Total RMS Power

[hrlslcbr]

Hello. I've just bought some new speakers, but I have to use a transformer (220v - 110v) to use them. My question is: If my speakers are rated at 70 Watts (RMS), do I need a transformer capable of outputting those 70 Watts, or the 140 Watts of peak power (or they don't have any relation?).
Cheers.

[reboot]

Output of the speakers (in watts RMS) has (almost) no relation to power consumption.

[hrlslcbr]

Yep, just understood how it works.
The subwoofer says '110 ~ 115v' 525mA.
Does that mean that (according to something I found on google), the total power consumption is:
0.525 A = (consumed watts)/110v
That gives me 57.75 Watts. Is that right?
Cheers.

[redwudz]

Correct, 57.75 Watts is what it would use.

[ozymango]

Do I need a transformer capable of outputting those 70 Watts, or the 140 Watts of peak power (or they don't have any relation?).
Cheers.

Both redwudz and reboot gave good advice, and I'll add one more thing -- assuming you have to get a new transformer (I understood this is what you're getting at here?), probably the more useful way of looking at the situation is --

You want the voltage to be exact.

You want the current (or amperage) to be at least enough to cover the wattage, and then some.

You won't hurt anything by inputting more current (amps) the way you'll damage things with improper voltage; your system will only draw the current load necessary. So it's safe to supply more current (amps) because that can also help clarity of sound -- depending on the quality of the speakers and a whole bunch of audio variables, transient sounds (like drum hits, cymbal crashes, "bursts" of noise) can really "draw" current through the speakers and the more current (within limits), the better the quality of the sound. Within very complicated limits, of course.

So you don't need a 140-watt power supply but if you can find something that'll put out more than the base current required (like the subwoofer says 845 milliamps but no worries if your power supply is 1amp or more), you may just get a little bit better sound. Anyway, you certainly won't hurt anything.

This goes for amps, not volts! Voltage is critical! Okay, maybe not always that critical but unless you really know what you're doing, don't mess with the voltage. But splurge on the amps, that's okay.

ADDENDUM: I just re-read your post and maybe we have another concern here -- do you know if the input to the subwoofer goes into a transformer, or does it go directly into some circuit board? Because when it comes to electronic components, it's not alway just a matter of changing the voltage, there could be phase issues here (if we're talking 220v 50hz as compared to 120v 60hz). I'm guessing the power is going to a transformer to begin with, but unless you know this is indeed the case, I would read the manual very carefully before just putting a 220v to 120v transformer in the mix, it might not fix the problem and end up frying some components (or frying the 220v transformer).

[hrlslcbr]

Thank you. I bought a 100 Watt transformer. The back of the subwoofer says 110v @60Hz, and that's what I have here too; 220v @60Hz.
BTW, the speakers are the Logitech x-530 (Ok, not the best ones, but I'm in a small room so there's no need for more power).
Any other advice?

[ozymango]

Thank you. I bought a 100 Watt transformer. The back of the subwoofer says 110v @60Hz, and that's what I have here too; 220v @60Hz.

Sounds just fine to me -- my only concern was the frequency 'cause sometimes that can be an issue for solid-state devices. But that ain't an issue so you're good to go!

[hrlslcbr]

Thank you all...
Going to see how they sound.
Good bye.