This is technically an ad for stuff sold by a manufacturer, but it's really just me trying to sell these for a good price so that they are used instead of sitting in a bin. If I'm violating any terms, please delete the post. Because of the untested tube lots we buy, by the time we sort and test tubes for noise there are some loners left over that test well but probably won't ever find a mate. Here are 4 interesting old-stock 6SN7s to play with in your Lyr or anything else that only needs one tube. All were tested for noise and microphonics and measured on a Maximatcher Preamp tube tester to the same standards that we apply to the tubes we use for production amps. 1. RCA bottom-getter 2. Crosley (probably made by RCA, possibly GE), black glass. This one measures like it has been used a bit more than the other three. 3. RCA side-getter 4. GE side-getter $45 shipped CONUS. That's less than $40 for the tubes, which would cost $70-$100 if you got them from Brent Jessee, without the Crosley.