What do I have SRS, 1.2 or 1.2TL????

Beachmover · October 27

Forgive the dumb question and hopefully this is posted in the correct spot. I've been looking for a set of these locally for a long time and one popped up for an incredible price and had to jump on it. They are definitely not in the best shape and have been messed with at some point.

Unfortunately, I am at a loss as to what model they are, the label on the back was removed.

-They both have the 1.2 or 1.2TL crossover plate with the single bolt but not sure as to which crossover is installed.
-Both have the pin and flat cable connector
-Both have the S2000 tweeters
-One has a solid oak top cap and the other is a veneered oak top cap.
-One box is full of 6510 and the other 6511 drivers.

Any help or other features to look out for to figure out what Frankenstein speakers these are would be greatly appreciated. Would like to ultimately restore them and keep them for the long term.

xschop · October 27

They are hybrids awaiting more hybridization.

Beachmover · October 27

Do you have any suggestions as to where to go from here?

xschop · October 27

Is there a part# located on the Xovers?

Gardenstater · October 27

With those SL2000 tweeters and that manufacturing date they would have to be 1.2. 1.2tl had the SL3000 and came out in 1989. They are not supposed to have MW6510; they should have MW6511 for the SDA drivers and MW6503 for the stereo drivers.

xschop · October 27

Should be easy to "TL" them with the earlier crossovers since you have the 6510s already.

What passive radiators do they have?

https://forum.polkaudio.com/discussion/37333/sda-srs-1-2tl-crossover-upgrade

Gardenstater · October 27

What is the bolt configuration on the crossover plates? You said they have the single bolt? It sounds like you have the 1.2tl configuration if you have four bolts across the top, four bolts across the bottom, and a single bolt in the center. The crossover for the 1.2 is #BE2000-B and the 1.2tl is #BE2000-C

Also, the MW6510 has pretty similar Thiele/Small Parameters to the MW6503 and maybe someone swapped those in for the original MW6503. They are supposed to be on the inside edges of the speakers. You should install them that way and make sure they are wired to the stereo part of the circuit boards.

Beachmover · October 27

Thanks for all of the help.
Here are some more photos to help identify these. Was Polk still making these in Baltimore in 88? Only thing I could think of this is a hodgepodge of parts put together by an employee since I picked these up a few blocks from the original location.

Gardenstater · October 27

According to the SDA Handbook, the Fifth Generation SDA models were made from 1989 to 1991.

Polk was at 5601 Metro Drive, Baltimore. Md. 21215 in 1988 and 1991.

If that was done by an employee he must've been trying to sabotage the Polk reputation by putting all 6510s in one cabinet, which is about 8 ohm impedance and all 6511s in the other cabinet, which is about 4 ohm impedance. It's all wrong. Most likely someone chimped them up between then and now.

Looking at the values of capacitors, at least the ones visible, you have the 1.2 boards.

Gardenstater · October 27

Blue +/Green - are the wires to the SDA Drivers (MW6511) and Black +/White - are the wires to the Stereo Drivers (MW6503 or in your case MW6510).

Beachmover · October 27

Awesome. I was just going to ask that. Thank you for all of the information. Can't wait to get these cleaned up and set up like they should be.

Gardenstater · October 27

They don't show it in the 1.2 Schematic but they are hooked up in Series/Parallel as shown in this screenshot from the SRS Schematic:

Link to your schematic 1.2:

https://us.v-cdn.net/5021930/uploads/attachments/1/8/5/1/1/26686.pdf

Tweeters are numbered 1 to 4 with 1 at the top. I'd check them to make sure someone didn't mess them up too. Assuming the wiring is the same as the 1.2tl:

T1: Red (+), White (-)
T2: Blue (+), White (-)
T3: Yellow (+), White (-)
T4: Green (+), White (-)

If it isn't the same as the 1.2tl hopefully someone else will chime in.

michaeljhsda2 · October 27

Gardenstater wrote: »

With those SL2000 tweeters....they would have to be 1.2. 1.2tl had the SL3000.

Exactly right, no doubt about it. Pin/blade interconnect socket excludes them from being 1st gen. SRS.

Beachmover · October 27

It makes sense now. I was thrown off by the drivers and solid wood end caps.
Everything I read was the 1.2 had the 6503 drivers and laminated end caps.

Already started dynamatting the drivers using what I had left from the RTA12.

Does anyone know what kind and how much fill or cabinet lining went into these?

michaeljhsda2 · October 27

Beachmover wrote: »

Does anyone know what kind and how much fill or cabinet lining went into these?

There's not any in there?! There are 2 columns in each cabinet. Each column of dacron starts at the top of the cabinet and extends to the bottom mid-woofers.

Beachmover · October 27

Completely empty.

Gardenstater · 6:24AM

Is there a picture of the guy you bought these from in the Post Office 🤣?!

Beachmover · 8:56AM

These were buried in a back corner of a dirty garage full of junk and engines. I knew they were far from mint and would require a lot of work. They have definitely been messed with over the years but at least it all seems fixable. All the drivers still function and none of the magnets have shifted, only need to replace one of the surrounds.
For $300 though I can't complain.

xschop · 9:00AM

At least they didn't paint them Acid Trip Red.

Gardenstater · 9:18AM

And you are already dynamatting them. Kudos. I heard a rumor there was a guy who used to haunt this forum who owned them for 10 years or so and never did that.

What do I have SRS, 1.2 or 1.2TL????

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