SDA 2A Crossover Question

smglbrth

Well, I finally got ahold of some 2A's. Got them home and found that the dimensional driver wasn't working on the left channel. So, changed it out with a spare 6510 and that wasn't the problem (uh-oh). Anyway, took the passive out and noticed a white wire connector just hanging there. Sure enough, there was an open spot so I put it back on. Slide right back off so I just tightened it up a bit. Then I thought I should check the other speaker, just in case. Opened it up and it looked the same. Figured all was good but I have a question about it. When I turn on the amp/pre together (12 volt trigger) the drivers move initially, like all my other speakers. Funny thing is, on the left channel both drivers move in opposite directions when it happens. On the right channel they both move in the same direction. Is this correct? The speaker wires are connected correctly, positive and negative. I'm wondering if someone else had a similar thing happen and put them on backwards.

I tried finding a pic of original crossovers wired on 2A's and didn't come up with anything. Guess my question is, does anyone know for sure how these wires get hooked up on each side? There is one white, one black that comes down from the dimensional crossover and hooks to the binding post crossover with spades. Do they both get hooked up the same or are they different, i.e. opposite on one side compared to the other? I know that crossovers on SDA are a little screwy which is why I'm asking.

I did look at the wiring schematic for the 2A and can't make heads or tails of it, not to mention they don't show a left/right schematic.

Any help would be greatly appreciated.

xsmi

At the bottom of the schematic, it tells you the black and white wires are found in the left channel. Judging from the schematic, the white wire should go to the positive of the dimensional driver and the black to the negative. Try to trace the cables from where they came off all the way to the driver to make sure they are going to the correct side of the speaker. I hope this helps.

smglbrth

That's what's funny about the schematic. The dimensional driver wires for the left channel are white and blue, these go directly to the dimensional crossover. The black and white wires which come down from the dimensional crossover to the binding post crossover aren't directly connected to the dimensional driver itself, only to the dimensional crossover. Hence, do these two, short black and white wires that connect the dimensional crossover to the binding post crossover get hooked up exactly the same or are they opposite on the left/right speakers?

Thanks for trying to help though! I know there are some here who have redone their own crossovers on 2A's so I'm hoping someone will chime in..., with a good memory...

bmbguy

Not sure if this is what you're looking for, but it sounds like it might be:
http://www.polkaudio.com/forums/showthread.php?131743-Need-Help-SDA-2A&p=1756584&viewfull=1#post1756584

Maybe it'll help...

smglbrth

Thanks for the reply! I've checked both speakers and while the blue/white (right channel), black/white (left channel) wires are coming from the blade/blade interconnects these aren't the wires I'm speaking of. Both channels have black/white wires coming from the dimensional crossovers to the binding post (stereo) crossovers. Right now they are both going to the same spades on each speaker, which is the way I put it since it made sense. However, the two drivers on the left channel move opposite one another while the right channel drivers move the same direction. I don't see how that could possibly be correct. It would seem that the left channel drivers are way out of phase with one another. Granted these are SDA's so I don't know if they should be this way or not.

Confusing for me since, when hooked up exactly the same I lose tons of low end but gain in the mid's/highs. When I hook them up differently (change the left side so both drivers move the same) I gain the bass but lose more of the mids/highs. Never had this problem with the 1C's I used to have.

?

F1nut

Check that the binding posts are correct. Red on left, black on right.

smglbrth

Binding post are correct. Heck, I just switched those two wires back opposite the right channel so both the drivers on the left channel move in/out together the same way the right does, for now. Until I hear something different or read about it different. This really has me befuddled...

On the plus side I snagged 'em for $150. Pretty good price for the shape they're in. A little peeling in a couple of spots but not bad for a 1986 manufacture date.

F1nut

not to mention they don't show a left/right schematic.

That's because they are exactly the same.

Judging from the schematic, the white wire should go to the positive of the dimensional driver and the black to the negative.

That's not correct. Black or blue is always positive. White or green is always negative.

smglbrth

...just like house wiring..., it would have been nice if Polk would have put a positive/negative on these connectors, that would have made it easy peasy! Unfortunately, where these wires plug into aren't labeled as such.

xsmi

I missed the backwards designation on the schematic. Sorry about that. I see it now.

smglbrth

Found the problem and even though I don't want to admit this, I will, being an adult and all. When I hooked the 6510 back up, after finding that wasn't the problem, I hooked the sucker up backwards! I feel like such a bafoon (sp?). All is well in my SDA land, now that I'm back into 'em. Talk about being a moron, I know better than that!

Thanks for all your guys' help. Both speakers are, indeed, wired the same way.

Now to start with spikes, then...

westmassguy

smglbrth wrote: »

Found the problem and even though I don't want to admit this, I will, being an adult and all. When I hooked the 6510 back up, after finding that wasn't the problem, I hooked the sucker up backwards! I feel like such a bafoon (sp?). All is well in my SDA land, now that I'm back into 'em. Talk about being a moron, I know better than that!

Thanks for all your guys' help. Both speakers are, indeed, wired the same way.

Now to start with spikes, then...

They'll sing with new tweets and rebuilt crossovers

smglbrth

New tweets are already in, crossovers in the future at some point.

westmassguy

smglbrth wrote: »

New tweets are already in, crossovers in the future at some point.

Enjoy them

littlewoodboats

Here is the start of my 2A saga. I did not know for certain which ones I had. Nice speakers

http://www.polkaudio.com/forums/showthread.php?130514-So-far-SO-GREAT

westmassguy

littlewoodboats wrote: »

Here is the start of my 2A saga. I did not know for certain which ones I had. Nice speakers

http://www.polkaudio.com/forums/showthread.php?130514-So-far-SO-GREAT

They are nice, but the crossovers are a bit of a pain to work on. Would have been nice if Polk labeled all the little connectors.