The Dynaco Tube Audio Forum

Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Dynaco VTA tube amp kits, all Tubes4hifi.com products and all Dynakitparts.com products


    One tube is brighter

    Share

    Dogstar

    Posts : 81
    Join date : 2014-06-23

    One tube is brighter

    Post by Dogstar on Mon Jan 18, 2016 10:35 pm

    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.

    GP49

    Posts : 718
    Join date : 2009-04-30
    Location : East of the sun and west of the moon

    Re: One tube is brighter

    Post by GP49 on Mon Jan 18, 2016 10:43 pm

    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.

    Dogstar

    Posts : 81
    Join date : 2014-06-23

    Re: One tube is brighter

    Post by Dogstar on Tue Jan 19, 2016 9:04 am

    The filament is the brighter part. The tubes probably have 300 hours on the. Performing perfectly ok. Thanks.

    GP49

    Posts : 718
    Join date : 2009-04-30
    Location : East of the sun and west of the moon

    Re: One tube is brighter

    Post by GP49 on Tue Jan 19, 2016 6:52 pm

    Enjoy the music!

    deepee99

    Posts : 1260
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: One tube is brighter

    Post by deepee99 on Fri Jan 22, 2016 7:42 pm

    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.

    Sponsored content

    Re: One tube is brighter

    Post by Sponsored content Today at 12:54 am


      Current date/time is Fri Sep 30, 2016 12:54 am