Labor of Love

BobMcG

Just started working on the 2.3's crossover mods. I'll need to order four small 1000pf caps though to finish the job. (I had bought two 750pfs thinking they were what I needed.) With one done (except mentioned caps) I took some shots for comparison. The only change done on the still stock crossover is the new upgraded polyswitch, then I thought to take some pics.

F1nut

Bob,

You need 4 total 750pF, 5% tolerance silver mica's, not 1000pF. The schematics call for 750pF, but Polk used 1000pF with a 50% tolerance, not good!

Order them from these guys, http://www.justradios.com/mica.html

BobMcG

Thanks Jes. I have two of those now, I'll just get two more.

Yeah, I shook my head in amazment when I read 1000 +\- 50% !

trubluluc

Guys this thread has come at the perfect time.
First, HOLY **** Bob, look at the size of those caps.

Questions:

1. As I'm sure I don't want to have to solder in new caps. Has Polk done anything in the way of upgrading their stock crossovers?
I mean if I were to buy new ones from them would they be any better than what originally came with the speakers?

2. Do you really have to go that big to make the upgrade worthwhile?
As they're hanging off the plate, how are you securing them.

3. What does all this labor of love get you in Sonic improvements?

I just ordered my new replacement tweeters for the 1.2TL's, so while I'm messing around, this would be the time to look into crossover upgrades.

Thanks,

-Luc

BobMcG

Jessie, I installed the two 750 +\- 1% mica silvers into the first crossover and ordered two more. They should arrive while I'm at work next week.

Luc, Actually the caps are the size they are because they are all uniform with a 400volt rating. The stockers are all different sizes because they are all over the map with their (lower) voltage ratings. (The stock 40 is smaller than one of the 12s but is lower in voltage.) The big 40fu cap is the only one hanging slightly off the board and I used a jumper and hot glue gun to secure it and the rest of the caps. The center 12fu is onboard a 20 via jumpers and the other 12 is ontop of and pigtailed to a new Mills resistor.

Caps can deteriorate over time and use and none of the SDAs are very young making it a good idea to replace them. This allows you to replace the stockers with higher quality parts.

F1nut

1. You can not buy SDA crossovers from Polk any longer.

2. The original caps are mylar and electrolytics. By nature they are small in size. The replacement caps can be metalized polypropylene film, paper in oil, film and foil, polystyrene and some are combinations of the aforementioned. All of these caps are larger by nature with the most popular upgrade cap for crossovers being the metalized polypropylene. You can mount the new caps in a vertical position if desired, so that they don't hang off the edges. Doing a dry fit will give you the best idea on how to position them. As Bob mentioned, hot glue should be used to help secure them.

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



Bob, are you getting the 1% mica's from Handmade's? I found the guy and his site hard to deal with and opted for Just Radio's 5% mica's. In either case, a vast improvement over the stock garbage.

BobMcG

Yup, Handmades. I've had no problem with the company.... so far. I've got a couple of more orders coming from them. I'll let you know how it goes.

trubluluc

I'll have to do the upgrade now for sure.
Thanks Bob and Jesse!
Of course I may need you to talk me through it.

-Luc

WilliamM2

I've been thinking about upgrading the crossovers in my SDA-1C's. Is there a parts list, or a schematic available?

I was just going to take them out and replace with the same values, but it sounds like some of the values could be different, such as the 1000's and 750's mentioned above.

Has anyone done 1C's?

F1nut

William,

Contact Ken at Polk, ask him for a schematic.

Total parts list:
(2) Polyswitches from Polk
(2) 750pF 500V 5% or better tolerance silver mica caps
(2) 4.4uF at least 220V 10% tolerance or better cap
(2) 12uF at least 220V 10% tolerance or better cap
(2) 20uF at least 220V 10% tolerance or better cap
(2) 40uF at least 220V 10% tolerance or better cap
(4) 7.5ohm 5 watt Mills wire wound resistor
(2) 2.7ohm 5 watt Mills wire wound resistor

Depending on the caps you choose, you may have to piggy back some of the caps to get the right values. A 4.3uF can be used instead of the 4.4uF with no problem.

Suppliers:
http://www.soniccraft.com/index.htm
http://www.partsconnexion.com/partscomponents.php
http://www.justradios.com/mica.html
http://www.hndme.com/storesilvermica.html

Questions, just ask.

WilliamM2

Thank you F1!

I have a friend who is a very skilled tech, he will be doing the upgrade, so I may not need a schematic.

Are the quantities listed enough for BOTH crossovers?

BobMcG

WM2, yes.

WilliamM2

Thanks Bob.

SCompRacer

Thats the same parts list as I ordered for my SRS 2's.

If you go with Solen PB series caps from Parts Connexion, here is a parts list for you.

(2) Solen-62366 PB Series 4.3uf cap
(2) Solen-51556 PB Series 12uf cap
(2) Solen-51558 PB Series 20uf cap
(2) Solen-51560 PB Series 39uf cap
(2) Mills-64619 MRA-5 2.7 Ohm resistor
(4) Mills-64402 MRA-5 7.5 Ohm resistor

EDIT:
$63.60 plus shipping based on 08/08/05 pricing. $79.55 was the total with two other items I needed.

An option, you could use 12 watt resistors;

(2) Mills-62746 MRA-12 2.7 Ohm resistor
(4) Mills-62754 MRA-12 7.5 Ohm resistor

Add $8.10 to above amount.

F1nut

I'd piggyback a 1.0 to that 39 and stick with the 5 watt resistors.

WilliamM2

Your list does not seem to include the 750pf's? Do all models use the same caps?

Parts express has everything, except the mills resistors, and the 750pf's, for $51 + shipping.

F1nut

William, I provided links to all that you will need.

WilliamM2

Thanks again F1.

I also noticed that parts express has Dayton caps, and they have a 40uf available. With all Dayton caps it's only $42. Is there a big difference between these, and the Solens? They also have a brand called Jantzen.

I assume any of these are better than stock, is there a prefered brand?

F1nut

There is a difference between all caps. Dayton caps are the house brand of PE and are made by Bennic in China, not as good as Solen. You mean Jensen? They are paper/oil caps, the tolerances are as great as 20% and they have a limited value range, you don't want them. Solen is a good solid cap and Sonicap is a excellent high end cap.

C'mon man, do you want better sound or are you just looking to save a few bucks.

WilliamM2

Nothing to do with money, the difference is not that great. The reason I looked at the Dayton's, was because they have a 40uf cap available, no need to piggy back.

I really know nothing about caps, that's why I asked. And I appreciate all the answers.

Oh, and it is Jantzen:
http://www.partsexpress.com/webpage.cfm?&DID=7&WebPage_ID=197#capacitors

But I see they do not have the values needed.

F1nut

Ah, I was looking at Parts Connexion, not PE. I haven't heard of Jantzen before, so no idea on how they sound. Piggybacking isn't a big deal, just solder the 1.0 leads to the leads on the 39, done!

reeltrouble1

F1nut wrote:

Ah, I was looking at Parts Connexion, not PE. I haven't heard of Jantzen before, so no idea on how they sound. Piggybacking isn't a big deal, just solder the 1.0 leads to the leads on the 39, done!

Jesse, you are determined to keep this up till I cant stand it anymore and starting ripping my crossover's to shreds. :eek:

RT1

F1nut

Ted, I didn't start this one.

BobMcG

I had all of my equal value caps matched. Being that the actual value of caps varies, I requested the caps not only be matched but choosen by measurement as close to the actual value I needed. It was extra but I feel and hope it was worth it.
If you take a mismatch like a 4.3 and use it in the place of a 4.4 I believe the % difference (What, roughly 2.3%?) is close to the same as the % difference between a 39 and a 40. If you have the 4.3s and 39s measured and matched at actual values that are higher than 4.30 and 39.0 respectively it would seem things should work out ok, no???

F1nut

Good point Bob. I get the Sonicaps matched to 1% tolerance. On a 4.3uF cap that's +/- 0.086% and a 39uF would be +/- 0.78%. Insignificant really. In all honesty, a standard 5% +/- isn't going to be noticeable, but why not get them closer, can't hurt. And you're right, you can ask for a pair of 39uF's (for example) that measure closer to 40uF.

SCompRacer

WilliamM2 wrote:

Your list does not seem to include the 750pf's? Do all models use the same caps?

Parts express has everything, except the mills resistors, and the 750pf's, for $51 + shipping.

I have a local source on the 750pf's. And I edited my post for the dollar amount as I read off the bottom line and missed I had a couple of other items on the order form.

janmike

Now that's what I call high end diagnostics. Not that I understand much of that, but well done gents.

WilliamM2

Last questions before I order. Does the 750pf have to be 500v? If I go with 300v I can get all parts from 1 source. The reason I ask, is because all of the voltages listed above seem to be at least double the originals, according to Bob's pics.

And does anyone have a pic they could post for the SDA-1C crossover, either moded or not. Or better yet, both.

Thanks again.

F1nut

Get the 500V

WilliamM2

Ordered from handmade. $10 for two 80 cent caps, too bad there is not 1 site that has everything needed.

How much does Polk charge for the new polyswtches?

BobMcG

WM2, I've never been charged for the polyswitches. Just call Ken.