Crossover upgrade on the SDA IA

245

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  • Face
    Face Posts: 14,340
    edited March 2008
    http://www.polkaudio.com/forums/showthread.php?t=46489

    4.1 TL upgrade.
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • dcmeigs
    dcmeigs Posts: 708
    edited March 2008
    F1nut wrote: »
    1. Go with the 3.5 ohm.
    2. You can not use the RD0198-1, you must use the RD0194-1.

    The new tweeters are a vast improvement, period.

    Thanks, F1Nut, I will use the 194s on the SDA IAs.

    And Face, thanks for the link to DarqueKnights post. That is exactly what I was looking for: the rational for doing the upgrade to the 198s. I knew I had read that post long ago and had not been able to find it.
    The world is full of answers, some are right and some are wrong. - Neil Young
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  • candyliquor35m
    candyliquor35m Posts: 2,267
    edited March 2008
    TroyD wrote: »
    Shut up, Carl. This was/is a good discussion without your banality.

    No comment. My question wasn't directed towards you or anyone else except dcmeigs.

    Have a good day. I know I am :)
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  • Jstas
    Jstas Posts: 14,842
    edited March 2008
    dcmeigs wrote: »
    I'm am a little jealous. Can you send them my way?

    I dunno. It'll be hard to do because they all like to talk at once and there is one guy that I thought was speaking Spanish but turns out it's Portuguese so I can't understand a damn thing he's saying. But every time I try to tell them all to shut up so I can get a word in edgewise, this one guy pops up in the back and starts screaming "I DON'T LIKE YOU!!!" and then it all just goes to hell again. What REALLY pisses them off is when I play music way too loud then they all start telling me that they can't hear themselves think 'cause of all the noise. Then I say "Now you know how I feel!" Then they just pout while I rock out! :cool:
    Expert Moron Extraordinaire

    You're just jealous 'cause the voices don't talk to you!
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  • dcmeigs
    dcmeigs Posts: 708
    edited March 2008
    Jstas wrote: »
    What REALLY pisses them off is when I play music way too loud... Then they just pout while I rock out!

    Female voices. Why didn't you say so. I have those voices too.
    The world is full of answers, some are right and some are wrong. - Neil Young
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  • dcmeigs
    dcmeigs Posts: 708
    edited March 2008
    I just got off he phone with Jeff at Sonicraft. He makes a passionate if not persuasive case for the use of his 0.1 uf platinum caps as bypass caps on both of the caps in the high pass crossovers. He claims the difference they make exceeds the difference brought bout by upgrading the tweeters. Has anyone tried them? He said a lot of the improvement is brought about by better precision in the phasing of the two channels. If so, I would conclude that it would be difficult to appreciate the difference by doing one speaker and the listening for the differences. You would just about need to add them to both speakers after the burn-in and then listen. The cost $29 per cap, $120 for the set.
    The world is full of answers, some are right and some are wrong. - Neil Young
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  • F1nut
    F1nut Posts: 50,746
    edited March 2008
    Yes, I tried them and I'm much happier without them. They create artifacts, which at first sound kind of neat, but soon become very annoying. Live music just doesn't sound the way those bypass caps make it sound.

    I passed some of them on to another Polkie who came to the same conclusion.
    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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  • dcmeigs
    dcmeigs Posts: 708
    edited March 2008
    F1nut wrote: »
    Yes, I tried them and I'm much happier without them. They create artifacts, which at first sound kind of neat, but soon become very annoying. Live music just doesn't sound the way those bypass caps make it sound.

    I passed some of them on to another Polkie who came to the same conclusion.

    Thank you. Jeff described them as adding spice to a recipe. Spice does seems like a good analogy for an artifact, does it not? I'll pass on the bypass caps and spend the $120 elsewhere.

    Here's where I'm now. The big decisions have been made and everything is on order.

    SDA IAs get:
    1 each RD0194-1 silk tweeters, the other tweeter is disconected. I'm going to call it a passive twadiator mod (TM) and pretend it is important to the effect.:cool:
    Sonicaps for the 12uf and 0.5 uf high pass.
    Dayton 25+2uf caps for the low pass.
    Mills 12 watt resistors.

    SDA 2B/CRS+ get:
    1 each RD0198-1 silk tweeters
    Sonicaps for the high pass, 5.6uf and 12uf (Elliot said he would find a 5.6 at the high end of the tolerance- for the 5.7)
    Daytons for the 20uf and the 30+10uf caps for the low pass
    Mills 12 watt resistors

    Again, thanks to everyone who offered advise. I can't wait to get started. Photos to follow.
    The world is full of answers, some are right and some are wrong. - Neil Young
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  • F1nut
    F1nut Posts: 50,746
    edited March 2008
    For the record, it's a 5.8uF that you want.

    Maybe it's just me, but for your own speakers, I'd go all Sonicap.


    CL, it's not the only way for most of us, just you. In fact, your idea is the worst way to judge.
    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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  • dcmeigs
    dcmeigs Posts: 708
    edited March 2008
    F1nut wrote: »
    For the record, it's a 5.8uF that you want.

    Maybe it's just me, but for your own speakers, I'd go all Sonicap.


    CL, it's not the only way for most of us, just you. In fact, your idea is the worst way to judge.

    That's interesting. I was on the horns of that dilema earlier and have held back sending the email to Sonicraft. Reason being, the SDA 1As only cost about $100 more since they only require the four 27uf. No big deal. The SDA 2Bs cost more but then again they are my own speakers and I plan to keep them. Lets see, with the money I saved on the 0.1 uf bypass caps... OK you win.
    The world is full of answers, some are right and some are wrong. - Neil Young
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  • F1nut
    F1nut Posts: 50,746
    edited March 2008
    dcmeigs,

    I'm not sure if you've ever read this before, so I'll offer it up. The way he describes bypass caps is exactly what I hear and the same conclusion I came to before reading his article.


    Bypass capacitors. In addition to the Multicap RTX, I have tried either .1 µF or .01 µF bypasses from Sonicap (Gen I and the Teflon® Platinum cap), Hovland, AudioCap, and Wima. In every case the results were similar. Let me digress for a minute or so (depending on how fast you read) and talk about crossovers.

    In the simple first order high-pass crossovers we are using for this capacitor comparison, the value of the single capacitor, together with the impedance of the loudspeaker driver, determines the crossover frequency. An 8 µF capacitor with the 4 ohm impedance of the Magnepan quasi-ribbon tweeter gives a crossover frequency of about 5000 Hz (1/2πRC). A smaller value capacitor (for example, 4 µF instead of 8 µF) will raise the crossover frequency. If we used only the very small value .1 µF capacitor without the 8 µF, we would hear nothing because the crossover frequency is now almost 400,000 Hz. Even a dog would not hear it!

    So why use a bypass at all? There are actually components of very high frequencies in some audio waveforms. Some are high order harmonics. If you think of a square wave, the right angles at the top of the wave are extremely high in frequency. Sometimes there are high frequency components in very fast audio sounds, for example, the instantaneous tap of a drum stick on a cymbal. These are the sounds that should be "helped" by including a small-value bypass capacitor in a high pass crossover.

    Well, I don't think so. If the 8 µF capacitor blocks frequencies below 5000 Hz and passes frequencies above 5000 Hz, why do we need what is actually another crossover for the same tweeter, but operating at frequencies already passed by the big cap? I am sure engineers have a very good reason, and a couple of them have tried to educate me on this subject. I respect the science and electrical theory on this subject, and my technical background helps me to understand it fairly well. But there is one small problem: the bypasses all sound bad! They add a quality that at first sounds like an increase in air and detail, but after a couple of hours becomes an intrusive harshness and discontinuity in the upper treble. Remove the bypass: all of the detail is present but without that grating and annoying sound. The high frequencies are cleaner, smoother, and much more enjoyable. It doesn't matter if the bypass cap is Teflon®, polystyrene, or common polypropylene, the results are very similar. And to be avoided.

    The entire article: http://www.10audio.com/sonicap_oimp_multicap.htm
    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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  • candyliquor35m
    candyliquor35m Posts: 2,267
    edited March 2008
    dcmeigs wrote: »
    I just ripped the stereo and sound array boards out of my buddies SDA IAs for the crossover upgrade. They used to be mine and I still love them so I'm going to do the deed. My SDA 2s are next if there is a significant improvement. It was nspindels post that got me off my arse.

    http://www.polkaudio.com/forums/showthread.php?t=62106&highlight=crossover+upgrade

    I do have a few questions. I have read quite a few of the posts on crossover upgrades, several dozen anyway, and I'm starting to get the gist but I haven't found a thread specifically for the SDA IA yet. If anyone can link me to a specific IA thread, that would be greatly appreciated.

    So, now with the silly questions:
    1) The schematics posted by DarqueKnight show a 3.5 ohm resistor with a rev.A note. These on my boards are 4 ohm. I will assume that a change to 3.5 ohms was the revision and use 3.5 unless someone can offer a reason to stay with the 4 ohm.
    2) It seems that the cap values change with tweater upgrades. I suppose I will upgrade to the 198s if they are still the recommended favorite. The schematics for my boards show 12 uf caps on the tweeters. If I do go with the 198s, what caps should I order?
    3) My boards dont seem to have polyswitches. Instead they have a pair of fuses. I think these need to go away. Any reason why I should not be done with these? (200w Hafler amp and reasonable -wife limited- listening levels).
    4) I have a total of three of the 750 silver mica caps (that are often refered to as the bypass caps, I think). Do all three of these go away with the polyproplyene caps?
    5) My stereo array board has a 0.5 uf ??? cap in parallel with the 4 (3.5)ohm resistor. The drawing says mylar but it looks electrolytic to me. Anyway, is polyproplyene the way to go with this cap and am I correct about the value? The drawing is a little hard for me to make out.
    6) The 6501 driver caps are 27 uf. I'm going out on a limb here and assuming they dont change with a tweeter change. Correct, or did I break an arm?
    7) I see the holes refered to as alpabetically labled. I'd love to see a drawing of the SDA IA board with these labels. Can anyone offer a link?

    Finally, most of the posts I read concerning the tweeter upgrades are several years old. Are the 198 tweeter upgrades a cut-and-dry issue or should I give that some more consideration? I'm not saying cost is no object, but hey, it's not my money. I just want these babies to rock.

    Thanks in advance.

    Dave

    Are you planning on doing any scientific before and after comparisons to see how the upgraded x-over and tweeter sound compared to the old ones?
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  • dcmeigs
    dcmeigs Posts: 708
    edited March 2008
    candyliquor35m wrote: »
    Are you planning on doing any scientific before and after comparisons to see how the upgraded x-over and tweeter sound compared to the old ones?

    Scientific?
    The world is full of answers, some are right and some are wrong. - Neil Young
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  • candyliquor35m
    candyliquor35m Posts: 2,267
    edited March 2008
    dcmeigs wrote: »
    Scientific?

    Yes I know how I would do it. If comparing the old vs the new in as scientific manner as possible to see if your money was well spent is important to you then give some thought to this subject. If it's not important then don't think about it.
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  • Face
    Face Posts: 14,340
    edited March 2008
    dcmeigs wrote: »
    Scientific?
    Just ignore him, most of us do.
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • Jstas
    Jstas Posts: 14,842
    edited March 2008
    candyliquor35m wrote: »
    Yes I know how I would do it. If comparing the old vs the new in as scientific manner as possible to see if your money was well spent is important to you then give some thought to this subject. If it's not important then don't think about it.

    Oh, I get it. Like when you used that super scientific method to figure out how well your self-titled "SL2000WC" tweeter worked, right?
    Expert Moron Extraordinaire

    You're just jealous 'cause the voices don't talk to you!
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  • ben62670
    ben62670 Posts: 15,969
    edited March 2008
    Face wrote: »
    Just ignore him, most of us do.

    I so wanted to say that, but I thought I shouldn't, but then I thought I should. It would not be fair to not warn you about the waste of your time with CL's off the wall numerous post about babbling.



    CL please don't stink up his thread.
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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  • candyliquor35m
    candyliquor35m Posts: 2,267
    edited March 2008
    ben62670 wrote: »
    I so

    No comment. I said nothing to you.

    dcmeigs can make up his own mind based on everyones suggestions. Mine are only worth $.02 just like yours.
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  • F1nut
    F1nut Posts: 50,746
    edited March 2008
    Scientific manner? Oh, you mean like the graph charts that clearly show what everyone was telling you to begin with. That it creates more problems than it solves such as new peaks, more of a roll off and let's not forget that 29dB suck out! You mean like that scientific manner!?! :rolleyes:
    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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  • dcmeigs
    dcmeigs Posts: 708
    edited March 2008
    There are a few interesting things I will do. I'll be getting a pair of 194s and 198s from Polk soon. The SDA 2B CRS+ are still together and playing right now. I can install the 194s intended for the 1As in the 2Bs without crossover modification or burn-in time and listen to the difference the new tweeters should bring to the party. Then when the electrolytic caps in the crossovers have been replaced with Sonicaps and the 198s are installed I can listen to that difference.

    I will also be able to compare the completed 1As with their 194s and Sonicaps to the moded 2Bs. I have said that I prefer the sound and sound stage of the 2Bs, but I plan to do away with the dimensional array tweeters in the 1As and I expect them to sound more like the 2Bs. We'll see if my expectations are realized.

    I had considered using the Dayton caps that Ben has used with good success and was persuaded to try the Sonicaps instead. It made sense to me to go "whole hog", as they say in Ft Smith, so as to have a reference at the current state of this art. This will allow me to use the bag of Dayton caps that wil be here soon to mod the crossovers in another set of 2Bs that I have and then I should be able to compare them in order to do a Dayton/Sonicap comparison. I'm thinking about doing them all in Daytons, high pass too, with 198s. If I can detect a significant and annoying difference, I can set out to "fix" them; first with Sonicaps on the high pass...etc.

    It's not science, but it's a journey.

    (But not that journey; there will be no Journey played through these speakers if I have any say in the matter)
    The world is full of answers, some are right and some are wrong. - Neil Young
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  • candyliquor35m
    candyliquor35m Posts: 2,267
    edited March 2008
    F1nut wrote: »
    Scientific

    No comment. This thread is not about anything you just mentioned :D
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  • Joe08867
    Joe08867 Posts: 3,919
    edited March 2008
    DCMEIGS, I have a question. Are you going to be using the CRS+ with the SDA1's or SDA2's? You may not want to do the TL upgrade to the RDO198 then. As they will not be as voice matched.

    I can't remember if you said what you be using them for. But if it is to create some kind of Home theatre setup you may want to think about it.
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  • F1nut
    F1nut Posts: 50,746
    edited March 2008
    You may not want to do the TL upgrade to the RDO198 then.

    Joe, your comment doesn't make sense. For him to use the RD0198-1 tweeters in either the 2B's or the CRS+'s, he has to upgrade the crossovers to TL status.
    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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  • dcmeigs
    dcmeigs Posts: 708
    edited March 2008
    Joe08867 wrote: »
    DCMEIGS, I have a question. Are you going to be using the CRS+ with the SDA1's or SDA2's? You may not want to do the TL upgrade to the RDO198 then. As they will not be as voice matched.

    I can't remember if you said what you be using them for. But if it is to create some kind of Home theatre setup you may want to think about it.

    Joe, I have confused you. When I said "together" I meant put together as in functional- whereas the SDA1As are apart with the crossovers on the bench- rather than 2 sets of speakers working together. English is my native tounge and I hope to learn it some day, but it's a tricky one and I don't hold out a lot of hope. (Or as they used to say in East Texas, I ain't never gonna learn no grammar nohow)

    There are only two sets of speakers. One is the SDA 1A. The other is a SDA2B/CRS+. I don't have a set of CRS+s, although I wouldn't mind having a pair. I suspect a guy could make a nice suround setup with them. I keep watch on craigslist.

    The 2Bs are mine and the 1As used to be mine but are now in a friends listening room. It's unlikely that they will ever meet again.

    Dave
    The world is full of answers, some are right and some are wrong. - Neil Young
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  • nspindel
    nspindel Posts: 5,343
    edited March 2008
    Hi - Just caught this thread. I don't think you'll be let down with using all Sonicap at all. I wish I had some advise for you on the 1A's, but I know nothing about them, I've only done the 2B mod. I did have 194's in there before I did the mods, then I put the 198's in when I did the TL mod. The highs are much, much better now, although I can't say how much of that is due to the Sonicaps vs. the tweeters themselves.

    One thing to note - you're going to need to peel off the hot glue covering one of the inductors in order to get to one of the holes for the 5.8uF cap. Be careful there!!!

    As far as the bypass cap is concerned. I took F1's advise and passed on it. However, one thing to note about the artifacts it introduced - according to the guy who modded my Squeezebox with the Sonicap Platinums, they take a LONG time to break-in. He's telling me I should be playing my Squeezebox between 600-1000 hours continuously in order to really open up the Platinums. So I'm not sure if the artifacts they introduced for F1 could have been the result of them just not being burned in yet. All I know is my 2B's sound just fine without 'em....

    Have fun, post some pics - you're going to love what it sounds like. You're in great hands with all the advice you're getting here. Well, almost all the advice, but I won't go there....
    Good music, a good source, and good power can make SDA's sing. Tubes make them dance.
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  • F1nut
    F1nut Posts: 50,746
    edited March 2008
    The Squeezebox guy's advice is a bit hard to take. Even Jeff Glowacki, the guy who makes them, says 200 hours. I had far more than that on them.....yuck!
    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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  • dcmeigs
    dcmeigs Posts: 708
    edited March 2008
    nspindel wrote: »
    Hi - Just caught this thread... I've only done the 2B mod...Have fun, post some pics - you're going to love what it sounds like. You're in great hands with all the advice you're getting here.

    Welcome to the thread. It was your enthusiastic thread on the 2B mod that prompted me to do this, and I owe you compliment for your well documented posts. And yes, I have gotten some very useful advise, most of it within hours of a midnight post; don't you people ever sleep?

    As for the bypass, the best way to know independantly would be to burn in the crossovers with the bypass mod for 6 months and then remove them and listen to the change. That's pretty much what F1Nut did and I'm happy to take his experience at face value. We don't need to know everything independently, especially given first hand testimony from an erudite source.

    And, on another matter, perhaps you can enlighten: My very lovely wife took off on a road trip with her friends this weekend. With no one around to suggest that I "turn that damn thing down", how will I know when it is too loud? Is it a flashing LED or something like that?
    The world is full of answers, some are right and some are wrong. - Neil Young
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  • ben62670
    ben62670 Posts: 15,969
    edited March 2008
    dcmeigs wrote: »
    don't you people ever sleep?
    Its kinda like a passing out kinda thing:D

    I hear you on the Sonicaps. People have questioned whether or not to replace resistors. I have not done a solid test whether the Mills are better than stock(I can't imagine them not especially at higher power levels), but if I didn't replace them I would have a feeling inside "should I have replaced them?". Funds is a big issue with me, and I have not been able to do a Sonicap comparo between speakers. It shall come.
    Ben
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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  • nspindel
    nspindel Posts: 5,343
    edited March 2008
    :cool::cool:
    dcmeigs wrote: »
    ...With no one around to suggest that I "turn that damn thing down", how will I know when it is too loud? Is it a flashing LED or something like that?...

    Nah - more like flashing lights from the police car in your driveway! If nobody's home to tell you to turn it down, then you're good to go until the neighbors start complaining...
    Good music, a good source, and good power can make SDA's sing. Tubes make them dance.
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  • nspindel
    nspindel Posts: 5,343
    edited March 2008
    F1nut wrote: »
    The Squeezebox guy's advice is a bit hard to take. Even Jeff Glowacki, the guy who makes them, says 200 hours. I had far more than that on them.....yuck!

    You know what the problem is though, Jesse? It's just like Ben said - once the guy tells me 600-1000 hours continuous to burn in the Platinums, if I don't do it then it'll always be in the back of mind that maybe it would have sounded better if I'd have let it go longer.

    At the end of the day, who really cares - it's not like speakers or an amp. It can keep breaking in without the system being on. And it's easy enough to do. I can make the thing play a lot longer than a thousand hours just by selecting Artist | Grateful Dead | Play ;)
    Good music, a good source, and good power can make SDA's sing. Tubes make them dance.
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