Jafox,
I started rummaging through my tube drawer, because I know that I have a pair of Brimar's, but I think that they might 6922's rather than 12AX7's. Nevertheless, if I have them, I have tried them in the CAT before and am still stuck on the current Telefunken combination. When I find them, whether they are 12AX7 or 6922, I will evaluate them and report back on this thread.
I have noted that some Audiogoners tend to compare tubes across various tube equipment and I think this is a mistake. I find that while one might be able to make certain generalizations about a certain brand of tube, no matter in what piece of equipment it is used, generalizations that any tube is perfect, great or even good in nearly all equipment are a grave mistake. Characteristics which make a particular tube sound so right in one application are often completely absent when that tube is placed in another product. An example of this would be the Telefunken 6922: Rich, dynamic, with a very ripe midrange, great extension at both extremes in a CAT Ultimate, but undynamic, slightly bright and boring in the First Sound. The same could be said of a Siemens 7308: in the CAT, too forward in the midrange, a little thin-sounding and undynamic; in the F.S., exceptional dynamics, great imaging and midrange smoothes out. You really do have to compare tubes in the particular circuit in which they will be used. If you get too hung-up that a particular tube is great or terrible based on some previous experience in another piece of equipment, you may never hear your tube equipment to its best advantage. I have been surprised by this phenomenon several times.
I started rummaging through my tube drawer, because I know that I have a pair of Brimar's, but I think that they might 6922's rather than 12AX7's. Nevertheless, if I have them, I have tried them in the CAT before and am still stuck on the current Telefunken combination. When I find them, whether they are 12AX7 or 6922, I will evaluate them and report back on this thread.
I have noted that some Audiogoners tend to compare tubes across various tube equipment and I think this is a mistake. I find that while one might be able to make certain generalizations about a certain brand of tube, no matter in what piece of equipment it is used, generalizations that any tube is perfect, great or even good in nearly all equipment are a grave mistake. Characteristics which make a particular tube sound so right in one application are often completely absent when that tube is placed in another product. An example of this would be the Telefunken 6922: Rich, dynamic, with a very ripe midrange, great extension at both extremes in a CAT Ultimate, but undynamic, slightly bright and boring in the First Sound. The same could be said of a Siemens 7308: in the CAT, too forward in the midrange, a little thin-sounding and undynamic; in the F.S., exceptional dynamics, great imaging and midrange smoothes out. You really do have to compare tubes in the particular circuit in which they will be used. If you get too hung-up that a particular tube is great or terrible based on some previous experience in another piece of equipment, you may never hear your tube equipment to its best advantage. I have been surprised by this phenomenon several times.