Conrad Johnson Premier 140 6922 tube swapping


Hi

I recently aquired the above amp and the stock 6922 is a bit noisy, I sure I have read that this tube in the C-J should not be changed?
Is this tube a candidate for tube rolling and suggestions of a new tube?.
I have read good things about the EAT 6922
Thanks
David
agathe79
I had one of these--great sounding amp but mine was problematic--and rolled a few tubes in it. I even bought some vintage Tung-Sol 6550's which made an enormous difference, more than the 6922's. I thought the Siemens CCa was the best sounding 6922 variant but the Tungsram mentioned above is also good, as well as some Ediswans I bought at Upscale Audio.
That probably is their stock tube of choice. Very commonly spec'd tube. They don't totally suck - in fact, when mixed with NOS tubes in my SF Line 1 they do a fine job of adding bass slam.
Does anyone know where I could get 8 NOS Tungsol 6550 tubes?, I know it's asking alot