[ethebull]

I own a Little Dot MkIII. I've bought a few driver tubes to roll and purchased four pair of power tubes for back-ups. The power tubes were sold as NOS but were not matched.

After installing a pair of the NOS power tubes, I noticed one glowed a good bit brighter than the other. I pulled out a couple more from the batch and found two that glowed much more closely. I wasn't aware of any sonic change and frankly wasn't really paying close attention - just making sure my new tubes were working.

So - Is brightness an indicator of matching? Also, since I don't have a tube tester, is a brighter tube stronger generally, or is a tube that doesn't get so bright the stronger unit?

Hoping someone who owns a tube tester can provide some insight for me.

Thx, E

 

[sacd lover]

Quote:

Originally Posted by ethebull /img/forum/go_quote.gif I own a Little Dot MkIII. I've bought a few driver tubes to roll and purchased four pair of power tubes for back-ups. The power tubes were sold as NOS but were not matched. After installing a pair of the NOS power tubes, I noticed one glowed a good bit brighter than the other. I pulled out a couple more from the batch and found two that glowed much more closely. I wasn't aware of any sonic change and frankly wasn't really paying close attention - just making sure my new tubes were working. So - Is brightness an indicator of matching? Also, since I don't have a tube tester, is a brighter tube stronger generally, or is a tube that doesn't get so bright the stronger unit? Hoping someone who owns a tube tester can provide some insight for me. Thx, E

The brightness has nothing to do with matching or how strong a tube is. The brightness is due to certain tubes having more of their heater filaments exposed .... and that is a production variation. I have quite a few tubes that glow brighter than others too. This is not unusual, so dont worry about it.

 

[ethebull]

Quote:

Originally Posted by sacd lover /img/forum/go_quote.gif The brightness has nothing to do with matching or how strong a tube is. The brightness is due to certain tubes having more of their heater filaments exposed .... and that is a production variation. I have quite a few tubes that glow brighter than others too. This is not unusual, so dont worry about it.

Or perhaps what we see has no correlation to tube performance measured or heard.

Thanks SACD. No more worries