MW6510 impedance fluctuation

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stubby2
stubby2 Posts: 47
in Vintage Speakers
Long time since I've posted, lots of things going on.
I just picked up a pair of SRS 2.3TL that need a little help. 3 tweeters were blown and will be replacing them with 098's.
All the midwoofers are free and move smoothly. I have measured the resistance on 5 of them so far and with 4 of them the impedance jumps from 5.9 to 8.4 ohms. 1 has measured a steady 8.1 ohms.
I have already rebuilt the crossovers and that has helped with clarity. I stole the 098 tweeters from my 3.1TL and used the remaining good measuring SL3000. Sound is not right yet and I'm guessing the 6510's that measured squirrely are part of the problem.
Any thoughts?

Stubby
Polk SDA SRS 2A
Aragon 8008X3
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Comments

  • xschop
    xschop Posts: 5,746
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    Hmmm... I call meter anomoly.
    Don't take experimental gene therapies from known eugenicists.
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  • F1nut
    F1nut Posts: 52,305
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    They should measure 6.5 ohms.
    Political Correctness'.........defined

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  • stubby2
    stubby2 Posts: 47
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    I considered the volt meter might be flakey, it's possible but I did get steady readings from the tweeters and at the speaker terminal binding posts. (3.5 ohms)
    Looks like I should start looking for some new(er) 6510's. None of them registered 6.5 ohms consistently.
    Also, when I did the left/right balance test for proper SDA function, the dimensional drivers were barely audible. Barely.
    Polk SDA SRS 2A
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  • F1nut
    F1nut Posts: 52,305
    edited August 23
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    The dimensional drivers play at a reduced volume compared to the stereo drivers.

    You did disconnect the drivers before testing, right?
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

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  • stubby2
    stubby2 Posts: 47
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    F1nut wrote: ยป
    The dimensional drivers play at a reduced volume compared to the stereo drivers.

    You did disconnect the drivers before testing, right?

    I was pretty sure that was the case with the dimensional drivers, these seem to be particularly low output. Had to put my ear just a few inches away from them to hear anything.
    I did disconnect them. ๐Ÿ™‚
    Polk SDA SRS 2A
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  • Gardenstater
    Gardenstater Posts: 4,886
    edited August 23
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    First off I would try another meter if you have one, and/or put fresh batteries in this one because DC resistance (not impedance ๐Ÿ™‚) should 6.57 Ohms. Are the driver's voice coils scuffing or rubbing at all when you manually move the cones? I think those MW6510s have a really high compliance and may be likely to over extend or have the suspensions wear out. Even if no rubbing detected, I'd also try measuring the resistance with the cone in different positions to see if that changes the measurement. 3rd I'd check the tinsel lead connections at the terminals. If that doesn't yield the answer, I'd cut the dust caps off and look at the connections there. Heck I'd be installing Rob's phase plugs anyways on the good ones so that's just the first step ๐Ÿคฃ
    George / NJ

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  • F1nut
    F1nut Posts: 52,305
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    stubby2 wrote: ยป
    F1nut wrote: ยป
    The dimensional drivers play at a reduced volume compared to the stereo drivers.

    You did disconnect the drivers before testing, right?

    I was pretty sure that was the case with the dimensional drivers, these seem to be particularly low output. Had to put my ear just a few inches away from them to hear anything.
    I did disconnect them. ๐Ÿ™‚

    Possibilities, wiring/connection/polarity issues, crossover components in the wrong place, bad drivers. Are the red binding posts on the left or right?

    Post some pics of the crossovers, etc.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • stubby2
    stubby2 Posts: 47
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    Well I feel a little stupid. Nothing new, but I always hoped I would get better.
    ALWAYS double check your work!!
    Polk SDA SRS 2A
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  • F1nut
    F1nut Posts: 52,305
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    What did you find?
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • stubby2
    stubby2 Posts: 47
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    On the right channel I managed to swap 16 uF cap with 18uF cap.
    And don't give any hassle with the Solens. ๐Ÿ˜‰
    Polk SDA SRS 2A
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  • stubby2
    stubby2 Posts: 47
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    Lol, post 45 was supposed to have pics.
    Polk SDA SRS 2A
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  • F1nut
    F1nut Posts: 52,305
    edited August 23
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    That'll do it. Glad you found the issue. Still doesn't explain the driver readings though.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • stubby2
    stubby2 Posts: 47
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    Thanks to everyone who chimed in!

    And that is true about the driver readings. Burn one bridge at a time !
    Polk SDA SRS 2A
    Aragon 8008X3
    Aragon Soundstage
    Multiple Digital Sources
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