 33 VDC
this means 66 V total
this means you will have to use a step up circuit that makes 5.5 higher voltage.

For 400 Watt you need even higher voltage.

what those car amplifiers do, they use switch mode power supply
to create a high voltage within the amp, from those 12 volts
This is not very easy, but can be done. There are DIY Projects for this.

The amplifier itself is not the hard part.
You have plenty of good 100 Watt and 400 Watt subwoofer amplifiers to pick from, to build yourself.
Here and elsewhere on the internet.

[kuldeepsingh]

Use SMPS to get > 30 V from 12 V battery supply. SMPS is commenly used to get high voltage for automobile audio solutions

[pacificblue]

Here is an example for the power supply. You will probably notice that it is not exactly a beginner's project. The same goes for a 200 W amp.

You should probably start with project that needs less experience. If you do that, you will be surprised, how little you need 200 W.

[dudio_me]

ouch! okay, so thats way over my head!

what would you guys say is the highest rms output available from a simple 12v supply? im not sure i could manage all that confusing power supply stuff, and even if i could i have no idea where to source those parts.... anyone know of a good reliable place on the net to buy the components from?

thanks for all your replies, its nice to get help rather than funny looks when people realise you dont know as much as they do!

cheers guys
scott

[Minion]

There are also some Higher power Class D Amp modules out there that run off of 12v...

[lineup]

From 12 VDC you can theoretically get like 4.5 Watt max into 4 Ohm.
If you use two 12 volt batteries in series = 24 Volt total
then you can theoretically get 18 W into 4 Ohm

[pacificblue]

You can also get 18 W from a bridged amplifier at 12 V in theory. In practice it is a little less.

On the other hand you have a bit more than 12 V in a car, that is why you get lots of nominal 25 W amplifiers in the market. Or up to 50 W on stupid measurement conditions that are used for better marketing.

You could try something like the NEC µPC2500 or µPC2505 for that task. It is an internally bridged IC that needs few external components and is 2 Ohm stable.

Be aware that you can get decent car amplifiers quite cheaply used as well as new. E. g. I bought one for my girl friend's car, which has four of the a. m. ICs in it, for 10 € from the famous on-line auction house that starts with an e. That was not even a bargain, because a few days later I bought another one for the subwoofer, a bridgeable real transistor amp with 2 x 100 W nominal, for the same price. Both amps are from a renowned manufacturer.

Of course building your own is priceless.

[dudio_me]

hey guys, i have found a suitable amp to build, but it says it needs 2x 30vac, is there any set schematic out there to acheive this from 12v?
or does anyone know where i could purchase one?

thanks
scott