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Polk SDA-1C Restoration?

K

Keswiik

New Member
I came across a cheap pair of Polk SDA-1Cs and decided to pick them up as a project.

Not sure what all has been stuffed in these, but at a glance:
  • two original tweeters, two missing tweeters
  • 3 mystery midrange drivers
  • 5 original midrange drivers
Several of the midrange drivers are bad and need to be reconed. I'll probably just replace them.

What recommendations do people have for replacement drivers? I've seen two options for tweeters:
  • RD0194
  • RD0198
The former seem to be the correct drivers, but I'm not sure if the latter are also compatible.

As for the midrange, are there any upgrades or alternatives besides the MW-6510 (oem) and MW-6503-8?

left speaker.jpg right speaker.jpg
 
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Calling @F1nut. :D he will get you sorted out. He helped with my Monitor 10's. The Polk Audio forum, vintage speaker section will have a lot of info also.
Just Google it.
 
looks like an SDA-1C came with two SL2000 tweeters, two MW6511 and two MW6510 mid-woofers.
The SL2000 tweeters are very common. As you noted, many replace them with the RDO-194 or -198 which are getting scarce.
 
The correct tweeter is the SL2000 or the much better, but seemingly out of production RD0194. The RD0198 is not compatible.

The MW6511 and MW6510 are the only compatible mid-drivers.

If you have the SDA cable and plan on using it you cannot use a non-common ground amplifier(s). I should add that not using the SDA cable renders half the mid-drivers silent nor will you get what SDA is about.
 
Several of the midrange drivers are bad and need to be reconed.
Click to expand...

The magnets have shifted, which can be repaired with a jig. There's no reason to recone them.
 
F1nut said:
The correct tweeter is the SL2000 or the much better, but seemingly out of production RD0194. The RD0198 is not compatible.

The MW6511 and MW6510 are the only compatible mid-drivers.

If you have the SDA cable and plan on using it you cannot use a non-common ground amplifier(s). I should add that not using the SDA cable renders half the mid-drivers silent nor will you get what SDA is about.
Click to expand...
When did the RDO-194's go out of production? I bought a pair a few months ago.
 
F1nut said:
The correct tweeter is the SL2000 or the much better, but seemingly out of production RD0194. The RD0198 is not compatible.

The MW6511 and MW6510 are the only compatible mid-drivers.

If you have the SDA cable and plan on using it you cannot use a non-common ground amplifier(s). I should add that not using the SDA cable renders half the mid-drivers silent nor will you get what SDA is about.
Click to expand...

These did not come with the SDA cable, but I plan on getting one once I get the speakers working. Thanks for the heads up about about amplifiers, definitely need to do some more research before I hook them up to anything.

Finding parts might be difficult, though, as both the RD0194 and MW6510 have both been discontinued.
 
Those mid-drivers and SL2000 tweeters pop up on eBay. Not sure if the RD0194 will though.
 
I've managed to snag one pair of the RD0194 tweeters, so I will be playing the waiting game for another set.

Gonna have to look up how to make a jig for those mids and try my hand at fixing them in the next week or two.
 
It's too bad the clone 194's aren't being made anymore. I wonder why? I see the 198's are available and still being made. Maybe they can be used if the crossovers are reworked? But you wouldn't want 194's in one speaker and 198's in another if that's true. At leased you found two 194's already. Hopefully you can find another pair. When I replaced the SL-2000's with RDO-194's I gave the SL-2000's to someone that needed them. I guess I'll be keeping an eye out for another RDO-194 as a back up if needed in the future now that they aren't being made anymore.
 
Keswiik said:
I've managed to snag one pair of the RD0194 tweeters, so I will be playing the waiting game for another set.

Gonna have to look up how to make a jig for those mids and try my hand at fixing them in the next week or two.
Click to expand...
Just a heads up on installing the 194's. Get four #10 washers. The support posts around the screw holes are just a bit short. Without the washers, the tweeter bezel can warp when tightened down.
 
Lavane said:
It's too bad the clone 194's aren't being made anymore. I wonder why? I see the 198's are available and still being made. Maybe they can be used if the crossovers are reworked? But you wouldn't want 194's in one speaker and 198's in another if that's true. At leased you found two 194's already. Hopefully you can find another pair. When I replaced the SL-2000's with RDO-194's I gave the SL-2000's to someone that needed them. I guess I'll be keeping an eye out for another RDO-194 as a back up if needed in the future now that they aren't being made anymore.
Click to expand...

Yeah, I've got my fingers crossed that I'll be able to find another set in the next month or so.
In the meantime I'll look at replacing the MW6511s with some MW6510s if I can find them. I may give the MW-6503-8s a try as well if I have no luck. Midwest speaker lists them as the closest aftermarket replacement for the 6510s....
 
Lavane said:
Just a heads up on installing the 194's. Get four #10 washers. The support posts around the screw holes are just a bit short. Without the washers, the tweeter bezel can warp when tightened down.
Click to expand...

I'll keep that in mind, thanks for letting me know!
 
Alright, so far here's what I've found out.

Left speaker has working mids and missing tweeters.
Right speaker has working tweeters and no mids.

Decided to open them up before doing anything else and found out that whoever worked on these speakers previously didn't reconnect the mids correctly..... Everything seems to be in working order after redoing the wires.
Just ordered a used set of SL2000s to hold me over while I wait for the 194s to become available later.

Also, @F1nut, I reached out to midwest speaker repair and it seems the 194 is still in production, but are being produced in very small batches. They said to not expect anything until at least February/March of next year.
 
Color code:
Black or blue is positive
White or green is negative

Interesting info on the tweeters. Polk is no longer selling them or any vintage speaker parts.
Midwest clearly stated out of production. I now see Midwest is saying more next year. I guess we'll see.
 
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