500 watt pc speakers

Hey guys, I have the Logitech Z-680 5.1 speakers (great set), but I want to use it overseas where they use 220V instead of
ours of 110V.

My question is what kind of power inverter do I need? Are they all the same or different? I saw some that said 200W and 400W
etc and the price goes up and up the higher the Watt of the inverter. My speakers say they are 500W RMS.....not sure then if
I can use a power inverter rated at 150W or 200W or would that not be enough power draw for my speakers? Do all power inverters have the option to switch going from 110 to 220 and 220 to 110 or are they specific only (in that case i need to read carefully and make sure i buy the proper one).

Does that mean I have to keep my speakers on low volume to not use more than 200 watts?

 

the speakers will be externally powered. So will I need a "step-down" transformer (220V to 120V) or a step-up transformer (120V to 220V).

I'm confused.

 

do you think a 1000 watt step down transformer will be enough for my speakers or should I get the 2000 watt step down transformer?

 

An inverter is "An electrical converter that converts direct current into alternating current". They are expensive.

You need a step-down 230V to 110V transformer. Ensure the wattage is the same or greater than the current power supply.

Forget about the power output of the speakers. That is something totally different. Consider this - the Earth Leakage Unit in my home has a sensitivity of 30 mA. Times that by 230 V and you get 6.9 Watt. Anything more could potentially kill a person. If you expose the wires of your 500 Watt speakers and touch them, will that kill you? :eek

 

thanks everyone for your advice. I have decided to buy the 2000 Watt Step-down transformer (220V to 110V).

 

That's exactly what you need.

 

Please make sure you know what you're saying before posting. The advice you're giving might get somebody killed.

The power output of the speakers is very important because in order for an amplifier to put out 500W, it must draw AT LEAST 500W. If that amplifier was a perfect design with 100% efficiency, it would need to draw 500W in order to output 500W. However, I doubt if the amplifier in that set of speakers is more than 75% efficient so that means that only 75% of the power it draws makes it to the speakers, the rest is lost internally (mostly given off as heat). That 75% efficient amplifier must draw 667W in order to produce 500W at the output.

Wattage is calculated as Voltage x Current. Let's say that 500W output is 100V at 5A (100Vx5A=500W). Do you think 100 Volts at 5A is enough to kill you? It most definitely is so I wouldn't be advising people to expose the wires of their 500W speakers and touch them.

 

I asked a question.

I did not advise anyone to expose the wires of their 500W speakers and touch them.

Do not falsely acuse me.

FYI There is a big difference between Eletric Power and Music Power.

 

You don't need a step down transformer. The international adapters will suffice. All the adapters do is shunt one phase, use the other for power, and send the neutral prong from the device to the ground/neutral bus in the panel. Or, if there is no ground then you need a transformer. Most countries have 3 wire circuits. If you only have a two wire circuit, then you need a transformer.

In other words, you only draw 120 on one phase (prong), instead of 220 from two phases (two prongs).

Don't make this harder than it has to be. And, it's the amperage that kills you, not the voltage. Amperage is power flow, and voltage is potential. The higher the voltage, the more likely you are to produce an arc.

 

For reference:

http://www.adaptelec.com/info-by-country-c-15.html?zenid=096gbg3uaajdcl97pn1r6bmgu5

 

This is true except you are overlooking the fact that it's the voltage that will determine how much current will flow thru your body. The higher the voltage, the more current that will flow. In order to get any current to flow, the voltage needs to be high enough to overcome the resistance in your body.

Oh and Eldon, there is a no difference between electric power and music power. Power is power. There is a difference between DC and AC power in that DC power is constant and AC power fluctuates so that AC power is more or less an average value but at some point in time the power is at it's max and can still be lethal. Also, with AC, as the frequency varies, the impedance of the load fluctuates, as the impedance fluctuates so does current flow.

Your "question" was stated in a way that it seemed as if you were meaning to state the opposite, at least that's how I interpreted it. If I misread that then I apologize.

 

strollin, we're going way off-topic. Let's keep it short. Kindly have a look at the following article.

http://en.wikipedia.org/wiki/Audio_power

There is a big difference between Electric power and Audio power. 230V at 1A (230W) can kill an adult person. The voltage/amperage of a 230W speaker cannot kill a person. The next time you visit an audio retailer, look at the power consumption of a 2000W amplfier. Also, considder a 1200W car amplifier running of a 12V battery. I would like to see a car battery producing 100A.

the mekanic, South Africa and most European countries use 220/230V. It's single phase power.

cornflakes, ignore our debate. You did the right thing.

 

Believe what you wish to believe Eldon but I will just say that a car battery can most certainly produce 100A of current.

 

When the car starts, yes. After work I went to a friend who has a sound system with 500W speakers. He turned the volume to maximum, I touched the speaker wires... and here I am. Audio power is measured differently to Electric power. Ask any audio engineer. :wave

 

Eldon - I'm glad you didn't die from your experiment but I'm not sure what you proved other than that you are reckless. Did you measure the output to see if the amplifier was actually putting out 500W?

At any rate, I'm weary of this debate. As I said before, you will believe what you will believe.

 

strollin,
Did you read and understand the article I linked too?
Did you look at the power consumption of a 2000W Audio Amplifier?
Did you speak to an Audio Engineer?

Calling me reckless is the second time you insulted me. Don't do it again.

 

I guess all those electronics classes I took in college were all for naught since you know more about it.

BTW, I didn't insult you, I stated a fact. If your little experiment of touching the wires wasn't reckless, what would you call it? Back when I had techs working for me, if I would have observed them doing what you did I would have fired them on the spot for unsafe practices.

Do you have a degree in Electronics? Have you ever worked in the electronics field? I do and I have. Because I have worked in the electronics field I have more respect for the fact that you can be injured or killed by electricity.

 

Eldon - A better question for you to ask is did YOU read and understand the article you linked to?

If you look in the section titled power calculations you will see that the formula for P (Watts) is P = I * V (Hmmm... that seems to be the formula I used in my post above). It goes on to show that Power can also be calculated as P = (V*V)/2R. If we plug in 8 ohms for the speaker impedance and 500 for P we get 500 = (V*V)/16. If we now multiply both sides of the equation by 16, we get 8000 = (V*V). If we take the square root of both sides we now get V = Square root of 8000, so V = 89 volts. If we now plug the 89 volts into our original formula, of P = I * V we can see that I = 500/89 so I = 5.61A. Do you think 89V @ 5.6A is enough to kill you? If we use 4 ohm speakers then the Voltage drops to 63V but the current would be 500/63 or 7.9A.

Now do you believe me?

 

You started this pointless debate by taking the thread completely off-topic. And by suggesting I'm giving advice that could get someone killed. I did not. FYI I studied electrical engineering at university. I worked on 25,000KV locomotives (some people call them electric units).
You refuse to admit there are differences in measuring electric power and audio power. In audio power output frequencies and harmonics are taken into account with manufacturers using different criteria. An amplifier delivering 10W RMS per channel can be quoted at 80W total PMPO.

How many people have died by touching the wire(s) of a 500W speaker?

 

Actually no, it's not. Voltage and amperage have an inverse relationship. When you raise the voltage to supply a load, you reduce the amperage drawn by that load. This is why we use high voltage for transmission lines. Any unregulated, unfused circuit can kill you. That is why we have GFCI, and IDCI devices.

Prime example (and this is not exact) if you have a motor load which draws 8 amps at 120v, it will draw 4 amps if supplied with 240. The inverse rule applies to all AC circuits.

 

I have no idea and neither do you. I personally don't know of anyone that would take the chance of doing that (other than you).

It's true that the output power could be expressed as either RMS or P2P. You're making the assumption that it is P2P but if you're wrong, then what? I prefer to err on the side of caution so, since we don't know (because it isn't stated), wouldn't it be better to make our calculations based on RMS to know what the potential is?

Did you test those 25000KV units by touching them with your fingers as well?

When I worked on transmitters, 500KW power supplies and other electronic devices, I guarantee I used meters and scopes to test with, not my fingers. Testing using your fingers is foolish regardless of whether you survived or not.

 

You're absolutely right when you say the current kills you BUT if the resistance is high enough and the voltage too low, no current will flow. A 12V car battery can deliver hundreds of amps (for a short period) when the + and - terminals are shorted but if you were to accidentally touch the + and - terminals, you wouldn't get shocked. Why is that? It's because 12V is too low of a voltage to overcome your skin resistance, so no current flows.

Voltage and current do NOT have an inverse relationship. If the resistance stays the same and the voltage increases, then more current will flow. Ohm's Law says I = E/R so if E (voltage) increases while the resistance stays the same, then I (current) will increase.

Your example of the motor drawing less current using 240V then when using 120V is because Power = Amps * Voltage, so 120V * 8A = 960W and 240V * 4A = 960W. In both instances the motor uses the same amount of power.

Have you ever touched your tongue to the terminals on a 9V battery? If you did, you would get a mild shock. The reason why is because your wet tongue has a lower resistance than the skin on your fingers so, in this case, 9V is high enough for current to flow because the resistance is also low.

About 40 years ago, I was working on a 500KW power supply measuring some of the internal voltages with an oscilloscope. I accidentally came in contact with 400VDC between my pinky finger and my elbow of my right arm. I got a terrible shock but I didn't get killed. That's because the current flowed only thru my arm and not across my chest and thru my heart. If I had made contact using both hands, I probably wouldn't be here today. That's why one of the safety tips for working with high voltages is to keep one hand behind your back. It takes a very small amount of current to flow thru your heart to kill you but it takes a high enough voltage, I think I read about 25V or something like that, to get enough current flow thru your body to your heart to kill you. Your body resistance goes up and down depending on if you're sweating or if your dehydrated, water is a good conductor. On different parts of your body your skin is thinner so has less resistance. Your fingers have fairly thick skin with high resistance while the skin on your inner arm is thinner with less resistance.

I always thought that high voltages were used in transmission lines to overcome the losses due to the resistance of the wire which becomes significant over long distances. Periodically, the power is routed thru a step up transformer to keep the voltage high. This is definitely not my area of expertise so you might be right about reducing current flow.

 

Apparent power (VA) versus true power (watts) is a final calculation. Voltage and amperage drawn by a load are inversely proportionate. Reducing the voltage increases the need for current, and increasing the voltage reduces the current drawn. This is basic electricity, and I completed my degree over twenty years ago.

The laws of physics have not changed since then.