SDA SRS 2 need CPR and ICU life support

proffitt

Hi everyone. Brand new here. Been reading alot over the past few days and you all seem very passionate about my new interest.... my "new" vintage finds.

They were beat up pretty bad by the evil previous owner. And I got them for a steal. And now want to bring them back to greatness. The components all seem in fine shape. no rubber rot or pushed in covers. No frayed wires. and the "inner" enclosure still seems solid. All seems well under the hood.

Since I brought them home, I've been reading here about the crossover refresh and the tweeter upgrade, so I'm interested in both of those. Also need to find out where I can get the SDA interconnect cable, mine is blade/blade. Something weird is that the post cup doesn't look like the one listed on Polks model ID page. Mine doesn't have four posts, each pair connected with a wire pigtail. Mine only has two posts, and three little holes above. Are these some type of connection for something? And my blade/blade interconnect terminal is not in the cup at all, but way down on the cabinet back, several inches below the cup. I'll get pictures up. So I'm interested in advice on the crossovers, the tweeters and the interconnect cable.

And, I'm going to address the looks of these ragged old girls. The walnut top cap on one is cracked in several places and somebody did a horrible job of a restain (slapped on some paint on all wood surfaces). The fabric is shredded. and the side panel on one has been NAILED!!!! back on. I think I have all this under control... and will certainly post pics of the "before", during and after transformations. Plan to strip all wood, sand, restain, all new fabric, etc. A good Thanksgiving project.

Somebody on one of the posts I read asked that if anyone was going to disassmble this model, to let them know, they needed some measurments of something. I'll try to find it and contact, but I've read alot, so if its you, let me know... I'll have these gals in many pieces.

Wish me luck!!! (pics coming soon) (sorry for the long intro post)

bikezappa

yes pictures would help..

JayCee

Welcome to Club Polk, proffitt. Looks like you'll have your work cut out for you. From someone that's modded several sets of SDA's, and currently doing so, I can assure you the time and money will be very well worth it.

proffitt wrote: »

Somebody on one of the posts I read asked that if anyone was going to disassmble this model, to let them know, they needed some measurments of something. I'll try to find it and contact, but I've read alot, so if its you, let me know... I'll have these gals in many pieces.

I believe you are referring to Gimpod's recent thread. He's a great guy and can be of help to you, too: http://www.polkaudio.com/forums/showthread.php?138234-Inductor-DCR-Insanity-For-SDA-s

Looking forward to seeing pic's and progress. Congrats on the find.

John

TNHNDYMAN

Good luck with your restoration. THey are worth it.

pitdogg2

proffitt wrote: »

Hi everyone. Brand new here.
Since I brought them home, I've been reading here about the crossover refresh and the tweeter upgrade, so I'm interested in both of those. Also need to find out where I can get the SDA interconnect cable, mine is blade/blade. Something weird is that the post cup doesn't look like the one listed on Polk's model ID page. Mine doesn't have four posts, Mine only has two posts, and three little holes above. Are these some type of connection for something? And my blade/blade interconnect terminal is not in the cup at all, but way down on the cabinet back, several inches below the cup.

The SDA-SRS2 you have are the first generation. The 3holes you speak of are where Polk had the fuse's prior to using poly switches which are on the board itself. You can call Polk audio and they will make a blade/blade IC for you. If you're interested I have one I made with better cable. The cable itself is 13' long originally they were 20'.
The second generation SRS2 had the pin/blade and the ability to bi-amp or bi-wire so hence the 4 binding post. Both are very good BUT different in the approach that Polk took in the maturity of the SDA line.
If you have quality amplification and know its limits you can remove the poly switch and either use a jumper or a .5ohm 12watt mills resistor. If you plan on using a receiver to drive these I'd suggest you replace the poly switch with a new one. The poly switch does wear out and sounds like it may have been tripped a lot do to the description you gave.

proffitt

Thanks Jaycee... Gimpod, if that was you looking for dimensional info of deconstruction details on SDA SRS 2, just let me know, I'll be elbow deep in them soon. pics to come first though.

Pitdogg... ahhh, holes for fuses, that makes sense. And I figured it might be a Gen1 vs other issue is why mine look a little different (2 post vs 4) than what's shown online. Thanks!

Should I stick with the factory blade/blade interconnect? Or i've read that some are modding to more conventional type connectors. What's best? pros/cons?

On the tweeters, we'll discuss later, bigger fish to fry.

On the crossovers, is this a complex task of order all the parts and DIY soldering project that i need to come up to speed on? Or are one of you gents taking the removed crossovers in, modding them and sending them back all buttoned up and ready for reinstall?

I've been a more contemporary, later models, surround sound kind of guy, and have a fairly nice system in the living room, but its recvr only, no ext amp, no real high power. The wife is going to exert her powers and disallow these SRS2s from being in that system in the living room. I got these SRS2s to put in my much more manly cave to be built into a new home theatre down the road... something else we can talk about here much later.

So i could get these SRS2s in the living room system for a very short time to get a before/after experience, or i could just finish the project while i look for an amp and hear them for the first time, new and improved.

What watt per channel amp should i be looking for, on a budget? i was thinking target 150 wpc was at least not doing Mr. Polk a disservice. Advice there?

Schurkey

proffitt wrote: »

On the tweeters, we'll discuss later, bigger fish to fry.

Direct replacement is RD0-194. Don't order those. Order RD0-198s, then change one capacitor in each crossover from 4.4uF to 5.8uF. (5.6uF is acceptable, and easier to source.)

proffitt wrote: »

On the crossovers, is this a complex task of order all the parts and DIY soldering project that i need to come up to speed on? Or are one of you gents taking the removed crossovers in, modding them and sending them back all buttoned up and ready for reinstall?

Piece of cake if you can solder. Impossible if you can't. Did mine over a weekend. Biggest problem is that the new capacitors will be physically larger than the originals, requires some problem-solving and creativity to fit them onto the original boards. You'll want to REDUCE the resistor value for the tweeters from ~2.7 or 2.5 ohm--I forget which is the original value--to about 1.75 ohm or so. There's tons of advice; some folks are married to this brand of capacitor, others to another brand. I bought cheap stuff and couldn't be happier. 1% tolerance Daytons in the high-frequency crossover; 5% Daytons and 3% ERSE on the low-frequency board. I don't have a photo of the HF board, but I've got a couple photos of the LF caps. All of this is for an SDA 1B, which uses the same crossover and active components as your SRS 2 except for one resistor per crossover.





Sometime this winter, the big red-wire inductor at the bottom of each crossover will be replaced with ERSE steel-core inductors having the same inductance but lower DC resistance.

proffitt wrote: »

What watt per channel amp should i be looking for, on a budget? i was thinking target 150 wpc was at least not doing Mr. Polk a disservice. Advice there?

When the speakers were new, they were rated at 4-ohms nominal impedance. By the time you get done with the crossovers and especially if you, like me, intend to replace the big red wire SDA inductors, they'll be lower-impedance than that.

Rated amplifier watts as measured with an 8-ohm load is practically meaningless. WHATEVER amp you buy had better accept a sub-4-ohm load without wetting it's pants, especially if you turn the volume up. This is very easy...but usually not inexpensive. There's a bunch of amplifier manufacturers that can supply your needs; you won't find any of them in Best Buy.

The amp I chose is rated at 200 watts/8 ohm, 400 watts/4 ohm. I could have purchased half that wattage and not run out of steam in my room, at my listening level.

proffitt

OK, with your advice Shurkey, I think I can handle the crossover mods myself. I can solder. But I'm not very technical on the caps vs resistors. But some guidance would get me there. Is there a parts list, and guide anywhere for DIY?
On the tweets, are teh RDO 198s better than the 194s? I'll take your advice... but tell me why?

So the xover mods are a few caps and a few resistors and I'm good to go? I can do that (with some help).

First things first though... I decided last night to do the cabinet restoration and look for an amp first. Then, after that, do the xover mods and tweeter mods. That will let me hear a before and after to satisfy why I'm doing this.

So, recommendations on amps? I guess a little back story needed here:
I hope to use the SDA SRS 2 set as my fronts in a HT set up. 50/50% music vs movies. I have an Onkyo head unit that drives much newer towers now (that will become my side surrounds) and small satellites that are sides now, that will become rears. There is a 15" polk sub in there too. (i've heard i may not need it once i set up the SRS2!)

So I'll plan to ext amp the SRSs for the front, and run all the rest of the surrounds out of the Onkyo outs.

Promise, pics coming as soon as i can find someone to help me move these monsters to the basement where i can get back far enough for a pic.

evhudsons

Welcome to club polk! I have the blade blade srs2 as well and am in the middle of refurbishing them. I haven't done the crossovers yet.

this should get you started:

http://www.polkaudio.com/forums/showthread.php?133384-All-the-Polk-SDA-upgrades-located-in-one-place!

When you do the screen material, research how to do the sides. They are glued on and have to be carefully pried off but it can be done. So far I did the front of mine and left the sides as they were in good condition. Get a good dark heavy acoustical screen material.

I went with rdo194 tweeters for now until I do the crossovers, but will switch to 198's then. I have a friend in need of 194's so the ones I have will have a home and no waste. I am new to soldering so don't experiment on your speakers unless you know how to do it.

Others will chime in but there are tweaks with immediate payoff you should do pretty much now, and some that can be done anytime. While you still can go ahead and get larry's rings (tool66), they may not be available long and are incredible. I just did one speaker, working on the other. It's a big difference in the speaker with and without rings.

anyway, keep us posted! I will be doing mine about the same time. Nice advice about the jumpers. I might do that as it's a quick thing to do.

Schurkey

proffitt wrote: »

OK, with your advice Shurkey, I think I can handle the crossover mods myself. I can solder. But I'm not very technical on the caps vs resistors. But some guidance would get me there. Is there a parts list, and guide anywhere for DIY?
On the tweets, are teh RDO 198s better than the 194s? I'll take your advice... but tell me why?

So the xover mods are a few caps and a few resistors and I'm good to go? I can do that (with some help).

evhudsons wrote: »

Welcome to club polk! I have the blade blade srs2 as well and am in the middle of refurbishing them. I haven't done the crossovers yet.

this should get you started:

http://www.polkaudio.com/forums/showthread.php?133384-All-the-Polk-SDA-upgrades-located-in-one-place

After the thread linked-to above, go here: This thread is old, and the first half is bickering, dead ends, wrong info. Second half is GOLDEN. Written for the SDA-SRS 2, but the SDA-1B is essentially identical, electrically.
http://www.polkaudio.com/forums/showthread.php?74946-SDA-SRS-2-Crossover-Parts-list&highlight=parts+list

All questions about RD0-198 tweeters, and the resistor/polyswitches are answered, but read to the END of the thread, it gets better as it progresses.

evhudsons

great info!



I think it's oliver bubbles that wants measurements of the interior.

proffitt

here they are. Not so bad on the inside. Components all seem fine. If you don't look at the tops, sides, backs or bottoms, and if you take off the fronts, these are just fine. I've removed the top 2 drivers to get to the nuts securing the really bad cupped and split top cap.

proffitt

Please, if you have a weak stomach, turn back now. If you might be uncomfortable seeing our Polks in distress, don't scroll down. For what is about to be seen, can't be unseen.

And don't blame me for what you are about to see. Some previous evil owner tortured these SRS 2s and tried to drive all the amazing out of them. I'm going to try to resurrect them.

Rated R for extreme violence and destruction....

Here we have the top plate which has been either restained, or painted, i can't tell which. And someone seems to have thrown in a handfull of junk out of the shop vac into the wet paint for good measure.

and the view of the side showing that great stain job.

proffitt

I think the previous owner had a pet lynx or bobcat

I had to remove 6 NAILS that had been added to hold on these side panels... nails!!!

proffitt

i'm guessing the tweeters are original, but look ok.

here's the connector cup, with a broken post

proffitt

Seriously, please go back if you aren't prepared for this. The dismantling began tonight.

Now remember that the these speakers have an "inner box" and the surfaces are all cosmetic. And my cosmetics were in dire shape. I say that because some of my tools were not really precise and....well, let's just say that most people probably don't work on their vintage Polk speakers with.... a machete.

Its not too late to turn back.... OK, the side wood strips were trashed and the only way to fix them is to remove them. Same with the side panels that are fabric over pressboard. and the caps and bottoms. It all needs to come off. New fabric is on order and on its way.

So, the side panels came off easy on one of the speakers. fell off one side after i removed the nails, and the other side just needed a little prompting.

Not so much on the second speaker... they must have used alot more glue. Had to get creative...

And it didn't go so good.

But this is just pressboard, and wrapped with fabric. So I'll just have to replace this pressboard, and wrap it in new fabric and reattach. Should be easy. What was the important part in this step was to remove the walnut (or oak?) strips in one piece. They came off easier and are fine.

So now, over Thanksgiving... stripping (the stain/paint!) sanding, restaining, a little cutting new pressboard, new fabric, and reassemble.

A question. What color to stain? Stick with classic original walnut? Looks kinda 80s. Go with a deeper more timeless color that's not original? Or... all my other wood audio gear is black. I would never paint these black... But what about a black stain? You'd still see the wood grain, and there would still be depth. But they would more match the rest of my gear. Is that blasphemy? Half of me thinks it would be. Weigh in and let me know. 1)Original walnut tung oiled? 2) stained a deeper warmer dark honey antique oak? Or 3) stain black and do a poly rub to give it a little sheen?

evhudsons

I have a feeling this will be an time classic thread. We have experienced members, some some others following and doing about the same thing, and a phoenix polk ready for resurrection. I'm glad you are posting pictures. I also liked your disclaimer, it was needed. I used tung oil on mine because if I didn't like it the fix was easy. I had started a similar thread upgrading mine and posted pictures there. I haven't posted more because I haven't done more, but your story here is excellent and I want to see more of your progression.


I've wondered what they would look like without the fabric'd siding and just all wood siding.

proffitt

Actually i thought about the all wood siding just moments after breaking the thin particleboard side. What would this look like with all wood side? Not particle board, but a nice veneer stained to match. Or, all fabric sides losing the small wood strip altogether. One thing of interest, the wood on the caps and bottoms is solid walnut. The side strips are thin veneer oak over pressboard. they'll take stain differently, and if i do all oak sides, they'd be very different from the tops. The small strips of oak won't seem as contrasting because of their small size. And all fabric, will just look too weird. I think the wood strips will break up the black fabric just enough. First impressions are that I'll go with how it was.

proffitt

evhudsons.... how do I reach out to oliver bubbles to let him/her know that this is going down. If they need some measurements from something internal, I'm ready to help.

helipilotdoug

First off WELCOME!! Thanks for posting the photos, although they are sickening! :sad: It will be interesting to watch your progress on them. :evil:Those speakers have been through hell:evil:, and you are their savior! Lots of work ahead, but so well worth the blood sweat and tears involved. I have the SRS II B/B model also, and absolutely LOVE these speakers. Have done all the upgrades and tweaks to them, plus the tl upgrade in the thread posted above. The sound from them is amazing. One of the things I love about them is how low they dig! There is no need for a sub in my system, unless it's for the LFE channel when watching movies. Wonderful sound across the whole spectrum, and the sound stage is wide and deep. These are fantastic speakers, and when you get them done you'll be very happy with them I'm sure. Subscribing to this thread.

TNHNDYMAN

Nice job so far. Since you are having to start from scratch, I'd recommend going with the dark stain of your choice. I also think an all wood stained side panels would be cool. You are right that the oak and walnut would take the stain color different but that might be a cool custom look. I've seen some late 30's early 40's cathederal style table top tube radios that had a dark and light stained wood that look awesome. Just a thought.

littlewoodboats

I have been told that in many cases, drawings of the various cabinets no longer exist. From an archiving standpoint I think it would be cool if everyone rebuilding a set of speakers take accurate measurements. (assuming it had not been done prior)

Great project

michaeljhsda2

Kudos to you on the restoration. If you want to get rid of the rust on the screws, take them out of the cabinet and let them soak in naval jelly. On the other hand, new screws are cheap enough or you could replace them with socket cap bolts and hurricane nuts (or Larry's rings) for a really solid fit.

F1nut

well, let's just say that most people probably don't work on their vintage Polk speakers with.... a machete.

Yeah, that was certainly the wrong tool for the job!

What would this look like with all wood side?

Horrible!

Or, all fabric sides losing the small wood strip altogether.

A lot of the SDA's have all fabric sides, looks great.

One thing of interest, the wood on the caps and bottoms is solid walnut.

Trash the solid tops and bottoms. Make new ones from MDF and veneer them.

The side strips are thin veneer oak over pressboard.

Those are not oak, that's walnut!

proffitt

So the really bad cap gets glued and clamped. It had splits in the wood and cupped warping. I think there was some minor moisture damage just on the top. You can make out some staining on the top of the inner cabinet, the black surface of one of them, with white powdery stains. Next will be planing the caps down about 1 mm. Gouges too deep to try to sand!

The terminal/connector cup comes out. Need to see how to replace posts... have two pair on order. Hopefully easy remove, replace, solder.

proffitt

F1nut...
I think the machete, while unconventional... was the perfect tool. I needed something strong and thin, and sharp, that i could wedge between the "good side" speaker and the "bad side" thin particle board. I held one hand on the handle and bumped the other end of the blade down with a hammer, seperating the two. Its not like i was wailing on it like hacking through vines in the jungle. OK, it broke the particle board anyway, but anything would have, the glue bond was stronger than the particle board. Even before it broke, i had conceded that on this one speaker, i was going to have to replace the outer particle board. Noting that fabric was getting glued back over it and the whole thing was getting glued back to the cabinet wall, I didn't too much care. This just looked the easiest way to get it off, albeit sometimes in chunks.

I agree with you that the sides all in wood wouldn't be a look I'd like. But I don't think all in fabric either. I think I'll stick with the original look here. But I'm still torn about stain color when I'm done.

I think I'm going to stick with the original solid walnut tops and bottoms too. I know i can make these really nice looking. And its much more fun working with good quality solid wood than MDF.

Are you sure the side strips are walnut too? I know the tops are, and the sides look a little different grained, not that it matters to me. I thought i had read somewhere that the sides were oak... but that person may have known as little about it as i do!

Thanks very much for you input. Please keep it coming guys... I need all the help i can get.

EVHud and Shurkey... I'll be reading both those links thoroughly this evening. Thanks.

bikezappa

It's nice to see some one go head first into a project not knowing how much time it will take or how it will all work out.

Go for it.

By the way how old are you?

F1nut

So the really bad cap gets glued and clamped.

Nice brand new clamps, but you really need two more on the piece you're gluing up.

It had splits in the wood and cupped warping.

That's why veneered MDF is the better choice, something even Polk realized later on.

Are you sure the side strips are walnut too?

Yes, 100% sure.

proffitt

I'm 44. Or 45? Can't keep track anymore. I've always had a knack for making things right or better, and not always in the most conventional ways. I can just look at the cabinets and tell i can make them better, even though i don't exactly know how yet. Wasn't even sure what i was going to see when i ripped off the outers, but there's nothing there that i can at least replicate. Its the electrical components that I'm most unsure about. I can solder, I'm just not an electrical engineer, can't read a schematic, and don't know much about the difference in values of caps and resistors, are they directional? things like that. So I'm going to be lost there without some good guidance. But i think its all here with this group. i'll read the threads and then post here when i get stuck.

I hope it helps someone out, and i hope to give back as much take from this group.

proffitt

My old clamps were just too large for my workbench and kept poking me in the ribs where they hung off. So i had to pick up some smaller new ones. I only got two because the splits in the wood only came in about three inches in from the side. I kept a good watch for any leveraged movement towards the center caused from clamping the ends, and was happy to see that the splits didn't lengthen from that counterforce. I had a plan for it if it had occurred.

Even Polk thought to try to start with really nice Walnut before he got wise to MDF. I'm just getting started and i like the way the walnut looks, and way better than oak too, so I'm glad to know for sure that the side strips are certainly walnut. They'll stain similarly if that's what i decide to do with the color.

If i stay with the original format, mostly fabric sides with the strips of walnut... any suggestions on stain color for wood? Original walnut, something warmer, or black stain?

evhudsons

my strips looked slightly different too but I assumed because it was veneer rather than solid wood. Personally I like my walnut and the solid wood. I understand the cracking, warping etc but It's nice to keep it stock unless the caps are broken. Darqueknight, and I think Lasareath took their oak or walnut off and replaced it with beautiful exotic wood. It looked breathtaking, but is an endeavor that for me would be down the road if at all. There's something about aged wood that seems just as refined and since I like the black walnut I'm sticking with it.

there's a guy on ebay selling sda's which he put all wood on the sides, it looks bad so that answers my curiosity. But of course there are others that may love the look. It's really cool that you have such a beginning that you can do pretty much whatever you want with these and not be accused of ruining classic speakers.

I know that mdf would be the better choice longterm if warranted but is it also because of the acoustics, or is it just the warping/cracking issues?