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New member needs infos on AR-2ax


quebecois59

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Hey there

I knew nothing about AR speakers before yesterday evening. I gave a hand to one of my neighbour to bring all sorts of scraps to the ecocenter. I realized that he had a pair of old speakers in his trailer. They were quite dirty and didn't look in very good shape at first. You threw lots of garbage in the bins at the ecocenter and then it was the speakers turn. I first removed the damaged grills (and threw them in the bin) to have a look at the speakers and even if I'm not an expert I thought that they might be of good quality.

I asked my neighbour if I could keep them to check for infos. Later in the evening I surfed on the web and discovered that AR-2ax speakers are pretty good ones! So I hooked them on my system one at a time. One of them was working well, it delivered a better sound than my usual speakers even if the woofer foam surround is toasted! The other AR speaker didn't perform very well, it sounded like the MID et HI speakers were not working at all, and the woofer surround is toasted too.

So I'm a bit ambivalent if I should keep and restore them or not. I went back to the ecocenter this morning to get the grills back even if they look terrible, so I'm ready to get involved in the process!

I already restored my JVC Zero 3 surrounds 2 years ago so I'm not a total newby in this kind of work, but I do need some good basic infos and advices to achieve the AR-2ax restoration. I haven't touched anything for the moment except that I gently removed the gyproc dust off of the tweeters and Mid-ranges with a toothbrush.

English is not my first language so please take it in consideration.

I read a couple of threads and realized that I don't know what "drivers", "pots" and "caps" refer to.

Thanks in advance.

Francois

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bienvenue Francois

Those ARE good speakers. Please download the AR3a restoration manual: http://www.classicspeakerpages.net/library/acoustic_research/original_models_1954-1974/original_models_schematicss/restoring_the_ar-3a/restoring_the_ar-3a_full_pd.pdf

The 2ax is from the same time period and was very similar to the 3a. Much of what you need to know is covered in that booklet.

If you have replaced speaker surround foam before, you're on your way to a successful restoration.

Your problem with the mid and hi speakers is probably the pots. So....

Drivers are the individual speakers (woofer, mid-range and tweeter)

Pots are potentiometers. These are the volume controls on the backs of the speakers. The AR pots become corroded and need to be cleaned or replaced. See the AR3a booklet.

Caps are capacitors. Your 2ax will have a wax block inside that is a double capacitor. The values are 4 microfarad and 6 microfarad, usually shown as 4uF and 6uF. They should be replaced with film capacitors. I don't know who sells these in Canada. Good brands are Solen, Erse, Dayton (from Parts Express) and others.

This will be a fun and rewarding project. Ask us any questions.

A bientôt

Kent

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Hey Kent

Thank you very much for your quick answer. I appreciate the link to the restoration manual, i'll download it today and have a look at it tonight.

You mentioned that the original capacitors should be replaced with film capacitors. Should I test them before or should I assume that they are finished and they have to be replaced anyway? Don't send me a long answer if this topic is covered in the manual!

Francois

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The crossover in the 2ax is simpler than the one in the 3a. You probably have the wax dual cap as shown below and you could test it but as long as you are inside the speaker most of us prefer to replace. New caps are cheap (in the US anyway) and will last forever. You want one 4uF and one 6uF per speaker. Voltage should be at least 100v but higher is fine. Something like this is good (link gives price in Canadian dollars):

http://www.erseaudio...l/MPX63-03-3-90

You can go +/- 10% on the value, so a 3.9uF and a 6.2uF are fine.

These are also good, and quite inexpensive (USD)

http://www.madisound...-mylar-3.9-mfd/

Kent

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Thanks Kent

Since replacing the surrounds seems the first thing to do, I phoned the store that supplied the parts for my JVC speakers years ago. I asked for foam surrounds for my AR speakers. They sell 10 inch foams for 4 dollars, but they are not specifically for AR speakers. Are there different qualities in these foams or are they all the same? They also told me that using special Lepage glue #6 would be fine for foams, is that correct?

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There is some disagreement here but many of us think this is the best AR2ax foam: http://www.ebay.com/...=item4cfbac3dc4

The "Boston filled fillet" style seems to work best. I don't know what Lepage #6 glue is, but the glue that comes with this kit is excellent.

If you decide you want only the foam surrounds and not a complete kit, send MSound (moonlistener) a message. Tell him you are a CSP member and that you want just surrounds. Or just surrounds + glue, or surrounds + dustcaps + glue. He will put together as complete a kit or as minimal a kit as you require.

Most of us agree that "generic" 10 inch surrounds are not a good idea.

Kent

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what a (long) strange trip, eh !!! good evening all ... my first link-up ! long live walls of sound !!!

just this afternoon, i decided to "open" my two ole AR2ax's ... in the hopes of maybe salvaging them as they've begun snapping and popping ... and out of curiosity i googled (of course) and voila ! two canadians on the same day wondering about restoring ! bonjour francois and hello kent ... thanks ! ... i'm not a techie so may not dive into this project but i did open one and lots of black edge stuff - foam - fell out from the woofer...

got the download for restoring and i'll take this on soon and keep reading other guidance requests ...

anyway, greetings from nova scotia ......... in spirit, armand

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Hey Armand and bienvenue in this forum!

I decided to step in the process tonight. I just removed the woofer from its hole (only four bolts instead of 8 for the AR3). No sealant around the edge, only a ring of thin, white foam. I had to unsolder the two leads from the terminals.

I hooked up my ohm-meter to the terminals, I had a 6.5 ohms reading, I wonder if it's OK or not?

With one terminal hooked up, when I touched the other one with the second wire of my ohm-meter, the woofer surround goes up slighlty with a "tick" noise. I suppose this is normal...

I cut out the old foam surround and removed most of it. Now I can see easily the base of the cone, but not the voice coil, is it inside the base?

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I cut out the old foam surround and removed most of it. Now I can see easily the base of the cone, but not the voice coil, is it inside the base?

Yes. Take a look at the cut-away diagram here: http://www.citlink.net/~msound/refoam/

Also see p5 of the AR3a booklet.

The voice coil is visible when you remove the dust cap. See page 6 of the re-foam instructions: http://www.citlink.net/~msound/refoam/page6.htm

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I hooked up my ohm-meter to the terminals, I had a 6.5 ohms reading, I wonder if it's OK or not?

With one terminal hooked up, when I touched the other one with the second wire of my ohm-meter, the woofer surround goes up slighlty with a "tick" noise. I suppose this is normal...

I cut out the old

foam surround and removed most of it. Now I can see easily the base of the cone, but not the voice coil, is it inside the base?

Your resistance reading is normal, and your voice coil is probably OK. Removing the dust cap is necessary for shimming, but is not likely to tell you if there are voice coil problems.

I would just concentrate on re-foaming.

Roy

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I would just concentrate on re-foaming.

And repairing or replacing the pots. You said English is not your first language, so the AR3a manual may be challenging. Don't go looking for problems. The woofer surrounds are obviously bad and must be replaced. Your mid and high on one speaker do not work. This is PROBABLY caused by corroded pots. If you replace the surround and clean the pots the speakers will probably be fine.

If you wish to go further, you can replace the caps. You "could" also replace the pots, using L-pads but this is NOT absolutely necessary. The advantage to L-pads is they do not corrode.

There is an English idiom: KISS. Keep It Simple, Stupid :D . Medical students are taught "If you hear hoof beats, don't look for zebras."

My point is: Start with what you know is broken and fix those things. Don't look for other possible problems.

One more thing: Listen to Roy. He's one of the authors of the AR3a booklet and his advice is sound.

Kent

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Kent

I'm also a member of motorcycle forum and the usual idiom is: If it ain't broken, don't fix it!

I'll follow your advice and fix what is obviously broken. If I don't have to remove the dust cap to put shims or whatever, I won't touch it.

Next step: removing the pots to check them and clean them, hoping the'll be OK then. And ordering new surrounds!

Thanks again!

Francois

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Francois,

I'd say your mastery of English is pretty good!

The dust cap issue is somewhat controversial. MSound strongly states that the only way to re-foam speakers correctly is to remove the dust cap, place shims around the voice coil and replace the dust cap after the job is finished. If you read his step-by-step instructions, he shows that. I agree. I have re-foamed many woofers and always use shims. One benefit of the shims is that it allows you to position the speaker cone up or down as you work on it. Roy, who has re-foamed many, many speakers agrees. Sometimes he does not replace the dust cap but instead cuts the original around about 90% of the outer edge, leaving a "hinge" so the cap can be lifted out of the way for shimming, then put back in place and glued.

Some experienced members, as you will read, do not believe shims are needed and instead use a 30Hz test tone during re-foaming.

All I can tell you is, my first re-foam was a pair of 2ax speakers. I got a kit from MSound and followed his instructions exactly. The speakers turned out great and ever since I have only used MSound kits.

A note on the pots: There are instructions in the AR3a booklet and you can also find instructions other places on the internet. Sometimes the pots are so badly corroded there is pitting (some little pieces of the metal are gone). In that case, the pots will never be 100% perfect. Also, on pots that look OK, sometimes there are still dead spots because the coils or the wiper are not perfectly clean. You have an ohm meter. After cleaning a pot but before you put it back in the cabinet, check it with the meter. The reading should go from 0 to about 15 ohms as you turn the shaft. If you find dead spots, take it apart again and clean it more.

Kent

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Kent

THank you, my written English is not too bad, but I still have recurrent problems with conversations!

I don't know for the moment what I will do about the dust caps and shims. Maybe I'll wait until I get the kit and instructions and I'll make a decision then.

I'll be taking pictures during the process. What is the best way to post pictures on this forum?

Francois

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Hi Francois

I can assure you that your English is WAY better than my French :lol: I visited your beautiful city in February for the winter carnival and was fortunate that one of our traveling companions was Quebecoise, or we never would have survived!

When you post a reply, go to "More Reply Options." At the bottom is a place to attach files. For best results, resize your pictures to about 100KB.

Looking forward to seeing them!

Kent

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I don't know for the moment what I will do about the dust caps and shims. Maybe I'll wait until I get the kit and instructions and I'll make a decision then.

Francois

Hi there

I already posted my experience refoaming a pair of 12" AR woofers back in the early - mid '90's.

The first woofer took me about 1 1/2 hour to clean up the woofer and refoam it.

The second one about 10 minutes.

I bought a mailorder kit and had never done this before.

I laid the woofer face up and glued the surround to the cone first.

I then used a low level signal from a Stereophile cd at maybe 100 hz so as to not overdrive it's travel.

Centering the surround on the frame, gently I moved ever so slightly off center until I heard a buzz (voice coil rubbing).

Marking this with a pencil on the frame, I then moved my hands about 90 degrees around the surround and repeated my offset until it also rubbed.

A pattern was forming as to where, approximately, the center of the cone movement was.

I dabbed a small drop of glue at 4 points and centered the surround with my pencil marks.

Again I turned on the signal and increased the volume slightly to have the cone move a little faster without buzzing.

Turning down the level again, I very gently slid slightly the surround material towards the frame exterior.

With no buzzing in any of these sliding tests I then glued the balance of the surround down, using wooden clothespegs.

To do it in a more professional way, I would remove the dome or at least cut around near the base and leave perhaps 1/4" uncut and use this as a hinge.

The shims that I would then use would be 4 only 3/8" - 1/2" wide strips of ordinary business card stock cut lengthwise.

If I had the time and energy I would totally remove the cone, spider and dome to clean out the voice coil gap of filings or dirt ( do not attempt ).

This is a very critical job and what I did do was done just by luck, stupid luck.

With the two woofers that I did do there has been no further noise, but if there was, I would not have been happy shortcutting the process.

I believe that in the AR-3A repair manual you will find the most and best information for the average speaker owner.

Don't fix, what's not broken, is a good policy, which I don't always adhere to..

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Hi Francois

I can assure you that your English is WAY better than my French :lol: I visited your beautiful city in February for the winter carnival and was fortunate that one of our traveling companions was Quebecoise, or we never would have survived!

When you post a reply, go to "More Reply Options." At the bottom is a place to attach files. For best results, resize your pictures to about 100KB.

Looking forward to seeing them!

Kent

I use photobucket to create albums and tinyurl to create short url that I can post. Would it work if I post a tiny URL here?

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Hi there

I already posted my experience refoaming a pair of 12" AR woofers back in the early - mid '90's.

The first woofer took me about 1 1/2 hour to clean up the woofer and refoam it.

The second one about 10 minutes.

I bought a mailorder kit and had never done this before.

I laid the woofer face up and glued the surround to the cone first.

I then used a low level signal from a Stereophile cd at maybe 100 hz so as to not overdrive it's travel.

Centering the surround on the frame, gently I moved ever so slightly off center until I heard a buzz (voice coil rubbing).

Marking this with a pencil on the frame, I then moved my hands about 90 degrees around the surround and repeated my offset until it also rubbed.

A pattern was forming as to where, approximately, the center of the cone movement was.

I dabbed a small drop of glue at 4 points and centered the surround with my pencil marks.

Again I turned on the signal and increased the volume slightly to have the cone move a little faster without buzzing.

Turning down the level again, I very gently slid slightly the surround material towards the frame exterior.

With no buzzing in any of these sliding tests I then glued the balance of the surround down, using wooden clothespegs.

To do it in a more professional way, I would remove the dome or at least cut around near the base and leave perhaps 1/4" uncut and use this as a hinge.

The shims that I would then use would be 4 only 3/8" - 1/2" wide strips of ordinary business card stock cut lengthwise.

If I had the time and energy I would totally remove the cone, spider and dome to clean out the voice coil gap of filings or dirt ( do not attempt ).

This is a very critical job and what I did do was done just by luck, stupid luck.

With the two woofers that I did do there has been no further noise, but if there was, I would not have been happy shortcutting the process.

I believe that in the AR-3A repair manual you will find the most and best information for the average speaker owner.

Don't fix, what's not broken, is a good policy, which I don't always adhere to..

Hey Vern

Your method was creative and apparently effective! I understand that the reason to put shims is to make sure the voice cone is correctly positioned and can't no longer move to a wrong position while gluing the new surround. It sounds like a good idea.

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Hi again

I left out something very important.

Sagging spiders is the loss of the ability to center the voice coil and still allow back and forth movement.

This is something that could have critical alignment as try to center the cone without removing the spider.

In theory the voice coil should be equally distant from the magnet and coil top to bottom, or parallel.

Sagging spiders may allow a voice coil form to sag to one side unevenly or allow the voice coil to ht the backplate or jump out of the gap even.

Jumping out of the gap does not mean that it will return back into the gap undamaged.

Driving or pushing the cone to hit the backplate can peen the voice coil edge in or out and reduce the forms inner or outer diameter.

I did have an opportunity to see what a 12" AR-3A woofer pair look like after having 120 volts AC applied.

The cones of the cloth surround alnico magnet system pushed outwards and when returning to the gap, missed and hit the pole piece, crushing the end of

the voice coil form and destroying the woofers instantly.

One would not want to do this a second time.

Must have been one heckuva transient, possibly more than 2,000 watts AC for a microsecond.

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Hi again

I left out something very important.

Sagging spiders is the loss of the ability to center the voice coil and still allow back and forth movement.

This is something that could have critical alignment as try to center the cone without removing the spider.

In theory the voice coil should be equally distant from the magnet and coil top to bottom, or parallel.

Sagging spiders may allow a voice coil form to sag to one side unevenly or allow the voice coil to ht the backplate or jump out of the gap even.

Jumping out of the gap does not mean that it will return back into the gap undamaged.

Driving or pushing the cone to hit the backplate can peen the voice coil edge in or out and reduce the forms inner or outer diameter.

I did have an opportunity to see what a 12" AR-3A woofer pair look like after having 120 volts AC applied.

The cones of the cloth surround alnico magnet system pushed outwards and when returning to the gap, missed and hit the pole piece, crushing the end of

the voice coil form and destroying the woofers instantly.

One would not want to do this a second time.

Must have been one heckuva transient, possibly more than 2,000 watts AC for a microsecond.

Vern

Is a saggy spider very obvious at first look ? How would I know if one of mine is "a bit" saggy?

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I did some work on one of my speaker this afternoon. I removed all of the insulating material to access the pots. I partially unsoldered both of them. I can't figure for the moment how one can re-soldered the pots without having three hands but I count on the gurus here to explain!

One of the pots was very badly corroded (see second picture). Even after some sanding with a 1500 grit sanding paper, there is still close to half of the contact surface that looks pitted (third picture). Should I go any further with coarser paper?

The other pot was pretty clean compared to the first one (picture 4), and it cleaned up completely (picture one, I don't know why they ended up in the wrong order).

I also noticed that the wire between the T post and the #2 post is broken. Is that enough to prevent the Tweeter to work even if its pot was almost clean?

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post-120422-0-71854200-1342385639_thumb.

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I can't figure for the moment how one can re-soldered the pots without having three hands but I count on the gurus here to explain!

My advice is to solder pig-tails, that is short lengths of insulated wire say about 9" long to the pots before you re-install them. Then all you have to solder inside the box are splices. Just be sure to use enough tape to insulate the splices so that there's no chance for a short circuit. You can also tin the wires at the ends where the splice will be made ahead of time. This should make it even easier. Good luck.

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My advice is to solder pig-tails, that is short lengths of insulated wire say about 9" long to the pots before you re-install them. Then all you have to solder inside the box are splices. Just be sure to use enough tape to insulate the splices so that there's no chance for a short circuit. You can also tin the wires at the ends where the splice will be made ahead of time. This should make it even easier. Good luck.

Thanks for the trick. Actually, it won't too bad because the only leads that I unsoldered were the two long ones connected to the mid range speaker and the long yellow one going from the tweeter to its pot. THat was enough to give me some slack to work on the pots (sanding).

The first two leads are easily accessible. For the last one, I will put a small block of wood in the box as a stand so that I can use both hands to solder.

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