SDA Phase Issue?

Denzel

Hello Everyone,

Have a strange issue wit my SRS 2.3's. Seem to have an hollow out of phase sound. I have verified the cable are all connected to correct + and - terminals on speakers and amplifier. They are pin and blade interconnect, which i am using a DIY pin only cable, so i dont believe a phase issue there. The only real troubleshoting i have done so far is to flip the + and - of the left channel on the speaker end. That seemed to have better center imaging, but the bass was not centered. Besides that it bothers me not knowing where to look first elsewhere for issues. Could e the crossovers, I havent sprung the money to have those replaced yet. Any thoughts are of course appreciated. Might be the amp as well I realize, but doesnt eem tobe an issue with my 15TLs.

jimbo1421

Hi Denzel,

There is a wealth of information here: http://www.polkaudio.com/forums/showthread.php?55888-POLK-AUDIO-Speaker-Wiring-Schematics-amp-More-Stereo-Dimensional-Array(SDA)

Scroll to the bottom for the troubleshooting guide.

Jim

Schurkey

Denzel wrote: »

Seem to have an hollow out of phase sound.

When I had a similar problem with my 1Bs, it turned out that my supposedly "common ground" amplifier had 20 ohms of resistance between the channels.

Put an ohmmeter set to the lowest-ohms scale across the negative posts of the two channels of your amplifier and see how much resistance there is. (Amplifier shut off.)

I've read here that the GFA555 is supposed to be a common-ground amp...but it wouldn't hurt to verify that YOUR amp is, indeed, common-ground.

As has been stated and linked-to, the troubleshooting guide is very good.

Toolfan66

Strap the grounds on the 555

heiney9

The 555 is common ground. I suppose if it's having an issue it could cause these symptoms although not likely. An amplifier doesn't go from common ground to non-common ground just like that.

Toolfan66

heiney9 wrote: »

The 555 is common ground. I suppose if it's having an issue it could cause these symptoms although not likely. An amplifier doesn't go from common ground to non-common ground just like that.

It is?? I thought the 555 was non common ground. So is the 535/545 common as well??

heiney9

Toolfan66 wrote: »

It is?? I thought the 555 was non common ground. So is the 535/545 common as well??

Nope they are ALL common ground

The 5400, 5500, 5800 and 5802 are NON-Common ground amps.

H9

GlennDog

I think? I read here once that any Adcom 5xxx (4 digit model #, starting w/ 5) was Non-Common Ground. Implying the 5503 was, too (Non-Com Grnd) . . . . Please clarify, Thank You!

heiney9

I don't know anything about the multi-channel Adcom amps. Never had a need for one so I never really looked at them technically.

H9

GlennDog

oh, btw, I know for a fact that the 555 & 555 II are both Common Grnd

GlennDog

OK . . Thx, H9

Denzel

Thanks for the verification everyone on the GFA common ground questions. I am perplexed as to where to check next, I will probably swap with my 555 II or 545 and see the results.. these were not modded (yet) other than replacing the tweets with the RDO-194's. What are the odds the crosoover has crapped out in some componeent that would cause the phase issue? Am I right is stating that the pin/blade interconnect only requires the single-conductor connection (unlike the blade/blade). Just to verify I might not have an issue with phase on the SDA drivers?

TennMan

I would do the battery phase test all the way from where the wires connect to the amp to make certain all the drivers are in phase. It will reveal problems that doing a visual inspection of all the wire connections can miss.

gimpod

Denzel wrote: »

Thanks for the verification everyone on the GFA common ground questions. I am perplexed as to where to check next, I will probably swap with my 555 II or 545 and see the results.. these were not modded (yet) other than replacing the tweets with the RDO-194's. What are the odds the crosoover has crapped out in some componeent that would cause the phase issue? Am I right is stating that the pin/blade interconnect only requires the single-conductor connection (unlike the blade/blade). Just to verify I might not have an issue with phase on the SDA drivers?

It has been my experience that 90% of most problems can be traced back to the last thing done. i.e. Replaced tweeters.

So where you having this problem before you replaced the tweeters or after. If after you've got some or all the tweeters wired wrong. On the SDA SRS 2.3 (not the 2.3TL) the positive wires from top to bottom are Red, Blue, Yellow and should connect to the tweeter terminal that has the red dot or bit of red paint, the white wires go to the terminal without any paint or marking.

The odds that some component in the crossover has crapped out is pretty low, not unheard of but would not be the first place I would be looking. Check the tweeter wiring first (it's the last thing you messed with).

Denzel wrote: »

Am I right is stating that the pin/blade interconnect only requires the single-conductor connection (unlike the blade/blade). Just to verify I might not have an issue with phase on the SDA drivers?

Yes you are right.

drumminman

Denzel wrote: »

Hello Everyone,

Have a strange issue wit my SRS 2.3's. Seem to have an hollow out of phase sound. I have verified the cable are all connected to correct + and - terminals on speakers and amplifier. They are pin and blade interconnect, which i am using a DIY pin only cable, so i dont believe a phase issue there. The only real troubleshoting i have done so far is to flip the + and - of the left channel on the speaker end. That seemed to have better center imaging, but the bass was not centered. Besides that it bothers me not knowing where to look first elsewhere for issues. Could e the crossovers, I havent sprung the money to have those replaced yet. Any thoughts are of course appreciated. Might be the amp as well I realize, but doesnt eem tobe an issue with my 15TLs.

Gimpod has a very good point. Your description of swapping phase at the speaker end and the results support this as well - if the new tweeters were installed with the phase reversed and you reversed phase at the binding posts you then would have the tweeters in phase and the mid woofers out of phase. That would account for the change in bass imaging.

Denzel

To be honest it just started a week or so ago, not really ties to any one individual event or timeline that I can think of... I changed the tweeters at the beginning of May.

I will verify the polarity and wiring of the tweeters.. I am color blind so i will have someone help with colors. I will let you know what post I find out.

Thanks all...