Think I fried my speaker -- what else might have fried along with it?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by bizzwriter, Dec 21, 2009.


  1. bizzwriter

    bizzwriter Member

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    735
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    left coast...
    Had a jam session last night with a new guitarist. Wanted my '67 Princeton Reverb to SHINE, so I put in one of those THD 10" speakers that Andy Marshall was selling on ebay for cheap last month. It's only rated for 10 watts, but he said it should hold up in a Princeton Reverb.

    I don't think so.

    We were doing a cooking dual lead thing -- southern rock-ish -- and I twisted the volume from 4 to 7 to keep up with the other guy. A few seconds later *ZAP* -- my output went to almost nothing. A little smoke and stink. I cut off the amp about 10 seconds later.

    So, I think I fried the speaker -- never blown one before. I'm going to pull the speaker tomorrow and drop the chassis to see if anything else got toasted along the way.

    Any advice on what else might have happened, or what I should look for inside the chassis?

    Cheers! :drink
     
  2. TweeDLX

    TweeDLX Member

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    Make sure that the speaker is the problem. Should read an ohmage close to it's stated rating. If it reads "0", atsa no good. Smoke and stink make me think it's something more than that. Look at the tube sockets for burn marks.

    Mike
     
  3. gitarzilla

    gitarzilla Member

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    What kind of 6V6s are you using? Sounds more like you smoked one of those along with an accompanying reisitor. Pretty rare for a speaker to go with smoke and stink. Hook the speaker up to another working amp and if it sounds OK, try hooking up the Princeton's brain to a working speaker -- test both variables against known good quantities.
     
  4. bizzwriter

    bizzwriter Member

    Messages:
    735
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    Thanks for the tips guys -- I'll check the speaker continuity/ohms with my voltmeter in just a bit.

    In addition to putting in the new speaker (which sounded GREAT, by the way, until my amp went up in smoke), I pulled the JAN Phillips 6V6GTs and popped in a couple of my old (1951) Visseaux 6V6GTs (which ALSO sounded GREAT).

    I'll also do a separate test by plugging the amp into my 1x12" cab.

    Hope it's no worse than a toasted resistor and/or tube...before I turned off the amp, both 6V6s were glowing so I thought they might be okay.
     
  5. SatelliteAmps

    SatelliteAmps Member

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    Smoke is almost always a capacitor. Occasionally a transformer. Rarely a resistor, even rarer would be a speaker coil.

    Does the amp have original caps in it?
     
  6. bizzwriter

    bizzwriter Member

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    735
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    No -- caps were changed out before I bought it 7 or 8 years ago on ebay. I've still got the old caps the guy sent me in a bag. I guess if a capacitor blew, it will be pretty obvious once I drop the chassis!
     
  7. bizzwriter

    bizzwriter Member

    Messages:
    735
    Joined:
    Jul 15, 2006
    Location:
    left coast...
    Good news -- it was indeed a fried speaker.

    I first checked the continuity of the speaker with my voltmeter -- 0 ohms.

    I then ran a speaker cable from the speaker output of the amp to my 1x12 speaker cabinet with Weber blue dog. Worked great.

    I'm bummed the THD speaker didn't stand up to the PR at full tilt. It sounded really good until it fried. I've fortunately still got the original Jensen -- it's going back in tomorrow.

    Thanks again for the advice!
     
  8. donnyjaguar

    donnyjaguar Member

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    Just chalk it up to a Spinal Tap moment. :)
     
  9. RGB

    RGB Supporting Member

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    We flamed a JBL 15 once...voice coil got so hot it actually started the cone on fire!

    Glad to hear your amp's ok!
     

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