Kek, just put some other NOS in it. You are used to the sound of the Sylvania 6SN7. It is different from the NOS Russians that Rogue includes.
I own a Magnum 99. I am similar to the other repliers, in that I noticed such an improvement over my former tube preamp, that I didn't notice the break in changes. However, I do believe there were improvements. The Rogue 99 is a great preamp.
Worse case scenario, it doesn't match your other equipment, but I wouldn't judge that yet. Play a CD on repeat, or FM station for 72 hours, then you should have it broken in. Let us know your findings.
I own a Magnum 99. I am similar to the other repliers, in that I noticed such an improvement over my former tube preamp, that I didn't notice the break in changes. However, I do believe there were improvements. The Rogue 99 is a great preamp.
Worse case scenario, it doesn't match your other equipment, but I wouldn't judge that yet. Play a CD on repeat, or FM station for 72 hours, then you should have it broken in. Let us know your findings.