Hey, I thought it may be a good idea to have a sort of "database" of people's experiences with tube manufacturers and models. I searched and could not find anything of the sorts. This way, people looking to upgrade or change tubes in equipment could have a reference to whether a certain tube may be darker, brighter, glittery, etc. I understand that tonal differences can be difficult to describe and subject to interpretation, but try your best! Personally, I have used the Groove Tubes 12AT7's in my preamp and it gave the mid's a significant boost. The high end seemed to not stand out as much also.