a question about tube amp lights...

Hi all,

I just purchased a Jolida 302 new. One of the large tubes is very slightly dimmer then the others. I tried reseating the tube and it didn't make a difference. Is this normal? Still sounds great -- just curious...


Marty (a very newbie at all this stuff)
One additional question. Does it matter if the tubes are seated completely straight? It is hard to get all four of the smaller tubes to sit perfectly straight in the socket.

I imagine I'm probably just being nuts, but am curious whether all this makes a difference.

I would not be concerned about how bright the light is.

As far as tubes being in upright positions, I pay less attention to the angle while I do want to be sure that it is snug in place. If the tube is tight and comfortable, you will be too.
Pretty hard to have them all perfectly plum..Being so small I would think its impossible to get all the tube seats perfect..If the tubes fit in snug, leave em....

As far as the brightness of the tube you mentioned ,,if there is a matching tube and its brighter I might be concerened..Other than that if it sounds good,enjoy.........
You can't really judge a tube by filament brightness unless it is unusually off. Slight variances in alignment as tubes are assembled can make brightness appear to vary between tubes.

The only way to really tell for sure is to put the tube in a tube tester and check the readings.

However, do check your bias settings for each output tube. These can affect brightness and cause problems if they are too far off. If the bias settings are correct, the amp sounds good and the brightness variance isn't just a matter of "slightly" then I'd quit worrying.

As far as the perfect vertical aligment, this doesn't affect performance at all. It is just an appearance issue.
awesome -- thanks everyone for the explanations! I've been fiddling with everything for days and just need to quit and leave all alone!