I need help with my SDA2bs!!!!

sda2mike

Why do they distort when asked to do the SDA effect? No interconnect - no distortion..I checked all drivers...they seem OK...I have the pin/blade arrangement..The blade has a white wire coming off it's connector and runs to a white wire on the speaker connector...What do you guys think?? The SDA connection never seemed very snug..Maybe I need a new interconnect?? Thanks!

bikerboy

Hi,
Do you have a common ground amp? Its not likely a cable will cause distortion but it could. Test the pin to pin continuity but check the amp first. If its not common ground it wont like it. It thinks there is a short. There are many other things it could be but check the amp first and dont use the interconnect till you do.
Good luck.

sda2mike

Thanks! It is common ground...Marantz 2270 circa 1970-75:D . I'm not using the interconnect, till I get it figured out. It really doesn't sound too bad either, without the interconnect! I've heard the blade doesn't do anything beyond support the pin connector. However, mine has a wire that goes to the white spkr terminal?? Can anything go bad on the SDA board? BTW, I had the rcvr at the shop for a week. The tech had it on his bench running all day. So, it's not the amp making the noise. Besides since disconnecting the interconnect the noise stopped

schwarcw

Try running a single wire from pin hole to pin hole. Nothing fancy, a 14 guage multi strand or solid wire. You can use a crimp-on pin connector to secure the connection to the speaker. Check out these from Radio Shack

This little test will give you some indication if you have a bad cable. If not, something may be at fault in your female connector or the crossover.

Let us know what you find. Good luck!

sda2mike

OK....I setup the speaker wire. I used the whole pin/blade arrangement...It still distorted...I disconnected the blade connections and there was no distortion...But, when I did the balance test only the right speaker, the one with the distortion, had the SDA signal. How do I troubleshoot the SDA board? Where is it? Thanks!

Ricardo

You might have a bad SDA driver? Gently push on them with your five fingers well distributed on the cone and see if you hear/feel any scratching.

The white wire between the blade and the negative post is ok; the blade connects negatives (low freq.).

Ricardo

sda2mike wrote:

...I disconnected the blade connections and there was no distortion...

This doesn't sound right....there should be absolutely no difference if you disconnect the blade, as long as you have a common ground amp. You mention it is....but have you actually measured resistance between the amp's negative posts?

sda2mike

no...i have no measuring devices, just my ears:cool: ....the distortion comes at louder passages, when it seems the SDA effect would make sense..yes, there was definately a difference when i disconnected the blades...maybe i have a modded pair of spkrs?? i checked the drivers as you described, the seem healthy..thanks again!

Ricardo

Any chance you can borrow a multimeter, or buy a cheap one? For less than $20 you can get one. You don't need anything fancy.
I'd start by measuring if the amp is common ground, and then checking the measures for your model according to the check guide that you'll find here (post 13).

http://www.polkaudio.com/forums/showthread.php?t=48018&highlight=sda+check+sheet

sda2mike

sounds good but, I know for a fact it's common ground. i think there's probably a bunck of members using the old marantz receivers and least one who uses the same model. it makes sense to get a multimeter tho. i'd like to be able to check the bias/offset as part of my yearly cleanup

ben62670

let us know when you have a multi meter, and we can give you the specs between the different terminals

sda2mike

i will, thanks! You know, the speakers actually sound better w/o the cable! I was missing the classic 70s stereo separation. once in a while i'd hear what i thought was an SDA effect. the balance test always worked. who knows, maybe the condition has been getting progressively worse? now, everything opened up w/o the IC! i guess it will only get better when i figger out WTF is causing the distortion!:rolleyes: thanks for the responses!

ben62670

Hey Mike where in S Fla are you?

sda2mike

Atlantis! palm beach county...about 10 miles south of wpb

F1nut

Call Polk, ask them to send you the SDA troubleshooting guide. You will need a VOM for the tests.

sda2mike

i ordered the test procedures and this today...price sems fair;)

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320071983846

Ricardo

I gave you a link to the test procedures in post 9 above.....

sda2mike

yes you did! thanks!

Eiderlon

Wish I could help.