step up transformer noise

You can probably send your amp back to the factory and have them convert it to NA voltage.

Or a cheaper alternative would be to do as I have done - run a 240 wire to a new outlet. You'll have a dedicated power source and better performance.

Do a search here on Luxman as there is an in depth discussion on step up transformers and what works best.
Either that or as Zd542 offered, you can send it back and have it converted.

All the best,
Nonoise

You don't even need a new outlet. Google "240 volt split duplex receptacle (adaptor). Easy.

Is it better to position a step up transformer near the phonostage or near the turntable to prevent issues with hum?

Is it better to position a step up transformer near the phonostage or near the turntable to prevent issues with hum?

Are you talking about moving coil cartridge SUT?

https://forum.audiogon.com/discussions/where-to-insert-the-step-up-transformer?sort_order=asc

Is it better to position a step up transformer near the phonostage or near the turntable to prevent issues with hum?

Best to keep anything with a strong magnetic field as far away from your TT and phono stage as possible.

but the transformer produces noise through the speakers, even when the amp is turned off.

I suspect this isn't true. I do suspect that the transformer is noisy, even with no load. I would use a transformer with **at least** double the capacity needed with the amp at full output at the very least (this will prevent it from distorting the AC power sine wave). The transformer does not need to be rated for 'audio duty' (not sure there even is such a thing) but it does have to be quiet and there are ratings/specs for that although they are not always published.