Polk SDA SRS 2 crossover rebuild

[Ratamahatta 437]

I recently got some of these and was really impressed with the sound but know these older Polk's benefit with a crossover upgrade. These have dual boards for the crossover, one for highs and one for lows. Polk used OK caps for the highs 25 years ago but certainly better caps these days. I have used Dayton in the past but with some advise I decided to use Clarity Cap ESA and Mundorf MOX resistors on the highs Clarity cap PX for the mid and Dayton for the SDA circuit. I barely got all the stuff on the high board and not a chance in hell of getting everything on the low board. I had to make a  board and jumper them in. Sound was brighter as expected, I ditched the polyswitch but the caps needed to burn in but sounded better from the get go. They keep on sounding better and better and will go back on main duty when I rebuild the X-overs in the Infinitys.  

 

Before and after pics

 

 

 

 

[Daddyjt 9,878]

That is some nice work!

 

Where do you get the Clarity Caps? I have a treasured pair of Polk LS 70 that I use every day in my living room - is this something I should be doing to them? Also a CS 350 center....?

[Ratamahatta 437]

Thanks, I had some LS90 but I did not do anything to them I am sure better quality caps would have make a difference.  I have rebuilt a bunch of Polk speakers and it always made a difference. It didn't matter if I used Dayton caps Dayton resistors Mills resistors it always made a difference. Polk used some OK caps on the high side but better Caps have come out since then. I got the parts from Madisound and Parts connection. I also have used Parts express.  I was going to do a complete rebuild and build new boards and everything and it may be a possibility in the future but for now I am happy with the results. 

  As far as what you should do you will need to decide if the cost will be a worthy upgrade but there are many options available.  

[Nahash5150 11,028]

Did you omit those small mica caps altogether?

[Ratamahatta 437]

yeah those bypass caps,  gone. 

[helicopter pilot doug 110]

Nice Job!!!