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Old 25th August 2005, 12:30 PM   #11
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I think there is some confusion about the input voltage of 6.5v. That's the preamp level signal and it's simply the maximum that the amp can handle.

You need a 12-14 volt power supply.

If the amp can produce 2000 watts, you'll need ~185 amps of current at ~13.5 volts. If you use a battery with a charger, you won't be able to keep it at 13.5 volts. At lower voltage, you'll need even more current to reach full power. Remember that standard, liquid electrolyte batteries produce flammable/explosive gasses when being charged and should not be used indoors. 'Gel-cell' batteries are safer but expensive.

You really need to find a switching power supply for this. You can likely find some that were pulled from older mainframe computers. They are 5v each and you can wire them in series. I've purchased some that are capable of producing 125 amps continuously. There are some that can produce 200 amps. Keep in mind that this is not an inexpensive option but it will be safe and will do what you want to do. Please note that this cannot be done with ATX type power supplies because their grounds are tied to the AC mains ground.

Note: The sub doesn't 'give out' 2000 watts. It can handle/dissipate 2000 watts of power.
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Old 25th August 2005, 12:31 PM   #12
Eva is offline Eva  Spain
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6.5V is the maximum input signal level, not the power supply voltage

ROFL!
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Old 25th August 2005, 12:40 PM   #13
JohnnyJ is offline JohnnyJ  Australia
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Quote:
Originally posted by Tweeker
Er why do you need 560 amps of 6.5V? Not sure what an ordinary household outlet is in Australia, but thats 3,640 watts. With an 85% efficient converter, which is pretty good, that would be ~4280 watts and probably more VA. It would pull 19+ amps at 230V.

If your using batteries and capacitors you dont need to supply peak power from the outlet and that helps alot. I assume average consumption isnt 3kW+?

Also, do you mean a supply of +/- 6.5V?
Yes that is correct, those specifications are actually UNDER RATED from it's actual performance, it produces just over 2000RMS continuously at 2Ohm when calculated technically - in the world of physics. That equals to SOMETHING like 3800watts max (can't remember the exact figure since it was about a week ago that I last calculated it).

I THINK I just realized something that I didn't know before, that this: Input Level Control Hi-Volt (200mV ~ 6.5v) means that it can handle at maximum 6.5V LESS or 6.5V MORE than it's TARGET (or most efficient) voltage. IS THAT RIGHT? Or can it not handle more than 6.5V input? It is a "PWM Regulated MOSFET Power Supply". As far as I understand that regulates the INCOMING voltage so that it reaches the "wanted" voltage when it gets to the part of the amplifier where it starts "amplifying" or whatever. If I grasped this correctly then this means I can use a 12v power supply?

As I am typing this I am reading 2 replies to me previous post, and realized that what I was just busy typing is correct. Man I feel somewhat better now! Much better in fact.

OKAY, so I can just use 3 of those batteries then, which will provide enough juice(in watts, voltage and current) to power this amplifier to it's full potential?
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Old 25th August 2005, 12:53 PM   #14
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The RMS continuous power ratings are the only useful power ratings. Virtually anything that states power as 'maximum' power can be dismissed as garbage.

The 6.5 volts is the signal from the head unit and has nothing to do with power supply voltage. Depending on the gain setting, the amplifier can be pushed to full power with 200mv (0.2 v) or 6.5v.

The PWM regulation regulates rail voltage inside the amplifier. It allows the amplifier to have the same rail voltage regardless of the battery voltage (within reason).
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Old 25th August 2005, 01:14 PM   #15
JohnnyJ is offline JohnnyJ  Australia
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Okay.. so can I use 15v input? I am asking because I am thinking of buying 3 ATX PSU's and running them at 5V each. About your comment earlier about not being able to use ATX PSU's for this use, you actually can. All you have to do is connect the green wire (power on) to any black wire (ground). You can just cut them and permanently wire them together. Once they are shorted the power supply runs at all times. Which means you can shut them ON/OFF by the wall switch. You may have known this and not suggested it because that's not it's INTENDED use, but if you didn't then there it is

ALSO: Can I use 10V input? Or does it have to be over 12V?

Thanks for your help so far mate, helping me lots.
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Old 25th August 2005, 01:25 PM   #16
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You cannot use ATX supplies in series because each ground is connected to the mains earth ground. If you connect them in series, you will be shorting the output to ground. You cannot lift the grounds for reasons of safety.

If you could find some of the switching supplies I described, you would adjust them to something near 13.8 volts. Each supply would be set to ~4.6 volts.

You may be able to run that amp at 15 volts. Some amps have high voltage shutdown and 15 volts would be near the set-point for some amps to shut down.

I doubt that the amp would run at 10 volts. Many amps require at least 10.5 volts.
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Old 25th August 2005, 01:47 PM   #17
JohnnyJ is offline JohnnyJ  Australia
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Alright, well I don't know where to get NON-ATX PSUs from so I haven't got anything to work with. Where can I buy NEW and decent PSUs from that will supply me with the appropraite current/voltage/watts I need?
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Old 25th August 2005, 02:07 PM   #18
JohnnyJ is offline JohnnyJ  Australia
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What are the PSUs called that you are talking about? Are they called "AT"?
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Old 25th August 2005, 02:19 PM   #19
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I suggest you might re-read my original post.

I described a DC power supply (not AC - rectification means we are changing AC to DC).

Tweaker you will also notice if you read the bottom of my first post I DID post estimated current draw for a 2-ohm load at 150A.

What is this about running 5V PSU's in series? If you are going to pay for three supplies of that current rating, might as well just buy a real 12V supply. The normal PC powersupplies are good for 10-20A at 5V, nowhere near your "560A" you claim to need. You calculations for the figure are incorrect...there is no need to multiply the number by 4 for the current with 4 ohms...70A into 4 ohms, and double that for a rough estimate at 2 ohms...150A is overkill but that is fine.

The other thing I don't think you will realize is that this power needs to come from somewhere! It is not safe to just plug a 1.5kW supply into the wall and expect everything to be fine and dandy.

Parallelling many batteries is not safe, because as time goes on, one of them will weaken and they will all fail and you will be left with nothing.

You might try reading the manual to understand current and supply requirments.



-Matt
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Old 25th August 2005, 02:28 PM   #20
JohnnyJ is offline JohnnyJ  Australia
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zagisrule! > I confused the voltage input of my amplifier with another rating, that is why I thought I needed a 6.5vdc supply. I got that cleared up and I am now just looking for a normal power supply to power an amp like a car battery would, between 12-14V. That's why I 'claimed' I needed that sort of current.

I'm not an audio expert - I stress that point AGAIN. Ok, a Switch Mode 12VDC power supply that can supply me with 300amps continuous, where on earth do I find that and how much would that cost me?

Thanks again!!
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