If you need 220v line voltage why not just hire a electrician and run a line from your fuse box?

In Europe 220 is the basic current of all wall plugs so they would not need a transformer. The main reason I suggested an electrician is that you should be able to tap 220 at your fuse box and not only have the correct voltage but have the correct breaker/fuses in case of any problems. Of course I don't know what the plug looks like on your unit but these days it is code to put in 4 pole plugs not 3 pole most places.I have used step down transformers in Europe but not step up. I at one point inherited some european rack gear that was 220 but was able to switch the internal transformers wiring (the standard transformers were designed so that the units could be set up for 220 or 110 depending on where they were being sold so I just switched it to 110 and switched out the cord). This was pretty easy because I had some help - someone who had done this before - and the company schems).

it's output rating is 700 RMS, so was going to get 2000 or 3000 watt transformer. should i be concerned about it introducing noise? anyone have any recommendations on a transformer?

oops. i may have phrased that poorly. the sub only operates on 220 volts. i was going to purchase something like this so i could run it: https://www.amazon.com/gp/product/B0717 ... PV13&psc=1a bit cheaper than the electricians i know. but curious if this is overkill/inadequate for what i want it to do. power output of the sub is 700 watts RMS. i figured some folks here likely have some british or german gear and may have recommendations on brands/models.

Not sure what you are asking. Replace a faulty part? Or you have wrong line voltage?Introducing noise? Like hum from an emagnetic field?

Are you in the US? What sub is this? Are you sure it isn't 115/220 switchable? It will work with a step up if the step up provides the amps you need, but I bet there is an easier solution.

If the transformer isn't switchable (either externally or internally) I wonder if replacing it with a US one would be the same or similar price to getting a step-up.

I am in the US. It s a bowers and Wilkins ASW2500. This particular one does not seem to be switchable - have yet to receive it (currently en route) but going on pics and by seller s explanation - we have discussed somewhat (he went the electrician route).