Manley Steelhead Tube Rolling

Zender,
Save your money! The manufacture has selected the ideal tube designs for their equipment. The transformers are wound and matched to the particular tube design. Yes, you can tube roll, and yes your system will sound different, but not necessarly better! I fell into the 'rolling trap' a few years ago, and wound up going back to the manufactures recommended tube type.
Regards,

I second the above. In theory, you can improve upon the stock tubes complement (with tubes sporting closer tolerances, vacuum, etc, to the originals' specs) -- but it would be a very expensive undertaking... sort of like a small, self-financed, PhD research project (far too many 6922's around).

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.