ADS L1290 mid not working

[Joe VW]

Okay, so I decided to keep my L1290's. However, I discovered that one of the mids is not working. Could this be a crossover issue, or does the speaker need a rebuild? Is Richard So the only guy around to repair ADS speakers?
Thanks guys!

 

[dc270]

Richard So repairs the tweeters/ dome mids as far as I know. Try pulling the driver out and testing it at very low volume- if it works then you know the rest. Is it fused?
DC

 

[dbCooper]

Richard So repairs the tweeters/ dome mids as far as I know. Try pulling the driver out and testing it at very low volume- if it works then you know the rest. Is it fused?
DC

The woofers are not protected by fuses. If it is a model 1, there are separate fuses for the mid and tweet. If its a model /2, there is a PTC built in to the crossover protecting the mid and tweet, no fuses.

 

[jnoyes4]

FYIi, There is a brand new set of mids on Ebay.

Jon

 

[Joe VW]

I can't find that auction. Link?

 

[Joe VW]

So I pulled it out and it sounds fine. These are series 2, so they have the protection at the x-over. I think this may be where the problem is. Tonight I will take a look at it and post a pic or two.
I must say, that is one gorgeous mid!

 

[ericj]

Free it from the baffle and put an ohm meter across the solder lugs on the back. Should read somewhere in the neighborhood of 4 ohms. If it reads way higher than that (this is still in-circuit) it needs to be rebuilt.

 

[Retro Stereo]

I can't find that auction. Link?

It's against the rules to post an auction link anywhere but the Dollars & Sense forum. However, you can PM (Private Message) the AK member who knows where the aution is and try and find it that way.




Retro

 

[dbCooper]

So I pulled it out and it sounds fine. These are series 2, so they have the protection at the x-over. I think this may be where the problem is. Tonight I will take a look at it and post a pic or two.
I must say, that is one gorgeous mid!

Minnesotatv corrected me regarding my earlier post. The schematic on the XXXX/2 series shows the PTC protecting the tweeter. The mid appears to be unprotected.

I would say that is a good reason to not clip your amp!

 

[Joe VW]

Okay, I have an update. The reason I thought a mid was not working was someone came by to look at them for a possible purchase and brought a sound meter. He would put the meter in front of the left mid and the needle would almost peg out. On the right it would only slightly move.
I have pulled BOTH mids and they each read exactly 6.1 Ohm's. Pulled out the x-over of the supposedly bad one and everything looks ok.
So, my question is, is there a way to check the x-over? Or should I put it back together and get a meter and check this myself, because I'm starting to think somone may have been trying to pull a fast one.:scratch2:

 

[minnesotatv]

Okay, I have an update. The reason I thought a mid was not working was someone came by to look at them for a possible purchase and brought a sound meter. He would put the meter in front of the left mid and the needle would almost peg out. On the right it would only slightly move.
I have pulled BOTH mids and they each read exactly 6.1 Ohm's. Pulled out the x-over of the supposedly bad one and everything looks ok.
So, my question is, is there a way to check the x-over? Or should I put it back together and get a meter and check this myself, because I'm starting to think somone may have been trying to pull a fast one.:scratch2:

First, I am not "an expert". No doubt Soundmotor, Richard
So, or others on this board have more knowledge about
these issues than I do.

If I understand your issue, I ran into a similar problem
with my L-1290/2's. Output from one mid-range was
substantially less than the other. Both drivers DC
resistance measured the same.

I contacted Richard and he told me that's not unusual.
Apparently the fluid (ferrofluid?) in the driver dries out
and inhibits full output. Its also quite possible that the
dome has hardened with age, which would also have
some effect. The solution is to rebuild the driver. I had
Richard rebuild mine, and he did a beautiful job.

You easily can, and should check output thru the crossover.
Either swap the "louder" driver from one speaker to the
other and use a sound meter to measure the output, or
listen closely to the output.

Or disconnect both mid-range drivers and at lower
volume generate a single tone thru the speakers.
Connect your volt meter to the driver leads on each
speaker and read the output. They should be very close.

Most of the original capacitors used on the crossovers of
these speakers were electrolytics. They're old, and it
wouldn't be unheard of for them to be bad. Resistance
tends to increase with the age of the cap.

If you bought your loudspeakers used, its possible they
were abused. You might remove the terminal plates and
crossovers from both speakers, carefully inspect and test
all the components and traces that you can.

Hope this helps.

 

[dbCooper]

Okay, I have an update. The reason I thought a mid was not working was someone came by to look at them for a possible purchase and brought a sound meter. He would put the meter in front of the left mid and the needle would almost peg out. On the right it would only slightly move.
I have pulled BOTH mids and they each read exactly 6.1 Ohm's. Pulled out the x-over of the supposedly bad one and everything looks ok.
So, my question is, is there a way to check the x-over? Or should I put it back together and get a meter and check this myself, because I'm starting to think somone may have been trying to pull a fast one.:scratch2:

I recently sold a pair of L1590/2s to a guy who brought his own material to audition. After 10 minutes or so of letting him listen, I checked back to see how he liked them. He was concerned about the lack of midrange output from the right speaker which I too noticed when he played the piece for me. Since I'd never noticed this previously, I switched the speaker leads. As I suspected, his recorded material was the culprit.

I hope your problem is as easily solved!