Hi all,

I bought a Sweet 16 off a BAMmer for a steal a few months back, but have only just had a chance to put it through its paces. While it sounds fantastic, one thing I noticed is that if I look through the back grill with the amp on in a darkened room, the 2nd small tube (from left to right) doesn't glow at all. I've never had a tube go out on me on my other tube amp (16 year old Fender HRD), so I'm not sure how else to diagnose this other than by visually checking. What effect would a dead tube have on sound (having never heard a normally operating Sweet 16 in person?)

Thanks in advance!