Tube rolling in Modwright LS 100 preamp

I just swapped the stock tubes (JJ) for Sophia Electronics 6SN7's and a Genalex Gold Lion rectifier. I was quite surprised that I didn't really notice much of a difference. The preamp sounds wonderful, really, but the SE's have been touted as a nice improvement. Perhaps I just need to be patient for them to break in. Any comments? Thanks.