I had another amp and preamp running for a while and just went back to the VTA ST-120 and I just re biased the tubes with a new multimeter. The 25 year old Fluke 85 I was using died. Anyway...I noticed the right front tube is brighter than the others. I'm using TungSol KT120's. Is this ok? If not what should I check? Thank you.
3 posters
One tube is brighter
Dogstar- Posts : 361
Join date : 2014-06-23
GP49- Posts : 792
Join date : 2009-04-30
Location : East of the sun and west of the moon
What looks brighter? The visible filament? I wouldn't worry about it. Maybe a bit more of it is exposed so you can see it; that's normal production tolerance.
If ANY part of the plate is red, however...another story.
If ANY part of the plate is red, however...another story.
Dogstar- Posts : 361
Join date : 2014-06-23
The filament is the brighter part. The tubes probably have 300 hours on the. Performing perfectly ok. Thanks.
GP49- Posts : 792
Join date : 2009-04-30
Location : East of the sun and west of the moon
Enjoy the music!
deepee99- Posts : 2244
Join date : 2012-05-23
Location : Wallace, Idaho
It could just be a line of sight matter, especially if the key-ways are in different places. I have a couple of tubes whose filaments look brighter than the others, until I can eyeball them from exactly the same perspective and from the top, in which case they all look pretty close (unless you've got getter flashing on top, in which case only a side view works). Same holds for novals, if they're centred differently on your chassis.
As GP 49 says, Enjoy the music. Or as I have learned, if it ain't broke don't fix it.
As GP 49 says, Enjoy the music. Or as I have learned, if it ain't broke don't fix it.