Picked up a mint pair of SDA CRS +'s...I'd like to bring them back to their former glory, or better.

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  • F1nut
    F1nut Posts: 52,406
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    One could rework the high frequency circuit as JayMX posted, but how well that would blend in to the rest is up for debate. Polk obviously thought changes were needed to the rest, so I think it's safe to assume they found it didn't blend well.
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  • 91rtstealth
    91rtstealth Posts: 125
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    I'm going to think it over..right now i'm leaning towards just buying some rdo194's this week..listening to them for a while, and then doing the caps and resistors to see if I can actually hear a difference after...I"ll be shocked if the caps and resistors totally blow me away and dramatically transform the speakers..I always have my doubts about that kind of stuff, but I would like to be proven wrong.

    If I end up being totally blown away and they de-throne the Mofi's, then maybe i'll go crazy on them with the vr3 mod stuff..but man, at that price, you can buy some pretty amazing speaker kits to build yourself...but whatever..we'll see what happens..if high end caps transform these speakers, then maybe i'll recap some of my JBL's...and my Pioneer HPM100's..etc...typically I don't like highly modified things...even with my cars, I keep them fairly stock...but for whatever reason, with this Polk stuff, I don't mind messing around with them. It helps that they are cheap to buy from the start. I'm afraid to modify my JBL 4425's or L100's...they are expensive and people usually won't buy them unless they are un-molested, myself included....

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  • xschop
    xschop Posts: 5,821
    edited February 2
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    Polk did whatever was in the budget at Gallagher Mansion.
    Did they actually evaluate the 86 B/B for the RD0198 Tweeter, or is all this just speculation, since Polk did not investigate it?

    (Edited to agree with @JayMX)

    Common sense says that if another CRS was ok'd to TL, then any CRS with the same STEREO MW driver and stereo inductor/cap network would be OK, because the tweeter only meshes with the stereo driver.
    Don't take experimental gene therapies from known eugenicists.
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  • F1nut
    F1nut Posts: 52,406
    edited February 2
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    Common sense says that if another CRS was ok'd to TL, then any CRS with the same STEREO MW driver and stereo inductor/cap network would be OK, because the tweeter only meshes with the stereo driver.

    Not the same stereo inductor.
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  • F1nut
    F1nut Posts: 52,406
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    I"ll be shocked if the caps and resistors totally blow me away and dramatically transform the speakers.
    Prepare to be shocked.
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  • invalid
    invalid Posts: 1,559
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    My 2As Finally Finished...Almost - Page 2 — Polk Audio Forum https://share.google/Kr579hMnWptv2Jzze
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  • xschop
    xschop Posts: 5,821
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    F1nut wrote: »
    Common sense says that if another CRS was ok'd to TL, then any CRS with the same STEREO MW driver and stereo inductor/cap network would be OK, because the tweeter only meshes with the stereo driver.

    Not the same stereo inductor.

    Good catch. Had to get on the big screen monitor to see that. Wish WMG were still around to ask about this discrepancy.
    Don't take experimental gene therapies from known eugenicists.
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  • invalid
    invalid Posts: 1,559
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    According to westmassguy, on the link I posted, the 2A and the 86 crs with identical crossover should be able to accept the TL mod with just a 5.8uf cap. He tested the 2a with the resistor omitted and with it in circuit and found it better to leave it in circuit.
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  • Emlyn
    Emlyn Posts: 4,905
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    I think you're on the right track with replacing the nasty sibilant SL2000 tweeters with the 194s. I consider that a necessity. Crossover parts upgrades can come later if you're into that. Although the crossover parts are aging by now, Polk was using similar quality parts back then to what goes into speakers that cost several thousand dollars now. Other mechanical things like dampening the midwoofer baskets and better securing the drivers into the cabinets are easy changes.

    The best thing about the CRS is they are unique in the audio world and worth keeping around in the audio closet just on that basis. But as you've guessed doing upgrades on them isn't going to make them significantly more valuable. Having the original stands is a bonus but the CRS can also be placed on better stands.
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  • Unknown
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  • Unknown
    Unknown
    edited February 2
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  • invalid
    invalid Posts: 1,559
    edited February 2
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    When you click on a link from this forum, why do you have to click another link that says you are leaving the polk audio forum even though the link is a forum link?
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  • invalid
    invalid Posts: 1,559
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    pitdogg2 wrote: »
    invalid wrote: »
    When you click on a link from this forum, why do you have to click another link that says you are leaving the polk audio forum even though the link is a forum link?

    You found it through google.

    I found it through Google even though I was searching for it on this forum, that's weird.
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  • jmardy
    jmardy Posts: 27
    edited February 2
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    yj7nzmh4wmcg.jpg
    [/quote]

    I'm just watching from the sidelines and trying to learn but aren't you putting two capacitors (the 5.8 and the 12) in series here?
    Why not just use a single 3.9µ cap?
    https://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-series-and-parallel-capacitor
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  • 91rtstealth
    91rtstealth Posts: 125
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    i'm also at the sidelines trying to learn as much as I can..it's a little overwhelming at this point...haha..but still, i love to learn..it's my favorite thing to do...

    i'm really tempted to go grab some rdo194's..listen for a while...

    then upgrade the caps and resistors..listen for a while...see what I notice...

    Then if I get bored with that, I can get back in there and do the rdo198 thing and then see where it takes me..

    someone on facebook might give me their extra crossovers that they have laying around...I haven't verified yet whether they are blade/blade or not...hopefully they are the ones that can "correctly" be TL'd...if so, i might grab them, along with the 6511's that he has...then I could two sets of "guts" for my speakers...I dunno...might be interesting...
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  • 91rtstealth
    91rtstealth Posts: 125
    edited February 2
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    alright...interesting turn of events...

    so this guy on Facebook has the following...he said I could have any of it for almost nothing...just shipping and a minimal fee...

    two questions:

    1. are these the desirable crossovers (and 6511 drivers) I would need in order to make some seriously gnarly CRS Plus TL-super-mega-awesome-name-people-call-them?

    2. If so, who thinks I should get these, some rdo198's, some caps and resistors and go that route?


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  • F1nut
    F1nut Posts: 52,406
    edited February 2
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    Get all of that, then proceed with the RD0198-1 tweeters and TL upgrade.

    Make sure you get the SDA cable.
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  • 91rtstealth
    91rtstealth Posts: 125
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    F1nut wrote: »
    Get all of that, then proceed with the RD0198-1 tweeters and TL upgrade.

    Make sure you get the SDA cable.

    cool..I think I just might do that..

    question though..are those crossovers complete? are there seriously only THREE caps in that whole crossover to replace?
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  • F1nut
    F1nut Posts: 52,406
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    Quit dragging your feet, get them before they change their mind. Look at the schematic to answer your question.
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  • 91rtstealth
    91rtstealth Posts: 125
    edited February 2
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    F1nut wrote: »
    Quit dragging your feet, get them before they change their mind. Look at the schematic to answer your question.

    i'm not dragging anything..I have to wait for them to respond..

    you could also just answer the question...like i've said probably 7-8 different times at this point, I don't know what i'm doing and i'm tryin got learn, and there's so many schematics in this thread at this point that I don't know what i'm looking at....and there's so many different models out there and they all have different schematics..I didn't come out of the womb with Polk SDA knowledge just like you didn't come out of the womb knowing how to play a 19/16 drum groove or which fuel pump will work best in my 3000GT.

    If anyone else out there wants to actually patiently help me, that would be great..thanks in advance
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  • xschop
    xschop Posts: 5,821
    edited February 2
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    Get them yesterday.

    I machined big brake adapters for a 3000GT long ago. Fun little car.
    Don't take experimental gene therapies from known eugenicists.
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  • F1nut
    F1nut Posts: 52,406
    edited February 2
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    jmardy wrote: »
    yj7nzmh4wmcg.jpg

    I'm just watching from the sidelines and trying to learn but aren't you putting two capacitors (the 5.8 and the 12) in series here?
    Why not just use a single 3.9µ cap?
    https://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-series-and-parallel-capacitor

    I'll start with I'm not a circuit genius.

    I believe the reason is the 5.8uF is in parallel with the resistor. If one subbed the 5.8 and 12 with a 3.9 and put it in parallel with the resistor the result would be different.



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  • jmardy
    jmardy Posts: 27
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    F1nut wrote: »

    I'll start with I'm not a circuit genius.

    I believe the reason is the 5.8uF is in parallel with the resistor. If one subbed the 5.8 and 12 with a 3.9 and put it in parallel with the resistor the result would be different.



    Ah, I missed the resistor placement. Thanks.
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  • 91rtstealth
    91rtstealth Posts: 125
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    Ok. Looks like I’ll be ordering those parts. Once they get here I’ll slowly start acquiring the rest of the stuff.

    Other than caps, resistors, and tweeters, do I need anything else?

    I know the tweeter connector is different but I have about 800 of those around here from my car audio days.
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  • 91rtstealth
    91rtstealth Posts: 125
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    once I get those other crossovers I posted above, do I NOW have all the correct schematics below? If so, I'm going to try to learn how to read them properly.

    1. stock


    2. upgrade


    3. the step by step process of doing the upgrade

    u1ef9lv3d846.jpg


    are these all correct?

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  • billbillw
    billbillw Posts: 8,245
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    Do you have soldering supplies? If you have never soldered before, there is a bit of learning that should be done before you ever take an iron to the crossovers.
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  • 91rtstealth
    91rtstealth Posts: 125
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    that's the one thing I actually do know how to do..haha...I'm not the best, but I have a fair amount of experience....I used to install remote starts/alarms/keyless entry and stuff like that in cars for a living..so i've soldered a TON of wires...and I've rebuilt a few modules for my Dodge Stealths/Mitsubishi 3000GT's over the last 20 years....I built a Dynaco ST70 and a Bottlehead Tube Amp....I recapped some things before...so I do know how to solder and desolder enough to get by...so far, the ECU that I recapped in my 1991 Stealth has been working since 2001...haha...

    I just have no experience with working on the crossovers of these speakers...I've only ever did small stuff like replace tweeters and drivers, binding posts, dynamatting the baskets, etc...I never did any major work to their crossovers before...

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  • JayMX
    JayMX Posts: 464
    edited February 3
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    91rtstealth wrote: »


    3. the step by step process of doing the upgrade

    u1ef9lv3d846.jpg


    The circuit diagram I marked up is ONLY applicable to modifying the 1986 version. If you acquire the newer pin/blade, single-board crossovers, then you should use the 4.1TL schematic as your reference to update to RD0198’s and 6510/6511 midwoofers. Forget the marked up diagram. It does not apply to the single-board crossovers.

    Current Collection: Monitor 4a (Peerless), Modified Monitor 7b (Peerless), RTA15TL (SL3000), Full mod SDA CRS 4.1TL (198’s), SDA SRS 2.3TL (198’s), R100's, R200’s, R300 🤩
    Pairs that have passed through: Monitor 4b (Peerless), Monitor 5a (Peerless), Monitor 5B (Peerless), Monitor 5b (SL1000), Monitor 5b (SL2000) (4x pair), Monitor 7b (Peerless), Modified Monitor 7c’s (194’s), Monitor 10a (Peerless), Monitor 10b (5x pair), RTA8, RTA8TL, RTA 11T, RTA12c (194's), SDA1(mod to “a” & SL1000 Wuhan mod), SDA CRS, SDA 2 (2x pair), SDA 2a, SDA 2b, SDA 1b, SDA 1c, SDA SRS 2 (2x pair), SDA SRS 3.1TL (198’s) (2x pair)...and more to come, it’s a sickness.
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  • 91rtstealth
    91rtstealth Posts: 125
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    JayMX wrote: »
    91rtstealth wrote: »


    3. the step by step process of doing the upgrade

    u1ef9lv3d846.jpg


    The circuit diagram I marked up is ONLY applicable to modifying the 1986 version. If you acquire the newer pin/blade, single-board crossovers, then you should use the 4.1TL schematic as your reference to update to RD0198’s and 6510/6511 midwoofers. Forget the marked up diagram. It does not apply to the single-board crossovers.

    got it..thanks...seems like a done deal on getting those single board crossovers..I just gotta work out the shipping and payment with the guy, but you never know...i'll let ya'll know on here when or if I definitely get them...and on facebook...I'm sure i'll need help navigating that TL mod...I still need to get the tweeters and other components anyways..I gotta do it slowly...my work schedule is slow and I have entirely too many hobbies that cost money..I'd love to bang this out asap, but I gotta watch my spending right now...
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