SDA II tweeter and midrange problem...

Buckyboy

Hi,

Newbie here, but not to Polk Audio products.

I'm the original owner of a pair of SDA II speakers bought overseas in 1985.

The left speaker is perfect with audio in all drivers and the big bass radiator. However, the left speaker has a couple of problems.

The right tweeter and midrange driver located directly under that tweeter are inop. (The tweeter tests okay when connected to the left tweeter's spade connectors.) Both speakers are connected to the white/blue circuit.

I'm stumped when it comes to accessing the internal wiring.

BTW, these speakers still sound GREAT. I wouldn't have known there was a problem if I hadn't removed the grills and put my ear up to each driver.

Thanks!

Bucky

On3s&Z3r0s

Buckyboy wrote: »

The left speaker is perfect with audio in all drivers and the big bass radiator. However, the left speaker has a couple of problems.

The right tweeter and midrange driver located directly under that tweeter are inop. (The tweeter tests okay when connected to the left tweeter's spade connectors.) Both speakers are connected to the white/blue circuit.

Which speaker has the problems? Is it the right hand side drivers of the right speaker? If so, that sounds like the dimensional array isn't getting a signal. The first thing I would check would be the SDA cable plug and socket in that speaker. If it's loose and not making good electrical connection, that's probably your problem. It could be something with the internal wiring in the crossover, but the socket is the more likely culprit. You might try bending the prongs on the plug slightly to get a more solid fit. It's a temporary fix at best, but if that (or even just wiggling the plug around in the socket) gives you sound in those drivers then you know for sure that's your problem.

Joe08867

I agree 100%. Check the SDA connection on both speakers.

On3s&Z3r0s

Joe08867 wrote: »

I agree 100%. Check the SDA connection on both speakers.

Good point... it could be the plug/socket in either speaker.

Buckyboy

Thanks, On3....! And you other guys for confirming the fix.

Checking the interconnect on the problem speaker didn't do it, but (thanks to a later post) when i wiggled the other speaker's interconnect plug, the tweeter and midrange lit up. Whew! Great to know I don't have to try to open these bad boys up . . . or take them to a repair shop.

While I'm here I'd like to ask your opinions about a couple of things related to the SDA II speakers:

1) Do you listen with or without the grilles snapped in place? I know the speakers were "designed" to be listened to with the grills intact, but remember that back in the 1970s it was in vogue to remove them.

2) My SDA II pair are now on wall-to-wall carpeting. Back in the day, "spikes" were used to overcome the damping effect of the carpet on the speaker. Still a good idea? If so, where might I buy a set?

Thanks, again, for all your help.

Bucky

On3s&Z3r0s wrote: »

Which speaker has the problems? Is it the right hand side drivers of the right speaker? If so, that sounds like the dimensional array isn't getting a signal. The first thing I would check would be the SDA cable plug and socket in that speaker. If it's loose and not making good electrical connection, that's probably your problem. It could be something with the internal wiring in the crossover, but the socket is the more likely culprit. You might try bending the prongs on the plug slightly to get a more solid fit. It's a temporary fix at best, but if that (or even just wiggling the plug around in the socket) gives you sound in those drivers then you know for sure that's your problem.

On3s&Z3r0s

I leave the grilles on mine... my ears aren't good enough to hear a difference in the sound and the somewhat sticky coating on the mid cones attracts dust, pet hair, etc., so I count on the grille cloth to keep that stuff from getting there in the first place.

Lots of guys do spike their SDA's. Because of the little particleboard skirt Polk built for the 2's to stand on, it's a little tricky. You probably don't want to put the spikes in that. Some people remove the skirt and put the spikes in the bottom of the cabinet, but the more common solution, I think, is to cut some wood blocks at the same depth as the skirt and glue one into each corner, then put the spikes in the blocks. I use Dayton spikes from Parts Express.

Buckyboy

Yes, I noticed the sticky stuff on the midrange drivers (and a few cat hairs when I drove them sans grilles). Memo to self: Grilles ON!

Re spikes: Thanks for the corner block advice in the skirt. I'll hold off on spikes for now until my enginer son-in-law weighs in on them.

Bucky

PolkMaster1

If you plan to use spikes, you can use MyeSpikes from MyeSound. They cost more than anything from Parts Express, but for me, it was well worth it!!!

www.myesound.com

PM1