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DAC 1.2 kit regulator tube question

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Hi all,
I have a AN DAC 1.2 kit which works well but on occasion (more times than not) the OB2 gas regulator tubes do not light. This has been a problem since the unit was new. Interetingly, my friend who also owns a 1.2 kit has no problem with his unless he brings it to my house and plugs it in. We both live within several miles of one another and measure similar AC voltage (~120)
I vaguely recall Michael Kerster of AN suggesting a value change of the Mills resistor for those who had a problem keeping the OB2's lit, but i do not recall the value.
Any ideas?
Thanks in advance.
Mike

Follow Ups:

Re: DAC 1.2 kit regulator tube question - brett 12:33:52 06/12/05 (6)
I listened to my 1.2 for two years never having the 0B2's light up. Being such a tube novice, I didn't know they were supposed to. Then one night I decided to slip on some herbie tube dampers while the dac was playing. I hate to turn it off. With music playing, I removed the cover and the music instantly transformed. It opened up dramatically, and sounded much smoother with more detail. Bass tight and full. So the cover stays off from now on. Anyways, I slid the tube anchors on and before my eyes the regulators lit up in a purple hue. Since then I've turned it off a couple of times, and in order to get the regulators on I hold my fingers to the sides of the 0B2s, and with the same hand touch the heatsink next to them. I don't know why, but it works every time. I theorize that energy or vibration coming off the LM317T help to ignite them. Or maybe it being grounded that does it.
After two years of contentment with this DAC I realized another level when these things finally turned on. See if it works for you. I'm curious if it does.
-Brett
- Re: DAC 1.2 kit regulator tube question - MikeH 08:00:25 06/14/05 (5)
  Hi Brett,
  Thanks for the info. I'll give it a try and get back to you with the results...
  Mike
  - Re: DAC 1.2 kit regulator tube question - Tom R 17:36:15 06/14/05 (4)
    I have had similar problems with my DAC 1.2, except the OB2's
    will conduct, then shut down, then start to glow again every few minutes. This may be because they are drawing to much current??? Not sure. But strangely I did not hear any change in sound in between the tubes conducting and when they were not, so I just pulled the tubes out, and have been running with out them. My DAC has been modified from the original, so not sure why the extra current draw, My be it's time to look into it again.
    Tom
    - Re: DAC 1.2 kit regulator tube question - brett 23:06:40 06/16/05 (3)
      Those are fickle aren't they? I noticed that mine weren't lit tonight, and had a tougher time get them going again. With a little trial and error, I realize now that it's sliding the tube dampers up or down either regulator that gets them lit. It must be the friction or static that's making it happen.
      http://herbiesaudiolab.home.att.net/
      As a last resort. :)
      -Brett
      - Re: DAC 1.2 kit regulator tube question - diho@hifi.nl 03:47:31 08/01/05 (2)
        
        In Reply to: Re: DAC 1.2 kit regulator tube question posted by brett on June 16, 2005 at 23:06:40:
        
        You can pull out both OB2's.
        Dac will sound better without them.
        Give it a try
        
        Re: DAC 1.2 kit regulator tube question - Peplohifi 18:53:22 08/11/05 (1)
        
        In Reply to: Re: DAC 1.2 kit regulator tube question posted by diho@hifi.nl on August 1, 2005 at 03:47:31:
        
        The OB2 in my pre-amp also lit up intermittently. Music sings no whether it lit up or not, however, during the sudden transistion, pop sounds come up.
        Anybody knows any electrical differences between dark and bright and what makes it lit
        
        Re: DAC 1.2 kit regulator tube question - brettjm 12:14:50 09/01/05 (0)
        
        In Reply to: Re: DAC 1.2 kit regulator tube question posted by Peplohifi on August 11, 2005 at 18:53:22:
        
        I asked the same question over at the Decware forum and got some good answers. There are a few tube gurus over there who have a knack for explaining the technical to the novice. Here's the thread.....
        http://www.decware.com/cgi-bin/yabb/YaBB.cgi?board=Tubes;action=display;num=1111171660

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