Well, I got my first tube! A RCA 6AS7G vacuum tube - top getter - black
I got it from Leeds on etsy for $18 shipped. I had a slight channel imbalance with my first tube, and that is gone with this new tube.
I do notice that the tube is extremely sensitive to vibration. The amp sits on my desk, and if I tap my desk, I can hear some distortion through my headphones. I put some DiversiTech 3" square HVAC vibration isolators under the crack, and it really helped. Note, these isolators come in 2, 3, and 4 in sizes, are really inexpensive, and are great. At any rate, is it common for tubes to be ultra sensitive to vibrations?