What's a properly lit 6SN7 tube look like?

I just purchased an SET 300B amp here on the 'Gon, and after a bit of light cleaning of pins and sockets, etc; I fired it up.

All the tubes light up, but the single 6SN7 tube only lights at the top, while the 6BX7's light top and bottom. I get no sound out of the amp, with the exception of a very weak sound (music from the source) in the R/channel, with the preamp turned all the way up.

Any help would be greatly appreciated!

128x128Ag insider logo xs@2xislandmandan
That's exactly what I needed to hear, thank you Brownsfan! Got a new one on the way, hopefully, that will do it.

Best regards,
A "properly" lit tube can still be faulty. You have to replace with a known working tube. Jallen
Make sure the tubes are all seated correctly, you might have to wiggle them a bit in their sockets until you're getting both channels. 6SN7s, I have three of them, may light up very faintly, and in a lighted room you can just barely see they're on.
Hi Dan

What kind of 6SN7 tube are you having a problem with? Also do you think the tube got damaged when the amp was shipped to you and that is what cause the 6SN7 to only glow at the top? Where do you get your 6SN7 tubes from? I've bought from Jim McShane in the past and he is great to deal with.