Help!!!!

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sda2mike
sda2mike Posts: 3,131
edited June 2005 in Vintage Speakers
When I received my SDA 2a's around 2.5 years ago, they arrived by UPS. They were double boxed and took alot to get free.. On the right speaker there was something loose inside.. I don't like to tear into things, because I've been known to break stuff. So, after determining that the speakers sounded fine I left 'em as is.

Fast forward to today. I've been getting myself ready to do the crossover and tweeter upgrade. So, I took off the PR and much to my dismay.....the crossover was lying flat in the bottom of the spkr!!... The 2 black wires that go to the large coil were disconnected!!

My questions: 1) How should the coil face? It's easy to turn by hand.
2) How do I hook the black wires up again?
3) Have I been missing anything - sound-wise?

Thanks guys!!! I know I'll get the right answers here:cool:

Guess What???? I just opened the left speaker and it's the same thing there, too! Crossover laying on the floor, coil disconnected!
Eff UPS!!!
Post edited by sda2mike on
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  • DarqueKnight
    DarqueKnight Posts: 6,765
    edited June 2005
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    1) How should the coil face? It's easy to turn by hand.
    You need to first determine if the threaded hole for the retaining bolt for the large coil is stripped. Carefully turn the bolt while holding the coil with one hand. If you can tighten it securely, great. If it turns and turns and turns, well, you've got a small problem because the coil's threads are stripped. I assume that the coil's threads are not stripped since the coil did not come completely off, but I could be wrong. I once received a pair of SDA CRS+'s that had both coils and crossover boards knocked off (thanks to UPS :mad: ). I repaired the stripped threads in the coil by filling the holes with steel epoxy resin and then redrilling and rethreading them.

    In order to determine the correct orientation for the coil relative to the crossover board, the coil must be removed from the speaker cabinet. There should be four white plastic posts (trelocks) on the coil which match up with four small holes on the crossover board.
    2) How do I hook the black wires up again?
    The wire connection should be obvious since there is only one correct orientation for the crossover board that will properly allign the black wires from the crossover board with the metal flanges of the coil.

    Sometimes the trelocks become damaged in shipping and will no longer hold the crossover securely. In that case binding straps, tape, or some other binding mechanism may be required.
    3) Have I been missing anything - sound-wise?
    Yes, you have been missing a lot. You have not been getting any SDA effect. The large coils in each speaker are in the SDA circuit that sends the inverted signal to the other speaker.
    Proud and loyal citizen of the Digital Domain and Solid State Country!
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  • sda2mike
    sda2mike Posts: 3,131
    edited June 2005
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    Hi! Thanks for your reply!!! The coils are not stripped.. I positioned the board on the coils, but, it is not obvious to me where the black wires go..on the coil, one wire runs to the inside and the other to the coil itself...of course on the board bothe wires are black :confused:
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  • DarqueKnight
    DarqueKnight Posts: 6,765
    edited June 2005
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    Unless one tab (flange) was broken off, there should be two metal tabs on the coil, one for each black wire. If one of the tabs was broken off, you can repair it with a little solder. The tabs are located on a very small board that is attaced to top outer edge of the coil spool with a rivet.

    Also, for future requests for assistance, you will get quicker and more responses if you use a more descriptive title in your posts.
    Proud and loyal citizen of the Digital Domain and Solid State Country!
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  • sda2mike
    sda2mike Posts: 3,131
    edited June 2005
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    the tabs were'nt broken..the only problem is, they're identical. on the board the wores are marked 'p' and 'r', i think...the coil connectors, however are not marked..:confused:
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  • DarqueKnight
    DarqueKnight Posts: 6,765
    edited June 2005
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    The inductor coil is a non-polarized component, and as such, it will work properly regardless of the way it is oriented in the circuit (just like a resistor, or non-polarized capacitor).

    The order of the wires on the board corresponds to the order they are connected on the coil. However, the inductance value of the coil would not change if the tab connections were reversed. That is why there are no orientation markings on the wires or coil tabs.
    Proud and loyal citizen of the Digital Domain and Solid State Country!
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  • sda2mike
    sda2mike Posts: 3,131
    edited June 2005
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    great! that's what i was looking for!!! here i go! i wonder if i'll fall in love all over again with these beauties?
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  • sda2mike
    sda2mike Posts: 3,131
    edited June 2005
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    DarqueKnight,
    Thanks for your help!! I got everything back together. I don't notice a difference, though. Before I noticed the disconnected coils, I was getting an SDA effect. I did the balance test. So, what do the coils do?:confused:
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