hey ive built a 50w amp to power what i belive to be a 350w car subwoofer 4ohms

is there any voltages or things i need to know about >?

Typicaly amp kits need a seperate 32-0-32v power supply (some need a 48v supply) to power them, no direct mains feeds or piddly little transformer packs.

Don't go touching the outputs whilst powered - your looking at about 70-110v AC depending on the signal passing through.

Don't try and crank the amp right up - you'll kill the amp way before you kill the speaker.

Into 4ohms, your amp should be putting out 100w.

Got a pre-amp (seperate/built-in)?
Allows you to easily hook the amp up to most audio sources and adds volume control.

Got that crossover?
High frequencies are where the power is at, these will push your amp harder (not good) and your sub will try to reproduce them - sloppily, and because of the stress from working the speaker driver outside it's specs, you'll shorten the life of your sub.

i have just built 1 of thease

Silicone ship
SC480
http://www.siliconchip.com.au/cms/A_30285/article.html
Dicksmitsh cat number =k 3431


Has a 240v 2A to 28-28 then it goes into a Power Supply Module which puts out 2 40v rails with 0v

Performance
Output Power 50 watts into 8Ω 70 watts into 4Ω
Music Power 77 watts into 8Ω ;105 watts into 4Ω
Frequency response -1dB at 14Hz and 70kHz (at 1W- see Fig.1)
Input sensitivity 0.875V for 50Ω into 8Ω
Harmonic distortion <.05% from 20Hz to 20kHz; typically <.003%
Signal-to-Noise Ratio -114dB unweighted (22Hz to 22kHz); -119dB A-weighted, both with respect to 50W into 8Ω
Damping factor >140dB at 100Hz & 1kHz, with respect to 8Ω and without PTC thermistor
Protection fuses plus "Polyswitch" PTC thermistor
Stability unconditional

It works it took me 3 days to build it in a computer case (because i needex the inside of a powersupply for the massive transformer)

I dont have a pre-amp so im thinking of using my computer as one since im thinking of running it off the soundcards subwoofer outputs ,



Its a $60 sub from cashconverters lol they even have a 20" for like $30 this 1 had a box tho

Yah it works tho i need a crossover of some sort because the sub is putting out mids and ,,, highs >< But the bass is quite nice like in starwars when a ship goes past

*Updated

Im looking for a Software Eq/Mixer/and maby a digital crossover it is possibe

Depending on the sound card, the supplied software may have a crossover function - usually labeled LFE.
NvMixer Example

Otherwise, look for an active subwoofer crossover, a unit designed for car use is perfectly fine - I've got one for my P.A subs. All you'll need to do for this is setup a 9-12v DC rail and link it between your amp inputs and your PC

i just grabbed 1 off ebay for 30 it has 80hz and two other settings

80Hz is the duf-duf setting, 120Hz for a bit of beef and 250Hz for that chunky bottom end.
Play about with it for taste, though you'll probably prefer the 250Hz setting for general use and ambience.

im sick of this 50w amp im gonna try and get my hands on a 350w or 500w amp if you see any kits please post themh i like doing the kits than buying some japanease heap

about the crossover
at 80hz setting will it allow all the frequencys up to 80hz?

Yep