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  1. #1

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    Default Please help clarify.

    I have been looking at the wiring diagrams for the SDA's in the sticky and think I understand them for the most part. I just want to be sure I am seeing something correctly. I will be using the SRS's for reference only though this seems to apply to several different models in their respective series.

    The SRS interconnect connections are reversed internally in the left and right cabinets (the positive signal wire is attached to the top larger blade in one cabinet and to the smaller lower blade in the opposite cabinet) (leaving the other blade connected through a high pass filter to the dimensional array). In the 1.2 and 1.2TL, the negative signal lead is connected to the pin terminal inside BOTH cabinets and the negative side of the dimensional array is connected to the blade terminal in BOTH cabinets. This would have the negative signal lead tied together from 1 cabinet to the other cabinet (something already done in a common ground amplifier if I am not mistaken), and the negative leads front the dimensional array running to the negative leads of the other cabinets dimensional array.

    Is this correct or am I missing something?

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    As best I can follow, you're correct.

    There are AT LEAST two completely different ways that Polk transferred signal from one cabinet to the other.

    On some SDA speakers, there is a full-range, full-voltage signal from one speaker to the other (SDA 1B and SRS 2 blade/blade, for example) which uses two conductors in the SDA interconnect cable. On newer SDAs, they used a single conductor to tie the negative side of the dimensional drivers in one cabinet to the negative side of the dimensional drivers in the other cabinet.

    I rewired my SDA 1Bs to work like the single-conductor schematic; it "works" but sounds a bit "off".

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    Quote Originally Posted by oliverbubbles View Post
    I have been looking at the wiring diagrams for the SDA's in the sticky and think I understand them for the most part. I just want to be sure I am seeing something correctly. I will be using the SRS's for reference only though this seems to apply to several different models in their respective series.

    The SRS interconnect connections are reversed internally in the left and right cabinets (the positive signal wire is attached to the top larger blade in one cabinet and to the smaller lower blade in the opposite cabinet) (leaving the other blade connected through a high pass filter to the dimensional array). In the 1.2 and 1.2TL, the negative signal lead is connected to the pin terminal inside BOTH cabinets and the negative side of the dimensional array is connected to the blade terminal in BOTH cabinets. This would have the negative signal lead tied together from 1 cabinet to the other cabinet (something already done in a common ground amplifier if I am not mistaken), and the negative leads front the dimensional array running to the negative leads of the other cabinets dimensional array.

    Is this correct or am I missing something?
    In my 2.3TL's the blade connection is only for testing/trouble shooting. Can't remember what it's connected to inside the speaker cabinet, but when I installed Cardas BP's for the new IC cable I left that intact. There is mention of this in one of the sticky's for SDA speakers. The pin is the only signal carrying connection.
    "Science is suppose to explain observations not dismiss them as impossible" - Norm on AA; 2.3TL's w/sonicaps/mills, polyswitches removed, Lg Solen inductors, RD-0198's, MW's dynamatted, Armaflex speaker gaskets, H-nuts, brass spikes, Cardas CCGR binding posts, upgraded IC Cable, Black Hole Damping Sheets (3" strips) installed on back wall behind MW's & Tweeters, interior of cabinets sealed, AI-1 interface with 1000VA transformer

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    I rewired my SDA 1Bs to work like the single-conductor schematic; it "works" but sounds a bit "off".
    Schurkey, when you did this , did you bypass the high pass filter (capacitors- I think they are a 130 and 55uf in parallel in that model) in the negative path of the dimensional circuit?

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    Quote Originally Posted by drumminman View Post
    In my 2.3TL's the blade connection is only for testing/trouble shooting. Can't remember what it's connected to inside the speaker cabinet, but when I installed Cardas BP's for the new IC cable I left that intact. There is mention of this in one of the sticky's for SDA speakers. The pin is the only signal carrying connection.
    The blade exists only to supply a ground path for the AI-1 transformer winding. It's connected to the - speaker terminal.

    Quote Originally Posted by oliverbubbles View Post
    Schurkey, when you did this , did you bypass the high pass filter (capacitors- I think they are a 130 and 55uf in parallel in that model) in the negative path of the dimensional circuit?
    Yes. So now you've got me thinking I should re-wire (again) and try the single-conductor cable with those caps in the circuit. I may get around to that...someday. Winter project.

    I used a pair of 91uf (3%) film caps to replace the 130/55 caps when I upgraded the crossover.

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    Yes. So now you've got me thinking I should re-wire (again) and try the single-conductor cable with those caps in the circuit. I may get around to that...someday. Winter project.

    I used a pair of 91uf (3%) film caps to replace the 130/55 caps when I upgraded the crossover.
    Shurkey, I'm confused; you said yes That (I assume)you bypassed the 130/55 caps but then state that you replaced them with 91uf caps. If you replaced them why would you bypass them. Also a 130 and 55 in parallel equate to 185. Did you select 91 since it is roughly half that and the 2 cabinets would effectively be in series? One last question; did you change the values of the inductors and shunt capacitors in the dimensional circuits to compensate for the effective series configuration as well?

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    He said he replaced them with a pair of 91uf caps, a pair would be 182uf. I think he forgot to add the term in parallel.
    Quote Originally Posted by Timothy Smith View Post
    WOW!

    That's like working your way through Katie Perry in order to get to Rosie O'Donnell.

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    Quote Originally Posted by oliverbubbles View Post
    Shurkey, I'm confused; you said yes That (I assume)you bypassed the 130/55 caps but then state that you replaced them with 91uf caps. If you replaced them why would you bypass them. Also a 130 and 55 in parallel equate to 185. Did you select 91 since it is roughly half that and the 2 cabinets would effectively be in series? One last question; did you change the values of the inductors and shunt capacitors in the dimensional circuits to compensate for the effective series configuration as well?
    Quote Originally Posted by Joe08867 View Post
    He said he replaced them with a pair of 91uf caps, a pair would be 182uf. I think he forgot to add the term in parallel.
    Yes, two 91s in each crossover, four caps per speaker pair. 182uf (3% tolerance) vs. "stock" 185uf at--what?--10% tolerance plus 25 years of electrolytic cap degradation.

    I did not deliberately change the values of the caps except for replacing the 4.4uf in the high-frequency crossover board with a 5.8; a modification done to allow the use of the RD0-198 tweeters instead of the SL-2000s. I did not change inductors. The crossovers are built "as normal" so that the older-style stock 2-conductor SDA interconnect can be used. However, I spliced into the wire harness at a point ahead of the double 91uf caps, and added a separate speaker cable terminal. That way I can remove the double-conductor SDA cable and install a single-conductor cable in its place for comparison testing, at a point that bypasses the 182uf of capacitance in each speaker. An AI-1 style transformer could be used by connecting to this "additional" speaker cable terminal, with the other end of the transformer windings connected to the existing - speaker terminals.

    The intention was to modify the 1Bs to accept the AI-1 isolation transformer in order to use non-common-ground amps (a pair of bridged monoblocks) which is not possible with the blade/blade style SDA interconnect. It "works" but doesn't sound right--bass is lean, for example. If I remove the single-conductor cable, and reinstall the stock double-conductor blade/blade, the crossovers function just like Polk intended but with film caps instead of the cheapies.
    Last edited by Schurkey; 09-27-2011 at 03:56 PM.

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    He said he replaced them with a pair of 91uf caps, a pair would be 182uf. I think he forgot to add the term in parallel.
    I wasn't sure if he meant he used a pair in each speaker cabinet or a pair total for both speakers ( since that would equate to roughly the original amount since the 2 cabinets would be run in series once rewired like the 1C's). Sorry I should have been more clear.

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    Quote Originally Posted by oliverbubbles View Post
    I wasn't sure if he meant he used a pair in each speaker cabinet or a pair total for both speakers ( since that would equate to roughly the original amount since the 2 cabinets would be run in series once rewired like the 1C's). Sorry I should have been more clear.
    Crap. Maybe that's what I'm doing wrong...

    [McCoy Voice]Dammit, Jim! I'm a doofus, not an electrical engineer![/McCoy Voice]
    Last edited by Schurkey; 09-27-2011 at 03:56 PM.

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    I wasn't sure if he meant he used a pair in each speaker cabinet or a pair total for both speakers ( since that would equate to roughly the original amount since the 2 cabinets would be run in series once rewired like the 1C's). Sorry I should have been more clear.
    Talk about being a doofus; what i typed there doesn't add up. My logic there was correct but not my addition with those particular caps.

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    I hate when i get my turds all wisted I mean words all twisted..:tongue:
    Quote Originally Posted by Timothy Smith View Post
    WOW!

    That's like working your way through Katie Perry in order to get to Rosie O'Donnell.

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