SDA 1

crisbep

Hi all, first post. Can anyone identify these SDA’s? They say Sda 1 on back. I was told they are considered SDA A1. I never see these for sale anywhere, always 1B, 1C etc. Are these the original SDA’s? I’ve had them since 1988. I replaced the sl1000’s 20 yrs ago with sl2000’s. Would the RD0194’s be the correct tweeter replacement? Any info on power handling or other historic facts would be much appreciated. Thanks

Gardenstater

Welcome!

Looks like the First Gen. SDA 1 to me. Those look like RDO-194s in there already, which I believe is what Polk recommends as the update to the SL1000. Are they sealing properly without enlarging the cutouts?

The SDA Handbook is a wealth of information:

https://us.v-cdn.net/5021930/uploads/editor/fe/zg3wih4m7prz.pdf

pitdogg2

The problem with going from the SL1000 to the RD-0194 is the cut out it tends to really push the connection points into the magnet assembly. Because the SL1000 connection was lower it was more in the oval radius and not affected. The RD-194/198 series is straight out to the sides. Typically you need to remove a slight amount of the tweeter hole to relieve the pressure. Usually its just a smidge maybe 1/8" or 3/16" which still should not be outside the tweeter face/bezel.
If you've ever seen the SL2000 cut out it has two little half moon relief's right where the tweeter wires connect.

Gardenstater

The SL2000 has a completely different appearance to the dome, different bezel, wires showing on front bezel. So different. See https://forum.polkaudio.com/discussion/182943/the-tale-of-5-tweeters-sda-tweeter-replacement-guide/p1

crisbep

Hi George, thanks for your reply. I didn’t think they made the rdo194’s that long ago. My older brother gave me the tweets to upgrade from the SL1000’s. I popped one. I could swear he said they were SL2000’s. As far as sealing they are flush against cabinet and there are ports right below so I figured sealing would not be an issue. Thanks for the download also..

Gardenstater

You're welcome and you've got a point there....in this case it might not be an issue because of those overpressure prevention ports in the upper chamber. As long as they are firmly seated you may be OK. Don't want them rattling at all whatsoever.

These speakers were reviewed in Dec. 1982 Stereo Review:

https://worldradiohistory.com/Archive-All-Audio/Archive-HiFI-Stereo/80s/HiFi-Stereo-Review-1982-12.pdf

crisbep

Thank you so much for the SDA handbook. What a wealth of info. Looks like I have first gen SDA 1 with tweeter fuses on binding post plate. I’m reading the review also. What a blast from the past with the old ads. 82 was also the year I graduated HS.

xschop

You can use a belt sander to make those plastic plates fit. Take off 0.09" from top and 0.09" from bottom. Smooth out the corners and it drops right in.

pitdogg2

crisbep wrote: »

Hi George, thanks for your reply. I didn’t think they made the rdo194’s that long ago. My older brother gave me the tweets to upgrade from the SL1000’s. I popped one. I could swear he said they were SL2000’s. As far as sealing they are flush against cabinet and there are ports right below so I figured sealing would not be an issue. Thanks for the download also..

When he ordered them as replacements for the sl2000 they may have said sl2000. IIRC I believe on the paperwork they are listed as SL2000.

crisbep

Here’s what’s in there. IIRC I only had to drill new holes for them. They don’t have anything stenciled on them, how do you tell if they are SL2000 or RD 0194?

xschop

Wow, not even an SL1000 tweeter route-out.

Gardenstater

xschop wrote: »

Wow, not even an SL1000 tweeter route-out.

Wow is right. Photo was dark and I thought maybe they painted it black I guess. It could've been a management decision based upon the SL1000 nearing its end and they knew it would piss off the customers to have to route out the baffle or cut down tweeter bezels to install an SL2000. Maybe it was just a cost saving measure since a seal wasn't critical.

crisbep

Hi George. I read that 5 tweeter discussion, can’t believe I missed that pic. Thanks again for the info..

xschop

Those may be 198's. Looks like they didn't bother changing the faston, instead soldered directly to dome tab?

Gardenstater

xschop wrote: »

Those may be 198's. Looks like they didn't bother changing the faston, instead soldered directly to dome tab?

Good catch!

RDO-194 (same size terminals?)



RDO-198 (clearly different size terminals)

F1nut

NM

xschop

There's a thread here that someone made an adapter plate and just installed a single RDO in the middle.

F1nut

There was also a "signature" version of that model that had a plate covering the 2 holes.

pitdogg2

F1nut wrote: »

There was also a "signature" version of that model that had a plate covering the 2 holes.

The holes are also plugged with dowel rods. Changes were also made to the inside of the cabinet.

Copied from a thread from yrs ago.

The difference are as follows SDA1 had ports for the top 2 MW and each had their own box. SDA1 had 3 inductors. SDA1a had no ports and the MW boxes removed SDA1a had 2 inductors and came with SL1000 and SL2000. Now here is where slight difference's came to play SL2000 SDA1a had the MW's lowered slightly to make room for the SL2000 tweeter The SDA1a with the SL1000 tweeter when you used a SL2000 or RDO-194 tweeter dome it is almost behind the top of the grill frame"

Here's a thread if you ever want to change them.

https://forum.polkaudio.com/discussion/55888/polk-audio-speaker-wiring-schematics-amp-more-stereo-dimensional-array-sda#latest

Look for SDA 1 to SDA 1a conversion.

Gardenstater

^^ Pretty cool and I had never read that. So they actually had a modification kit that could be ordered. Interesting that the instructions implied that there WERE tweeter gaskets in the SDA 1 (which OP is missing). Also, I think that quote from the forum above is in error because, as far as I can tell, the SDA 1A Signature still had the 3 large inductors. The "Z-balance Network" in the low frequency module was disabled and the two 130uf caps were replaced with a 2.5 Ohm resistor in the Dimensional Driver and the Stereo Driver. The holes were plugged and the horizontal partition removed, and more Dacron was added. Cool.

Gardenstater

Browsing craigslist this morn I just happened upon a "SDA 1" for sale which must actually be a SDA 1A with the SL1000. There sure ain't much room for a larger tweeter bezel.

xschop

Those would be a great score for someone that enjoys tweeter echo.

pitdogg2

Gardenstater wrote: »

^^ Pretty cool and I had never read that. So they actually had a modification kit that could be ordered. Interesting that the instructions implied that there WERE tweeter gaskets in the SDA 1 (which OP is missing). Also, I think that quote from the forum above is in error because, as far as I can tell, the SDA 1A Signature still had the 3 large inductors. The "Z-balance Network" in the low frequency module was disabled and the two 130uf caps were replaced with a 2.5 Ohm resistor in the Dimensional Driver and the Stereo Driver. The holes were plugged and the horizontal partition removed, and more Dacron was added. Cool.

I disagree with that in bold, I have a set of SDA1 signatures from the factory. They never had 3 inductors nor the midwoofer boxes inside. They also have the big plate in the back that all the crossover and binding posts and fuses are on. The SDA1a had a small round binding post cup and no fuses.

Gardenstater

pitdogg2 wrote: »

Gardenstater wrote: »

^^ Pretty cool and I had never read that. So they actually had a modification kit that could be ordered. Interesting that the instructions implied that there WERE tweeter gaskets in the SDA 1 (which OP is missing). Also, I think that quote from the forum above is in error because, as far as I can tell, the SDA 1A Signature still had the 3 large inductors. The "Z-balance Network" in the low frequency module was disabled and the two 130uf caps were replaced with a 2.5 Ohm resistor in the Dimensional Driver and the Stereo Driver. The holes were plugged and the horizontal partition removed, and more Dacron was added. Cool.

I disagree with that in bold, I have a set of SDA1 signatures from the factory. They never had 3 inductors nor the midwoofer boxes inside. They also have the big plate in the back that all the crossover and binding posts and fuses are on. The SDA1a had a small round binding post cup and no fuses.

^^ Well the plot certainly thickens then. I read the instructions for converting the SDA 1 to SDA 1A and it still would retain the 3 large inductors. The schematic we have for SDA 1A clearly shows that there are still 3 large inductors. The only discrepancy I saw was that in the schematic for SDA 1A it did NOT show a 2.5 Ohm resistor in place of the 130 uF capacitors, although the capacitors were removed.

I guess the only conclusion is that the SDA 1 "Signature" was different crossovers from SDA 1A. Maybe the filename in archives for conversion from SDA 1 to SDA 1A is mislabeled as "SDA 1 to SDA 1A Signature edition.pdf" <<attn. @DarqueKnight

So maybe there were 3 distinct models. First SDA 1, then SDA 1 Signature Edition, and then SDA 1A (with two baffle variants depending upon tweeter). All 3 have different XOs.

pitdogg2

Yes the SDA 1 signatures were intermediate models. The brass plate covered the ports that had dowel rods glued into them. Mine also have a tweeter contouring network where one resistor has a 5.8uf cap across it. Which in the beginning I thought I could use a RD-0198 tweeter.

I also liked the dimensional tweeter in the beginning, after about a year I understood why folks disconnected it. I'd find myself looking around the room because of the artifacts it produced. My tweeters did come with gaskets as I feel all of them should have. The gasket for the SL1000 also extended outside of the tweeter face and some may have removed them because of the look they had. (it was ugly).

Gardenstater

pitdogg2 wrote: »

Yes the SDA 1 signatures were intermediate models. The brass plate covered the ports that had dowel rods glued into them. Mine also have a tweeter contouring network where one resistor has a 5.8uf cap across it. Which in the beginning I thought I could use a RD-0198 tweeter.

I also liked the dimensional tweeter in the beginning, after about a year I understood why folks disconnected it. I'd find myself looking around the room because of the artifacts it produced. My tweeters did come with gaskets as I feel all of them should have. The gasket for the SL1000 also extended outside of the tweeter face and some may have removed them because of the look they had. (it was ugly).

So the schematic for the Signature Edition isn't in the archives I guess.

pitdogg2

No it is not. It should be the same as the 1A with the exception of 1 amp fast blo fuses instead of the polyswitches.

Gardenstater

pitdogg2 wrote: »

No it is not. It should be the same as the 1A with the exception of 1 amp fast blo fuses instead of the polyswitches.

Well I'm in it now but I will try to clear it up for anybody reading this who is probably confused

If you look at the 2 schematics we have, for the SDA 1 and the SDA 1A, they both show 3 MW inductors, and by that I mean the 5.6 mH inductor for the two sub bass MWs and a 1.82 mH inductor for the stereo MW and the dimensional MW. So that's 3 by my count.

Also, neither of the schematics show a 5.8 uF capacitor in parallel with a tweeter resistor.

So it would *seem* to me that there are more XO differences between your SDA Signature 1 and SDA 1A than just fuses/polyswitches

pitdogg2

I made a mistake. it was the .5uf not 5.8. too early to talk tech evidently this a.m. I remember the cap just didn't remember the value.

If I think about it after work I'll take a picture of my XO to help relive your anxiety

Gardenstater

pitdogg2 wrote: »

I made a mistake. it was the .5uf not 5.8. too early to talk tech evidently this a.m. I remember the cap just didn't remember the value.

If I think about it after work I'll take a picture of my XO to help relive your anxiety

I hear that. What about the 3 inductors that yours "never had"?

It's more like Engineer's OCD than anxiety

pitdogg2

Gardenstater wrote: »

pitdogg2 wrote: »

I made a mistake. it was the .5uf not 5.8. too early to talk tech evidently this a.m. I remember the cap just didn't remember the value.

If I think about it after work I'll take a picture of my XO to help relive your anxiety

I hear that. What about the 3 inductors that yours "never had"?

It's more like Engineer's OCD than anxiety

Read step 4 Z-network that is what I was referring to. Mine did not come with that network. I'm assuming that was the 3rd big coil you were referring to. YES mine has the normal inductors on the board.