SDA1C crossover upgrade complete

WilliamM2 · August 2005

Got the final parts today to do the crossover update. Pictures came out poorly, but figured I'd post them anyways, as I haven't seen pics of the SDA1C crossover posted before.

Also put in new binding posts, gold, but nothing fancy, and eliminated the SDA cable connector using the old original negative binding posts. Now plain old speaker wire works for SDA, and a much more solid conection than the plug. I did retain all the original parts, so it could be put back if wanted.

As a side note, I have seen comments on the poor quality Silver Mica cap that Polk used, on mine, it was a 300v 800pf cap with 1% tolerance. Changed it anyways, since I had the parts. Other than what can be seen in the pics, there is a 1uf cap paralleled to the 39uf on the back of the board, and if you look closely, you can see the .10uf cap paralleled on the 4.3uf.

Didn't finish in time for any serious listening today, maybe tommorrow.

trubluluc · August 2005

Looking good William!
Hey that's a great idea using the old binding post as a SDA connection.
Simple, clean, effective.

-Luc

SCompRacer · August 2005

Fine job William! Very clever using the old binding post on the SDA interconnect.

I still haven't been able to sit down and give mine a good listen since the upgrade. So I've got the mother in law putting some hours on them while I'm working. Dug her old Glen Miller albums out of storage. I asked her to show me how she used to jive and Jitterbug to that music, but she says not a chance at 82 years old.

BobMcG · August 2005

WM2,
Congrates! Nice job, looks good.

WilliamM2 · August 2005

Thanks for the positive comments.

I can't take all the credit though.I have a friend that repairs electronics for a living, his soldering skills are a better than mine (or anyone else I have ever seen), and he also has a solder removal machine. He removed all the old components, and soldered in the new polyswitch and silver mica in about 3 minutes per crossover. I hot glued all the new caps in place, and he soldered them up, and installed the new resistors. Whole thing took about half an hour for both. It took me longer to do the binding posts than it took him to do both crossovers!

They don't sound much different, perhaps clearer in the midrange and highs, but not the difference I hear others describe. But maybe that's because I paralelled the 1uf and .10uf caps, and have EXACTLY the same values Polk did, Most seem the skip those two extra caps, maybe it changes the crossover point slightly, resulting in a bigger difference.

I mainly did it because of the age of the components, so even if there isn't much difference, I still think it was worth it for the peace of mind of knowing everything is working as it should, and my polyswitches won't fail, as I have read about here.

With this, and the new tweeters I installed three months ago, they should be set for another 16 years of listening pleasure...I hope.

danger boy · August 2005

nice work. looks very good. maybe the need time to break in?

WilliamM2 · August 2005

I left them playing from 8am to 11pm, 3 days in a row, and again for about 8 hours today, that's over 50 hours.

As I said, I do think they are a little clearer in the mids and highs, but it's such a small difference I'm not sure.

I'm beggining to think most of the sound improvement tweaks I read about here, are purely placebo effect in the mind of the listener. This belief is confirmed when I see threads like this:

http://www.polkaudio.com/forums/showthread.php?t=31599

Either way, as a said above, I do think it was worth it for peace of mind. Like preventive maintenance.

Dennis Gardner · August 2005

WilliamM2 wrote:

I'm beggining to think most of the sound improvement tweaks I read about here, are purely placebo effect in the mind of the listener.

Blasphemy!!!!!!!!!!!!!!

Just think, now you have a freshly modded version of 1Cs! Mods are all the rage now. People pay top $$ for tweaked and modded stuff. I'm glad you did the mod with pics so I know what to look for when I get the time this winter to upgrade my pair.

Thanks,

DG

danger boy · August 2005

M2 what are you driving them with?

I have non upgraded SRS's. two things that recently improved my sound was an upgrade to the pre amp, and adding a better CD player. both yielded good sound quality improvements.

I have yet to replace the tweeters in mine.. that's probably the next upgrade. i hope that yields good improvements too.

WilliamM2 · August 2005

I'm driving them with a Denon POA-2400 amp, 200 watts per channel at 8ohm, 400 watts at 4ohm, 750 watts at 2ohm. Being a 6ohm load, they should be recieving about 300 watts, they definetly have enough power. I have had this amp and speaker combo for 16 years, I have tried several other amps over the years (Adcom, Parasound, etc.), and always go back to the Denon, to my ears, it's the best SS amp I have heard.

I have it set up through a Yamaha RXV-1500 as pre-pro for 5.1 channel listening, or direct from the player to the amp for 2 channel. Players are a Yamaha 5 disc and a Marantz single disc.

After listening to Al Di Meola - Kiss my Axe, this evening, I am sure there is some improvement, but very slight.

Don't get me wrong, the SDA's already sound incredible, that's why I have kept them so long, so I really didn't expect a huge change in the sound.

As far as the tweeters go, you will love the new ones. That was a much bigger improvement than the crossover upgrade, noticable immediatly.

F1nut · August 2005

WilliamM2 wrote:

They don't sound much different, perhaps clearer in the midrange and highs, but not the difference I hear others describe. But maybe that's because I paralelled the 1uf and .10uf caps, and have EXACTLY the same values Polk did, Most seem the skip those two extra caps, maybe it changes the crossover point slightly, resulting in a bigger difference.

Increased clarity and detail are mostly what you get from the crossover upgrade. Generally, it's not a night and day difference, not much in audio is. It's got nothing to do with having the exact same values either. I think the only placebo effect in force here is that you were expecting a night and day difference. It may also be a case of what is upstream. Better caps might have made a bigger difference too.

WilliamM2 · August 2005

I think the only placebo effect in force here is that you were expecting a night and day difference.

I was only expecting what others had described:

Well, that was a no-brainer. After listening to the single modded xover and the original, side by side, it was a night and day difference. It took me less than 20 minutes to do the second one.

3. Benefits can include, increased detail, greater speed, smoother top end, deeper/tighter bottom end, lusher mids and better separation/soundstage.

But I'm not complaining, as I said above, I think it was worth it. Every improvement adds up, no matter how slight.

F1nut · August 2005

I didn't think you were complaining, I was just offering possible explainations for your findings. What can I tell you, one man's night and day is another's yawn. There are so many variables involved in audio not much is written in stone.......note I said, "can".

BobMcG · September 2005

I can't honestly tell you what improvements came from the crossover upgrades I made to my 2.3s. In the middle of the project I received my new DODD AUDIO MLP which immediately went into my main 2ch system which was running the Carver Amazings. When the 2.3s were done they went into the system. So I was left running the upgraded 2.3s with the new DODD. (I know, that sucks

) I do know the total result which is greatly increased clarity and detail. I feel comfortable with the knowledge that the 2.3s now have fresh, higher quality components now and are better than new. I can live with that.

SDA1C crossover upgrade complete

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