Somethings burning up HELP!!!

Discussion in 'Amps [BG]' started by Mktrat, Jun 29, 2013.


  1. Mktrat

    Mktrat Wait. What?

    Joined:
    Apr 9, 2013
    Location:
    Berkley, MI
    I was running my Hartke 3500 head into a SWR Goliath I and suddenly it smelled like a campfire.

    I had a small amount of smoke coming from the rear port.

    Where do I start?

    I don't know what went wrong. I have a little knowledge about speakers and cabs but I really don't know where to start.

    I also don't know how to test individual speakers crossovers or tweeters.

    Please HELP!!!
  2. 1958Bassman

    1958Bassman

    Joined:
    Oct 20, 2007
    How loud was it? If you say it wasn't loud, the number of assumptions about what happened is limited. Among them, your hearing has been damaged by high SPL, the amp may have died and taken the speakers along with it or your opinion of "not too loud" needs context.

    Speakers have a thermal limit and you have apparently found it. Crossover capacitors have a voltage limit, but when they go, it doesn't smell like a campfire. Usually.

    The first thing you would need to do is remove the jack plate from the cabinet and do a visual inspection. If you see anything that's obviously damaged, you may have found the whole problem. If a cap went away, it may have bulged ends, the rubber/aluminum may have popped out or the aluminum shell may have burst. If the last one happens, you'll see shredded cardboard and maybe some foil. If the crossover looks normal, use your nose to search for the source of the smell. If the crossover seems to be OK, you'll have to check the speakers- if the woofer has a vented voice coil, you may see a hold in the rear of the magnet. Sniff around that and if you smell the same thing as when you noticed the smoke, you'll want to measure the speaker's resistance and check for rubbing. If you saw smoke, plan on replacing or reconing the speaker now, or soon. If you measure the resistance and it's far less than what's on the label, repair it- don't connect it to the amp until this is done. BTW- measuring the resistance won't show the same numbers as the impedance- most 4 Ohm speakers will show about 3.2 Ohms, most 8 Ohm will show about 6.4 Ohms and most 16 Ohm speakers will show 12-14 Ohms. This difference isn't a problem, it's the DC resistance. Impedance is a characteristic involving resistance to alternating current and this will vary with frequency.
  3. Jim Carr

    Jim Carr Dr. Jim Gold Supporting Member

    Joined:
    Jan 21, 2006
    Location:
    Denton, TX or Kailua, HI
    It is possible that you burned out the fuse bulb for the tweeter. Were you using effects?

    Assuming the 410 drivers are not cooked, fire it up, and listen to each driver and the foster horn/tweeter. If you are lucky, only the tweeter is not working. Yes, you will need to sit in front of it and put your ear next to each driver. Obviously you will want to play very softly. Crank the highs to test the tweeter.

    I had a gII, and am assuming that the design (Eden built), is the about same—iirc only the 410 drivers and cabinet dimensions were upgraded for the gII.

    Remove the back panel where the input plate is. There should be a small light bulb (yes, an actual light bulb) wired into the circuit. Remove it carefully, keeping it fully intact. Take it to a good hardware store and buy 2 replacements. Replace it.

    Don't play with effects as loudly or slap without a compressor. Carry on.
  4. Hankenstein

    Hankenstein Supporting Member

    Joined:
    Jul 7, 2010
    Location:
    Piermont, New York
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  6. Mr. Foxen

    Mr. Foxen

    Joined:
    Jul 24, 2009
    Location:
    Bristol, UK
    Disclosures:
    Amp tinkerer at Ampstack
    Some cab lining burning on hot crossover.
  7. Mktrat

    Mktrat Wait. What?

    Joined:
    Apr 9, 2013
    Location:
    Berkley, MI
    I could only get so lucky!


    The obvious first choice.

    No effects, compressor on the amp in use.

    It was running on 7, so not maxed out but as far as I was willing to push it.

    After unplugging it, I removed the grill and gently pressed on each of the woofers. One of them has more resistance in relation to its brethren. I just didn't know how to verify that before I started paying someone to probe my cab.

    I think the amp is still okay. I have to borrow a cab to check it.


    The dissection will begin shortly.


    Thank-you to all you guys (or gals I can never really be sure on TB) for your help.
  8. 1958Bassman

    1958Bassman

    Joined:
    Oct 20, 2007
    Sounds like one of the woofers has a problem- test its resistance ASAP.

    Your car's accelerator goes all the way to the floor- would you stomp on it and drive that way all day long? No, of course not. Does it make sense to turn your amp wide open? No, of course not. FYI- your amp won't develop full power at 10, it does that well before that point. You need to learn how to listen for distortion and use your amp the way it was intended.
  9. Mktrat

    Mktrat Wait. What?

    Joined:
    Apr 9, 2013
    Location:
    Berkley, MI
    I was listening for distortion.

    I didn't hear any.

    Thanks for your help. I'll pull the speaker and check it.
  10. anderbass

    anderbass

    Joined:
    Dec 20, 2005
    Location:
    Phoenix. Az.
    The crossover in my old goliath II cab actually caught on fire after I'd used it with the L-pad knob turned all the way down for several years. If you remove those 4-screws, you'll find the wires are long enough so you can pull the L-pad assembly out a few inches to see if it looks/smells burnt like mine was.

    If you want to bypass the L-pad/tweeter in your cab, you'll find its pretty simple procedure to make the connection between the 10" speaker wires and the input jack. I didn't have to cut/splice any wires, I just swapped them around to different positions where they plug into the L-pad. Just make sure you keep the same (+/-) polarity, so your cab wont be out of Phase if used with another cab.
  11. Mktrat

    Mktrat Wait. What?

    Joined:
    Apr 9, 2013
    Location:
    Berkley, MI
    Finally got around to peeking under the hood of my cab.

    Tweeter bulb is blown. Does this HAVE to be replaced?

    Or would that basically bypass the tweeter?
  12. Downunderwonder

    Downunderwonder

    Joined:
    Aug 26, 2009
    Location:
    New Zealand
    No bulb, no tweeter. I'd still be looking into the suspect woofer.
  13. Mktrat

    Mktrat Wait. What?

    Joined:
    Apr 9, 2013
    Location:
    Berkley, MI
    i am not done sniffing around yet.....tweeter could have been blown forever never really got down in front of the cab.
  14. Mktrat

    Mktrat Wait. What?

    Joined:
    Apr 9, 2013
    Location:
    Berkley, MI
    Tweeter bulb blown crossover/hpf toast. All 4 drivers working great! I'm using it as is. It sounds great!!

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