What is tube rolling?

I agree.I've never heard the term used for anything different
in audio.

I also agree that you should read, (and reread) Joe's Tube Lore at the link provided. It's pretty much the bible for the different ways tubes sound.

Just remember that the actual component that each tube is used in, makes a BIG difference. I have never found the same tube(s) sound the same in different gear.

I really like the Amperex USN-CEP 6922 tubes in my DAC, but they suck in my phono preamp. Each circuit and the way it "uses" each tube is completely different.

check out sonicfrontiers.com Go to the anthem side of the site and search for "A Taste of Tubes". It will teach you a lot of basics.

One of the oldest of audio addictions in the quest for perfect sound. the addiction is gradual and eventually leads to bankruptcy, but at a much slower pace than power cables, interconnects, and speaker cables!

While others have clearly defined tube rolling, I would like to add the benefit of NOS tubes. The difference in sound quality you will experience is astounding. Unfortunately this may be somewhat design dependant and not 100%. I would recomend numerous specific inquiries before spending hard earned cash'