Problem converting large PDFs to EPUB

[rmolina4819]

I've been trying to convert me PDFs to EPUB in my Calibre library to send to my Sony Reader. I have no problem with small files, but it seems that with anything over 1MB I´m having a hard time with. It takes for ever to convert them, and the EPUB file is just as large as the original PDF. I am able to convert these files using Stanza, and the resulting EPUB is under 1MB, but the resulting formating in Stanza is horrible, and I much rather use the Calibre directly. Do I need to change some of the settings, or convert to another format first? Thanks!!