Do step up/step down transformers create noise?

[dualphin]

I am tentatively planning a move to Berlin from the USA.

I just bought a pair of Yamaha monitors, which sound I really like. I realized, however, that the power supply is rated for 120V only. I was surprised, as so much gear today works with both 120V and 240V.

So, my question is should I just buy a step down transformer for use in Europe, as a permanent solution? Or would this introduce too much electrical noise into my rig, especially at that critical phase?

I might be powering additional gear from the same transformer, as well.

[EdisonRex]

I moved from the USA to the UK 12 years ago. I had much the same problem in that some of my gear was not 240V capable, at least not at the time. Although over time I've managed to get most of the studio converted, a significant amount never converted.

So I have a stepdown transformer which I use to power those portions of the studio which don't do 240V. I use a fairly large transformer (1kVA) even though the equipment is a fraction of that. For much of the equipment, this has not been a problem and I don't have noise problems - but that transformer is powered from the same mains circuit as the 240V portion of the studio. I wouldn't put them on separate mains circuits, just because I like having a single ground.

Of much more concern is the 50Hz/60Hz problem. Simple power supplies are tuned to the frequency (50 or 60Hz) and running them outside of that frequency causes fairly significant problems; for instance, my Nord Lead kept blowing fuses until I opened it up and discovered jumpers inside that let me convert it to 240V/50Hz. And the 12VAC adaptor which originally came with my Metasonix Wretch Machine actually exploded after about 18 hours of use, it just wasn't able to deal with the 50Hz. I also had a QSC power amp that was completely unable to deal with 50Hz and kept popping its own circuit breaker. There was nothing I could do for that one, I ended up buying a new amp.

So to sum up how I did this, when I moved over I converted all of the obvious power supplies (things like changing the fuse block around, jumpers, red switches, and looking at the nameplates to see if they could handle 240V/50Hz, then found the problem children after a couple months, and then convert/replace over time. That said, I still have a few pieces that do not want to run on 240V.

Hum has not been an issue, but again, I power the whole studio from one circuit (draws about 8 amps at 240V). Hum from individual 115V modules usually came down to the 50/60 problem, and converting/replacing was the solution for those.

In any case, over-rating the stepdown transformer for me seemed to make sense. I did use a "isolator/line filter" for a while, it actually increased the noise on the line, as it couldn't do the changed frequencies. It too burned out eventually. I've not had problems since I got rid of that.

[dualphin]

EdisonRex,

Thanks, that's just the kind of info I was looking for!