Tube Static

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Early B.
Early B. Posts: 7,900
edited February 2005 in 2 Channel Audio
Changed out the smaller tubes in my Jolida SJ502A. Formerly used EH but swapped them out for Mullard 12AT7s and a pair of Groove Tube 12AX7M's. So far, I'm hearing a little more detail, but not a significant change in SQ yet. More to come...

Anyway, I turn on my system and let it warm up, but when I pop in the first CD, for the initial 2 or 3 seconds, I get static. I believe the static is emanating from the Groove Tubes. I never had an issue with the EH's. So why am I getting static? Any damage being caused? Will it go away after break-in?

I had this issue with my tube CD player with the stock Chinese tube. Once I changed the tube, the problem went away. I'd like to keep the GT's, but not if it will cause problems.

Thanks.
HT/2-channel Rig: Sony 50” LCD TV; Toshiba HD-A2 DVD player; Emotiva LMC-1 pre/pro; Rogue Audio M-120 monoblocks (modded); Placette RVC; Emotiva LPA-1 amp; Bada HD-22 tube CDP (modded); VMPS Tower II SE (fronts); DIY Clearwave Dynamic 4CC (center); Wharfedale Opus Tri-Surrounds (rear); and VMPS 215 sub

"God grooves with tubes."
Post edited by Early B. on
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  • Tour2ma
    Tour2ma Posts: 10,177
    edited February 2005
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    Hummmm... Goes away when you roll the EH's back in?
    More later,
    Tour...
    Vox Copuli
    Better to remain silent and be thought a fool, than to open your mouth and remove all doubt. - Old English Proverb

    "Death doesn't come with a Uhaul." - Dennis Gardner
    "It's easy to get lost in price vs performance vs ego vs illusion." - doro
    "There is a certain entertainment value in ripping the occaisonal (sic) buttmunch..." - TroyD
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  • organ
    organ Posts: 4,969
    edited February 2005
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    Does it do this all the time for 2-3 secs?

    Maurice
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  • Early B.
    Early B. Posts: 7,900
    edited February 2005
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    Does it do this all the time for 2-3 secs?
    No. Only the very first CD immediately upon warm up.
    HT/2-channel Rig: Sony 50” LCD TV; Toshiba HD-A2 DVD player; Emotiva LMC-1 pre/pro; Rogue Audio M-120 monoblocks (modded); Placette RVC; Emotiva LPA-1 amp; Bada HD-22 tube CDP (modded); VMPS Tower II SE (fronts); DIY Clearwave Dynamic 4CC (center); Wharfedale Opus Tri-Surrounds (rear); and VMPS 215 sub

    "God grooves with tubes."
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  • BlueMDPicker
    BlueMDPicker Posts: 7,569
    edited February 2005
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    Check the pins for oxidation - with special attention to pins 2 and 7 (counting clockwise from the open space.) It sounds like the control grid of one or both triode sections may not be at negative potential until a signal is presented for amplification.
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  • Tour2ma
    Tour2ma Posts: 10,177
    edited February 2005
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    BMDP,
    Was thinking pins, or sockets, myself. There's enough "wiggle room" in sockets that sometimes a new/ different tube's pinch points are not in the exact same location. So you can run into oxidation on an unused area of one or more contacts.

    It's in apart why I was wondering if rolling the EH's back in eliminated the static...
    More later,
    Tour...
    Vox Copuli
    Better to remain silent and be thought a fool, than to open your mouth and remove all doubt. - Old English Proverb

    "Death doesn't come with a Uhaul." - Dennis Gardner
    "It's easy to get lost in price vs performance vs ego vs illusion." - doro
    "There is a certain entertainment value in ripping the occaisonal (sic) buttmunch..." - TroyD
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  • Early B.
    Early B. Posts: 7,900
    edited February 2005
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    Interesting you mentioned the sockets. One of the sockets looks like it's been in a war zone and took heavy fire. I'd love to replace it someday because it looks worn (i.e., burned -- it has brown discoloration).
    HT/2-channel Rig: Sony 50” LCD TV; Toshiba HD-A2 DVD player; Emotiva LMC-1 pre/pro; Rogue Audio M-120 monoblocks (modded); Placette RVC; Emotiva LPA-1 amp; Bada HD-22 tube CDP (modded); VMPS Tower II SE (fronts); DIY Clearwave Dynamic 4CC (center); Wharfedale Opus Tri-Surrounds (rear); and VMPS 215 sub

    "God grooves with tubes."
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  • Tour2ma
    Tour2ma Posts: 10,177
    edited February 2005
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    Ahhhh...

    Socket ceramics will discolor with heat over time so it may not have been any acute incidents... then again could have been one of Mike's recent fireball episode in it's past... :eek:

    A pipe cleaner and a little deoxit may help...
    More later,
    Tour...
    Vox Copuli
    Better to remain silent and be thought a fool, than to open your mouth and remove all doubt. - Old English Proverb

    "Death doesn't come with a Uhaul." - Dennis Gardner
    "It's easy to get lost in price vs performance vs ego vs illusion." - doro
    "There is a certain entertainment value in ripping the occaisonal (sic) buttmunch..." - TroyD
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  • BlueMDPicker
    BlueMDPicker Posts: 7,569
    edited February 2005
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    Cleaning the sockets and pins is a great first step. I'm inclined to think that you may have a load or control resistor out of tolerance. Some triodes won't complain, others will exhibit behavior as you've described when they don't see enough resistance across the control grid - especially the high mu triodes. Marshall guitar amps are classic for this type behavior.
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