Tube Rolling for Convergent Audio SL1 Preamps


just wondering if anyone has experience in experimenting with different tubes in a convergent audio sl1 preamp....ken stevens, the preamps designer, will tell you that premium nos tubes like old telefunkens, mullards, amperex, etc will make NO DIFFERENCE in the sound quality....that his design works with todays current tubes just fine.....i find that hard to believe since they can make a HUGE difference in other pieces of gear.....does anyone have an opinion that they can offer?.....many thanx!
dante
I have a SL-1 Ultimate Mark II but have previously owned a Reference Mark II and a Signature Mark III. And tube rolling definitely makes a difference. I have spoken to Ken in the past and his response was that the stock tubes made the preamp sound the most "neutral", but that the sound can be tailored by using NOS tubes. I also think Ken is insuring that the current production tubes will always be available, whereas NOS tubes will not be. I found the best tubes, to my ears at least, to be Siemens CCa's for the 6922 positions and Raytheon D-getter 7729's (just try to find these!)for the 12AX7's. I tried some 5751's and didn't like the lower gain and reduced dynamics. Ken doesn't recommend these and I can see why. Others seem to like these but I don't know why.
i appreciate everyones input....i had a hard time believing that different tubes wouldn't produce different results....your experimenting will point me in the right direction.....many thanx!
What brand of current production 12AU7 and 12AX7 are used now for CAT replacements?