A Few Questions About SDA 2's
AudioMan612
Posts: 11
Hey,
So a family friend recently gave me a pair of mint condition 1st generation SDA 2 speakers (dimensional tweeters, midrange with lower crossover frequency, and RS-1000 tweeters). I've got a few questions about these.
1. I know one of the best ways I can make them sound even better is to upgrade to the newer silk dome tweeters. I have two questions about these. First, I've read that electrically, the RD0-194's (not sure if it's a "O" or a "0" lol) are drop-in replacements for RS-1000's and RS-2000's, but the size is a bit different for RS-1000's. What would need to be done? Do the holes just need to be enlarged? I'm decent at woodworking, and I have friends who are great at it, but I'm still nervous as I can't exactly afford another pair of speakers this nice (college student here lol). Also, I've read that some people like to mod their crossovers to accept SL-2500's and SL-3000's. If I were using old drivers I would definitely do this, but is there enough difference between the RD0-194 and RD0-198 to warrant this? I know that this will require woodwork as well.
2. As far as the crossover goes, I will eventually upgrade the capacitors when I can afford it. I know a good amount about audiophile capacitors, so no questions there, but does anyone have any suggestions for the inductors? I've read that in some inductors you can upgrade the AWG and DCR, but in others, you shouldn't. Does anyone have any info on the specs I should use for the inductors? I haven't studied them anywhere near as much as I've studied capacitors.
3. What binding posts do you guys recommend? Another issue I have not research extensively yet. Also, how do you go about replacing these? I haven't taken the speakers apart at all yet, and I can't right now as I'm letting a friend borrow them until I find room for them (they're hooked up to his Fisher 400 and I have to say, vinyl sounds awesome through them).
4. I will probably upgrade the gaskets around the drivers to help tighten the bass response seeing as these rely on a passive radiator. I've read a few things (http://www.polkaudio.com/forums/showthread.php?132007-Brgman-s-gaskets-or-Mortite and http://www.polkaudio.com/forums/showthread.php?123136-SDA-Driver-Seals-Original-Foam-vs.-Mortite-vs.-Armaflex-Foam for example), but I'm still not positive what seems to be considered the best to use overall. Hopefully this isn't too hard to do lol...
5. This is the one that I'm the most skeptical about: the shifting magnets issue. I have read that some people have been able to repair midranges with this problem, but better yet, have been able to upgrade the glue used to hold the magnets in place. I'm pretty sure I'm too scared to attempt this, but is there anyone in the Southern California area who has experience with this? I would be willing to pay to have this "saftey" mod done when I have the money for it.
6. Just some general SDA 2 questions. I know a lot of people recommend disconnecting the dimensional tweeters to improve sound quality. I think I'm going to shy away from this one. I understand why it helps, but meh, I think I'm going to leave mine hooked up. Here is my bigger question: why did they get ride of the lower midwoofer on the newer models of the SDA 2? I haven't found any information on that. Was it determined to make the sound a bit muddy? These are the nicest speakers that I currently own, and I have to say, I know they can sound better, but I'm already quite happy with the sound quality. Even the tweeters (I know the opinions on the SL-2000's, but how are SL-1000's generally considered?) aren't too harsh since they're hooked into tube gear at the moment.
Thanks in advance!
So a family friend recently gave me a pair of mint condition 1st generation SDA 2 speakers (dimensional tweeters, midrange with lower crossover frequency, and RS-1000 tweeters). I've got a few questions about these.
1. I know one of the best ways I can make them sound even better is to upgrade to the newer silk dome tweeters. I have two questions about these. First, I've read that electrically, the RD0-194's (not sure if it's a "O" or a "0" lol) are drop-in replacements for RS-1000's and RS-2000's, but the size is a bit different for RS-1000's. What would need to be done? Do the holes just need to be enlarged? I'm decent at woodworking, and I have friends who are great at it, but I'm still nervous as I can't exactly afford another pair of speakers this nice (college student here lol). Also, I've read that some people like to mod their crossovers to accept SL-2500's and SL-3000's. If I were using old drivers I would definitely do this, but is there enough difference between the RD0-194 and RD0-198 to warrant this? I know that this will require woodwork as well.
2. As far as the crossover goes, I will eventually upgrade the capacitors when I can afford it. I know a good amount about audiophile capacitors, so no questions there, but does anyone have any suggestions for the inductors? I've read that in some inductors you can upgrade the AWG and DCR, but in others, you shouldn't. Does anyone have any info on the specs I should use for the inductors? I haven't studied them anywhere near as much as I've studied capacitors.
3. What binding posts do you guys recommend? Another issue I have not research extensively yet. Also, how do you go about replacing these? I haven't taken the speakers apart at all yet, and I can't right now as I'm letting a friend borrow them until I find room for them (they're hooked up to his Fisher 400 and I have to say, vinyl sounds awesome through them).
4. I will probably upgrade the gaskets around the drivers to help tighten the bass response seeing as these rely on a passive radiator. I've read a few things (http://www.polkaudio.com/forums/showthread.php?132007-Brgman-s-gaskets-or-Mortite and http://www.polkaudio.com/forums/showthread.php?123136-SDA-Driver-Seals-Original-Foam-vs.-Mortite-vs.-Armaflex-Foam for example), but I'm still not positive what seems to be considered the best to use overall. Hopefully this isn't too hard to do lol...
5. This is the one that I'm the most skeptical about: the shifting magnets issue. I have read that some people have been able to repair midranges with this problem, but better yet, have been able to upgrade the glue used to hold the magnets in place. I'm pretty sure I'm too scared to attempt this, but is there anyone in the Southern California area who has experience with this? I would be willing to pay to have this "saftey" mod done when I have the money for it.
6. Just some general SDA 2 questions. I know a lot of people recommend disconnecting the dimensional tweeters to improve sound quality. I think I'm going to shy away from this one. I understand why it helps, but meh, I think I'm going to leave mine hooked up. Here is my bigger question: why did they get ride of the lower midwoofer on the newer models of the SDA 2? I haven't found any information on that. Was it determined to make the sound a bit muddy? These are the nicest speakers that I currently own, and I have to say, I know they can sound better, but I'm already quite happy with the sound quality. Even the tweeters (I know the opinions on the SL-2000's, but how are SL-1000's generally considered?) aren't too harsh since they're hooked into tube gear at the moment.
Thanks in advance!
Post edited by AudioMan612 on
Comments
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Apparently there is no edit feature here? Anyways, I think I get how to remove the binding posts. I just haven't researched which ones people like best. Also, I forgot to ask, when removing the polyswitches, is it best to just jumper them or put a small resistor in their place?
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Hi (and welcome) AudioMan,
Most people have gone with either Cardas (various flavors, the short version is sufficient, available here at SonicCraft) or Vampire
The polyswitch seems to be a matter of preference. Some people have just added a jumper and are satisfied, others use a quality (Mills or better) resistor in the range of 0.1 to 0.5 ohms depending on their tastes (higher resistance here subdues the treble, as I understand it). "Best" is different to different people--If you're fully committed to crazy, order a couple of different resistors and try them, as well as a jumper, and try 'em all. Else, pick one option and you won't go too wrong with any of them.
The jumper/resistor will have sonic impact; the binding posts don't provide a sonic upgrade but are pretty slick and may offer better functionality with tightening if you use spades.
As for the tweeters, if you've got the silver face-plated SL1000 variety, I'm not sure if there is any simple "drop-in" replacement for those--something is differently sized on them, IIRC. I'm not even sure which tweeter (if any) is compatible electrically as a replacement. Maybe the 194, definitely not the 198. Perhaps someone more knowledgeable about this can chime in.
Hope this is helpful, and good luck with your project!
JayJay
SDA 2BTL * Musical Fidelity A5cr amp * Oppo BDP-93 * Modded Adcom GDA-600 DAC * Rythmik F8 (x2)
Micro Seiki DQ-50 * Hagerman Cornet 2 Phono * A hodgepodge of cabling * Belkin PF60
Preamp rotation: Krell KSL (SCompRacer recapped) * Manley Shrimp * PS Audio 5.0 -
Rest assured some experienced heads will come along and share their knowledge regarding your questions. It's a great community and welcome aboard.Monitor 7C's With Tubes
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I have the SDA 2Bs, and what you drive them with makes an incredable difference in the sound. IMO, THAY CRAVE POWER, . I'm currently running a Carver TFM 25,, 225wpc.. and it makes them come alive, even though I do 90% of my listening below 30 watts. They sound like Sh_t with most of my vintage gear. I also made a very noticeable improvement in the treble by changing out my CD player.I think they give ya what ya give them. I'm very happy with the sound.
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Mix epoxy per label directions. Slather onto the driver around base and top of magnet. Done. You're not RE-GLUING the magnets or taking the driver apart--you're building an epoxy reinforcement on the external surface so the magnet can't move out-of-position. If the magnet hasn't already shifted, this is a "no-skill, no special tooling" operation. This is done to drivers that are STILL WORKING SMOOTHLY.AudioMan612 wrote: »5. This is the one that I'm the most skeptical about: the shifting magnets issue. I have read that some people have been able to repair midranges with this problem, but better yet, have been able to upgrade the glue used to hold the magnets in place. I'm pretty sure I'm too scared to attempt this, but is there anyone in the Southern California area who has experience with this? I would be willing to pay to have this "saftey" mod done when I have the money for it.
a photo from Toolfan66: http://www.polkaudio.com/forums/showthread.php?98202-JB-Welding-your-magnets-on-your-old-drivers&highlight=glue+magnets
If the magnet has ALREADY shifted, you'll need specialized equipment to REPAIR the driver. The driver may not be savable. Some are...some aren't.
No schematics of the earliest SDA 2s; but if I remember correctly the SDA driver of the early SDA 2 does not also reinforce bass like the later models do. As soon as Polk learned how to get the SDA driver to share the bass load, they could cut costs on the SDA 2 by reducing the MW driver count; and discovering that the SDA effect didn't need a tweeter cut costs even further.AudioMan612 wrote: »why did they get ride of the lower midwoofer on the newer models of the SDA 2? I haven't found any information on that. Was it determined to make the sound a bit muddy?AudioMan612 wrote: »Apparently there is no edit feature here? ... Also, I forgot to ask, when removing the polyswitches, is it best to just jumper them or put a small resistor in their place?
The edit feature is time-limited, 20 minutes or so before the option to edit is removed. Can't tell you how many times I wanted to make "one more" change...and couldn't.
Older speakers may have fuses instead of polyswitches. Not certain, but reasonably sure. -
Thanks for the welcomes and quick replies! I just noticed I couldn't spell "rid" earlier lol...
Well that's a huge relief with the driver reinforcement. All 6 of my midwoofers are working perfectly right now. I have the original manual to my SDA 2's (they look like this: http://www.polksda.com/sda2.shtml). That lower midwoofer is crossed over lower than the ones above it and is not present in the newer versions of the SDA 2's. There are no dimensional versions of these lower midwoofers; just one per speaker. These were the ones I was wondering about.
As far as the tweeters go, from all of the research I've done, the 194's are electrical replacements for the SL-1000's and SL-2000's, but the mount is a bit different on the 1000. I'm not sure how it is different. I would love to do this upgrade, as I hear it makes a huge difference (I suppose that will affect how I handle the polyswitches as I'm sure I'll be able to take more high end from the silk domes then the stock drivers). I know the crossovers can be modified to take 198s instead, but I'm not sure about the difference in sound quality between 194's and 198's (if there is any). This and what to do about the inductors has proven to be the most difficult to find information on.
Thanks again! -
First Guess: You have fuses instead of polyswitches. (Unconfirmed, but suspected.)AudioMan612 wrote: »As far as the tweeters go, from all of the research I've done, the 194's are electrical replacements for the SL-1000's and SL-2000's, but the mount is a bit different on the 1000. I'm not sure how it is different. I would love to do this upgrade, as I hear it makes a huge difference (I suppose that will affect how I handle the polyswitches as I'm sure I'll be able to take more high end from the silk domes then the stock drivers).
The later SDA 2s can be modified to accept the 198s. I don't think the older models like yours have a procedure to modify the crossover to make the 198 work properly.AudioMan612 wrote: »I know the crossovers can be modified to take 198s instead, but I'm not sure about the difference in sound quality between 194's and 198's (if there is any).
"I" would leave the inductors alone, at least for now. Replace the caps and resistors. If at some future point you want to experiment with inductors, fine. Since there aren't any schematics for the earliest SDA 2s posted in the schematics section, you'll have to inspect the existing caps and resistors to determine the proper values; you'd have to measure the DC resistance and the inductance of the inductors since they're probably not marked. Do you have an LCR meter, or some other way to measure inductance? If not, you're more-or-less locked into the stock inductors.AudioMan612 wrote: »what to do about the inductors has proven to be the most difficult to find information on. -
(For the Moderator and/or the Polk Forum Elite, especially Darqueknight: )No schematics of the earliest SDA 2s
Now that I think about it...Is there a way to add those schematics to the "Sticky"???
Did they used to be listed but somehow got deleted? Are those schematics lost at the Corporate level, and that's why they're not posted? -
AudioMan612 wrote: »As far as the tweeters go, from all of the research I've done, the 194's are electrical replacements for the SL-1000's and SL-2000's, but the mount is a bit different on the 1000. I'm not sure how it is different.
The SL1000 is about 1/16 smaller all around just enough to skewer the holes a bit. Most all the SDA's with SL1000 had tweeters mounted flush with front baffle, most all SDA's with SL2000 had those inletted into the front baffle about 4mm. -
I definitely have polyswitches. I have the sheet of paper in the manual that explains the tweeter protection built into the speakers, and there are no fuses on the back.
Does anyone know the difference between the 194 and 198 as far as sound quality goes (if there is any)?
I guess I'll have to hold off on inductors. I have a multimeter, but I'm not sure if it can do inductance. I'll have to look later.
What would be the easiest way to mod the cabinet to accept the newer replacements if it's possible?
I noticed the lack of info on my speakers as well. I would be glad to upload any information that I have someday when I take them apart and give the insides a good look. When I have more free time, I can scan and upload the manual if that would help. -
I know the crossovers can be modified to take 198s instead, but I'm not sure about the difference in sound quality between 194's and 198's (if there is any).
That's not possible with your model. Yes, there is a definitely a difference in sound quality with the RD0198-1 being the better one.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 -
You can't modify these to take the RD0198. I have tried and it sounds weird. If you want the RD0198 you need 2B's not the originals like you have. The crossover is just a little too finicky in yours.
I would suggest disconnecting the dimensional tweeter. It is better without. -
Ah alright, thanks. Since you have experience with these, do you have any schematics for the crossovers? Or at least a list of parts so I can make an estimate of how much it's going to cost? Did you modify your cabinet to take 194's?
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AudioMan612 wrote: »Ah alright, thanks. Since you have experience with these, do you have any schematics for the crossovers? Or at least a list of parts so I can make an estimate of how much it's going to cost? Did you modify your cabinet to take 194's?
You'll need to get into your speaker and see for yourself just what was used and write down all values. Sometimes changes were made on the fly and will not be reflected on paper. This way you'll know for sure instead of finding out later yours used a little different stuff from said schematics. -
Well, I took another look at them today, and I must've been blind the first time I looked at them. The tweeters are SL-2000's, so it looks like I'll be able to drop 194's in without any modification
. It's probably still going to be a while before I take a look at the crossovers. I tried the leak test today (pushing in on the passive radiator), and the three midwoofers go back to their original positions almost instantly, so I will definitely have to improve those gaskets.
