Picked up a mint pair of SDA CRS +'s...I'd like to bring them back to their former glory, or better.
Comments
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yeah i'm getting a bit overwhelmed at this point...i've gotten a different response from pretty much every single person...i'm beginning to think it's probably best to just install rdo194, new caps, and new resistors and avoid the risk of completely ruining these speakers...
however, if I can upgrade immediately to the rdo198 instead of buying tweeters TWICE, that would be ideal...but this person says it's not possible..that person says it is..and so it goes round and round...
is this not the correct tweeter schematic for my speakers...and would this work without ruining my speakers..yes..or no? and what does you guys think I should do because i'm getting sort of sick of thinking about this....I just want to do it right the first time and move on with my life...
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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:
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.
thank you for actually explaining your thoughts instead of just saying yes or no..I'm on here trying to learn things and I appreciate anyone who's willing to help me do so...
I don't think anything is "impossible"...if that were the case, no one would have ever figured out how to TL mod these speakers in the first place, or formed any new ideas in the universe, in general....
if this is something that can be done fairly easily and not ruin the sound of my speakers, great!
if not, i'll just replace some worn out components and install rdo194's. -
Looks good to me!
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 -
That was me on “Buttbook”
Thank you Jay for diverting Jesse's anger away from me. Albiet briefly.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 -
Not angryPolitical 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 -
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.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 -
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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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. -
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.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 -
Prepare to be shocked.I"ll be shocked if the caps and resistors totally blow me away and dramatically transform the speakers.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 -
My 2As Finally Finished...Almost - Page 2 — Polk Audio Forum https://share.google/Kr579hMnWptv2Jzze
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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.
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. -
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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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. -
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.
Yes because the resistor/cap combination is part of the contouring circuit. My SDA1 signatures had the same cap/resistor in the tweeter circuit, unfortunately I also couldn't use the RD-0198-1 tweeter. -
westmassguy wrote: »Well boys and girls the operation was a complete success.Received the RDO-198s this morning, and already had everything else.
The modification was rather simple. To clear some space for the new 5.8uf cap, I relocated two of the resistors to the bottom of the board. On the shunt resistor, I left enough lead popping through the top of the board to get a set of alligator clip jumpers on for testing. I did the left speaker first, and put the jumper on to simulate the 4th generation/2B High-Pass configuration. Buttoned it up, and fired up the HTPC. Started playing a few very familiar tracks, and immediately noticed the stereo image had shifted to the left. The left speaker was slightly hotter on the top, and a bit louder. There was significantly more detail as well. I suspected this would be the outcome of the test, but for completeness and any doubters out there I wanted to be sure. I pulled the PR, removed the jumper, buttoned her back up, and started again. Stereo image was back dead center, the hot top end was gone, but the increased detail remained. I then rebuilt the right crossover, put her back together and sat down for some critical listening. Way more detail across the board. I would not say the difference was as dramatic as going from the SL2000s to the RDO-194s, but there is a very noticeable improvement, and it was well worth the effort. As I stated before, and others have also, the only difference between the 2A and 2B Hi-Pass section was the 2.7 ohm shunt resistor. The 2As use identical MW6510s for the stereo and dimensional drivers, where-as the 2Bs use an MW6503 for the stereo driver and an MW6511 for the dimensional driver. I can only surmise that the combined output of the two different sets of woofers is the main reason for the shunt resistor in the 2As. It was used to balance the output between the tweeter and woofers on the 2A, but was not needed for the 2B.
The bottom line is, 2As can be TL'd just like their younger sibling. This should apply to the 1986 CRS blade/blade as well.
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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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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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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'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...
