Step Up Transformer 100v

Someone at Naim told me I'd need a 500v step up transformer, so I thought I'd be OK with the EHU600. Am I wrong, however?
Thanks!

OK, thank you for the links. My amp - NaimUniti - is only rated at 50w. This could change in the near future to 80w. But I think the EHU600 is suitable for these ratings? Thanks!

Thanks for the reply. I would like further details but I think I'm looking for something simpler. Maybe this unit will be good for my purposes:

http://www.soundhouse.co.jp/shop/ProductDetail.asp?Item=307^EHU600^^

The Electro-Harmonix EHU600 is the only step up transformer I have come across with a three pin socket for earth. Thanks!

Thanks again for the replies. The Swallow transformer looks very good but it's pretty heavy and expensive. I have found another one, however. It's supposed to be made for audio, runs quiet I am told, and is rated at 1500v. Here's the link:

http://noguchi-trans.co.jp/index.php?main_page=product_info&cPath=308&products_id=4883

It's made by Noguchi Transformers. Its pretty expensive at 20,000 yen. Thanks!

Hello, thank you very much for the offer. I don't have a transformer yet but in the next week or so I going to visit Noguchi transformers in Akihabara. I think they do an audio specific step up trans. I'll let you know if it doesn't work out. But I think 56lbs would be very expensive to ship. Apologies for the delayed reply but I couldn't login recently. Thanks!

I did buy a Noguchi transformer. It's specifically for audio, so it's very quiet and works well. It's rated at 1500v, so it can easily cope with my 50w amp. Thanks!