Second pair of SDA-2As

spongebobsquarepants
edited October 2020 in Vintage Speakers
7etbwypr4kvy.jpg
The cabinets are in much worse shape than my original ones, and someone smothered them in a sticky product to mask their poor condition. I still picked em up for some reason.
«13

Comments

  • F1nut
    F1nut Posts: 46,266
    They may have put that nasty Howard's restore a finish on them, which would be even nastier if the cabinet covering is vinyl.
    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

  • spongebobsquarepants
    edited October 2020
    The left inner mw6510 makes a slappy noise when a bass drum hits.The noise goes away if the driver is disconnected. The dust cap has a weird stain on it. Any ideas?ey79cf8s43o6.jpg
  • F1nut
    F1nut Posts: 46,266
    The white residue is the adhesive used to attach the dust cover. You may be able to remove it with original Windex. Scraping means the magnet has shifted.
    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

  • pitdogg2
    pitdogg2 Posts: 19,451
    Or the spider has come loose
  • zakd2sa0yaiu.jpg
    Popped in this NOS mw6510 I got from ebay a while ago for a spare... and they sound good!

    I wonder if that bad driver is worth messing with or just trash. There's tons of used mw6510 on ebay right now.

    These things must've had some life. Both pin/pin sockets are cracked.

    Thinking about trying mineral spirits on a rag to get this goop off.
  • pitdogg2
    pitdogg2 Posts: 19,451
    If it has slipped a magnet ask @lawdogg he's been successful with that as well as @xschop
  • I was watching it slap away outside of the cabinet, and the spider seems to be securely attached inner and outer, and it has 6.7 ohms across the terminals. Would a slipped magnet throw off the resistance?
  • Gardenstater
    Gardenstater Posts: 2,014
    The spec I see is 6.57 Ohms, so that's pretty close. What does your NOS one measure? The resistance is strictly a matter of the voice coil but I don't know what would happen if the coating were rubbed off of the wires allowing a short through the pole piece. It's not really the magnet that it will rub on but the inner or outer pole piece. If anything I think you'd have a lower resistance that might even vary as you manually move the cone while measuring it.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • F1nut
    F1nut Posts: 46,266
    I was watching it slap away outside of the cabinet, and the spider seems to be securely attached inner and outer, and it has 6.7 ohms across the terminals. Would a slipped magnet throw off the resistance?

    Doubtful, the coil is simply rubbing on the pole.
    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

  • xschop
    xschop Posts: 2,036
    Does the Dust cap look as if it has become detached in the lower right-hand perimeter?
  • smglbrth
    smglbrth Posts: 1,337
    [/quote]

    Doubtful, the coil is simply rubbing on the pole. [/quote]

    Yup, I've had a few drivers go bad (young and dumb with the volume). The slapping sound, or "boinking" as I like to call it, is a sure sign of a bad driver...
  • Gardenstater
    Gardenstater Posts: 2,014
    edited October 2020
    xschop wrote: »
    Does the Dust cap look as if it has become detached in the lower right-hand perimeter?

    Definitely looks to me like it got wet at some point, which wicked upwards through the dust cap material and then white fungus grew on it (probably dead or dormant now), or at the very lest mineral deposits that were in the water. It sure looks funky where it is attached to the cone near the bottom.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • Tony M
    Tony M Posts: 9,907
    edited October 2020
    Did you push outward on the cone from the inside surface and look at the spider while doing so?

    Cones that come way out while playing + flapping...

    Number one reason would be the spider is loose on its frame. ;)
    Most people just listen to music and watch movies. I EXPERIENCE them.
  • pitdogg2
    pitdogg2 Posts: 19,451
    xschop wrote: »
    Does the Dust cap look as if it has become detached in the lower right-hand perimeter?

    Definitely looks to me like it got wet at some point, which wicked upwards through the dust cap material and then white fungus grew on it (probably dead or dormant now), or at the very lest mineral deposits that were in the water. It sure looks funky where it is attached to the cone near the bottom.

    Most Polk speakers get the look and have never been wet. Those do look unusual but not out of the normal white residue I've seen on just about every driver across the board through all drive models
  • xschop
    xschop Posts: 2,036
    I had a 6503 or 6510, dont recall which one that had the white film and did have slight detachment there.
    I chalked it up to fungus as well, as the cabinets looked like they were kept in a humid environment.
  • F1nut
    F1nut Posts: 46,266
    xschop wrote: »
    Does the Dust cap look as if it has become detached in the lower right-hand perimeter?

    Definitely looks to me like it got wet at some point, which wicked upwards through the dust cap material and then white fungus grew on it (probably dead or dormant now), or at the very lest mineral deposits that were in the water. It sure looks funky where it is attached to the cone near the bottom.

    WRONG, WRONG, WRONG!!!
    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

  • xschop
    xschop Posts: 2,036
    F1nut wrote: »
    xschop wrote: »
    Does the Dust cap look as if it has become detached in the lower right-hand perimeter?

    Definitely looks to me like it got wet at some point, which wicked upwards through the dust cap material and then white fungus grew on it (probably dead or dormant now), or at the very lest mineral deposits that were in the water. It sure looks funky where it is attached to the cone near the bottom.

    WRONG, WRONG, WRONG!!!

    Interesting final conclusion posited, Mr Nut. Gstater beat me to the punch, so to speak in coming to his conclusion, and answering. No fungal assays were done on my part, but having retired from biotech, it does indeed look like the a certain species of airborne fungus that would be happy in the fiber cellulose. A perfect carbon-based food source, as we're all familiar with....the Dust cap.
  • Gardenstater
    Gardenstater Posts: 2,014
    edited October 2020
    Yeeesss I concur! (<<<stuffy and pompous Old English accent). Aspergillus Niger perhaps? LOL
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • F1nut
    F1nut Posts: 46,266
    What part of the driver didn't get wet and leave mineral deposits don't you guys understand?
    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

  • xschop
    xschop Posts: 2,036
    F1nut wrote: »
    What part of the driver didn't get wet and leave mineral deposits don't you guys understand?

    Cladosporium doesn't require minerals.

  • xschop
    xschop Posts: 2,036
    Yeeesss I concur! (<<<stuffy and pompous Old English accent). Aspergillus Niger perhaps? LOL

    Or simply some Grey Poupon, good sir.
  • Tony M
    Tony M Posts: 9,907
    I think a "Special Council" needs to be appointed to get to the bottom of that white crud. It will disclose It's chemical compounds and how and why it affects only certain woofer caps.
    :)

    By the way...Jessie's ( @F1nut ) remedy of using Windex on a Q-tip WORKS. ;)

    I removed a lot of the white crud on a bunch of my RTi-12s woofer dust-caps a year ago.


    Most people just listen to music and watch movies. I EXPERIENCE them.
  • DaveHo
    DaveHo Posts: 3,133
    edited October 2020
    xschop wrote: »
    Does the Dust cap look as if it has become detached in the lower right-hand perimeter?

    Definitely looks to me like it got wet at some point, which wicked upwards through the dust cap material and then white fungus grew on it (probably dead or dormant now), or at the very lest mineral deposits that were in the water. It sure looks funky where it is attached to the cone near the bottom.

    So they were stored face down in basement? A Great Dane pissed on them? How does one get water damage way up there? Tend to side with Jessie on this.
  • xschop
    xschop Posts: 2,036
    Half the vintage Polks found on Craigslist look like a dog pissed on them, the other half smell as such.
  • invalid
    invalid Posts: 709
    I've owned my sda2A's since 1987 and never have I seen any white stuff anywhere on them. The drivers all looked like new, but a few were blown.
  • Gardenstater
    Gardenstater Posts: 2,014
    edited October 2020
    Humidity plus airborne mold spores could produce that very thing. Or perhaps it is faerie dust but why does nobody ever see it on the doped cone material, but only on the cellulose material which is a food for fungus and which absorbs and holds moisture? Who cares or knows how the moisture got there?
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • F1nut
    F1nut Posts: 46,266
    Oh for God's sake.....I already told you what it is, but like always you can't stop yourself. Your incessant pondering is beyond old not to mention usually way off base.
    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

  • F1nut
    F1nut Posts: 46,266
    You can LOL all you want, just know that I'm FAR from alone in my thoughts about how you present yourself.
    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

  • Tony M
    Tony M Posts: 9,907
    377slizto8hq.png

    hxvn5e1edicx.png

    WINDEX...

    9euqemia4cxi.png

    o3mpov1smk8u.png

    :)B)
    Most people just listen to music and watch movies. I EXPERIENCE them.