Axiom Home Page Forums General Discussion Technical Questions 220 volt vs 120 volt for subwoofers

So John. I think you're telling us 120 is for pussies.

I’d run a couple of dedicated 15 or 20amp 120v circuits into the room and call it a day.
Since I have no power in the media room at the moment ... I’m running everything off a single 15A circuit and haven’t blown any thing yet. It’s a lot more stuff then your talking about. The reason I can get away with it is that my power needs are mainly dynamic. I turn on the amps and subs one at a time and play it at reasonable levels. The dynamic power comes from the stored Power in each amp

In theory you can get twice the power into the room with 220 per circuit but you’re creating headaches for your self.

I dont know. I would send an email to them and ask.

advice@axiomaudio.com

4x the power is output if the load impedance is unchanged and voltage doubled assuming no heat loss. The example assumes a resistive load with no protection.

120v at 6ohm load

I=E/R 120v/6ohm= 20A P=ExI 120v x 20A= 2400w

240v at 6ohm load

I=E/R 240v/6ohm= 40A P=ExI 240v x 40A= 9600w

Thats why it’s a big no no to use a 120v recept (5-20R) with 240v. Plug something in that needs 120v normally and a fire can occur.

The subwoofer power cord for 240 is different than 120.

BTW, I power 2x500, 1x800, 1x1000-8, 1x1000-2, 1x1500-2, 2xDSP, active LFR1100, 2xQS10, Onkyo, PS3, wireless router, cable modem all from a single power bar. I've turned it up louder than my ears can stand in my 4200 cu.ft. space and even with the lowest lows, the voltage at the power bar is rock solid.

Hello Mojo,
Thanks for that, the power bar is supplied with 120 v at 15 A or 120V at 20A?.

Hello TrevorM,
Thank you for the illustration and the address. I will ask the people at Axiom about what their subwoofer cable can handle. Just would seem to me that they would have provided a power cable that would be able to handle the higher volt requirements. Having said that I realise one should never assume.

120V, 15A. That's good for 1800 continuous "RMS" Watts.

If you examine the document at the link Trevor posted, you'll see it takes 25 seconds for the molded circuit breaker to trip at 3 times the nominal current rating. For a 15A breaker, that's 45A for 25 seconds. 45A at 120V is 5400W of "RMS" power and 7600W of peak power. No musical transient lasts that long. This is what's called an overload condition. Overloads are different from short circuits. Breakers react differently to overloads (thermal loading) compared to short circuits (magnetic loading).

The link is for an industrial breaker of course. I'd like to find the curves for a typical household breaker. Not sure they're similar to what I described above. One thing I do know is a 15A breaker does not instantaneously trip at 15A.

fine 4x I know the math.
The point I was trying to make is that it’s easier to deal with what’s standard. And that it’s probaby not needed. That said, guess you can find 240 power strips and the like out there if you really want. Overkill will give you options. I put in a sub panel for my HT ... power will not be an issue in the room (as I can always add a circuit plus it keeps the ground runs short).

Lol. Always a smartie pants I am....

I knew you knew. Just making Vic aware of what can happen if he jury rigs stuff.

BTW thinking on this the 230v switch on the amp is likely for users overseas. It is not North American 240 with 2 hot legs. In the UK etc they have single leg hots at 230 instead of 120. Likely still set up for one pin as neutral with the torroid tap.

Just stick with 120....

Also, I can back Mojo and rrlev that a single 20A cct is fine. I run a 2200va centralised UPS in my mech room that serves the basement HT, living room plasma and oppo and a 2ch room setup. Runs all three no issues simultaneously.

Had a BBQ party once and the power went out. Ran the 2ch setupfor 45 mins on battery cranked and kept BBQing.... power came back. All good. Pretty sweet with 15 people here. Lol.