SDA-2B Crossover Questions

electricvalve
electricvalve Posts: 5
edited April 2009 in Vintage Speakers
I am new to the SDA concept and have a few questions. I have acquired a set of SDA 2B.

1. According to the crossover schematic there is an external coil at point P and R. Both crossovers are shorted together at these points with no parts. Do I need this for the SDA to work properly?
2. I read that by not using the interconnect cable only one of the vertical arrays will work. Both arrays seam to work without the cable in use. Is this because P and R is shorted?
3. My crossovers only has one wire used in the interconnect cable rather than two. Thats why I think they are the 2B going by the schematic, the label on the cabinet only says SDA 2. What is the difference in not connecting the negatives of both speakers together as in the CRS schematic?
4. Both crossovers are hanging by the wires. Should they be mounted to the cabnet in some fashion?

Thanks for any information. I have looked around for this info with no success. They sound great now but looking forward to enjoying these at there full potential.
Post edited by electricvalve on
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Comments

  • ben62670
    ben62670 Posts: 15,969
    edited April 2009
    If p is shorted to r then both sets of drivers will run full range.
    The one wire for the IC is indicative of the 2b's.
    Those XO's do need to be mounted.
    The SDA really needs to be fixed
    Do you have the IC cable?
    Where are you located?
    Welcome to Club Polk.
    Ben
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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  • electricvalve
    electricvalve Posts: 5
    edited April 2009
    Ben, Thanks for the welcome.
    Do I need to disconnect P and R for the SDAs to work properly?
    No, I don't have the I.C. cable but I think I can make one with blade type crimp connectors and a wire.
    I'm in Albany, KY
    Paul
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  • F1nut
    F1nut Posts: 50,746
    edited April 2009
    P and R need to be connected to the large inductor in order for the SDA to work. Of course, you'll need the IC to benefit.
    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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  • electricvalve
    electricvalve Posts: 5
    edited April 2009
    I can produce the IC but I did not get any inductors with the 2Bs. The P and R wires were just tied together. Someone must have removed them. What is the coil value? The schematic is hard to read, look like 10 Gauge, 16 mH. Can I get these inductors or possibaly make them?
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  • F1nut
    F1nut Posts: 50,746
    edited April 2009
    It's 18 gauge, 16 mH. You'll have to have them custom made, Polk no longer sells them.
    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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  • Face
    Face Posts: 14,340
    edited April 2009
    Give these guys a call: http://madisound.com/

    They can make a custom pair for you.
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • electricvalve
    electricvalve Posts: 5
    edited April 2009
    Thanks, I'll look around for info. to custom make these.
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  • ben62670
    ben62670 Posts: 15,969
    edited April 2009
    I have a pair of inductors.
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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