I used to own a Cary SLP 98 preamp that used 4 x 6SN7. Two were used as drivers and two were used as output buffers. I used the same, as well as different matched pairs in each position. My favorite combo was the Raytheon VT-231 in the driver position and Sylvania GTB in the buffer position.
Try the link below which provides an inventory of 6SN7 tubes, their sonic characteristics, and in some cases use preferences put together by Dennis Boyle of Chimera Labs:
http://home.att.net/~chimeraone/6sn7sound.html
Try the link below which provides an inventory of 6SN7 tubes, their sonic characteristics, and in some cases use preferences put together by Dennis Boyle of Chimera Labs:
http://home.att.net/~chimeraone/6sn7sound.html