CRS+ crossover miswired?

F1nut

Malbec wrote: »

Hey Jimbo, Ken's discription matches the '86 shcematic.

He doesn't have the '86 version, he has the '91 version shown in his pictures.

Malbec

Right, I became completely confused when I read Ken's post so I looked at the other schematics and saw it matched the '86 drawing and wanted to relay what I found.

Sorry if I added any confusion.

jimbo1421

gimpod wrote: »

Also what value are those black caps between the inductor and the 4 pin connector (I've never seen Polk use a black one there usually blue), it should be a 40uF cap. Also it would have been more helpful if you had posted pics of the bottom of the boards without that big inductor attached.

Hi gimpod,

Here is the bottom view of the right crossover without the big inductor. The red circle indicates a loose solder joint. It is a copper inductor wire and it slides up and down pretty freely.

I am about to desolder one end of the black capacitor to check its value.

Regards,
Jim

TennMan

I had my CRS+ apart a couple of weeks ago. I may be incorrect, but I remember the "pin" part of the IC cable connector on the back of the cup having a blue wire connected to it on both right and left speakers. I've slept since then so I could be wrong. If there is any doubt, and you need to know for certain, I will be happy to pull the cups out of mine and verify the wire colors and how they connect to the IC connector in the cup. I will even supply glossy photos if it will help.

jimbo1421

F1nut wrote: »

He doesn't have the '86 version, he has the '91 version shown in his pictures.

Thanks for clearing that up.

Jim

[Deleted User]

Sorry for the confusion!

jimbo1421

gimpod wrote: »

Also what value are those black caps between the inductor and the 4 pin connector (I've never seen Polk use a black one there usually blue), it should be a 40uF cap. Also it would have been more helpful if you had posted pics of the bottom of the boards without that big inductor attached.

I have attached a scan of the left crossover without the big inductor. I don't see anything obviously wrong with this one.

I loosened one end of both of the black capacitors. They have printing on them that reads:

T.I.
40uF
100V NP
K85?C

So that looks right. Anything else I should check while these CRS+ are all apart?

Regards,

Jim

TennMan

It's going to be interesting to see what the problem with the speakers actually turns out to be, and what it takes to fix it.

jimbo1421

Well, two of the problems will be fixed at one time: the loose solder joint and a proper, single wire IC.

Jim

jimbo1421

Thanks, gimpod, for persuading me to remove the big inductors. I would never have spotted that loose solder joint.

I have reassembled everything and made up a single wire IC. I spent some time last night listening to them. They sound quite lovely but the SDA effect is not as room filling as my SDA-1b. This afternoon I ran the function tests from this file: http://www.polkaudio.com/forums/attachment.php?attachmentid=47379&d=1268334955. I use a mono white noise track that I made in Amadeus Pro. This is played on my MacBook Pro through the DVD input on the Outlaw 1050. There is no mono setting on the AVR so I think I am putting two identical signals into the left and right channels. I hope this is right.

Test #2, which failed earlier, now behaves as described, with only the dimensional drivers putting out a signal.

However, Test #1 was only partly successful. With all leads and IC connected and the balance all the way to the left, all drivers on the left put out a signal as they should. On the right channel, though, only the dimensional driver has a signal. The test says that the right tweeter should also function, but it did not for me. Likewise, with the balance all the way to the right, all the right drivers put out a signal, as well as the left dimensional driver. The left tweeter is silent. During my first round of tests, before all this work, I did not notice whether or not the tweeters were operating during test #1 so I can't say if this is a new issue.

I will appreciate your comments.

Jim

jimbo1421

Well, I opened up these CRS+ again and double checked all the driver connections for in phase polarity. All looks OK (blue or black wire to red dot, right?). I also ran the DC resistance tests. Those were OK but with one slightly high reading: between IC pin #1 (the original blade part) to the black terminal the reading varies between 0.1 - 0.3 ohms. Touching the two leads of the voltmeter together gives a reading between 0.0 - 0.1 ohms. The reference reading is 0.0 ohms. The listening test #1, quoted below, still only partially works.

With a monaural broadband signal such as interstation noise on an FM tuner, set the balance control in the center position. The sound image should now be positioned directly in the center, between the two speakers. The ?dimensional? tweeter and driver on each speaker (see manual) should now be inactive. Note that the dimensional driver may vibrating in sympathy with the sound being produced by the ?stereo? drivers, but is not itself actively producing sound. Now, rotate the balance control to the left, the image should now shift decidedly to the left, appearing to the left of the left-channel speaker. All the drivers and tweeters on the left-channel speaker should now be producing sound; on the right-channel unit, however, only the ?dimensional? driver and tweeter should be operating. Similarly, when the balance control is rotated to the right, the situation is reversed, with all right-channel drivers and tweeters active and only the dimensional driver and tweeter active in the left-channel unit.

In my test, the tweeters seem to be silent. For comparison I ran this test on my SDA-1b pair. The tweeter signal is there, but quieter than when the balance is equal.

I can only account for this in three ways:

There is a poor connection somewhere on the PCB.
The tweeter signal is too quiet to be heard over the rest of the white noise.
The test result quoted above doesn't apply to this particular model.

Can anyone else interpret these results?

Regards,

Jim

TennMan

The tweeter should be working when doing the test. You can tell if it is working or not my covering it with something soft that won't damage it. You should hear a definite change in the sound when you do... even with white noise.

jimbo1421

OK, I covered the tweeters with a folded up towel; they are definitely not putting out a signal.

Jim

TennMan

I've sorta got lost as this thread gets longer so I will ask, does the tweeter ever work? If not you could swap a tweeter from the SDA1 as a test to see if the problem is in the crossover or the tweeter.

jimbo1421

Yes, both tweeters otherwise work as expected during these tests and when the balance is set at midpoint.

Jim

TennMan

jimbo1421 wrote: »

Yes, both tweeters otherwise work as expected during these tests and when the balance is set at midpoint.

Jim

Are you doing the testing with the IC cable disconnected?

jimbo1421

TennMan wrote: »

Are you doing the testing with the IC cable disconnected?

No, the IC is connected.

Jim

TennMan

Have you tried the test with the IC disconnected? Any difference?

Are you certain your amp is a common ground amp?

jimbo1421

With the IC disconnected and the balance shifted all the way left or right, none of the opposite drivers operate.

My Parasound HCA-1000A is a common ground amp. I have also double checked the speaker connections: red=positive all the way through.

Jim

TennMan

There has to be something wrong with the way the wires are connected to the IC connector on the speaker that you said you changed.

Is the blue wire, on both the left and right speaker, connected to the connector pin in the binding post cup correctly so that the wire in the IC cable connects the blue wire in each speaker together?

jimbo1421

TennMan wrote: »

There has to be something wrong with the way the wires are connected to the IC connector on the speaker that you said you changed.

Is the blue wire, on both the left and right speaker, connected to the connector pin in the binding post cup correctly so that the wire in the IC cable connects the blue wire in each speaker together?

Yes. I replaced both IC receptacles in the cup with blade/blade receptacles. The narrow blades replaced the pins. The IC cable itself is one single wire from narrow blade to narrow blade. See post #13 for the pics.

TennMan

I think I might see why you keep failing test #1. Test #1 appears to be written for 1984 model CRS speakers that had two tweeters in each cabinet. One tweeter was a dimensional tweeter. The CRS speakers had a different crossover and different circuits than the CRS+ speakers like you and I have.

Notice that the test #1 instructions say, "only the dimensional driver and tweeter should be operating" for the right channel speaker. There lies the problem. The CRS+ does not have a dimensional tweeter. Without a dimensional tweeter there would be no sound as the instructions indicate.

I have never done test #1 on my speakers because my AVR receiver doesn't have a balance knob and it is not easy to use the controls to switch from one side to another. If you are getting some SDA sound I suggest that you direct your efforts on getting the CRS+ setup perfectly before pursuing the wiring problem further. You may find that you don't have a wiring problem after all.

F1nut

If you are 100% sure all the wires are connected properly and working, I think you need to go over the boards again.

jimbo1421

Well, I also ran test #1 on my SDA-1Bs which also do not have dimensional tweeters and I do get a signal from the opposite tweeters. However, that system has a two wire IC.

Jim

jimbo1421

F1nut wrote: »

If you are 100% sure all the wires are connected properly and working, I think you need to go over the boards again.

What else should I look for besides loose connections?

Jim

gimpod

TennMan wrote: »

I think I might see why you keep failing test #1. Test #1 appears to be written for 1984 model CRS speakers that had two tweeters in each cabinet. One tweeter was a dimensional tweeter. The CRS speakers had a different crossover and different circuits than the CRS+ speakers like you and I have.

Notice that the test #1 instructions say, "only the dimensional driver and tweeter should be operating" for the right channel speaker. There lies the problem. The CRS+ does not have a dimensional tweeter. Without a dimensional tweeter there would be no sound as the instructions indicate.

Jim, TennMan is correct the statement in test #1 should be read as "only the dimensional driver and dimensional tweeter should be operating" and seeing how your CRS+'s don't have a dimensional tweeter they should not be making any sound when you do the test. As far as your 1B's go if you look at the schematics you will see that the tweeters are connecter to the dimensional circuit through the neg side so they kinda do have a dimensional tweeter in a round about way. Also the 1B crossovers are a series earlier than your CRS+'s and trying to compare the two in how they operate is like comparing apples to oranges. It sounds to me like there wired correctly and they are working the way there suppose to just like my 1C's. The crossovers look good to go now that you've fixed that solder joint with one exception you should zip tie that inductor back down.

Hope this helps.

jimbo1421

gimpod, TennMan, & F1nut — thanks so much for all your help. I had suspected that maybe the test result wasn't quite valid (post #42). I am still not really satisfied with their SDA performance but now that we have gotten the wiring right I can pursue that issue in a new thread.

Regards,

Jim