Dang -- my "Simple 2A3" amplifier. Just. Blew. Up.

For an as-yet unknown reason, the cathode capacitor on one channel of my (slightly modified) JE Labs "Simple 2A3" amplifier variant just self-immolated.
Big ol' pop.
Magic smoke.
Acridity.

Fug.

I am wondering if one of them big ol' Sofia "meshplate" 2A3s suffered a filament short... or just what the dang deal was.

Funny thing -- I thought that the other channel was lower in volume, and I was troubleshooting that when the fun began... but maybe the soon-to-immolate channel was actually higher in volume(?!?).

Fortunately, we do still have SE 2A3 backup at the ol' casa.

Paramours are go!

9835310896_f77fa68f7c_b.jpgDSC_0105 by Mark Hardy, on Flickr
(photo from a long time ago...)

Thanks for letting me -- ahem -- vent

PS - I did not try the Sofias in the Paramours :neutral: Tossed a pair of cheap-Jack "ValveArt" 2A3s in 'em. For now.

Comments

  • msg
    msg Posts: 9,306
    Dislike.
    Yet, like.
    I disabled signatures.
  • mhardy6647
    mhardy6647 Posts: 32,922
    as an aside - it was the low-volume channel that popped a capacitor; I forgot I was lookin' at it upside-down! I am not too good with spatial stuff.
  • bikerboy
    bikerboy Posts: 1,205
    Led Zep will do that!
    Main system: Lyngdorf TDAI 2170 w/ Pioneer 42" plazma-> Polk LSiM 703 w/Tivo, Marantz tuner, BRPTT: Nothingham Spacedeck-> Pioneer PL L1000 linear arm-> Soundsmith DL 103R-> SUT->Bottlehead ErosDigital: I3 PC w/ Jriver playing flac -> Sonore Ultrarendu -> Twisted Pair Audio ESS 9028 w/ Mercury IVY Vinyl rips: ESI Juli@24/192-> i3 PC server
  • agfrost
    agfrost Posts: 2,421
    Hope you get it sorted out, Mark.
    Jay
    SDA 2BTL * Musical Fidelity A5cr amp * Oppo BDP-93 * Modded Adcom GDA-600 DAC * Rythmik F8 (x2)
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    Preamp rotation: Krell KSL (SCompRacer recapped) * Manley Shrimp * PS Audio 5.0
  • [Deleted User]
    [Deleted User] Posts: 10,716
    :o
    That is why you need backup SS equipment o:)
  • mhardy6647
    mhardy6647 Posts: 32,922
    :o
    That is why you need backup SS equipment o:)

    ummm...

    24708700600_ce3816961b_b.jpg010 by Mark Hardy, on Flickr

    ;)

    The most likely "root cause", I reckon, is that the output tube on that channel shorted. I am frustrated because I don't have any means to test a 2A3 :( -- other than use test (i.e., plug it in another amp and see if something blows up). A shorted output transoformer's another potential cause.

    I can replace the cap and start checking voltages (with no 2A3s installed).

    It just wasn't something I was expecting to be worrying about this week :neutral:
  • mhardy6647
    mhardy6647 Posts: 32,922
    Well, the tubes have plenty of miles on 'em... and the caps per se are no problem to replace.
    I am just not looking forward to troubleshooting :#

    The oogy stuff from inside the eviscerated cap dissolved some of the print off the bottom terminal panel of the OPT on that side. Fortunately the other one's still legible.
  • EndersShadow
    EndersShadow Posts: 17,517
    First world problems.... just roll in another amp and put that one to the side till you feel like troubleshooting lol....

    The audio gods are saying, time to play with some other amps that haven't had any love in a while.
    "....not everything that can be counted counts, and not everything that counts can be counted." William Bruce Cameron, Informal Sociology: A Casual Introduction to Sociological Thinking (1963)
  • mhardy6647
    mhardy6647 Posts: 32,922
    Affirmative, Houston. Chinese 2A3s -- but relatively good ones (the TJ/Sophia "meshplates"), as such things go.

    16187805777_019bdb6d9f_b.jpgDSC_0128 by Mark Hardy, on Flickr

    Affirmative, Houston, backup amps (and tubes) are installed and on-line.

    :)

    35012452392_88f03899cc_b.jpgDSC_8376 (2) by Mark Hardy, on Flickr


    FWIW. Here's a forensic photo of the accident scene. Trigger warning - not for the squeamish.

    35011906962_64b4e0d2ff_b.jpgSimple 2A3 after the fire 08Jun17 by Mark Hardy, on Flickr
  • mhardy6647
    mhardy6647 Posts: 32,922
    I couldn't measure the DC resistance of either 2A3 (i.e., they're both at the residual level of the DMM I used, 0.3 ohm) -- so I cannot tell if one is different than the other (i.e., shorted). I don't (hard to believe though it may seem) have a tube tester that can check a 2A3!

    On the bright side, the DCR of both OPT primaries is (are?) identical: 157 ohm. The OPTs seem to be OK.

  • tonyb
    tonyb Posts: 32,902
    Just goes to show...your never too old to blow stuff up. lol
    HT SYSTEM-
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  • ALL212
    ALL212 Posts: 1,553
    edited June 2017
    Well...after looking the picture over it's quite obvious what the issue is here.

    Looks like you used a #4 star washer instead of a #6. Your flummox adapter's are both backwards and you didn't rosin up your bow.
    Aaron
    Enabler Extraordinaire
  • pitdogg2
    pitdogg2 Posts: 24,474
    yuuup^^^^ you nailed by jimminy
  • mhardy6647
    mhardy6647 Posts: 32,922
    youse guyses is good