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Are my tubes about done?

Discussion in 'Headphone Amps (full-size)' started by hordsak, Feb 4, 2014.
  1. Hordsak
    I have an original Glow Audio One tube amp, and as far as I know it has the original Chinese tubes.  I think this amp was built around 2009/2010.  I bought the amp used off Craigslist, and I've put probably 1000+ listening hours into.  Lately, the left channel gets the odd crackles and pops.  I've also noticed that the 2 smaller tubes are starting to glow blue at the bottom.  I've read that this means air is inside the tube?  I've attached a picture.  I'm not completely worried, as I should have a WA7 coming in the mail tomorrow, but if it is the tubes giving out I would like to replace them and maybe use this amp at work.  Thanks!
    How do I embed images?
    Edit: I just found out that this amp does have blue LED lights under each tube.  However, I'm not sure how many hours are on the tubes.  I may just look for some cheap replacements.  
  2. Spareribs
    It sounds like your tube is becoming microphonic. Tubes can after a while, become microphonic and create unwanted noises. I would replace that tube. Generally tubes last a very long time but don't hesitate to change them if they start acting funny. 
    A blue glow tube is not necessarily a bad thing but if it's becoming microphonic or acting weird, out it goes.
    By the way, here's a little read about blue glowing tubes.
  3. Spareribs
    One thing that some people might do is to dampen a microphonic tube with a tube damper. It may or may not work out fully. But keep in mind that a microphonic tube can sound fine with no problems in another tube socket in another amp. It's rare for me to throw away a microphonic tube.
  4. MDR30
    Pull out the tubes out, reinsert them a couple of times. Sand the pins if they're oxidized. Works 9 out of... 10 times.

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