SDA 1C Crossovers....this weekend

avguytx

It's now time to yank some speakers out of my 1C's and get to the crossovers. I've had them long enough to go thru quite a few listening sessions with various music and now I'm ready. I know from talking to Ken that these are apparently one of those 2 piece crossovers instead of being on one board. So, in order to find out exactly tolerances, I'm going to delve into them finally. I'll take some pictures along the way and, of course, write down all of the parts that I have inside.

What are thoughts on upgrading the wiring inside with something a little larger? I don't mean to open a can of worms here but I'm figuring while I'm in there, it's no major task to do and I do have some 16ga and 12ga wire around. I'm also going to tie up the wires to make sure they don't rest on the backs of the speakers. When I pull woofers out, I think I have the ability to bring them out 18 to 24" to undo them! I'd say that's a little much!

As I've read from other posts, I would imagine I'll be replacing the SL2000's with the RD0's after this as the new caps, etc might tend to make them a little more bright. But, one step at a time. a) Find out what's in there, b) order the parts, c) rebuild the crossover, and, d) evaluate.

Ron Temple

I and a buddy are axiously awaiting your step by step account...great timing for me . Make all the mistakes and clue me in

avguytx

Don't hex me, Ron! This won't be my first run into (re)building crossovers but it is the most "packed" area I've had to work with. I used to build passive networks for one amp systems back in my car audio days using programs (and my hearing) to design them along with the manufacturers help. So, this is going to be a fun project for me once I get the parts in!

I'll try to get as many pics as I can along the way.

Polk65

This may be helpful.
http://www.polkaudio.com/forums/showthread.php?threadid=28024

If they turn out to be one piece crossovers...
http://www.polkaudio.com/forums/showthread.php?t=31617
http://www.polkaudio.com/forums/showthread.php?t=40330

Oxidation can sometimes hide deep inside wire. Snip and re-use or re-wiring is up to you. Most likely you won't hear any difference with new internal wire. 4"-6" out of cabinet length is closer to normal. Solder the crossover ends with Cardas eutectic then crimp and treat the driver ends with Caig.

RD0 tweeters are smooth not bright. Remove the resistors near your SL3000's and order RD0194-1 replacements. These replace the stock SL2000's that go with your crossover.

Use an exhaust fan when soldering and this toy will make it easier.
http://www.radioshack.com/product/index.jsp?productId=2062731

avguytx

Finally got around to snapping some photos of the crossovers. Sorry one is rather blurry. Flash in a dark cabinet, you know. I wrote down all the values on the caps and resistors and then verified them with the Polk Compendium and they "jive" together. The 750pf mica cap that's paralleled with the 12uf mylar I'm assuming is a bypass capacitor?

It's a wiring nest inside of that cabinet with all those single stranded wires going everywhere. I'll definitely have to button those up some before they go back together. I wouldn't be able to handle it putting them back together knowing the wires were like that inside! Ok...I'm OCD. Sue me. I'm also going to get some new foam gasket tape for all the woofers, passives and terminal cups. I might even go ahead and trace some new ones out for the tweeters since they are smashed down. I can't see them having a perfect seal like that. (there's the OCD again)

So now I start perusing the websites and getting the parts ordered. I will eventually change the banana plugs and make a new IC cable but that's for the next project. While these are out of the setup, I pulled out my old Dynaco A-25's and hooked them up for awhile. Man, they have such a pleasing sound to them. Not fatiguing at all. You gotta love a simple 6db/oct crossover! Oh yeah...I swapped out the single cap on each one of those and rewired them with some spare 12ga I had around. A little overkill on the wire but, hey, it was here! That made a noticeable difference even on those little speakers. I also have a pair of A-10's I may have to tinker with one of these days. Sheesh...

avguytx

F1nut and others have talked about this in other threads I've been researching but I thought I would ask this for the hellovit. I need 2) 750pf caps which are only about a buck each at "justradios.com". Would anybody out there have a spare pair per chance? If not, I would assume they'll just stick these in a basic (or padded) envelope for mailing. It would be nuts to pay $5 in shipping for $2 in parts...but, I'm sure I've done it more than once. I was hoping partsconnexion.com had them but I didn't see them unless I overlooked them. I'm getting the Solen PB caps and the Mills resistors from them.

Thanks to all...

Edit: I take that back. Partsconnexion.com does have 750pf Silver Mica caps but they are rated at 300v and not 500+ like some others. Would that be a major concern? Especially seeing that some of the existing electrolytics are 50v to 100v and the new Solens will be 400v.

F1nut

You will not need the 750pF bypass caps since you are upgrading from the stock caps.

Even though you think the speaker gaskets are flat, they sre still providing an excellent seal. Using thicker gasket material can actually cause air leaks and stripped screw holes.

george daniel

I just did some 1c's,,I went with sonicaps and bypassed the 750 silver mica, polyswitch and unexpectedly had to replace the inductors,as one was laying in the bottom of the cabinet,,all in all,quite frustrating(I'm impatient and had to wait on parts) but in the end, very rewarding. Good luck and enjoy.

avguytx

F1nut wrote: »

You will not need the 750pF bypass caps since you are upgrading from the stock caps. Even though you think the speaker gaskets are flat, they sre still providing an excellent seal. Using thicker gasket material can actually cause air leaks and stripped screw holes.

That's kind of what I was thinking myself. Why were those little turds in there anyway?

It's not only the speakers, it's the terminal cups and tweeters. On a couple, they are even missing. I wasn't going to use any thick stuff...just some thin foam from a couple of the home and car speaker lines I rep already. Plus, I'm sure I have some gasket material left over from the last 20+ years of car audio I've done!

avguytx

anonymouse wrote: »

Splurge for Sonicaps for the tweeter sections. You will not regret it.

The nice thing is, there is only a single 4.4uf cap for the tweeter section so that is very doable! The bad part is, it's on the bottom side of the crossover and will have to be relocated to the top side. No biggie. Sonicap shows a 4.3uf cap. Being that they are probably 1% tolerance, shouldn't that be close enough instead of having to buy a .1uf cap to wire in parallel? Especially if the original caps were most likely 10% tolerance at best.

Thanks for the recommendation!

avguytx

All parts are ordered and hopefully will be here before I get back from traveling late next week. I hope to rebuild them next weekend. Thanks again to George Daniel for sending me some resistors and caps! I'm looking forward to this project but it's not like there aren't about 50 others I need to do. Gotta have priorities, though...especially since these are the main speakers I listen to!

heiney9

avguytx wrote: »

All parts are ordered and hopefully will be here before I get back from traveling late next week. I hope to rebuild them next weekend. Thanks again to George Daniel for sending me some resistors and caps! I'm looking forward to this project but it's not like there aren't about 50 others I need to do. Gotta have priorities, though...especially since these are the main speakers I listen to!

You need to MAKE it a priority . Because the improvement is excellent! we like lots of pics and documentation .

H9

avguytx

YAY! The crossovers made it in today and, although it's a beautiful day outside, I think I'll just go ahead and knock these out today. I have all the goods to get it done so there's no use for procrastination. I got the yardwork done for the weekend so that's out of the way and I still need to go grocery shopping but that can wait. So, the 1C's are unhooked and are ready to be dissected and in their place for awhile are my 1970's vintage Electrovoice Interface C's in their place that have been recapped and rewired. I always forget how good these sound. Definitely different than the SDA's, but good.

I'll try to get some pics along the way and post as I go. Mine are the 2 separate "boards" for crossovers where George Daniels are on the single board. (IIRC) So wish me luck and away we go...

george daniel

Hey,,, take your time and have fun

avguytx

First crossover (left channel) is done and I am buttoning it back up as I write. I'm taking a quick break to check something out. It only took about 30 minutes to do the actual soldering but longer for the preparation...taking stuff out, etc.

George...I'm glad you chimed in and maybe someone else who has done some 1C's can chime in, too.. I know your crossover layout is different than mine since mine are in 2 separate pieces versus yours being one. The right 2 mids for the stereo drivers in mine are wired kind of weird versus the dimensional. The dimensional drivers use blue for (+) and green for (-) and are wired in parallel. Makes sense. The stereo use black for (+) and white for (-) but...this side is wired in series from the crossover instead of parallel like the dimensional drivers! Hmmm...

Basically, both the stereo and dimensional drivers have one pair of wires going to them from the crossovers but the dimensional are wired in parallel and the stereo drivers are wired in series. Now I'm going to have to take the drivers out of the Right channel and see what's up with it and see if they coincide.

More to follow...

ben62670

One piece at a time, and you can't go wrong:)
I bet you with like them right off the bat.
You might have to change your screen name to 2ChannelGuyTX:p
Enjoy.
Ben

avguytx

Update...right side "jives" with left side on the wiring. That had me a little freaked and I haven't even had a beer yet! Maybe now is a good time. lol

avguytx

ben62670 wrote: »

One piece at a time, and you can't go wrong:)
I bet you with like them right off the bat.
You might have to change your screen name to 2ChannelGuyTX:p
Enjoy.
Ben

Oh, I'll always be a 2-channel preferred listener versus H/T no matter what! Although, the new Dream Theater (Systematic Chaos) bonus DVD with the 5.1 mix sounds pretty darn good right now.

ben62670

What is this "Systematic Chaos" you speak of?
Am I getting old?

Ben

avguytx

Dream Theater! They are one of my favorite bands...rock wise.

avguytx

Here are some pics of the first crossover done along with some inside of the cabinet photos after I shortened some of the wires, tied them out of the way and with some new connectors on them. I might rewire them with different wire some day but I can't see it making a night and day difference for such a short run. At least not to my ears.

The first couple of pictures are before the changes. You can see how the "rats nest" of wiring in the cabinet is cleaned up now and much nicer.

avguytx

Hmm...it won't add one of the first ones. Here's another before picture while they are still in the cabinet.

george daniel

looking good,,nice work:)

ben62670

Hey you put the resistors in backwards!

avguytx

Riiiiiiiigggghhhhhhttttt.......



2nd crossover is together and now going back in the cabinet. I should have tunes from them again in the next half hour after I get the wires shortened and tidied up. YAY! Then, the break in period begins......

ben62670

I am wondering what you used for resistors though, and how does it sound?
Ben

avguytx

Mills resistors from Partsconnexion.com. Little dudes, aren't they?

Well, I stayed up till about midnite listening to the freshly recapped 1C's and, although I know there is break in time, they still sound better. Strings are more detailed, bass is more controlled, etc. They just sort of opened up and dropped the veil...some. After break in, it will be more noticeable but I am extremely happy so far. I know it sounds weird but I feel better knowing all that extra wire isn't dangling around in the cabinet and they are shortened and "tidied" up.

The first CD I played thru them after getting them back up and running was Allison Krauss' newest CD because that's the last thing I listened to on them before starting on the crossovers. I was amazed that the SL2000's didn't sound overly bright like I had anticipated them doing. (one day I will do the RD0's) I am currently listening to Diana Krall's "When I Look Into Your Eyes" and everything still sounds great across the board. The bass definition has more control to it versus before which sometimes seemed a little "sloppy" (not awful, though...) I can hear the fingering of the bass strings with greater detail than before. The sound stage sounds wider and the instruments on anything I play are more localized and separated. Plus, there is definitely more depth of staging to the music especially noticeable on "good" recordings.

I have literally played all sorts of music thru them since last nite including Rush's "Moving Pictures (vinyl), Rickie Lee Jones debut LP from '79, Yes' "Close to the Edge (vinyl), a couple of Lyle Lovette CD's, Dream Theater's Systematic Chaos, Foreigner's "The Best and Beyond" CD, ZZ Top's Eliminator on CD and Amos Lee's "Supply and Demand". I swear, I hear new subtleties in tracks that I am familiar with on each new thing I play. I expected this as I have built crossovers thru the years for speakers I have built for myself for home...plus, back in my car audio days, I built elaborate passive crossover networks for single and dual amp systems. I am a firm believer in freshening up the crossover networks on older and, sometimes newer speakers, to step them up a notch.

Since I forgot to order them when I initially ordered my caps and resistors, I am going to order some new binding posts and make a new IC cable and connector for the SDA effect. I also need to order some new thinner black grill cloth and redo them as well. I agree with those who have redone them...that material is rather thick! I typically listen to them with the grills off just to squeeze all I can out of them.

All in all, that was a fun project and, while not the hardest I've ever done, was very enjoyable and the end results are outstanding. Now I just have to roll thru lots of music and hear things for the first time again. And after they are more broken in, I'll have to do it again! Oh well. Isn't that why we do this?

heiney9

It's a wonder thing, isn't it!! Just think they will only get better. RD0's are definetly your next step as that will take them up another notch

avguytx

Damn, these are sounding better all the time. I've got some Norah Jones as I'm working and it just sounds spectacular. You gotta love working at home and getting to listen to some tunes! At least I get to enjoy them about 2.5 out of 4 weeks a month as I travel the rest of the time.

Hmmm....the tops of these cabinets could use some Tung oil. They just literally soak up the furniture polish!

F1nut

The end caps were finished with lacquer. If yours are soaking up furniture polish, they need refinishing, not an application of tung oil.

avguytx

Thanks F1 for the info. What do you recommend? A light sanding and re-lacquer?