checked out the power supply,here is what my buddy used to do(he informed me that alot of shops do this) 3 OPTIMA YELLOW TOP(I RUN 2 IN MY TRUCK) IN PARALLEL.
charge them when not in use, do not use marine batteries as their discharge is a bit slower than the optimas.the yellow tops are car audio batteries they will run around $150 each.
this is probably the only way to get the current you are gonna need without spending(i've been told) at least $1000 for a stable,clean 100 amp power supply
to let you know, 2 optimas,2 1 farad caps,4-12's(in the cab),jbl component speakers,3 alpine amps(1507 in mono) for subs,i hit 151.2db in my s-10,took second in the shootout to a station wagon with 8-12's that only hit 152.4.man was i mad

I have a question about the AC to DC power supply. Why the toroidal transformer typically used in home amps (or all the AC amps) draws only a little bit of amperages from the wall outlet compared to the car amps for the same power output of 400 W? What is the difference? Is it possible to buy a raw toroidal transformer for very cheap and connect it into the car amps?

For example, my QSC 850 amps only draw about 5 amperages for the 4 ohm 600 W output. How can I achieve this with the car amp?

I am sorry if this may seems stupid. But, I want to know more about amplifier technology.

It all goes back to the interaction between amps, watts, and volts - and in this case, it's the volts that makes all the difference. A home theater amp operates on the 120V power available at the outlet (at least as far as the US is concerned - Europe does things a little differently). Since watts of power are related to volts X amps, an amp supplied with 120V will draw approximately 1/10th the amperage of an amp operating from 12V.

I would also like to know more about the toroidal transformer conversion from AC to DC? Why many people use it to convert power?

Also, is there anyway to modify 12V input to 120VAC?

How about DC bi-polar project?

From what I understand, car audio amps are designed to operate from a 12VDC power supply, which is why painttoad's buddy suggests driving amps with a bank of batteries (which provide DC power rather than AC). I did a little googling to try to find a little more info on exactly what all has to happen in a home theater amp, in order to help confirm some assumptions I was starting out with. First, there's the transformer, which is stepping the voltage down to a more manageable level. The output of this transformer is still going to be AC, though, so the car amp wouldn't be able to connect to it. You would still need a rectifier to provide DV voltage from the AC source. There are also some capacitors tucked in after the rectifier. The capacitors may be part of the car amps, but the transformer and rectifier are not - and the copper wire windings in a good transformer alone likely account for a significant portion of the difference in cost between car and home amps.

I guess the bottom line is that a big beefy transformer alone cannot allow a car amp to be plugged into a 120V wall outlet. The power supply package required to do this can be scratch built by someone with some electrical know-how, but it's not likely to be a straightforward process. The simplest route from an installation standpoint certainly sounds like it is to borrow the car audio shop approach of banks of 12V batteries that you charge when not using the system, but there's a hassle factor there. Having seen the code-mandated ventilation requirements for commercial buildings with lead-acid battery banks located inside, I also wonder about what hazards (both fire and health) might be involved in bringing a group of such batteries into the living room on a permanent basis. As tekdredger noted earlier in the thread, these batteries can produce noxious gases. Building a power supply that outputs clean 12V DC would be the surest and most convenient way to drive a car amp from house power, but there are two factors that make me tend to recommend against it for anything except experimentation. First, the cost involved in buying or building such a power supply is going to probably wipe out the money saved from buying the car amp. Second, when you buy a home theater amp you are getting a power supply section designed by an electrical engineer specifically to power that amp, with a myriad of design decisions that you and I may not have any idea about - if we try to duplicate that design effort for a power supply to drive a car amp, the end result is likely to not be as good, and that could yield a system that colors or distorts the signal being sent to the speaker.

Looks like we were writing our posts at the same time. I think I've partially answered your questions already, but want to add a little summary.

The transformer does not convert from AC to DC, but instead changes the voltage. A transformer of some sort is necessary in order to get the voltages involved down to a level that speakers can cope with. I believe that toroidal transformers are most often used in home theater amps because they are the most effective way to pack a transformer large enough to handle the required current - although most receivers elect to use a "square" transformer (technical term there...) that looks like a scaled down version of what you might see sitting behind a building to save space inside the cabinet.

All speaker amps are working with DC power at some voltage when it comes down to actually driving the speaker, so the amplification section itself cannot directly accept AC power. The only way to change the amp's power input from 12VDC to 120VAC is to build the sort of power supply (transformer / rectifier / capacitors) that home theater amps use - thereby producing DC power that the car amp's existing power input can accept.

Sorry, no clue.

the optima batteries are sealed,dry cell
and make a big difference in the sound in a car.
if anybody dabbles in multi amp car systems, then i highly recommend them,
there is a lot of reserve there,sorry to plug optima in this forum but we know who makes some of the best(if not the best value,with quality in mind) home theater products so i think everybody should know that on the same lines they are the best for car audio batteries

Gonk, thanks for the info.

Painttoad-

Is this what you are talking about?

http://www.1st-optima-batteries.com/

Tekdredger-

I am interested to know more about DC bi-polar supply project or any great idea about modification if anyone knows.

d34/78
yep that's them
make sure you get the yellow top which is "D" series ask for it by name or you may get a red top

Man, that is too awesome.

I am checking it out. They say it can run 50 hours? True?

I can chain them in parellel for more electricity, right?