Just received Polk SDA 1

madskaman

Hello,
I am brand new to the club here because I just received a nice pair of Polk SDA 1 from a family friend! After reading reviews and modification notes, I've decided to rebuild the crossovers and replace the tweeter (and I'm sure a couple other little things alone the way). I'm excited for this project, however I have a problem with the pair now. I set them up with a good amount of power and was a little concerned about their sound. They sound very muddled or echoed. These speakers sat for years, and I was told they "may" have a problem. Being that I've never heard a good set of these speakers before, I don't have a real reference for what they should sound like. I guess what I'm asking is: is this an issue with a specific component that has someone has seen before, and will complete replacement of the crossover components clear this up? I'd like to know whats wrong before I dive in. Also i'm looking at ERSE components. Any other suggestions?

pitdogg2

Which SDA1 do you have? SDA1, SDA1signature, SDA1a, SDA1b or SDA1c? There are better caps than ERSE. I recommend a good poly film cap. Sonicap, Clarity cap and others make for a good recap. If you're taking out electrolytic and replacing with the same you will not gain anything. Good film caps are much better and will bring out the best in your speakers.

madskaman

They are the SDA1. I forgot to mention they have the peerless tweeter. I'll look into a better cap for the tweeters. I was planning on replacing the electro with ERSE poly.

Schurkey

madskaman wrote: »

I set them up with a good amount of power and was a little concerned about their sound. They sound very muddled or echoed. These speakers sat for years, and I was told they "may" have a problem.

STOP. Verify that you have a common-ground amplifier. An ohmmeter connected across the negative terminals of the two channels should read less than one ohm, lower is better.

As with any new-to-you speaker project, you'll also want to verify that all the drivers work, and that they are all wired properly.

madskaman wrote: »

They are the SDA1. I forgot to mention they have the peerless tweeter. I'll look into a better cap for the tweeters. I was planning on replacing the electro with ERSE poly.

1. Begin reading-up on how to upgrade your SDA 1s to SDA 1 Signatures, which are essentially the same as SDA 1As. The modification instructions are hosted on this site. You'll have to come up with your own parts as the kit is no longer available (if there ever was a parts kit)--and you wouldn't want it anyway as newer caps are better. There is also some cost-saving here, as you won't have to buy expensive 130uF capacitors as the 1A uses relatively inexpensive high-quality resistors instead.
http://www.polkaudio.com/forums/attachment.php?attachmentid=31009&d=1201824729

2. Nothing really wrong with ERSE film caps; they're a considerable upgrade from the existing electrolytics and reasonably-priced as well.

pitdogg2

Schurkey wrote: »

STOP. Verify that you have a common-ground amplifier. An ohmmeter connected across the negative terminals of the two channels should read less than one ohm, lower is better.

As with any new-to-you speaker project, you'll also want to verify that all the drivers work, and that they are all wired properly.


1. Begin reading-up on how to upgrade your SDA 1s to SDA 1 Signatures, which are essentially the same as SDA 1As. The modification instructions are hosted on this site. You'll have to come up with your own parts as the kit is no longer available (if there ever was a parts kit)--and you wouldn't want it anyway as newer caps are better. There is also some cost-saving here, as you won't have to buy expensive 130uF capacitors as the 1A uses relatively inexpensive high-quality resistors instead.
http://www.polkaudio.com/forums/attachment.php?attachmentid=31009&d=1201824729

2. Nothing really wrong with ERSE film caps; they're a considerable upgrade from the existing electrolytics and reasonably-priced as well.

Completely agree with everything here^^^^^^

But I'm wonky on the fact that AFAIK no SDA's came with peerless tweeters unless you are using that term for SL1000 tweeters which they should of came with. they will need a good 4ohm stable amp as they can dip lower than 4ohm and they will need good clean power I have the SDA1 signature so I know what I speak. SDA tweeter and SDA woofer will not work unless you have IC cable installed just an FYI..I used all sonicaps on mine and they sound pretty darned good.

Moose68Bash

Welcome to the Forum, and congratulations on the very nice gift!

Read up on the prior experiences of Forum members in upgrading vintage Polks and take the advice that you are already beginning to receive. You will end up with a pair of speakers that are very hard to beat for the same money in today's market.

And, of course, you will have the pleasure of taking a plunge down the rabbit hole! :~)

madskaman

Great. Thanks for the advice already! As far as the amplifiers, all 3 amplifiers that I've hooked them up to are in fact common ground amplifiers. And as for the tweeters, I'm guessing the may be been replaced at one point. The 2 I've removed say "peerless" on the back, but I don't know how much it matters; I've got RD0194 tweeters on their way! I'm hooked...

I'm reading through the upgrade from SDA1 to SDA1 A, and cross referencing it with the crossover schematics. I'm running into a problem. I see that the 55uf capacitor is removed, but I do not see where the 25 watt 2.5ohm resistor is added in the schematic. I understand that it should be in place of the 130uf capacitor, however it's not showing that.

Since I'm going to build the crossover from scratch, should I just be looking at building the crossover for SDA1A and modifying my enclosure? Or build a hybrid of the SDA1 following the conversion guide? Also I'm having trouble finding the sonic differences between the SDA1 and the SDA1A. Can someone point me in that direction or enlighten me as to why this would be beneficial?

Thanks again.

madskaman

I disassembled the speakers last night and took a closer look at this crossovers. Nothing obviously blown there. I noticed that many of the woofers had been replaced. I measured them and found that they are pretty similar. When I measured the tweeters, I found that all of them were bad. Every one of them was open. Definitely found a problem here. I'm guessing a weak amplifier blew them?

pitdogg2

madskaman wrote: »

I disassembled the speakers last night and took a closer look at this crossovers. Nothing obviously blown there. I noticed that many of the woofers had been replaced. I measured them and found that they are pretty similar. When I measured the tweeters, I found that all of them were bad. Every one of them was open. Definitely found a problem here. I'm guessing a weak amplifier blew them?

Could be do you have fuses on the back panel? or do they have poly switches?

What are the woofer numbers? MW6600 MW6501 Mw6509 Mw6510?

madskaman

It has fuses. They are all there and intact. As far as the woofers: 5 of the 6501 and 3 6600X. Is this going to be a problem?

pitdogg2

Nope mine came from the factory with MW6600 in stereo and bass position and the MW6501 in the dimensional position. From what I understand MW6501 was a replacement for MW6600. Some came with all MW6501 or MW6600 as they used up older drivers. Maybe there was a reason for a particular in the top spot where the ports were on yours IDK mine do not have the ports they where doweled shut on mine with a Matt Polk badge where they covered them up.


Fuses should be 1.0amp if they are bigger there might be your reason the tweeters blew. I put a 1.5amp in mine when I ran out of 1.0amp and toasted a tweeter pretty quick. Since I redid the XO fuses never blow unless someone gets stupid

madskaman

pitdogg2 wrote: »

Fuses should be 1.0amp if they are bigger there might be your reason the tweeters blew. I put a 1.5amp in mine when I ran out of 1.0amp and toasted a tweeter pretty quick. Since I redid the XO fuses never blow unless someone gets stupid

Thank you, excellent point. Mine had a combo of 3A and 2A fuses, the most likely the cause of the blown tweeters I'm guessing.

pitdogg2

madskaman wrote: »

Thank you, excellent point. Mine had a combo of 3A and 2A fuses, the most likely the cause of the blown tweeters I'm guessing.

BINGO Polk ran then at the top of their ability with a 1amp anything even just a little more is WAY TOO much:)

madskaman

Tweeters came in today. Wow they are quick. I decided to go with the SDA-1A crossover with Clarity Caps for the tweeters and ERSE for the rest. Coupled with Mills resistors and ERSE inductors, I think I'm going to be very satisfied with this rebuild. I modified the cabinet yesterday, so I'm just waiting on the crossover components. Thanks again to those who have helped along the way.

madskaman

Just received the rest of my crossover parts earlier this week and built the crossovers. I installed them along with the drivers last night and I have to say, I'm happy with what I'm hearing right now. Very detailed and airy highs with deep yet refined bass. Perfect for 2 channel listening with their huge soundstage. They're only going to get better from here. Thank you for the help, direction, and motivation.

madskaman

I've been listening to the speakers for a couple weeks now and they're settling in nicely. Only issue I'm having is that they're bright. I tried unplugging a tweeter and it didn't sound nearly as good. I changed the resistor in front of the tweeters from 3.5 to 3.9 and found it to be an improvement, but still not there. I'm going to try a 4.7ohm resistor next. Any other suggestion on how to tune the brightness down?

Nightfall

What equipment is in the chain?

madskaman

I'm using a Marantz SR5004 through a NAD 2400. I was just using the Marantz before, but I thought something with more power would help it out a bit. Nothing really changed there with the addition of the NAD. The brightness shines through on all sources (cd, turntables, Apple TV). I have another set of speakers I'm running with all the same sources and the Marantz as well, but with another amplifier. I tried swapping the amplifiers and came to the same results. I'm running the Marantz through "pure direct" mode which is supposed to send a less altered signal to the amp, and when I a/b the speakers it very noticeable. All I can think to do is pad down the tweeters a bit.

Nightfall

Is the brightness at all volumes or just when turned up past about halfway?

madskaman

Nightfall wrote: »

Is the brightness at all volumes or just when turned up past about halfway?

It's all the time.

chuckeroo

Hi madskaman
I redid my sda 1 signatures a year ago or so, and one thing I remember needing to do is use a router on the cabinet around the magnets of the new rdo194 tweeters as they were bigger than the originals. I originally just stuffed them in the old hole, and it was a tight fit but they went in. They sounded very poor with the magnets in contact with the cabinet, so I took a bit off the top and bottom of each tweeter hole to get the cabinet away from the magnet and it helped a lot. This may be rudimentary and you've already done this, just something I learned going through the process.

I also got a big improvement in tonal balance when I got a more powerful amp. I was running them previously on a 110w amp and felt the speakers were a bit bright and had to use tone controls to up the bass a bit, and now that I have a much stronger amp it has helped a lot. Also, room positioning makes a big difference as well.

madskaman

chuckeroo wrote: »

Hi madskaman
I redid my sda 1 signatures a year ago or so, and one thing I remember needing to do is use a router on the cabinet around the magnets of the new rdo194 tweeters as they were bigger than the originals. I originally just stuffed them in the old hole, and it was a tight fit but they went in. They sounded very poor with the magnets in contact with the cabinet, so I took a bit off the top and bottom of each tweeter hole to get the cabinet away from the magnet and it helped a lot. This may be rudimentary and you've already done this, just something I learned going through the process.

I also got a big improvement in tonal balance when I got a more powerful amp. I was running them previously on a 110w amp and felt the speakers were a bit bright and had to use tone controls to up the bass a bit, and now that I have a much stronger amp it has helped a lot. Also, room positioning makes a big difference as well.

When you redid your crossovers did you start from scratch or did you modify the originals? And did you use the 25watt 2.5ohm resistor in your crossovers or omit it.

chuckeroo

madskaman wrote: »

When you redid your crossovers did you start from scratch or did you modify the originals? And did you use the 25watt 2.5ohm resistor in your crossovers or omit it.

Well, I used the original crossovers, but didn't need to do any modifications as mine were originally signature series from the factory. I changed everything except the inductors. I documented my process here:

http://www.polkaudio.com/forums/showthread.php?152133-SDA-1-Signature-Upgrade

most details and all parts are in post 18. I took some decent pictures which are here:

http://imgur.com/a/0qMYX

Using the close-ups of the crossovers you may be able to work out if there are differences to what you have done.

madskaman

Mine looked pretty similar, except I had three separate units. I started from scratch and replaced all the components. Thank you for sharing your photos.

Lately I've been cranking it up a bit more and have noticed the sound to be more full, but still not what I was expecting. Maybe I do need some more power. I was thinking of bi-amping them with the Marantz. I'm not sure it will be stable though; they drop below 5ohms correct? Maybe I'll need to get more power elsewhere...

Nightfall

https://sfbay.craigslist.org/sby/ele/4599888867.html

https://sfbay.craigslist.org/eby/ele/4597502498.html

https://sfbay.craigslist.org/sfc/ele/4568390519.html

Man, CA has a lot of good used equipment for sale. Not a single Parasound amp for sale on Denvers Craigslist, SF had multiple.

madskaman

i took a look/listen at the b&k amplifier and it was very hard to make a decision. the parasounds seem to be a better amp (on paper) but everyone raves about that b&k. considering i've never head a parasound, i can't really comment.

on another note, i received the larger resistors for my SDA's. i went with the 4.7ohm instead of a 4ohm and i am very happy. it really helped with the brightness. they are much less fatiguing now. i also removed some of the stuffing i had in the cabinet. this also seemed to help out the lower end. i'm still working on dialing in the sound, but i think i'm extremely close now. a little more bottom end wouldn't hurt...

madskaman

I ended up with the b&k amp recommended. Thanks for the heads up on it. I found it to really help out the lows. This amplifier definitely bumps them up. I'm going to try to pad the back of the drivers as well to clean it up a bit.

chuckeroo

Glad you are getting closer to the the sound you are looking for man, good work! Can be slow/frustrating, but rewarding in the end. Did you cover up or plug the port between the tweeters when doing your modifications? That was one of the big changes from the 1A to the signatures. Also, if you ever have time to post pictures of your home made crossovers I would love to see them!

madskaman

Here are the SDA's and the crossovers. I can't edit the picture to orientate it correctly now. I'll have to edit it later.

madskaman

I did plug the ports if you cannot see. I actually used a cork incase I wanted to reverse it.

boston1450

Fine looking speaker. Good luck with upgrades