Possibility of an 80 amp 12 volt power supply?

I'm just wondering about the possibility of me building one of these? I basically want to power a car amp inside a house. If its possible, how much money would I be looking at? How hard would it be to find the parts? And would I be better off paying $500 for a good home receiver, vs $200 for a good car amp plus whatever the cost of the power supply would be?

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iman1235 years ago
What kind of speakers are you trying to drive? Car speakers? In the house? Sounds like a car battery and trickle charger is in order.

Typically car stereo equip is spec'd very loosy goosy, as in barely complies with the ratings. Car amps are designed for low impedance speakers since theyve historically operated on 12V DC. Home stereo amps typ use +/- 40V or so rails to drive 6-8 ohm loads. (100W into 8ohms > 28.3V RMS or 40V peak)
Having read down the comments etc, two points come out to me.

They are right about the power supply needed, if you're a little cautious then a 750 PSU would be fair enough.

Second is that if you're using even sort of efficient speakers then 1000W is far more than enough for a house.

Find a 100W stereo and turn it all the way up... It'd be double that.

As an example, for smaller bars and places I'd often use a 1200W head with linked bins and tops to do the job of a PA...

If you wanted another option altogether a power amp from the likes of thaumann at 500W/side is less than £150 and would likely be a better bet overall, though it only takes XLR or Jack (1/4") in.

Of course the speaker set up you intend to use would also affect this a fair bit, as to what makes the best option for you.

By the way the efficiency of speakers makes a big difference, if you're not sure, EV don't steer you wrong.
guyfrom7up9 years ago
well, you could mod a couple microwave transformers (like 2) and just get some heavy duty rectifiers. But it wouldn't be regulated. By mod I mean cut off the secondary windings and wrap heavy gauge wire around for the secondary.
thats not a safe option, especially for 80 amps of power. there is a big risk of fire. also, how would you cram on the needed windings in very thick wire? to make it work, the primary and secondary would need re-winding. and diodes with 20V 80 amp PIV? sounds like several in series. you could never really regulat a power supply like that, but i would never attach an unregulated source to my expensive stereo
woops, didn't know it was for a stereo (must of skipped that) According to various DIY microwave welders you can get about 50 amps out of a 1000 watt microwave.
oh, and I was considering moding a microwave transformer to output like 5 or 6 volts at like 100 amps to create hydrogen and oxygen from water extremeley quickly. Even if I use circuit protection such as a circuit breaker or a fuse, would this be a bad idea?
yes, and for a good reason. as youve noted, i have little fear of high voltages. respect yes, but fear no. this is because you can survive very high voltages safely. on the other hand, 20 ma, the amount of power an led draws, is a fatal current. a cattle prod transformer is several kv, but 5ma. also, why would you want one of the most dangerous substances on earth (pure oxygen) in your house?
I forget, it was a projet for when I was messing around with fuel cells. Actually, it wouldn't be that dangerous, right? touching the 2 secondaries with your finger would be no different than a nine volt battery. The only danger would be touching the primary, but that can be solved with stuff like heatshrink.
1) touching the secondary on a hv transformer could give you electrical burns. touching high amperage leads would have several consequences
  • your central nervous system would be blocked, making extricating your fingers hard
  • you could get severe electrical burns, as the fats and water in your body boiled under the resistive heat.
2) the primary would be safer, as its current limited to a lethal 15 or 20 amps. the primary, unlimited, can draw several hundred amps before something blows. also, i would not trust heatshrink above 1 amp, and not above 50 volts.
right, but when the transformer is modded the secondary is only several volts. The heatshrink shouldn't be a problem either, the voltage is too low.
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