Does tube glow tell you anything?

[BowerR64]

Im still really green about tube amps and i did a search but im not really sure what im looking for or even what to search.

My question is, does the glow of the tube tell you anything about the tube?

I notice the 12AX7s have a more dim glow to them then say a 12AU7 which has WAY less gain.

I have 5 JJ ECC83s and a couple of them seem to glow a tad brighter then a few of the others so i wondered if maybe they had less gain like the 12AU7 which has about the same amount of brightness in its glow?

Or does it not mean anything?

 

[Blacque Jacque]

It tells you the heaters are working, nothing else.

 

[Vostre Roy]

^ This

Tubes from different companies are made slightly different from one another, sometime the filaments won't be exposed as much and might seems to not glow at all. It doesn't tell anything tonewise or gainwise though, don't worry

Edit: We're talking preamp tubes now, but power amp tubes glow can tell if something's wrong (red plate glow, for example) and even sometime get a lovely blue glow, wich doesn't really mean anything, though according to some website, its a good sign regarding the tube's quality.

 

[neikeel]

Old Mullards and Brimars will have an initial heavier glow from their heaters when they first fire up and then settle down, but the above is correct

 

[Guitar-Sam]

Old Mullards and Brimars will have an initial heavier glow from their heaters when they first fire up and then settle down, but the above is correct

Amperex and rft also flash when you first power the heaters. Ecc83s

 

[GIBSON67]

I've never based anything on tube glow!

 

[BowerR64]

ok well i wasnt sure just an observation that i noticed between the different tubes and how they sounded.

Also looking at some hi-fi tube amps seem to be really bright so i figured that a brighter glow was a sort of cleaner tube then one dim.

I have a few from china i pulled from a Jet city amp they are just barley glowing at all and those are the most dirty preamp tubes ive ever tried.

The china ones are the most dim of any i have and have the most hair. Thats why i kinda assumed thats how you can tell one from another or something.


Thanks for the info.