Author Topic: Crossover Mods  (Read 9832 times)

Offline paden501

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Re: Crossover Mods
« Reply #15 on: January 16, 2010, 08:47:31 PM »
Finally some photos.

First, a comparison of 40uf capacitors.  Not that bigger is always better, but DANG!   :o



Here's everything that came off of the left channel:



And here's everything that went on:



Next, a photo of the aforementioned burned up poly-switch (ewww):



And finally a photo of the finished product:


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.



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. 
~Matt
--- My System ---
Front L/R: Polk Audio SDA-1C w/ Modified xovers
Amp: Carver TFM-24
CD: Jolida JD100a
HTR/Pre: B&K Reference 20
Turntable:Pioneer PL-516 W/ Shure M97xe
Surrounds -Polk Audio Monitor 4As

Offline Slim-Shaddy

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Re: Crossover Mods
« Reply #16 on: January 16, 2010, 10:41:17 PM »
Looks like you did a great job. want to recap my macs?
I am confident that an SL-1200 is capable of outperforming turntables of much higher expense with minor modification.

Offline paden501

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Re: Crossover Mods
« Reply #17 on: January 16, 2010, 10:57:45 PM »
Looks like you did a great job. want to recap my macs?

If you buy the goods, I'll help you re-cap them. 

~Matt
--- My System ---
Front L/R: Polk Audio SDA-1C w/ Modified xovers
Amp: Carver TFM-24
CD: Jolida JD100a
HTR/Pre: B&K Reference 20
Turntable:Pioneer PL-516 W/ Shure M97xe
Surrounds -Polk Audio Monitor 4As

Offline Slim-Shaddy

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Re: Crossover Mods
« Reply #18 on: January 17, 2010, 03:19:00 PM »
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. 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
I am confident that an SL-1200 is capable of outperforming turntables of much higher expense with minor modification.

Offline paden501

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Re: Crossover Mods
« Reply #19 on: January 17, 2010, 10:57:43 PM »
Interesting.  Does that change your mind on whether or not you still want to persue the changes?

~Matt
--- My System ---
Front L/R: Polk Audio SDA-1C w/ Modified xovers
Amp: Carver TFM-24
CD: Jolida JD100a
HTR/Pre: B&K Reference 20
Turntable:Pioneer PL-516 W/ Shure M97xe
Surrounds -Polk Audio Monitor 4As

Offline Slim-Shaddy

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Re: Crossover Mods
« Reply #20 on: January 17, 2010, 11:02:02 PM »
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....
I am confident that an SL-1200 is capable of outperforming turntables of much higher expense with minor modification.

Offline F1nut

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Re: Crossover Mods
« Reply #21 on: January 18, 2010, 12:13:36 AM »
Sorry, but RR is wrong.....on so many levels.
  '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 turd by the clean end."
 

Offline Slim-Shaddy

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Re: Crossover Mods
« Reply #22 on: January 18, 2010, 09:51:37 AM »
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.
I am confident that an SL-1200 is capable of outperforming turntables of much higher expense with minor modification.

Offline F1nut

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Re: Crossover Mods
« Reply #23 on: January 18, 2010, 12:24:40 PM »
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.
  '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 turd by the clean end."
 

Offline Slim-Shaddy

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Re: Crossover Mods
« Reply #24 on: January 18, 2010, 01:05:45 PM »
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.

I am confident that an SL-1200 is capable of outperforming turntables of much higher expense with minor modification.

Offline bmwr75

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Re: Crossover Mods
« Reply #25 on: January 18, 2010, 07:18:55 PM »
Replacing resistors is rarely required in crossovers.  They don't go bad with age like electrolytic capacitors.
Media: CDs ripped to Apple Lossless files
Source: Mac Mini using iTunes and Bit Perfect
DAC: AudioSmile modded Behringer DEQ2496
Preamp: Rogue Audio Perseus
Crossover: miniDSP 2X4 HD
Amp: Vincent SP-331
Mains: KEF LS50
Subs: dual SVS SB-2000

Offline F1nut

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Re: Crossover Mods
« Reply #26 on: January 18, 2010, 08:55:29 PM »
Quote
  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.


Quote
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.
  '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 turd by the clean end."
 

Offline paden501

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Re: Crossover Mods
« Reply #27 on: January 18, 2010, 11:18:28 PM »
Quote
 
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.
~Matt
--- My System ---
Front L/R: Polk Audio SDA-1C w/ Modified xovers
Amp: Carver TFM-24
CD: Jolida JD100a
HTR/Pre: B&K Reference 20
Turntable:Pioneer PL-516 W/ Shure M97xe
Surrounds -Polk Audio Monitor 4As

Offline paden501

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Re: Crossover Mods
« Reply #28 on: January 22, 2010, 12:00:03 AM »
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.

~Matt
--- My System ---
Front L/R: Polk Audio SDA-1C w/ Modified xovers
Amp: Carver TFM-24
CD: Jolida JD100a
HTR/Pre: B&K Reference 20
Turntable:Pioneer PL-516 W/ Shure M97xe
Surrounds -Polk Audio Monitor 4As

Offline F1nut

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Re: Crossover Mods
« Reply #29 on: January 22, 2010, 12:31:29 AM »
Told ya!
  '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 turd by the clean end."