My tube rolling experiences with many tubed-based components is polar opposite to the comments made by Bartokfan. What exactly are people trying to wiggle out of? Quantifying how each and every brand/model tube will sound in each and every component? Sorry, but as Albert already alluded to, it's just not that easy.
In some cases, the differences can be subtle. And in others not at all. There have been times where a single pair of tubes changed in a component resulted in greater refinements than I had achieved in past component upgrades that costed far more. If all you hear time and time again is a subtle change, that indicates the limitations of the component or system under evaluation and not the process of comparing tubes.
From what I have learned with trying various Mullards, Telefunkens, Brimars, etc., EL34, 12ax7 and 6922/6DJ8 tubes, I would never make final judgement on any component that contained Sovtek tubes. These things are mediocre at best. No master audio engineer can resolve this with fancy capacitors, point-to-point wiring, teflon boards, chassis dampening, 18 stages of regulation, etc.
As for what tubes the designer puts in a new product, obviously new off-the-shelf tubes are the only option due to availability and guarantee issues. But with very little effort, many of us hear components perform at levels even their designers never heard.
Bartokfan, you are free to keep the stock tubes in your preamp all you want. And this is good news to the rest of us as there is one less person to compete with when a good deal on older tubes becomes available. But do not condemn the efforts and experiences of others who have significantly different results than yours. And to claim it is nonsense clearly indicates you have a lot less experience with this process than a number of Audiogon members whose reports in these forums echo mine to a T. Afterall, you are into component rolling while the rest of us do it at the tube level.
What I find silly is to go through preamp after preamp, amp after amp, etc., the cost of shipping and potential for damage, until I find a stock unit that meets my goal. Sorry Bartokfan, but it is not that simple...it is naive. I'd rather purchase a few pairs of tubes that cost me $10 or $20 to ship, try them in my system, keep the ones I like and put the rest back on the used market. Now that's simple. It sure beats packing and shipping 50-100 lb components around the globe.
Through the sharing of tube-rolling knowledge by others with the same components as mine, I have taken my system to a performance level that I never knew possible with these components. Rather than put a negative spin on this and call it a silly game, I think of this as a continued quest for refined magic.
