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mark heija

Help Teens Rebuild LaScala Speakers

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Hey Folks,

I work with teens at the Boys & Girls Club and we've recently acquired four very old (in poor shape, paint, rust, etc.) LaScala speakers. Three of the four are "working" (don't seem to sound quite right), the other has no bass. I'm not up to date with all the technical info I see on the posts but believe that with our wood shop we'd be able to refinish the boxes and replace the workings. What we need is a simple list of the parts (and where to order) to make them like new. Thinking we can sell a pair to pay for the project. I've had a pair of these speakers for 40 years and know how good they can sound. Thanks for any suggestions.

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If you post your location a member may be able to check them out for you.  Short of that, detailed pictures of all components would go a long way toward giving you assistance.

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There are many helpful and knowledgeable folks around here. You have come to the right place. That said, we need more info. A basic rundown of what to do might look like this:

 

1) - pull all drivers and crossovers from speakers.

 

2) - check cabs for structural integrity

 

3) - inspect & test all drivers resistance with a multimeter

 

4) - crossovers probably need refreshing

 

5)- re-veneering cabs

 

6)- rebuilding speaker cabs with drivers/crossovers.

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That's a good project.....need pictures......we have members all over and a location may even help you more.

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Welcome Mheijn.  Count me in for some help.

 

There are a lot of people here who are experienced with La Scala's.  You came to the right place to get some advice and technical support.

 

I would advise that you start by researching articles on La Scala using the search engine at the top right of this page.  Thread titles sometimes are:

 

LS (I don't think it will return results on two-letter words)

scala

lascala

la scala

la scalas

+++

 

Agree with everyone on needing pictures.  The best place to start is in the back.  We need a clear picture so we can read the serial numbers, and we need a picture of the top part with all the wires in it located in the top, back.  It will have some letters on that board, and on the far right in red it will have some letters, like AA.  We need to be able to read those letters.

Edited by wvu80

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Restoring La Scala's, ah - a painful pleasure indeed!

Yup, you stop at the right corner :)

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I'll make some suggestions without knowing what you need to know.

 

You'll want to take the components out to allow work on the wooden box.

 

My first suggestion comes from a Jimmy Breslin novel.  Assume that you will not be around for putting them together and someone will have to do so without your memory.  Therefore take pictures, tag wires with masking tape and pen describing where they go, etc.  Save screws in plastic baggies with labels. e.g., these four for the tweeters.  You're making up assembly instructions.  The "smart" you may be taking them apart now but the "forgetful" you have to put them back together in a few months. Of course this goes for each of the four.

 

Edit:

 

After some further ruminations: Congrats on the B&G club and your fine leadership.  I can only imagine that you'll be teaching the kids to do this work as part of their education.  Disassembly will be sort of archeology which needs to be recorded with care.  Then maybe the same kids or others will assemble.

 

- - - - - -

 

 

If there are serial number labels do what you can to save them.  At least photograph them of course.  There should be numbers stamped into the end grain of the top of the cabinet.  See if you can find and record.

 

Overall, there are four major components.

 

1) The K-77 tweeter up top.  You'll need a long screwdriver and a flashlight to see how it is attached to the inside of this "top hat" section.

 

2) The K-400 mid horn in combination with the K-55 mid driver.  Both in the top section.  Okay, I'm calling them one component. The driver unscrews.  And there might be a brace for the mid horn. Again, a long screwdriver to get to

 

3) An electronic crossover board in the top section just below the mid driver, with all the wires going to it.  Note which wires go to where. There is a wood screw or two holding it is place.

 

4)  The K-33 bass driver "woofer" is in the bottom section.  The bottom section is called the "dog house" because of its geometry.  (Ha, where the woofer lives.) 

 

The interior of the dog house is accessed though a hatch in the bottom held in place with a bunch of wood screws.  Note that there is a wire from the crossover to the top of the dog house with some brass screws. to make the pass though electrical connection.

 

Maybe you don't have to mess with the woofer and try to dismount it.

 

Generally: there is a simple way of testing whether these three drivers have or have not  been damaged.  Disconnect the wires connected to them from the crossover and connect the two wires, by hand, to a flashlight battery.  Size AA or C or D doesn't matter.  A good driver will produce a little scratching sound. A good sign.

 

The crossover board and its little city of components is a more difficult issue.  The frames of the metal components may be rusty (you say?) but that is not so bad.  Send us pictures. 

 

Certainly do examine the screws and mating brass/chrome of the terminal blocks and the spade (U-shaped) connectors on the end of the wires. A rubber pencil eraser can be used to shine them up.

 

 A lot of people suggest replacing the capacitors in the crossover system.  I'll let others discuss that when you send pictures.

 

critesspeakers.com is a good source of replacement part and knows everything.

 

WMcD

Edited by WMcD
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Gil, a very good start. If he can get the series of the crossovers, we can start a series of pics for possible restoration.

Bruce

Edited by Marvel
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Wow Folks, this is great! I'll certainly start with some photos (on some of the boxes the labels have been painted over so no serial numbers there).

We're gearing up for our summer program now with a start on the 30th. I'll keep you posted as the project progresses. We're located in San Francisco's Mission District at the Columbia Park Clubhouse...our 125th year of serving youth in SF.

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Wow Folks, this is great! I'll certainly start with some photos (on some of the boxes the labels have been painted over so no serial numbers there).

We're gearing up for our summer program now with a start on the 30th. I'll keep you posted as the project progresses. We're located in San Francisco's Mission District at the Columbia Park Clubhouse...our 125th year of serving youth in SF.

 

Depending on the vintage, the serial numbers may be stamped on the rear of the cabinet.

 

Welcome to the forum.

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Depending on the vintage, the serial numbers may be stamped on the rear of the cabinet.

 

It would look like this: 

 

post-58280-0-33200000-1463686929_thumb.j

(photo by Mustang Guy)

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Hello Folks,

we took some pictures and found the serial numbers stamped in the end grain (thanks for the location tip). Had to brush out the dust and wipe the surface with a damp cloth to reveal clearly.

Numbers are 7P383, 7P383, 8P346, 8P348. Electronics all labeled AA

We're hoping to save the name plates. If we post-63196-0-16120000-1463707579_thumb.jcan remove the paint without damage, is there a trick to getting them off the cabinets? I'm thinking a razor blade if the adhesive isn't to tough.

Anxious to get started...I'll keep you updated with the progress.

Thanks again!

Edited by mheija
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Looks like an interesting build, looking forward to watch the process. All 4 of those were made in 1976. Enjoy them

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Looks like an interesting build, looking forward to watch the process. All 4 of those were made in 1976.

 

The 1976 LS's are very desirable on the used market.  You said you'd like to keep one pair and sell the other to pay for parts.  If you go ahead and refurbish both pair you should be able to sell one pair to cover parts and materials for both, no problem.

 

Likewise the AA crossovers are desirable and well known to many people here.  That means troubleshooting the sound and finding replacement parts will be easy.  We can give you some tips for an economical rebuild as well.

 

Those boxes are going to take a LOT of time and work to restore, but I assure you it can be done.  Do you have access to an electric sander?  We have several people here who have done that exact kind of restoration and the speakers look GREAT after they are done, so don't lose hope.

Edited by wvu80
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The woofer in speaker "D", may just be a loose wire. If you are doing all of rhese, when removing the frivers, etc., label everything so you know whoch cabi,et they came out of.. To do simple tests, you will need a multimeter (DMM), which van be purchased inexpensively, or borrowed from aomeone. You will need it to check the dc resistance for each of the drivers. The dc resistance will be different than the ohm value for a given driver (impedence is an ac value).

Bruce

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Oh Boy Oh Boy :)

You have a small gold mine sitting there. Look forward to following along...

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Since these are 40 yrs old, the crossovers will need some work. You can go differents routes on these.

1. The least expensive is to clean the rust off, replace the old/out of spec metal can capacitors and call it a day. The AA crossovers have been one of the most popular used in LaScalas. You can get a new replacement that is the equivalent by spending more.

2. Get something with a newer design that will work well/great/outstanding with the original driver components.

If someone knows how to solder, number 1 can be done for very little money and you can achieve your goal. There are schematics/diagrams available for other designs, with parts prices varying low to high. Deang builds custom networks for various heritage Klipsch speakers, and they are exceptional. Wait times can be longer, as he has a regular job and some back issues that have caused him to change his schedule on building.

Bruce

Edited by Marvel
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1. The least expensive is to clean the rust off, replace the old/out of spec metal can capacitors and call it a day. The AA crossovers have been one of the most popular used in LaScalas..

 

That would be my suggestion.  Refresh the old caps and keep the cost down.  One of the sets will be used at the Boys and Girls Club so IMO reliability and practicality would be a higher priority than ultimate sound quality.  They will still sound pretty good.  B)

+++

 

Can anybody suggest a specific cap along with a vendor?  I'm thinking the Dayton Audio caps through Parts-Express would be a quick and easy way to get those, but I'd like someone with experience doing this to make that call.

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