SDA SRS 2 need CPR and ICU life support

[proffitt]

Here's the part that I think would have helped me the most. Everybody here has been a HUGE help. But let me take from that, build on it, and help the next nube just a little too.

Here is the hi and lo before mods:


Here are the old components that have been removed (left), compared to new components (right) they replace, before they go on. This first picture is the high crossover:


for the high crossover, its pretty easy, just mark the solder pin hole on the circuit board, on each end of the component. I lettered each component A, B, C, etc. Then lettered the two corresponding holes for each component. A and A, B and B, C and C....and its pretty easy. The very last component on the image, is a 3.5 ohm resistor on the old version. I was given a list of components to buy and was real confused that i had way too many components. The list it turns out, was to give me options on what to replace this 3.5 resistor with. After reading what much smarter people than i opined... i decided to try the 2.5 ohm resistor here to start with. Who knows if I'll ever change it, but i know i could.

And the same for the low crossover, old left... new right.

[proffitt]

then there is the polyswitch. There are options with it too. I read them all and decided for me to just remove it completely and jumper it. I took advice and just cut the leads on it off high, bend the leads over on each other, and solder the existing old leads together. i didn't get a picture of this, but it couldn't be any easier.

[proffitt]

It helps to keep your work area neat, and to have plenty of hops lube handy.


you can see the largest two caps that i had to solder the leads together then solder on a wire on each end. These no longer fit on the board. They will fit on top, but they don't leave clearance for your passive radiator. So i cushioned them with foam, zip tied them together, hot glued them together, then drilled a hold in the internal brace and zipped and glued them down. worked great.
here they are about to go in:

[proffitt]

so for the crossover component upgrades, here's my shopping list:

Lows:
2 Dayton DMPC 100uF
2 Dayton DMPC 90uF
4 Dayton DMPC 33uF

Highs:
8 Mills resistors 2.7 ohm
2 Mills resistors 1.5 ohm*
2 Mills resistors ~1.75 ohm*
2 Mills resistors 2.0 ohm*
2 Mills resistors 2.5 ohm*
2 Sonicaps 5.8uF
2 12uF

Of the items marked with "*"... these are all optional components to fill the slot of the single 3.5 ohn resistor on the high end crossover, right next to the polyswitch. Meaning... choose one, but you have a choice. I chose 2.5 ohm.

Of course this list is for two speakers....so where two items are listed, only one compenent per speaker.

[F1nut]

I used clear silicone sealant instead of hot glue on this,

One should never use silicone around electronics. It's acidic and can cause corrosion issues, not to mention it's just nasty stuff, period. Hot glue is the stuff you want to use.

[proffitt]

F1... Oh, I learn something new here every day. I did not know that. Thanks for the heads up. It'll be easy to remove and replace with hot glue. That'll be my first project on it today. Thanks.

[F1nut]

Well, the problem now is that the area is contaminated, nothing sticks to silicone. There are special solvents that remove silicone contamination, but may do harm to the items. Use at your own risk.

[PolkieMan]

Hey I thought I suggested the mahogany stain, anyway they look great! I hope you sent the tweeters back.

[proffitt]

Hey guys. Whew long day. Kids, Christmas coming up, scouts, etc. finally got time to work on them tonight. Polkie, did I miscredit the stain color to someone else? Sorry. It's hard to keep everybody straight who's helping me out with what. Thanks.
So I took advice and got the finished one up and running. Only half of the drivers were working at all so I assumed that was the sda effect and the missing ic cable. So I threw together the other speaker as fast as I could deciding that on this one I could do the drivers and top/bottom caps first and add the side panels later. So I got the drivers in and got it functional. Connected it all up and added the ic cable.
Wow they sound good. Really good. I can't imagine where all that bass is coming from.
But something weird, actually two things. First, the stereo separation or soundstage. There is none. It sounds as if ALL sound is coming from directly between the two speakers. I have them 3 feet from each wall and about 7 ft between them. And it sounds like all Intruments and vocals are coming from a single point between the two speakers. At first I thought I may have gotten right in the left position and vice versa. But I checked that and they are correctly positioned. Next I'm wondering If this has something to do with the break in period of components. I don't know.
The next thing weird is the varying volume level. I haven't gotten my new audio file grade amp yet so I have them powered through and old QSC band amp that I have t used for years. Not the greatest. So I put in a cd and set the volume pretty loud. It'll play at that volume for about 30 seconds and then slowly drop off about 50% in volume for a minute or so and then come back about halfway then drop off again. I don't know if this is a problem with the amp or maybe something else attributable to the burn in. Any ideas?
Still.... They are awesome!!!

[Schurkey]

The problems you're having have nothing to do with "burn-in" of components.

If only half of the mid-woofers are working, it's NOT due to the missing SDA interconnect cable. Not on a 1B/SRS2 Blade/blade, anyway. The SDA drivers will still function for bass. If the speakers are working correctly, pulling the cable will somewhat collapse the soundstage, but not affect the timbre much at all.

All the sound in the center? Either the preamp is set to "Monophonic"; or you've got polarity reversed. Amp-to-Speaker cables installed improperly, or speaker internal wiring not right. Seems to me that if BOTH speakers have the amp-to-speaker cables reversed, all the sound goes to the center. Look in the link below to confirm.

Volume level varying? First Guess: Amp protection circuitry going nuts due to above polarity problem. Additional thought: Is the QSC amp common-ground?



This might be helpful:
http://www.polkaudio.com/forums/atta...9&d=1268334955

[proffitt]

Only two of the four mid drivers were working on the single speaker when I had it operating alone. After bringing the second speaker online and adding the sda ic cable, all four on each speaker were functional.
Just now while playing... I disconnected the ic cable... Holy **** volume went through the roof. I jammin now. No volume vary. And stereo image separated a bit. This is awesome at a new level and no ic cable connected. Wow and weird at the same time.

[Schurkey]

THERE is SOMETHING WRONG!!! That is NOT how these speakers behave.

STOP.

Check all your wiring. Re-read my post above, I think you were typing while I was editing.

[proffitt]

Had already beat you to it. Was powering down while you we're typing. Yes... Didn't seem right. Will check everything. But damn those things sound awesome. Will update later. Thanks.

[Schurkey]

But damn those things sound awesome.

Wait 'til you get them working correctly, and some hours on the new components. You won't believe how good they sound.

[proffitt]

I checked the amp common ground issue days ago. I've got continuity between separate grounds so that's not it.

[F1nut]

Just now while playing... I disconnected the ic cable... Holy **** volume went through the roof.

Yeah, you've got something very wrong. They should never do that. You need to check the chassis wiring, your crossovers and the SDA cable/connections. You did use two wires for the SDA cable, right? Wide blade to wide blade, narrow to narrow. Yeah, I know you used Neutrik.

[proffitt]

Right. But the only thing that I didn't feel completely sure of was the reconnection of the wires to the new neutrik connectors. Soldering the wires to their posts. Which to witch. So I went with color of wires and the posts were marked positive and negative. I think (I'll have to go look) that the colors were blue and white on wash speaker. Or maybe one was blue and white and the other speaker was black and white. Regardless, I stuck with the color meaning something and I connected the white to negative post on each neutrik, and the blue/black to the positive on each. Even if this was wrong, it'd still be fine if I got them BOTH reversed. Because the cable doesn't care. It could only be wrong if the wire colors were supposed to be crossed.... Blue on one speaker attached to white on the other and vice versa. That didn't make much sense... But then again, I'm brand new to the sda concept.

[bikezappa]

If you haven't taken the second speaker wiring apart you can measure and compare DC resistance between the two speakers.

There was a post way back when that listed DC resistance between the connections for each model speaker as a basic check to see if is wired correctly.

[Schurkey]

I checked the amp common ground issue days ago. I've got continuity between separate grounds so that's not it.

CONTINUITY is NOT enough.

You need to measure the actual resistance in ohms from left negative terminal to right negative terminal.

I will absolutely guarantee that 20 ohms will make the speakers sound terrible. I have extensive experience with that. I don't know what the upper limit is for sound purity, but lets say "one ohm or less", less preferred.

[proffitt]

i'm not completely following you bzappa. I have replaced (with the originals) all mid drivers, and the tweeters, two have been replaced, but two came in damaged, so on one speaker, the original tweeters went back in temporarily, just to power up and listen to these gals. I've not taken any of the speaker wiring harnesses apart, just disconnected, and reconnected all drivers on both speakers. I think first its probably something in the SDA. THen the next best chance is something in the crossovers. Least chance is speaker connections, i marked each one color coded, and there would have to be alot wrong there to have this overall effect.

[bikezappa]

There was a post that listed the DC resistance checks for all the speakers made.

If I recall correctly you measue resistance from + and -, + to pin, - to pin, pin to spade.....

If the measured resistance valves are correct they will match the listed valves for you model.

It's a check to see if the cross over and speakers are wired corrrectly and working properly.

If you have rebiuild the cross over of one speaker and not changed any of the cross over components of the other speaker you can compare resistance.

If there is a large resistance difference bewteen something is wrong.

Yoo need an ohm meter to do this test/comparison.

[drumminman]

Follow Schurkey's advice and measure the the QSC. You may have several issues and I'm betting that is one of them.

[proffitt]

Well Schurkey, I hoped you were on to something there, and i was going to find this to be the case. I just measured, and i have .5 ohm resistance between ground posts on the amp. I guess this is good news cause it sounds if i had been wrong, damage most likely would have occured. hopefully I'm still undamaged, but not closer to a solution.

[proffitt]

I'm about to get the fam in the car and going on a most of the day family trip. Didnt want to drop off the radar screen this morning and seem i was ignoring the help coming in. I'll be going over everything in my head while driving and be looking at it again this evening. Happy Sunday all!

[Schurkey]

My 1Bs are coming apart Friday of this week for SDA inductor upgrade. Looks like I'll be building wiring diagrams for future use.

I DO NOT REMEMBER, but will take a guess: The SDA color codes are intended to be crossed--white from one cabinet connects to blue or black in the other cabinet.

Each 1B and SRS 2 Blade/blade LF crossover sends a full-range, full-voltage signal through the SDA cable to the other cabinet. That's why there's two conductors in the Blade/Blade SDA interconnect--Left channel signal goes to right channel, right channel signal goes to left channel. When the opposite-channel signal enters the cabinet, it's directed into the 185uF capacitors, and delivered to the NEGATIVE side of the SDA mid-woofers.

I'd expect the wire colors to switch.

I'll verify Friday.




Did you buy RDO-198s??? I'd put the two new tweeters in the upper tweeter positions of each cabinet, and the original tweeters in the lower position of each cabinet. Both cabinets will then have at least one tweeter that's directly compatible with the 5.8uF cap in the HF crossover.

The tweeter position is NOT the cause of your other problems, though.

[proffitt]

that would be great news.... The easiest fix. I'll be anxiously awaiting. THANKS....again.
I did get the 198s. The new ones should be in soon. If i get this fixed, and do any real listening, i will swap as suggested. Bigger fish to fry now though... i hope "fry" is not the operative word though.
In the meantime this week, I'll finish the exterior of the last one, fabric and wood side panels. These things are looking brand spanking new.

[proffitt]

getting in the car now... happy day to all.

[PolkieMan]

Hey I am sure that you have downloaded this.
Almost everything is here.
http://vr3mods.com/LCSDAUpgrade.php

[proffitt]

Pokie, yes, i was using that as one of my references. Thanks though... better safe than sorry. Thanks agian too on the advice what seems like a year ago (hahaha) on the stain color. Glad i went that direction and couldn't be happier!

[proffitt]

should i rebadge these with the Polk emblem, or leave them naked? Any idea if Polk, or anybody has them emblems for sale? The emblems were obviously missing when i took them in.