Question about Tweeter on SDA2

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BonnyM
BonnyM Posts: 17
edited November 2020 in Vintage Speakers
2ukphtmpn9ji.jpeg
Hello,
My first question in this forum (just joined).
I recently bought a pair of SDA2s.
One tweeter (SL1000) does not work. Guy selling did not disclose obviously:(
I have 2 extra SL1000s. Tried them too. None worked.
Tried swapping fuses on back too. What could be wrong? Will Appreciate help.
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  • Gardenstater
    Gardenstater Posts: 4,949
    Answer โœ“
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    If you put in MW6501 Polk there are 3 sellers on eBay right now. Polk hasn't sold these drivers for a number of years and they don't support them anymore. eBay is your best bet.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    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
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  • Gardenstater
    Gardenstater Posts: 4,949
    edited December 2020 Answer โœ“
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    I honestly would stick with the MW6501 rather than trying to substitute an MW6500 or MW6503. There are small differences in the Thiele Small Parameters, namely DC resistance and Total Q:

    https://forum.polkaudio.com/discussion/133992/thiele-small-parameters-for-mw6500-drivers

    I cannot personally vouch for those Midwest Speaker or Parts Express speakers that may purport to be the best available match for certain MW Polk models. That would be a bit risky in my opinion. Just make sure if you buy from a eBay seller to ask them if there is any voice coil rubbing and to tell you what the DC Resistance is if possible for them and to ask them to ship them with plenty of cushioning so that the magnets don't get jarred and shift during shipping.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    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
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Answers

  • BonnyM
    BonnyM Posts: 17
    edited November 2020
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    Picture attached.
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  • Gardenstater
    Gardenstater Posts: 4,949
    edited November 2020
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    I'd dig out the DVOM and start tracing the circuitry, continuities and resistances, using the schematic as a reference and do the resistance checks in the SDA Manual.

    wfu9k1vz5ipp.png

    iqw0lfi4mxii.png
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    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
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  • BonnyM
    BonnyM Posts: 17
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    @pitdogg2 Thank you. The cable is connected. Both tweeters on RH channel are working.
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  • BonnyM
    BonnyM Posts: 17
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    @Gardenstater Thanks a lot. I have never done such checks and repair....I could try I guess. Might be too much for me to handle ;) ๐Ÿ˜
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  • Gardenstater
    Gardenstater Posts: 4,949
    edited November 2020
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    It's not hard. Maybe you can get a friend with a little electronics experience to help out but if not we could walk you through it. First step get any old cheap meter and practice checking continuity and resistance with it on things like a light bulb or a paper clip.

    Even without a meter you could try swapping that RDO-194 (?), or lets just say the tweeter on the right with the SL-1000 in the problem speaker and see if the problem persists at the same location or if it follows the driver.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    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
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  • F1nut
    F1nut Posts: 52,406
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    Be thankful, SL1000 tweeters are horrible.
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  • tonyp063
    tonyp063 Posts: 1,157
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    I may not be remembering correctly, but isn't disconnecting that tweeter on that version SDA a recommendation in some threads here?
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  • BonnyM
    BonnyM Posts: 17
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    @Gardenstater Thank you Thank you. I will try next week :)
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  • xschop
    xschop Posts: 5,861
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    tonyp063 wrote: ยป
    I may not be remembering correctly, but isn't disconnecting that tweeter on that version SDA a recommendation in some threads here?

    I believe I've read that multiple times here also.
    Don't take experimental gene therapies from known eugenicists.
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  • BonnyM
    BonnyM Posts: 17
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    I think, based on feedback, Iโ€™ll leave this tweeter non-operational. I removed the fuses for 2 SDA tweeters. Much better (was muddled before).
    Appreciate responses.
    I will now try swapping the one non-operational speaker with working one to see if issue follows.....Will reach back with any questions ๐Ÿ™‚
    ๐Ÿ™๐Ÿ™
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  • BonnyM
    BonnyM Posts: 17
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    Another question:i need one woofer for SDA2. I think it is MW6501. Where should I get it from? Polk?
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  • BonnyM
    BonnyM Posts: 17
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    Thank you @Gardenstater
    I assume it is better to go with 6501 rather than 6503. Right!
    ?
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  • BonnyM
    BonnyM Posts: 17
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    Or any other options (w/o much compromise) on sites like Parts Express? @Gardenstater
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  • BonnyM
    BonnyM Posts: 17
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    Thanks so much @Gardenstater
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  • BonnyM
    BonnyM Posts: 17
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    @pitdogg2
    Thank you. So, MW6600 is same or are we losing something bu using them instead of MW6501?
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  • BonnyM
    BonnyM Posts: 17
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    @pitdogg2 Also, what do you mean by proper 650x? X could be anything from 1 to 9??
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  • F1nut
    F1nut Posts: 52,406
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    BonnyM wrote: ยป
    @pitdogg2
    Thank you. So, MW6600 is same or are we losing something bu using them instead of MW6501?

    As stated, the 6600 and 6501 can be interchanged, which means you can swap them without issue.
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  • BonnyM
    BonnyM Posts: 17
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    @F1nut Thank you.
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  • BonnyM
    BonnyM Posts: 17
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    Thanks @pitdogg2
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