It's a bit of a long and convoluted story, so I won't go into the details, but my cousin found out I was interested in preamp tubes and sent me one in the mail that he got for free through some line of friends of friends. It is a GE 12AX7 that has some redish-orange printing on it with the number 6681 and "Made In USA". I think it's from the 1960s, but I'm not certain. It seems to be working fine. The tube it replaced was a Mesa-Branded Electro-Harmonix 12AX7EH. Compared to the previous tube, it sounds a tad bit cleaner especially in the lower frequencies, speed and punch between the two are very close to the same, midrange is a tad bit more polite (with my bass (SR5), I think that's a good thing), and treble seems to be smoother than the EH. Overall, the GE is more clean & polite sounding with just a bit of a rounder tone. The EH has kind of a in-your-face grindy-wooly-ness to its sound from the lower midrange down that is better for most Rock and Blues. The GE has a better sound in general for just about any other type of music. I haven't played live with it yet, so these impressions are just based on listening to it in my house. I think it's a keeper though and the price was definitely sweet.