I have to repectfully disagree with the above two posts. As a long time tube head(built my first tube amp from a kit in the 1960s) I think tube rolling is not only fun but most times an improvement in sound reproduction. I changed out the stock 6922 in my Steelhead and added NOS Siemans CCa. I left the stock 7044 in place. In my system, I found the Siemans more detailed and musical than the stock 6922. There was also improved clarity and transparency. Were the changes night and day? No, but obvious improvements.
