SDA 2 Crossover

SDA2Guy
SDA2Guy Posts: 26
edited November 2008 in Troubleshooting
My SDA 2 speakers came out of the closet where they sat since 1995. Close examination revealed the left channel bass driver was not operating. Wired directly to the speaker cable it worked fine. So the problem must be with the crossover, right?

Does anyone have ideas or experience with fixing this sort of thing?
Post edited by SDA2Guy on
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  • ben62670
    ben62670 Posts: 15,969
    edited September 2008
    Welcome to club Polk. Where are you located? Did you have the IC cable hooked up?
    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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  • SDA2Guy
    SDA2Guy Posts: 26
    edited September 2008
    I am located in Jacksonville, Florida, just a few hours south of you. Yes, the IC cable is hooked up. I have read that there are instructions posted somewhere here by do-it-yourselfers who have repaired their SDA crossovers. Since the bass driver is not part of the SDA circuit it may be a simpler fix, I don't know. I'm guessing it's a bad cap, but I have no real knowledge to draw upon. What is your assessment?
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  • fbm211
    fbm211 Posts: 1,488
    edited September 2008
    You could pull out the xover and inspect it to make sure there are no broken leads.I had a problem sort of like that and ben helped me isolate the problem by using a multi meter.One of my inductors had broken leads.Resoldered them back onto the board and problem solved.
    SDA-2BTL with custom IC
    Adcom 565 monoblocks--Monarchy Audio M-10 preamp
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    Revelation Audio Labs Prophecy Cryo-Silver Reference AES/EBU
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  • ben62670
    ben62670 Posts: 15,969
    edited September 2008
    Which IC cable is it? pin blade, or blade blade?
    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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  • SDA2Guy
    SDA2Guy Posts: 26
    edited September 2008
    It's the blade blade style.
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  • SDA2Guy
    SDA2Guy Posts: 26
    edited September 2008
    So, what, is this a bad style? I need help to find the articles that will guide me through the process of fixing this crossover. So far I have not found those that were referred to.
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  • read-alot
    read-alot Posts: 812
    edited September 2008
    Which bass driver are you refering to?
    polkaudio SRS (rdo194 x 8)
    Dodd ELP (separate power supply)
    JC 1 blocks ( strapped )
    Rega Apollo
    MIT (speaker cables) Outlaw (ICs)

    polkaudio SDA2(rdo194x4) (front) polkaudio CRS (rdo194x4)(rear) polkaudio 400i (center)
    B&K 505
    Samsung LCD
    VIP 622
    HSU STF-2
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  • ben62670
    ben62670 Posts: 15,969
    edited September 2008
    Do you have 3 6.5" woofers, or two. I am going somewhere with this;)
    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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  • read-alot
    read-alot Posts: 812
    edited September 2008
    ben62670 wrote: »
    Do you have 3 6.5" woofers, or two. I am going somewhere with this;)

    I was already there.
    polkaudio SRS (rdo194 x 8)
    Dodd ELP (separate power supply)
    JC 1 blocks ( strapped )
    Rega Apollo
    MIT (speaker cables) Outlaw (ICs)

    polkaudio SDA2(rdo194x4) (front) polkaudio CRS (rdo194x4)(rear) polkaudio 400i (center)
    B&K 505
    Samsung LCD
    VIP 622
    HSU STF-2
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  • SDA2Guy
    SDA2Guy Posts: 26
    edited September 2008
    The left bass driver is not operating but the speaker is good, so the crossover has got to be the culprit. The two mid woofers are operating okay. So, in summary, there are 3 total 6.5" drivers per side.
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  • ben62670
    ben62670 Posts: 15,969
    edited September 2008
    Sounds like a bad connection, or inductor. If you pull the PR from the cabinet you should have plenty of access to the XO. Most likely there is a loose wire in there. Another easy test is to take a multimeter, and test from the pos speaker terminal on the back to the pos terminal on the bass driver. Negative is white. Let us know what you find.
    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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  • read-alot
    read-alot Posts: 812
    edited September 2008
    Or it could be the Dimensional Array driver not firing with the stereo drivers.
    polkaudio SRS (rdo194 x 8)
    Dodd ELP (separate power supply)
    JC 1 blocks ( strapped )
    Rega Apollo
    MIT (speaker cables) Outlaw (ICs)

    polkaudio SDA2(rdo194x4) (front) polkaudio CRS (rdo194x4)(rear) polkaudio 400i (center)
    B&K 505
    Samsung LCD
    VIP 622
    HSU STF-2
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  • ben62670
    ben62670 Posts: 15,969
    edited September 2008
    Well if it is the bass driver(the lower one) it has nothing to do with the dims. It only has an 11.2mh inductor between it, and the speaker terminal.
    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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  • read-alot
    read-alot Posts: 812
    edited September 2008
    ben62670 wrote: »
    Well if it is the bass driver(the lower one) it has nothing to do with the dims. It only has an 11.2mh inductor between it, and the speaker terminal.

    That was why I asked my question, I've owned SDA2 speakers for 21 years.
    polkaudio SRS (rdo194 x 8)
    Dodd ELP (separate power supply)
    JC 1 blocks ( strapped )
    Rega Apollo
    MIT (speaker cables) Outlaw (ICs)

    polkaudio SDA2(rdo194x4) (front) polkaudio CRS (rdo194x4)(rear) polkaudio 400i (center)
    B&K 505
    Samsung LCD
    VIP 622
    HSU STF-2
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  • SDA2Guy
    SDA2Guy Posts: 26
    edited September 2008
    Thanks, Ben. Will the multimeter reading for a bad inductor be the same as that for a bad connection?
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  • Face
    Face Posts: 14,340
    edited September 2008
    SDA2Guy wrote: »
    Thanks, Ben. Will the multimeter reading for a bad inductor be the same as that for a bad connection?
    A standard multi-meter can't test a inductor. You'll need a meter that can read inductance.

    You need(I need one too) a LCR meter. http://en.wikipedia.org/wiki/LCR_meter
    "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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  • ben62670
    ben62670 Posts: 15,969
    edited September 2008
    If you can take the reading, and let me know. I can go from there. A bad inductor can go bad in two different ways. Either open, or shorted. Seeing it isn't playing at all I would assume it is open, or there is a bad connection.
    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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  • ben62670
    ben62670 Posts: 15,969
    edited September 2008
    Face wrote: »
    A standard multi-meter can't test a inductor. You'll need a meter that can read inductance.

    You need(I need one too) a LCR meter. http://en.wikipedia.org/wiki/LCR_meter

    True, and false;)
    With the ohm rating I can compare it to the ones I have here. If the DCR is like .5ohms we know he has a short in it, but if it is 1.8-2.3 ohms we can assume that the coil is good:) Also if he does the same test on both speakers and get the same DCR we know its good.
    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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  • SDA2Guy
    SDA2Guy Posts: 26
    edited September 2008
    Okay, then, I shall obtain a multimeter and see what data comes up. As my experience is limited, do you have a recommendation for a good (but cheap) unit?
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  • ben62670
    ben62670 Posts: 15,969
    edited September 2008
    Any digital multimeter will suffice for the average guy. You should be able to find one at Rat Shack, Lowe's, or home depot for $20 or less. These are useful around the house for many other things including checking batteries. Car batteries too.
    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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  • SDA2Guy
    SDA2Guy Posts: 26
    edited September 2008
    Thanks, I'll let you know.
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  • ben62670
    ben62670 Posts: 15,969
    edited September 2008
    2 more post, and you can PM :)
    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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  • SDA2Guy
    SDA2Guy Posts: 26
    edited September 2008
    Would I be penalized for a gratuitous post toward that end?
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  • ben62670
    ben62670 Posts: 15,969
    edited September 2008
    Nope. Everyone can see you are here for a reason;)
    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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  • SDA2Guy
    SDA2Guy Posts: 26
    edited September 2008
    Thanks, then, toward that end I shall buy a cheap but adequate device tomorrow and let you know what I find. It would really make me happy to fix this problem and get on with listening to the music.
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  • ben62670
    ben62670 Posts: 15,969
    edited September 2008
    BTW you can't PM Polk Guru's till you have 100 posts.











    J/K:p
    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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  • SDA2Guy
    SDA2Guy Posts: 26
    edited September 2008
    Ben, I removed the PR and inspected all wires and connections and found them to be sound. Using my new EXTECH pocket multimeter ($26+tax at Lowes) I ran both resistance and continuity tests. This is my first try at this so forgive me if I'm heading down a wrong path. :( The speaker terminals on the back are not labeled + and - so I assume the red terminal is positive. You had said the black wire to the woofer was positive. I decided it wouldn't hurt to measure all possible combinations - I think the first is the correct one - let me know. The first number is resistance, 2nd is continuity:
    Red terminal to black wire: 2.2, 2.5
    Red terminal to white wire: 11.5, 11.8
    Black terminal to black wire:13.6, 13.9
    Black terminal to white wire: 0, 0.4
    Hopefully you'll be able to make sense of this. Let me know.
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  • ben62670
    ben62670 Posts: 15,969
    edited September 2008
    The first set of measurements is what I needed. Just to be thorough. The red terminal to the black wire of the speaker that is not performing correctly?


    Edit
    OK the 2.2ohms seems a hair high, but not way off. If you could pull the woofer on the other speaker and do the same test you should get roughly 2.2 ohms. You do know that these drivers only have full output below less than 100hz?
    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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  • SDA2Guy
    SDA2Guy Posts: 26
    edited September 2008
    Yes, this is what I thought was correct: the red terminal to the black speaker wire. I just did the other combinations in case this wasn't it. I will repeat the test on the right channel tomorrow and post the results.
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  • SDA2Guy
    SDA2Guy Posts: 26
    edited September 2008
    Ben,

    As you suggested I repeated the test on the good, right channel. The reading is 2.2 ohms. Yes, I am aware these drivers operate only below 100 hz. For the audible testing I used the bass-heavy Morph the Cat. The right channel woofer was going like crazy both audibly and visibly. The left channel woofer was still and lifeless. The speaker *did* work good when connected directly to the speaker cable.

    Where can we go next? I appreciate any help you can provide.
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