Vintage HiFi Audio Forum
Audio Discussion => DIY => Tweaks => Topic started by: paden501 on January 12, 2010, 09:26:48 AM
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hey just wanted to put this up as an FYI. I just ordered the parts to do a crossover upgrade on my SDA-1Cs.
I'll be using Mills 12w resistors and Clarity Cap PX line capacitors. Hopefully the parts will be in by the end of the week. :P
I'll update this with some photos as the action kicks up.
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Why the PX and not the ESA?
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I've got a limited budget. The ESA's came highly recommended, and I may someday step up to them. For now though, I can only really afford to go as far as the PX.
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Good luck on your project Matt! I have done several SDA crossover upgrades with ver nice results. Have you changed the tweeters?
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I haven't done the tweets yet. That's one of the reason that I went with the middle-grade PX caps, so that I could save money for RD0's in the future.
Hopefully this upgrade is as big of an improvement as others have hinted.
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I've got a limited budget.
That explains it alright.
Hopefully this upgrade is as big of an improvement as others have hinted.
It will be, but remember, they have to burn in for a couple hundred hours, so don't pass judgement until then. Get those new tweeters asap.
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Thanks F1.
I've got a 'tweeter fund' going right now. It'll take me a few months to save up the cash though. I'm also trying to pay off my car and our new washer/dryer and such at the same time (I hate it when the rest of life interferes w/ my audio obsession).
My long term plan is basically this. I'm going w/ the PX for now. I'd imagine that they're a good step better than the stock electrolytic caps on the board right now. If I fall out of love with them sometime down the line, I'll upgrade again and likely reuse at least the 12uf and 39uf PX caps in my monitor 5bs that I use as surrounds... so it won't completely be money lost.
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I hate it when the rest of life interferes w/ my audio obsession
I can relate.
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Caps made it today. I'll be installing them this weekend. The resistors are on their way from SonicCraft. They should be here on Tuesday.
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I'd suggest you wait for everything to arrive as it can get a bit tricking fitting all the new parts. A dry fit is always a good idea.
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I'd suggest you wait for everything to arrive as it can get a bit tricking fitting all the new parts. I dry fit is always a good idea.
While that's probably a good idea, I decided to dive right into it. I'll throw some pics up later on.
8)
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Well, you can't say you weren't cautioned. Resistors get hot, so make sure you leave plenty of open space for them.
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Thanks for the caution F1
The mod went fine. The caps are all soldered and glued in. I left a ton of space around the resistors so that I have room to work later.
Unfortunately, I can't seem to find my camera's USB cable right now, so photos will have to wait. I did run into some 'justification' along the way.
I had previously removed the left speaker's xover to inspect it and get the right values... but I've never been in the right cabinet before tonight.
Well... when I pulled the right xover, I knew right a way that I was in trouble, because somebody had been in there before and labeled the connectors. It looks like the previous owner had blown a poly-switch and to fix it he simply twisted the switch around until the leads contacted each other and jumped the switch. Well, the switch was completely burned up, as was part of the 12uf capacitor nearby. Lots of chalky black stuff was on the PCB and the end of the capacitor, and almost no evidence of the polyswitch remained, other than a little bit of the coating.
So right there, I feel justified in doing this modification. The system is back together for now, and sound pretty good. I can't make a judgement on the mod really just yet, as the caps are nowhere near broken in. I will say that immediately I notice more depth though.
M resistors will be in Tuesday. When I do them, I also plan on applying dnamat to the baskets of the woofers and PR, as well as appying mortite around the basket rings.
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Excellent, seems like you're on your way.
Mortite...yeah, I don't know I just can't get behind that one....oh well.
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Excellent, seems like you're on your way.
Mortite...yeah, I don't know I just can't get behind that one....oh well.
Well its only a couple bucks so I'm going to try it. We'll see what happens. I figure it can always come back off if it's no good.
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Finally some photos.
First, a comparison of 40uf capacitors. Not that bigger is always better, but DANG! :o
(http://farm5.static.flickr.com/4014/4279674219_b3018c051e.jpg)
Here's everything that came off of the left channel:
(http://farm5.static.flickr.com/4046/4280417336_060d22fc85.jpg)
And here's everything that went on:
(http://farm3.static.flickr.com/2628/4280416790_80c322fa36.jpg)
Next, a photo of the aforementioned burned up poly-switch (ewww):
(http://farm3.static.flickr.com/2740/4280416114_94f6676869.jpg)
And finally a photo of the finished product:
(http://farm5.static.flickr.com/4064/4280416464_f12d45371f.jpg)
as you can see from the last photo, i replaced the polyswitch with a .5ohm Mills resistor and used 2 2.2uf capacitors in place of the 4.4uf cap that came off.
This was a pretty easy job for the most part. The only piece that was a little tricky was the placement of the big 40uf cap. it needed to hang off the board quite a bit in order to clear the driver connector.
(http://farm3.static.flickr.com/2709/4279673637_09b85e4098.jpg)
I havent spent enough time with it for a real conclusion on the sound quality and I still have to replace the rest of the resistors later this week.
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Looks like you did a great job. want to recap my macs?
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Looks like you did a great job. want to recap my macs?
If you buy the goods, I'll help you re-cap them.
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So, I e-mailed Roger Russell, the designer of the xr-16s about recapping them and this was his reply...
You might contact www.audioclassics.com (http://www.audioclassics.com). It is very unlikely that you need to do this. You have been hearing too many opinions and no proof. If anything is to go bad in the system, it would be the drivers. Save some money and time. Roger
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Interesting. Does that change your mind on whether or not you still want to persue the changes?
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Yeah.... If I'm going to listen to anyone about changes to be made to a speaker system, it's going to be the one who designed and built them. Although, by his response it did seem like he was a little disgusted with the thought of someone else messing with "his" speakers....
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Sorry, but RR is wrong.....on so many levels.
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Please elaborate F1. The prospect of not wasting time or money is an intriguing one. The more I read about the project of recapping speakers, it seems less and less daunting, so, I really wouldn't mind doing it. But, sinking a couple hundred dollars into a pair of speaker for no noticeable improvement is something I definitely need sold on.
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There's only one way you're going to find out, try it.
That said, you will note that he didn't say upgrading to superior film/foil caps and better resistors wouldn't make a different, he said that it was unlikely that they have gone bad. Even that statement isn't true as electrolytic caps have a finite life span. Whether yours have reached that point I couldn't say, but I can say that without question, upgrading will make a difference.
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Yeah, I guess if I can only gain from the upgrade it's not pointless at all. I'll probably wait until I have another reason to open the speakers up. I should have done it when I refoamed... oh well. Since it seems like I'm not going to be able to get a schematic, do I just get the values from the existing caps and resistors? Here's a pic of the crossover from a XR 14. Mine will be very similar.
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Replacing resistors is rarely required in crossovers. They don't go bad with age like electrolytic capacitors.
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Since it seems like I'm not going to be able to get a schematic, do I just get the values from the existing caps and resistors?
Yes, everything you need to know is printed on the parts. If you've got any questions, I'd be glad to help. I will also guarantee that you will hear a difference.
Replacing resistors is rarely required in crossovers. They don't go bad with age like electrolytic capacitors.
While it's true that they don't have a finite life span like electroylic caps, resistors can and do affect the sound quality, so replacing those cheap cement block types with high quality non-inductive wire-wound types is highly recommended.
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While it's true that they don't have a finite life span like electroylic caps, resistors can and do affect the sound quality, so replacing those cheap cement block types with high quality non-inductive wire-wound types is highly recommended.
I'll be able to test and verify that theory tomorrow. Right now I only have caps done (except putting a resistor in place of old polyswitches). Tomorrow my resistors will be in, so I can do a comparison old vs new w/ just the resistors.
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Ok so the mod is now complete. I soldered in the mills resistors this evening, and while I was in there I added dynamat to the driver baskets and applied mortite to the driver-baffle mating surface.
The difference is stunning. I will say that I've been running with the new caps for about a week now and haven't been blown away totally, but with the addition of the new resistors i am SHOCKED. I've listened to several songs that I know very well in the last hour or two, using two different amps (Hafler DH-220 and a Carver TFM-25) and with both amps there is just a ton of little details in the music that were never there.
The vocals did seem to move back in the soundstage a bit, especially on the Carver, and the stage is wider with both amps. I can also hear a lot more 'SDA magic' than before.
Bass has more 'slam' than it did before. This is of course even more pronounced with the more powerful Carver amp, but is noticable with either amplifier.
In the middle, I get more sense of realism. This is especially true in percussion instruments and guitar plucks. Instead of a 'muddy' sense of when a key or drum was struck, drum hits and guitar plucks have more crispness about them now.
All in all, I'm very pleased with the mod.
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Told ya!
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Told ya!
Yeah you were dead on. Thanks for all your input! I could not have done this without the advice of experts like you and some of the other guys on the Polk boards.