Monitor power conversion issue

[airecordings]

Hello everyone,

I'm going to school at the University of Southampton in England studying for a M.Eng. in Acoustical Engineering. I live in New Jersey in the states and I brought some monitors with me so I could do a little bit of mixing and recording from my laptop while I'm here. The monitors are an Event Tria Series (2 monitors and a subwoofer). The subwoofer plugs into a wall outlet and the two monitors are powered via the subwoofer. The subwoofer would typically plug straight into the wall outlet in the U.S., but as the voltage and plugs are different here, I've had to get a transformer to provide the appropriate voltage. I have a 500 watt transformer that takes the 220v current here and turns it into 110 for American made electronics. The monitors will turn on and pass signal from my interface, but they also make a kind of humming sound as well as a sort of high frequency pulsating noise. And then after about 10 minutes of this, they make a loud popping noise, turn off, and the reset button on the back of the subwoofer pops out. If I push that back in, I can turn them back on again but the cycle just repeats itself.

Any ideas how to get around this problem and avoid buying monitors here??

Thanks!
-Brendan

[the shadow]

Brendan,
Forgive me if I'm stating anything obvious or something that you have tried already.
If this happens with the laptop plugged into the monitors try turning them on without anything physically connected to the audio inputs. If the problem still occurs try to substitute the transformer with another (maybe larger than 500 watts-although I really don't think it will make the difference if it's more than 500 watts). I can't remember off the top of my head if the 220v is on one leg and neutral is on the other, but if it is maybe the transformer is sending 110v to the neutral instead of the hot pin of the ac plug. I hope this helps. Let us know how you do.

[airecordings]

Yeah I already tried just turning the monitors on alone and they still have the same problem. As for the other stuff you're talking a bit over my head with the electronics language (I pretty much know nothing about that), but thanks for your help!

[the shadow]

Brendan,
I don't know those monitors but check if there is a 110/220 switch somewhere near the ac plug. If there is a switch you should set it for 110v to use with a transformer. Or you could get a correctly wired ac plug and bypass the transformer if you can set it for 220v.

[Dan]

Yeah I already tried just turning the monitors on alone and they still have the same problem. As for the other stuff you're talking a bit over my head with the electronics language (I pretty much know nothing about that), but thanks for your help!

The way AC wall current works is there are three conductors: Hot, Neutral, & Ground. For 110, if you were to measure the voltage between the Hot and the Neutral, you'd get 110V; between the Hot and the Ground, you'd get 110V; and between Ground & Neutral, you'd get 0V. For 220, it's the same idea, but with double the voltage.

What Joe's wondering is if instead of putting 220 on just the hot leg, the adapter put 110 on both the hot and neutral legs. That means that if you measure Hot-Ground, you get 110; Neutral-Ground, you get 110; and Hot-Neutral, you get 220.

-Dan.

[Max Gain]

Whoa, whoa!!!! Converting the neutral blade from ground is dangerous and it won't work. The problem is your converter is not big enough You should have probably 1000 watts or 10 amps available from your transformer. After the inefficiencies are factored(power cable, lights, heat, damping ect. the actual out put power that is audio is probably about 40%---a TPO of 500watts(L+R+Sub) will require around 1200watts.

[Dan]

Whoa, whoa!!!! Converting the neutral blade from ground is dangerous and it won't work. The problem is your converter is not big enough You should have probably 1000 watts or 10 amps available from your transformer. After the inefficiencies are factored(power cable, lights, heat, damping ect. the actual out put power that is audio is probably about 40%---a TPO of 500watts(L+R+Sub) will require around 1200watts.

Only if you're running the system at full-blast. If it's just sitting there w/ no audio feeding it, then the current draw is minimal.

-Dan.