What's a good step-up transformer?

Frank, Cotter has been out of business since the 80's. You can only get used or NOS units. They do typically go for about a grand, as stated above. They are very good sounding units, though. However, they are difficult to change cartridge loads on, and you have to perform some surgery, and have the correct jumper diagram. I have the diagram if you need it.

While not strictly a step up transformer, the Dynavector PHA-100 head amp is very good. It also has a cartridge impedance matching switch. Wally of Wally tractor fame put me onto it.
It is transparent to the source and adds a degree of bass slam compared to just using my premier 15.

cheers

Check out Jensen...it makes high quality transformers, too

I just saw that audiocubes started carrying the top of the line Denon AU-S1 step up transformer.

http://www.audiocubes.com/product_info.php?cPath=44_74&products_id=469

This transformer was available only in Japan. From what I've read, it is very good.

Stephens and Billington TX-103--very good.