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AR-2ax Project


Michael T
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Hello. I wanted to introduce myself and give you folks a heads up that I will be picking some brains on my upcoming project.

I recently won a pair of AR-2ax speakers at a Goodwill auction. I have yet to pick them up so I’m not sure of everything that will need to be done but they did some testing and I know a few things up front. They are early first generation (serial numbers 08375 and 08391). The folks at Goodwill say that they work, although they do not specify if all the drivers work. I know for sure that the woofers need re-foamed which suggests that they were replaced at some point since they have foam surrounds instead of cloth. I know that I will need one of the grill badges (early ARinc badge) and that the grill cloth will need cleaned. The cabinets appear to be in decent shape except there is damage to one of the corners (it appears to be in the back).

This is my first speaker project. Until a few months ago I had no idea of the quality of or the huge following of vintage audio equipment, especially speakers. From the research I have already done, it appears that I am starting out with a very popular and good quality speaker. I will be assessing them this weekend and will probably begin throwing questions out next week. Once I get them home I will get some good pictures to post so that anyone who is interested can see my progress. 

I am also a recent member of audiokarma, I know that there will be a wide variety of information and opinions out there so this may be a benefit or I may find myself with a case of information overload. :)

Thanks

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Welcome Michael

Photos will be helpful. Here are pics of one of my 2ax projects: http://www.classicspeakerpages.net/library/acoustic_research/original_models_1954-1974/original_models_pictures/ar-2ax_pictures_from_jkent/ar-2ax_pictures_from_jkent__3.html#previous-photo

Best grille cloth is 18-count linen in "lambswool" from 123 Stitch. That's covered in the AR-3a Restoration Guide. Be sure to download it and read it. The 2ax was a "little brother" to the 3a and much of the information is applicable to your project http://www.classicspeakerpages.net/library/acoustic_research/original_models_1954-1974/original_models_schematicss/restoring_the_ar-3a/

Another grille cloth option is the 28 count Irish Linen by CharlesCraft. http://www.michaels.com/10357706.html#q=charlescraft+linen&start=1 Many (not all) Michael's craft stores sell it. It's about $8 a roll and you need 2 rolls IIRC but Michael's always has 40% off coupons (and sometimes 50 or 60%) so figure about 5 bux a speaker. Not as nice or as authentic as the 18 count from 123 Stitch but much cheaper and not bad. That's what I used on the speakers pictured in the link in the first paragraph.

Corner damage can be repaired with Mohawk Epoxy Stick, or you could do a jigsaw puzzle patch like Glenn does.

I have repro AR Inc badges. PM me if interested.

This should be a fun and worthwhile project. One bit of bias: This forum is your best bet for AR restoration advice. Many of us are also members over at AK and we value that forum but CSP really specializes in vintage AR.

-Kent

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Nice!

Yes, those woofers have been changed. Maybe Roy will comment on any implications for restoration.

That corner bash could be filled with epoxy but it looks like the perfect candidate for a patch. Glenn's your man for advice on that.

Nice that the "a" logos are intact. They're hard to find and I just sold my last reproduction with no plans to get more.

You "may" be able to clean up the linen. I'm not optimistic but it may be worth a try. Search a bit or wait for ra.ra or some other member to chime in. I think some have used very dilute bleach and/or OxyClean solutions.

Then you'll probably want to clean or replace the pots. L-pads work great. And new capacitors--one 6uF and one 4uF per speaker. I like Carli film caps from Madisound. You can get a 3.9uF (close enough) for $1.35 and a 6uF for $1.80. Besides being cheap, Roy says the ESR of these Mylar caps is closer to the original electrolytics' values than are the various poly caps.

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Hi Michael - - glad to see you posting here on the CSP forum. You've already received most of my comments in the other thread you mentioned, but I just wanted to post the pic I was unable to attach on AK. This shows the Masonite adapter ring used to fit the 4-hole smaller diameter basket into the 6-hole larger diameter cabinet prep. Unlike this pic (on top of), I think your speakers have this ring on the correct side (under) of the metal basket rim.

Kent's advice is always great and Glenn is your cabinet veneer guy.

On the grille cloth, since there are no obvious tears, patches or holes, I'd make every effort to restore and salvage the originals. With a little patience and attention, I'm fairly optimistic that those can be returned to a very presentable appearance. Pic attached shows one stage of cleaning discolored original grille cloth.

10%22 ring.jpg

4x test grille.jpg

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18 minutes ago, ra.ra said:

Glenn is your cabinet veneer guy.

I just checked your thread on AK. Glenn is GD70, so you already know him.

If you have a place for them the 2ax's will give a lot of listening pleasure and the bonus is the satisfaction you get from DIY.

-Kent

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Thanks again folks. When I saw that this forum focused on AR I figured I would join. Turns out the guys who have been the most helpful from AK are the key guys over here :)

It's nice to know I'm in good hands with this project.

56 minutes ago, JKent said:

 

If you have a place for them the 2ax's will give a lot of listening pleasure and the bonus is the satisfaction you get from DIY.

-Kent

Even though I started out with the idea to flip these (I saw selling prices and dollar signs), the guys at AK and the research I've done has convinced me to MAKE the room for these speakers. I currently have a hodge podge surround system for the living room. Not sure if these will necessarily replace my fronts but at some point I plan to make a pure music room and that is where they will end up. 

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I got my speakers, yay! The guy at goodwill who helped me bring them out to my car had a funny look on his face when I put them in my back seat, covered them with blankets and buckled each one into a seat belt :)
 
The first thing i did when i got them home was to take pics of the exterior. I then hooked them up to my receiver. I then removed the woofer and pulled out that 50 year old insulation. After choking a bit I took my vacuum and tried to get the fibers still hanging around. I then took pics of the interior.
 
That's it for today....wait..what? oh you want pics and information? Well, I still need to go through the pics and pick out the best and reduce their file size. But I will give you the good, bad and the ugly (actually I am the ugly).
 
The cabinets are not horrible and should clean up pretty good. the chip in the corner is not as big as it looks in the pic from goodwill. Overall I am pleased with the cabinets.
 
I'm going to replace the grill cloth. there is a small hole up near the tweeter on one of them. I am not sure how thin this stuff is new, but it is pretty thin now.
 
When I wired them for sound the woofers worked on both of them but neither the mids nor tweets worked on either one. Of course the woofers sounded a bit blah because the surrounds are pretty bad.
 
I took the woofers out and found that they are mounted to the adapter ring with some kind of rivets that are typically used to attach stuff to Masonite board. On one of the woofers 2 of the rivets were barely holding on to the frame and one let go as I was working the speaker out. This should be easy enough to remedy, I am thinking that this isn't the best method for attaching them (i could be wrong). It seem that one would want the woofer mounted a bit more hard and fast. The sealing goop is pretty gross BTW.
 
All the wiring looks good on the inside so I went ahead and gave the tweeters a signal at the terminal posts and they both work (yay). I then put a signal on the mids at the pot and they both work (yay). I am pretty sure that the pots are pretty bad since they are quite difficult to turn. I will change them and the caps.
 
I have already exceeded my allotted time for this project for the day (I tend to obsess and my wife will lose me for hours on end). I will get those pics up soon. I will start working on the cabinets this weekend. I will be after Christmas before I order any parts.
 
Thanks for your attention.
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Hey guys, just wanted to give an update. I've been talking to Glenn and ra.ra through private message mainly because they have been with me from the start of my journey. They offer good advice but I think I should branch out, especially since some of you genuinely wish to follow this. Trying to post progress on 2 forums and a PM conversation is a bit daunting so I may stay exclusively here.

Not really a whole lot to report, I've downloaded and reviewed the AR-3A restoration guide. Great stuff, thanks to all who freely offered their time and knowledge. 

I'm in the process of making parts lists and sourcing them. Having an internal debate as far as l pads vs refurbished OEM pots. I'll probably go with l pads (against my OCD tendencies) just because I'll probably not know the difference with my untrained ears.

Thanks for reading, hopefully next post will have more progress.

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Just wanted to comment that you've got the "special" cabinets with the stamp from the inspector. This little guy with his overalls and Gumby hands and a nose that looks like a burning cigarette always cracks me up.

On the woofers, you'll probably never know what happened with the original cloth woofers, but the "service replacement unit" sticker (and the factory rivets to the masonite ring) might give a small clue - - - perhaps AR inventory had already exhausted their supply of earlier cloth woofers when these speakers required woofer replacement. Hence, foam woofers with the adapter ring were sent as substitutes.

For the record, I have often been an advocate to try to repair original pots if possible to keep things original, but after seeing Michael's deteriorating pots and looking at his two options (4 re-habbed pots @ 20 ea., or 4 new L-pads at 5 ea.), I found myself suggesting the L-pad option simply based on initial cost and projected longevity. 

Michael, you might want to post those pot pics in this forum - - it's likely that lots of good advice will follow.

 

a.jpg

inspector.jpg

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I have a pair of AR3a's that have service replacement woofers. They originally had the alanco cloth surround woofers. When I restored them I had to change the #7 inductor (1.88mH) with a #9 Inductor (2.85mH) which I unwound from a erse 3mH coil. I have all three woofer versions of the 2ax and am wondering if the same is true with these woofers.

 

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9 minutes ago, larrybody said:

I have a pair of AR3a's that have service replacement woofers. They originally had the alanco cloth surround woofers. When I restored them I had to change the #7 inductor (1.88mH) with a #9 Inductor (2.85mH) which I unwound from a erse 3mH coil. I have all three woofer versions of the 2ax and am wondering if the same is true with these woofers.

 

There was a change. The earlier 2ax with the cloth surround woofer and the first (wide flange) foam surround woofer had a #5 (1.20mh) inductor, and the later had a #7 (1.88mh) inductor.

Roy

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I've decided to order the l-pads and resisters. They are on their way. Caps are on their way

I have a few questions.

As for my woofers, a rivet had let loose from the masonite adapter plate and another was barely holding on on one of them. I carefully drilled all four out so I could use small bolts to hold them together. It looks like I will need to file out spots on the speaker to allow for the bolts since they won't be flush and the holes in the adapter are half on and half off the rim of the original hole. There was also a piece of foam seal between the driver and the adapter, I have some 1/8" weather strip, would this work ok for sealing this?

As for the inductor, mine has no number on it. I assume it has never been changed and since they have low serial numbers, 8300s, would it be #5? Is there a way to tell? Can you tell by looking at the woofers if I need the 5s or 7s?

I ordered some foam surrounds so they are on their way.

I think all I have left is the lambswool (expensive stuff, and of course 123 stitch is out of stock), some veneer, and things like epoxy, staples and such.

Thanks for your attention.

 

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7 hours ago, Michael T said:

As for the inductor, mine has no number on it. I assume it has never been changed and since they have low serial numbers, 8300s, would it be #5? Is there a way to tell? Can you tell by looking at the woofers if I need the 5s or 7s?

Your cabinets have very low serial numbers and were originally equipped with cloth surround woofers and #5 inductors. The only way to know for sure is to measure them, but they are most likely #5's. Your later style woofers should be used with #7 inductors.

Roy

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I was afraid of that. Maybe I'll be lucky and the inductors were changed when the woofers were. 

I did a cursory look around the net and those inductors don't appear to be readily available. I know someone who can measure the inductance. I may be hunting coils soon. :(

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5 minutes ago, GD70 said:

Hi Michael,

Good to see you're getting great advice and that Roy is chiming in. 

Looking forward to seeing your progress on these.

Yes, it's like having a celebrity helping :). Actually, you seem to be a bit of a celebrity yourself. At least when it comes to cabinet refurbishing, as well as a downright nice guy :).

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3 hours ago, Michael T said:

I was afraid of that. Maybe I'll be lucky and the inductors were changed when the woofers were. 

I did a cursory look around the net and those inductors don't appear to be readily available. I know someone who can measure the inductance. I may be hunting coils soon. :(

Michael,

I have many AR coils should you end up needing #7's.

Roy

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AR liked marking their coils with the number. Sometimes I have found them installed with the number facing down. 

MJRGx4q.jpg

I finally got this inexpensive inductance and capacitance meter which comes in handy, especially for matching and testing capacitors. 

https://www.parts-express.com/portable-digital-lc-inductance-capacitance-meter--390-570

Of course you are not going to need one until you really get infected with the classic speaker bug. 

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15 minutes ago, larrybody said:

I finally got this inexpensive inductance and capacitance meter which comes in handy, especially for matching and testing capacitors. 

Even cheaper--these are sold by several ebay sellers. My technician recommended it so I'm guessing it's a great deal for about 6 bucks :D

These test many kinds of components and even identify what the thingy is when you attach it. No case but you can make your own.

meter 2.jpg

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15 hours ago, RoyC said:

Michael,

I have many AR coils should you end up needing #7's.

Roy

I found that the AR inductor chart shows the weight of the different inductors. As I was getting into the process of removing it I knew what I would find. It was obviously never changed. Weighing it confirmed that it is a #5, 9.3 oz. I'll contact you with PM  to discuss getting a couple from you, Roy.

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