SDA 2B Crossover Rebuild

frickingruvin
frickingruvin Posts: 10
edited February 2012 in Vintage Speakers
Just acquired a pair of these. They are all original. I'm in process of replacing the tweeters, and one mid (MW6503), but am thinking the crossovers can stand a cap and resistor replacement. Most of the threads are on different SDAs, so wanted to ask for some insight on parts and any experiences you may have. Brand of caps and resistors, tolerances, etc... In addition, do the inductors require replacement? I've read in the forum that many have added Armaflex and Dynamat when these are apart-is that recommendable as well? Mine are the studio version I believe-they are approximately 65 pounds (one tweet, two mids and a passive) with a blade/blade IC.
Someone told me to remove the polyswitch in the circuit, as it is a tone robber. What is the consensus here?

They already give a pretty good sound. I'm pushing them with a Mac C32/MC2125...

Thanks in advance for your insight.
Post edited by frickingruvin on
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  • F1nut
    F1nut Posts: 50,565
    edited February 2012
    http://www.polkaudio.com/forums/search.php?searchid=565124
    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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  • frickingruvin
    frickingruvin Posts: 10
    edited February 2012
    Thanks F1..That link isn't working.
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  • F1nut
    F1nut Posts: 50,565
    edited February 2012
    Works for me. It's a search link, which takes you to many threads/posts about the 2B's. You can search though them to cull the info you desire.
    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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  • halo71
    halo71 Posts: 4,603
    edited February 2012
    Does not work for me either. I get "vBulletin Message
    Sorry - no matches. Please try some different terms."
    --Gary--
    Onkyo Integra M504, Bottlehead Foreplay III, Denon SACD, Thiel CS2.3, NHT VT-2, VT-3 and Evolution T6, Infinity RSIIIa, SDA1C and a few dozen other speakers around the house I change in and out.
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  • audiocr381ve
    audiocr381ve Posts: 2,588
    edited February 2012
    halo71 wrote: »
    Does not work for me either. I get "vBulletin Message
    Sorry - no matches. Please try some different terms."

    +1..
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  • frickingruvin
    frickingruvin Posts: 10
    edited February 2012
    F1nut wrote: »
    Works for me. It's a search link, which takes you to many threads/posts about the 2B's. You can search though them to cull the info you desire.

    Thanks F1....I have been searching the site for threads pertinent to my question. As I mentioned in my original post, most are a few years old. Are the caps built today the same values? Have any of these values been improved upon? Are the tweets and mids now offered by Polk the same quality as in years past?
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  • audiocr381ve
    audiocr381ve Posts: 2,588
    edited February 2012
    frickingruvin wrote: »
    Thanks F1....I have been searching the site for threads pertinent to my question. As I mentioned in my original post, most are a few years old. Are the caps built today the same values? Have any of these values been improved upon? Are the tweets and mids now offered by Polk the same quality as in years past?

    Caps are the same values.

    The direct replacement tweeter for your 2B's is the RD0-194, and is indeed BETTER than the original SL2000. Their is also a "TL" mod that involves tweaking the crossovers a little bit to use the even better RD0-198. It's a polk approved mod and I highly recommend it.

    The replacement mid drivers from Polk are just as good as the originals. You'd be fine ordering a MW6503 from them.
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  • F1nut
    F1nut Posts: 50,565
    edited February 2012
    Weird, but then again the search function here is simply awful. Use the Advanced Search at the top right, type in 2B*TL. I recommend jumping right to the TL mod as the RD0198-1 tweeter is better than the RD0194-1.
    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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  • frickingruvin
    frickingruvin Posts: 10
    edited February 2012
    Thanks audiocr: Is it necessary to change the inductors when recapping the crossover? I've already purchased the tweets and mid, so my next act is to order the crossover parts I need in order to revamp them. What is your opinion on the Dynamat and Arfaflex applications? From what I read here on the forum, they are also a good idea....
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  • audiocr381ve
    audiocr381ve Posts: 2,588
    edited February 2012
    frickingruvin wrote: »
    Thanks audiocr: Is it necessary to change the inductors when recapping the crossover? I've already purchased the tweets and mid, so my next act is to order the crossover parts I need in order to revamp them. What is your opinion on the Dynamat and Arfaflex applications? From what I read here on the forum, they are also a good idea....

    No problem!

    Yep, the Dynamat works well and takes the "ring" out of the mid drivers and passive radiator.

    If you're looking for more bass slam then the inductors are a good idea. Solen sells a 16mH 10awg that would work well. It's a pricey mod. I have the stock inductors in now and with 225 wpc, the bass is absolutely fine.
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  • inspiredsports
    inspiredsports Posts: 5,501
    edited February 2012
    You are on the right track as those old caps and resistors are most probably at the very end of their life expectancy.

    You can use original values and drop in RDO194-1 tweeters, or bypass the initial 2.7 ohm resistor with an additional 5.8 uf cap and upgrade to the RDO198-1 (I like the 198 "TL" mod best).

    Find the thread by "Face" where he used Clarity Caps and Duelund resistors (Sonicaps and Mills resistors would be a close second).

    Dynamat on the baskets of the 12" passive radiators and 6.5" drivers, new gaskets on all drivers and the binding post mount, Larry's Rings, and new (I like Cardas) binding posts will let those 2B's run with speakers costing an incredible amount more.

    P.S. Replacing the big SDA circuit inductors helps (in my humble opinion), and an upgraded SDA interconnect cable also yields improvements.
    VTL ST50 w/mods / RCA6L6GC / TlfnknECC801S
    Conrad Johnson PV-5 w/mods
    TT Conrad Johnson Sonographe SG3 Oak / Sumiko LMT / Grado Woodbody Platinum / Sumiko PIB2 / The Clamp
    Musical Fidelity A1 CDPro/ Bada DD-22 Tube CDP / Conrad Johnson SD-22 CDP
    Tuners w/mods Kenwood KT5020 / Fisher KM60
    MF x-DAC V8, HAInfo NG27
    Herbies Ti-9 / Vibrapods / MIT Shotgun AC1 IEC's / MIT Shotgun 2 IC's / MIT Shotgun 2 Speaker Cables
    PS Audio Cryo / PowerPort Premium Outlets / Exact Power EP15A Conditioner
    Walnut SDA 2B TL /Oak SDA SRS II TL (Sonicaps/Mills/Cardas/Custom SDA ICs / Dynamat Extreme / Larry's Rings/ FSB-2 Spikes
    NAD SS rigs w/mods
    GIK panels
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  • frickingruvin
    frickingruvin Posts: 10
    edited February 2012
    Are Larry's rings still available? In the threads I have read abouth them, it appeared they were no longer available...
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  • F1nut
    F1nut Posts: 50,565
    edited February 2012
    They are no longer available.
    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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  • frickingruvin
    frickingruvin Posts: 10
    edited February 2012
    I received a pair of 194s, and one 6503...am going to drop those in for the time being...still am yammering over the recap...I know that has to be completed, but am going to exercise a little patience and listen/rework these in steps, and try to gain knowledge as I go forward.
    Not much input on the the polyswitch removal. What are your experiences with this mod?
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  • F1nut
    F1nut Posts: 50,565
    edited February 2012
    Remove it and either replace it with a jumper or a resistor to keep the same resistance that was designed into the circuit. I prefer a .5 ohm, others like a .22 ohm.
    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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  • frickingruvin
    frickingruvin Posts: 10
    edited February 2012
    Thanks F1:

    What type of music represents the majority of your listening? I'm sure if you are of the "trebley" or "midrangey" music your resistor selection would be made accordingly....
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  • F1nut
    F1nut Posts: 50,565
    edited February 2012
    Good music.

    It will depend on numerous factors as to your preference. Experiment for yourself to find yours.
    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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