What made you change to a 6SN7 preamp?

In building preamp amplifiers, the 6SN7 based tube in general is a warmer sound, more relaxed presentation, more dimensional soundstage with real mid-range beauty.  That being said, the 6DJ8/6922 is generally more dynamic, faster, better clarity, and more slam.  It is a more upfront presentation.

Each one has benefits that may attract a person to that type of sound.

Happy Listening.

+1 bigkidz regarding the 6SN7. I once own a Carver cd player that had the 6DJ8 tubes in analog output stage.  Loved the sound of it, was as good to my ears as many more expensive players in the 90s. 

I run a preamp which uses 6 x 6DJ8's and the sound is as Bigkidz describes though perhaps a touch of warmth. Never had a 6SN7 preamp in my system always been curious.

The almost infinite choices,is what makes this hobby so wonderful. There is literally a different option for every single preference.  The fact is,I truly enjoy the choices I’ve made. But that’s not saying there are 1000’s more I would enjoy also. Or even more. 

@hilde45 another factor in responses so far may also relate to some people jumping up a level or two on design and improved parts quality with their next tube preamp purchase.

Strictly speaking, i.e bumping from something like a $1500 12Axx preamp up to a $3000+ 6SN7 based [a higher quality] tube preamp as a normal course of order.

With that said, I have no desire to change away from my own upgraded 6SN7 tube preamp and particularly so once I heard higher quality n7 tubes in it.