Tumult make my amps shut down...

Discussion in 'Home Theater Projects' started by Greg Yeatts, Jun 7, 2003.

  1. Greg Yeatts

    Greg Yeatts Second Unit

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    My Tumult makes my amps shut down at relatively low levels. Heres the story. I hooked my Tumult up to my Keiga 52100 (1,000 watts @ 4 ohms). I calibrated it to my mains, center etc at 70 db. This corresponds to a level of about 70 on my receiver. I then put in the pod race scene on Episode I and increased the level to about 75 on the reciever. This is about 10 db below reference level. My amp shut down. I unplugged everything and checked the woofer out of the box as well. The amp will make the sub move about 2mm. Any more input and the amp shuts down. I checked the Tumult on a 150 watt plate amp, and that amp shut down as well. I hooked my DVC 12" from PE up to the Keiga and the Keiga would make that sub go crazy. Lots of excursion. A 150 watt amp or a 1000 watt amp should be able to get a healthy amount of excursion from a woofer in no box. Anbody have any ideas?

    I checked my wiring on the Tumult. The coils are wired in series. That is positive goes into one positive terminal. The negative wire from that terminal is then wired to the positive terminal of the second VC. The the negative terninal of the second VC is wired to the negative terminal on the amp. There are no loose strands of wire from post to post, or to the connectors on the amp. What else can I do to trouble shoot this?

    TIA
     
  2. Seth_L

    Seth_L Screenwriter

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    Break out a multimeter and check for a short in your wiring or one of the VCs?
     
  3. Brian Fellmeth

    Brian Fellmeth Supporting Actor

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    Get hold of a multimeter as suggested above. Set for resistance, max sensitivity. Touch the leads and calibrate to zero ohms or note the level as an offset. Then out the leads on the amp lugs (amp off). You should get about 3 ohms. If its less, unwire the driver and measure the DCR of each VC- should be close to 1.5 ohms each.
     
  4. Greg Yeatts

    Greg Yeatts Second Unit

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    I measured the resistance of each coil independantly, then in series. Each coil measured 1.6 ohms. Strangely enough, when in series, they measured 2.5 ohms. I was expecting 3.2 ohms. This may be the problem. I doubt that the amp is stable at 2.5 ohms. Any advice?

    I measured the resistance using my rat shack multi meter and my Tenma LCR meter. The results were consistent from meter to meter.
     
  5. Brian Fellmeth

    Brian Fellmeth Supporting Actor

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    Sounds like there may be a short between a portion of the voice coils. This can be tested. Look at the resistance between the plus of coil A and both lugs of coil B, then the minus of coil A and both lugs of coil B. All 4 of these DC resistances should be infinity.
     
  6. Greg Yeatts

    Greg Yeatts Second Unit

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    Brian

    You Da Man. Sorry about that. You were right. The voicecoils are shorted. I checked the resistance between the positive terminal of coil A and the positive terminal of coil B and got a reading of 1.8 ohms. I also got a reading of 2.5 ohms from the positive terminal of coil A to the negative terminal of coil B. All of these measurements were with the connector that I used for the series connection of the voicecoils removed. The giveaway was that the results with or without the series conector are similar. I guess I will try to get Adire to fix this thing.

    I wonder if this happens often. I was just testing the driver at low level and it wouldn't really play.
     
  7. Sounds like a manufacturer problem is you only played it at low levels. Shorting coils from user abuse only really happens when you crank it so much that the coils heat high enough to melt the enamel on the views.
     

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