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

2

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  • 91rtstealth
    91rtstealth Posts: 89
    since I am basically clueless at the moment, can someone help me understand what I'm looking at on these two piece crossovers? and is that yellow thing the bypass cap? Sorry..totally new to working on these crossovers...the only thing I did to my SDA's of the past was change the tweeters and binding posts, and dynamat the baskets. I might have JB welded the magnets too..i can't remember..that was a while ago.
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  • xschop
    xschop Posts: 5,208
    edited January 31
    The big yellow cap is a Mylar 12uf? The little brown/black cap over it is bypass. When you update them, omit the small bypass cap. Thats the concensus here.
    Don't take experimental gene therapies from known eugenicists.
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  • 91rtstealth
    91rtstealth Posts: 89
    edited January 31
    do I replace that yellow mylar cap or am I just replacing the blue ones?

    or better yet, is there a tutorial for updating these speakers? a schematic or something that tells me exaclty what I need to buy and do? otherwise I may just get some tweeters for these and call it a day. I don't want to get into this rabbit hole unless I know where I'm going.
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  • F1nut
    F1nut Posts: 51,844
    You replace every cap and resistor.

    Schematics are posted in this section.
    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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  • 91rtstealth
    91rtstealth Posts: 89
    F1nut wrote: »
    You replace every cap and resistor.

    Schematics are posted in this section.

    replacing the caps and resistors seems easy enough...the one thing I don't totally understand is what to do with this yellow and black cap? Do I simply cut the leads and remove both of these? Do I replace them with a jumper wire? a different cap? i'm not sure what to do here....



    75n0f1qard64.jpg

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  • F1nut
    F1nut Posts: 51,844
    You replace the 12uF yellow cap with a new 12uF cap. You throw the yellow cap and the black bypass cap in the trash can along with the rest of the caps and resistors.

    Don't cut the leads on any cap or resistor, you desolder them.
    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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  • 91rtstealth
    91rtstealth Posts: 89
    alright thanks.....i'll get a parts list together and start shopping around...it's probably going to be a few weeks until I can actually start working on the crossover anyways, but I wanted to get a game plan together ahead of time..

    I think I'm going to grab the rdo194's next week and run them for a while and get used to the sound, and then do the crossovers to see what kind of difference it makes...
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  • pitdogg2
    pitdogg2 Posts: 27,114
    Don't cut the leads on any cap or resistor, you desolder them.
    This^^^
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  • audioluvr
    audioluvr Posts: 5,949
    91rtstealth wrote: »
    alright thanks.....i'll get a parts list together and start shopping around...it's probably going to be a few weeks until I can actually start working on the crossover anyways, but I wanted to get a game plan together ahead of time..

    I think I'm going to grab the rdo194's next week and run them for a while and get used to the sound, and then do the crossovers to see what kind of difference it makes...

    Make sure you take lots of pictures of all your connections. Check your PM's
    Gustard X26 Pro DAC
    Belles 21A Pre Upgraded with Mundorf Supremes
    B&K M200 Sonata monoblocks refreshed and upgraded
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables
    Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)

    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus
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  • audioluvr
    audioluvr Posts: 5,949
    edited February 1
    91rtstealth wrote: »
    qqss7h61fdfd.jpeg

    Looks like you have the 1986 schematic version with the two crossover boards and the two 6510 drivers and a single 260uF electrolytic cap on the dimensional driver. This would have to be replaced with a Mundorf electrolytic or a stack of poly caps (room permitting). OR you could see if anyone around here have a spare pair of 6511's which would allow you to TL them if that is your goal.

    edit: Jantzen Audio makes a 270uF which would work but I don't know what they sound like.
    Gustard X26 Pro DAC
    Belles 21A Pre Upgraded with Mundorf Supremes
    B&K M200 Sonata monoblocks refreshed and upgraded
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables
    Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)

    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus
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  • invalid
    invalid Posts: 1,487
    audioluvr wrote: »
    91rtstealth wrote: »
    qqss7h61fdfd.jpeg

    Looks like you have the 1986 schematic version with the two crossover boards and the two 6510 drivers and a single 260uF electrolytic cap on the dimensional driver. This would have to be replaced with a Mundorf electrolytic or a stack of poly caps (room permitting). OR you could see if anyone around here have a spare pair of 6511's which would allow you to TL them if that is your goal.

    edit: Jantzen Audio makes a 270uF which would work but I don't know what they sound like.

    The crossover looks identical to the 2A crossover, so why would you need to change the driver's to the 6511?
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  • audioluvr
    audioluvr Posts: 5,949
    They are identical to the 2A. Changing out the dimensional 6510 with the 6511 and then using the schematic for the 4.1TL mod to refresh the crossover would allow him to use the RD0-198 tweeters.
    Gustard X26 Pro DAC
    Belles 21A Pre Upgraded with Mundorf Supremes
    B&K M200 Sonata monoblocks refreshed and upgraded
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables
    Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)

    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus
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  • 91rtstealth
    91rtstealth Posts: 89
    alright..I just pulled all 4 drivers and verified that they are indeed all 6510's.

    that being said, can I still do the TL upgrade with my existing crossovers just by getting 2 6511's, caps, resistors, and rdo198's? if it's still somewhat easily feasible and my mind is going to be blown by the outcome, then I am down..it just might take me some time to save the money up to get the supplies. I'm a professional drummer in the Tampa Bay Area and this is the slow season, and I have other obligations right now, but I am interested in doing this if it's worth it...



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  • 91rtstealth
    91rtstealth Posts: 89
    there's a guy on facebook that said he would basically gives me his extra crossovers and 6511's for a nominal fee plus shipping, so if I can still do the TL mod to what I've got, I'm interested, provided ya'll help me figure out what to do..haha...i'll take step by step photos or videos to make sure I don't mess anything up....
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  • audioluvr
    audioluvr Posts: 5,949
    I don't see why not.
    Gustard X26 Pro DAC
    Belles 21A Pre Upgraded with Mundorf Supremes
    B&K M200 Sonata monoblocks refreshed and upgraded
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables
    Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)

    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus
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  • Toolfan66
    Toolfan66 Posts: 18,099
    audioluvr wrote: »
    They are identical to the 2A. Changing out the dimensional 6510 with the 6511 and then using the schematic for the 4.1TL mod to refresh the crossover would allow him to use the RD0-198 tweeters.

    Can you TL Mod the 2 piece crossovers? I was under the impression that you couldn’t..
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  • 91rtstealth
    91rtstealth Posts: 89
    Toolfan66 wrote: »
    audioluvr wrote: »
    They are identical to the 2A. Changing out the dimensional 6510 with the 6511 and then using the schematic for the 4.1TL mod to refresh the crossover would allow him to use the RD0-198 tweeters.

    Can you TL Mod the 2 piece crossovers? I was under the impression that you couldn’t..


    yeah that's the impression that I got too...that it's not possible with my crossovers...

    F1Nut?

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  • audioluvr
    audioluvr Posts: 5,949
    edited February 1
    Easy peasy. I think... No such thing as "can't"
    Gustard X26 Pro DAC
    Belles 21A Pre Upgraded with Mundorf Supremes
    B&K M200 Sonata monoblocks refreshed and upgraded
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables
    Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)

    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus
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  • invalid
    invalid Posts: 1,487
    audioluvr wrote: »
    They are identical to the 2A. Changing out the dimensional 6510 with the 6511 and then using the schematic for the 4.1TL mod to refresh the crossover would allow him to use the RD0-198 tweeters.

    I did the TL mod to my 2A without changing any drivers. I just followed Westmassguy's thread.
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  • 91rtstealth
    91rtstealth Posts: 89
    invalid wrote: »
    audioluvr wrote: »
    They are identical to the 2A. Changing out the dimensional 6510 with the 6511 and then using the schematic for the 4.1TL mod to refresh the crossover would allow him to use the RD0-198 tweeters.

    I did the TL mod to my 2A without changing any drivers. I just followed Westmassguy's thread.

    what drivers did your 2A's come with? I haven't had a set of 2A's in years so I forget what i had as well...were they both 6510's or 6510 and 6511?

    I guess what I'm asking:

    I thought the TL upgrade was simply a tweeter (rd0198) and a modification in the tweeter circuit, and that's it....is a 6511 a part of this equation as well?

    sorry for all of the questions...I like knowing as much as humanly possible about something before I start messing around with it...I plan to learn more about caps and resistors this week...haha..
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  • audioluvr
    audioluvr Posts: 5,949
    invalid wrote: »
    audioluvr wrote: »
    They are identical to the 2A. Changing out the dimensional 6510 with the 6511 and then using the schematic for the 4.1TL mod to refresh the crossover would allow him to use the RD0-198 tweeters.

    I did the TL mod to my 2A without changing any drivers. I just followed Westmassguy's thread.

    I'd have to look up the differences between the two were but if Dave said they were comparable then I'd tend to believe it. You should post a link to it for the OP.
    Gustard X26 Pro DAC
    Belles 21A Pre Upgraded with Mundorf Supremes
    B&K M200 Sonata monoblocks refreshed and upgraded
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables
    Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)

    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus
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  • pitdogg2
    pitdogg2 Posts: 27,114
    SDA 2a are driven by 2 mw6510.
    I, like @Toolfan66 had thought the dual boards were not eligible for TL mod.
    The contour circuit does appear to be a 5.8uf cap over the 2.7 ohm resistor. On my phone it's too hard to see if the inductors are the same in the 86crs verses the 89crs.
    However do not forget that the tweeter connection needs to change to a larger faston, that is the easiest part😉😁
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  • 91rtstealth
    91rtstealth Posts: 89
    pitdogg2 wrote: »
    SDA 2a are driven by 2 mw6510.
    I, like @Toolfan66 had thought the dual boards were not eligible for TL mod.
    The contour circuit does appear to be a 5.8uf cap over the 2.7 ohm resistor. On my phone it's too hard to see if the inductors are the same in the 86crs verses the 89crs.
    However do not forget that the tweeter connection needs to change to a larger faston, that is the easiest part😉😁

    yeah I keep getting so many different answers..it's making me think I should just leave these speakers alone..haha...kidding...I at least want to recap and replace the tweeters...

    so someone on the Polk Loudspeaker Page on facebook said the following, and i've read this in a few different places....so is it true? or not?:


    "Man, it’s been a long time since I’ve been in any of those crossovers. The TL possibility is based on the crossover design for the bass section (if I remember correctly). Without comparing yours to a schematic I cant tell.
    The TL models also had different drivers (MW6511 bass units,) along with different crossover values, and the Tri-Laminate tweeters (again if I remember it right)."
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  • 91rtstealth
    91rtstealth Posts: 89
    and then another guy sent me these two schematics...apparently one is my stock one, and the other is what I would need to do to TL upgrade (NOTATED AT THE TOP)....is this correct?

    also, i'm gonna take a break for a few minutes..i'm getting overwhelmed with all of this different data and research..haha..

    wp0u6pui4g8t.jpg
    ccfgovtdqdz2.jpg
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  • 91rtstealth
    91rtstealth Posts: 89
    another helpful response from facebook land:

    As suggested on the forum, you could perform the 4.1TL upgrade on yours top end board by adding a 5.8uF cap (I would use Clarity CSA) across the 2.7ohm resistor. While at it I would replace the 12uF cap with a Clarity CSA. Dispose of the black bypass cap.
    The inductors are .4mH in both versions so you could leave them stock.
    The 2.7 ohm resistor should be replaced with a Mills or Jantzen wirewound resistor. The difference in sound is not audible between the two brands imo. Mills are smaller, Jantzen is larger.
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  • pitdogg2
    pitdogg2 Posts: 27,114
    edited February 1
    Those schematics are available in the vintage speaker section.
    https://forum.polkaudio.com/discussion/55888/polk-audio-speaker-wiring-schematics-amp-more-stereo-dimensional-array-sda#latest
    Honestly, recapping and resistors and the 194's will be a great set of speakers all things considered. Try not to get too deep in the weeds.
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  • F1nut
    F1nut Posts: 51,844
    edited February 1
    91rtstealth wrote: »
    and then another guy sent me these two schematics...apparently one is my stock one, and the other is what I would need to do to TL upgrade (NOTATED AT THE TOP)....is this correct?

    also, i'm gonna take a break for a few minutes..i'm getting overwhelmed with all of this different data and research..haha..

    wp0u6pui4g8t.jpg
    ccfgovtdqdz2.jpg

    Neither of those schematics are your speaker. You have the very first version of the CRS+ with the blade/blade SDA cable. You cannot TL them.
    The TL possibility is based on the crossover design for the bass section (if I remember correctly).
    Wrong!!!
    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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  • F1nut
    F1nut Posts: 51,844
    Forgot to say...my advice, stay off of Buttbook for audio advice.
    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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  • audioluvr
    audioluvr Posts: 5,949
    That's not your schematic. But, if you consider the TL mod solely as a tweeter upgrade to allow the correct operation of the RD0-198 technically you just have to eliminate the 2.7 ohm resistor between the+ and - Tweeter circuit and add the 5.8uF piggyback cap and it's the same. Only it wasn't sanctioned by Matthew Polk.

    I believe I was wrong for suggesting that you needed to change the 6510 to a 6511 as that would alter the intended design of the driver and dimensional circuit not to mention create more work.

    What do you think Jesse? Could we do this? Please? Please? Please?
    Gustard X26 Pro DAC
    Belles 21A Pre Upgraded with Mundorf Supremes
    B&K M200 Sonata monoblocks refreshed and upgraded
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables
    Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)

    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus
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  • JayMX
    JayMX Posts: 456
    edited 12:08AM
    That was me on “Buttbook” and I did share the ‘87 schematic initially, accidentally and incorrectly, I removed the ‘87 schematic from the Facebook thread and replaced it with the ‘86 blade/blade schematic when I realized my mistake.

    From what I can tell, the tweeter section of the ‘86 blade/blade version can be updated to TL. Hive mind, please advise, hoping I have not offered incorrect recommendations…

    This is the top end of the ‘86 crossover, annotated by me:
    p0cpjcpns2w7.png

    If the OP decides to move fully to 4.1TL, the dimensional midwoofer must change to 6511 and the dimensional circuit would need to be completely reworked as the capacitors, inductors and signal paths are quite a bit different from the ‘86 blade/blade version.

    Current Collection: Monitor 4a (Peerless), Modified Monitor 7b (Peerless), RTA15TL (SL3000), Full mod SDA CRS 4.1TL (198’s), SDA SRS 2.3TL, 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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