Crossover upgrades and new tweeters

RandyCroissant

Hello!! My name is Randy and I would like to replace the resistors and caps on my Polk SDA2 speakers. I would also like to replace the tweeters I have SL2000's and would like to purchase the replacement RDO 194's any help would be much appreciated. My SDA2 have one tweeter and 2 mid base drivers and one passive radiator each.

jimclass

Sounds like you have same 1987 setup I do. I recently had a tweeter fail on my SDA 2As and purchased the pair of RDO replacements from Polk and installed. It seems that the brightness of the high end is diminished with the new tweets. They do sound smoother, but I wish they had a more crystal clear top end. Now I wonder if it is time to update the caps. Would that get me the clarity I am looking for? And I have no idea how to do the cap replacement. How do get to them in the cabinet, where do you buy new ones. Is there a step by step tutorial for a novice?

RandyCroissant

Hey Jim, I have read a lot on this topic, seems most agree the caps should be replaced after 20 something years. The other problems with the crossover are the poly switches for the tweets, my polks still sound good but not great as the use to..
I want to get them back.

F1nut

Guys, there is tons of info posted here on this topic.

jimclass

Thanks F1 but I have not found specific answers to my questions. I know how to solder, but I need step- by- step instructions for my model. There are tons of experts discussing arcane esoteric details. I just want to get them back to original specs.

Faustin

Most people here go with Clarity or Sonicap capacitors and Mills or Munford resistors. Best to pull out a crossovers and check the values of the components used. There are also schematicss available on the top of this forum to compare to your crossovers. The polyswitch can be replaced with a . 5 ohm resistor. Because the new components are larger than the original ones, it takes a bit of planning to fit them on the board. There are larger, aftermarket boards available for most SDA's that make the job easier. I am sure other members will chime in with comments.

westmassguy

Welcome to CP. First thing is to identify which SDA-2 you have. Single tweeter with two woofers could be a 2A or 2B. The 2As all had blade/blade interconnects and a split crossover. The 2Bs normally have a pin/blade interconnect and a single rectangular crossover, however some early 2Bs had blade/blade interconnects as well.
A photo may help, but it's best to pull one of the passive radiators and have a look.
If you're unsure, post a photo of the crossover too.

RandyCroissant

Thanks for the info; I believe they are the 2B's with the pin blade style but I will pull a passive radiator to make sure, I will be back after that.

RandyCroissant

My crossovers are the rectangle shaped boards, I am looking at replacing them with the larger gimpro boards, sono caps with mills resistors. One big question are the polk replacement RD0194 or 198 tweeters still produced and who has them??

ken brydson

RandyCroissant wrote: »

My crossovers are the rectangle shaped boards, I am looking at replacing them with the larger gimpro boards, sono caps with mills resistors. One big question are the polk replacement RD0194 or 198 tweeters still produced and who has them??

Polk still sells them both. 194's are drop in replacements for your 2000's. Tell them you a forum member for $48 ea and free shipping.

F1nut

the larger gimpro boards, sono caps

Gimpod and Sonicap.

One big question are the polk replacement RD0194 or 198 tweeters still produced and who has them??

You buy the new tweeters directly from Polk by calling them.

Seems you have the 2B's, which can be upgraded to 2BTL's. Do a search here as there are many threads addressing those upgrades.

RandyCroissant

Thanks for the correction F1 nut, Gimpod and Sonicap. Lots of info goin around in my head this site is a wealth of info...awesome

michaeljhsda2

If you're going to upgrade the caps and they are indeed SDA 2B's, I recommend doing the TL mod (quite simple) so you can use the superior RD-0198 tweeter.

jimclass

Good info, thanks. I know mine are 2As, as it says it on the cabinet back and on the original boxes. I get that I need to replace the caps; what about the polyswitch? What does that actually do? should it just be bypassed?

Faustin

Polyswitch is for tweeter protection. Most people remove it and put a .5 ohm resistor in place of it or just a jumper.

F1nut

A polyswitch is a thermal reset device, it is used in place of a standard fuse. You can replace it with a new one, you can replace it with a jumper or you can replace it with a resistor to keep that same circuit value. If you have never tripped the ones in your speakers you are safe to use a resistor, if you have tripped them, best to replace with a new poly or get a better amp.

RandyCroissant

Can you combine caps of different values to make specific value such as a 5.6uF and a .2 uF to make a 5.8 uF does anyone know??

westmassguy

RandyCroissant wrote: »

Can you combine caps of different values to make specific value such as a 5.6uF and a .2 uF to make a 5.8 uF does anyone know??

You can parallel caps of equal or close value. What you don't want is a large cap combined with a small one.

F1nut

RandyCroissant wrote: »

Can you combine caps of different values to make specific value such as a 5.6uF and a .2 uF to make a 5.8 uF does anyone know??

What westmassguy said, besides that, Sonicap carries the 5.8uF.

RandyCroissant

Well.. today I ordered all my caps, Sonicap 5.8 uF, 12 uF, and 20uF, also the mills resistors and new RD0198 tweeters from Polk. When I first put the parts order together Sonicraft was out of 5.8s but I guess they got some more in, hmm must be all the polkies fixin their crossovers ha.. Expensive but worth it I think, Can't wait..

westmassguy

RandyCroissant wrote: »

Well.. today I ordered all my caps, Sonicap 5.8 uF, 12 uF, and 20uF, also the mills resistors and new RD0198 tweeters from Polk. When I first put the parts order together Sonicraft was out of 5.8s but I guess they got some more in, hmm must be all the polkies fixin their crossovers ha.. Expensive but worth it I think, Can't wait..

You will not regret it. Your puppies will sing once everything is burned in

Sea

Be aware! I was warned and was skeptical but it happened. When you first fire the speakers back up after the crossover upgrade you will be impressed. After a few hours it will start to sound like S***t. It will gradually start to sound better and after 150 hours or so the speakers will sound even better. I left mine playing continulosy while I was at work for several weeks. I am not real clear about how volume affects the break in period. Mayber some will chime in with that info. Good luck!

RandyCroissant

Thanks for the info gents, I will post my progress once the hardware gets here.

drumminman

I don't think high volume is necessary to burn in the new Xover components. Moderate levels work well.

RandyCroissant

I'm glad to hear about the burning in part, I would have thought I f....d something up

jimclass

I plan to open up the cabinets this weekend and take a look. I already bought the RDO194 tweeters, so keeping that setup. Never done this stuff before. I have not found the post that says exactly what capacitors I need for a 1987 era SDA-2A speaker. It must be listed somewhere...a little help?

westmassguy

http://forum.polkaudio.com/discussion/55888/polk-audio-speaker-wiring-schematics-more-stereo-dimensional-array-sda#latest
Just download the PDF Schematic for the SDA 2A

jimclass

Okay, I opened up my SDAS 2As and see what caps I need to replace. But I don't know what the polyswich looks like. Is there a pic posted somewhere?

westmassguy

It will be blue or yellow, bout the size of a kernel of corn but flat.

jimclass

must be that little Tan disc marked MEXICO, about 3/8" diameter. How about that yellow component, about 2-1/2" long? Is it a capacitor? There are no markings on it

westmassguy

That's the 12uf Mylar Capacitor