Advice needed for Refurbishing AR-2ax

StarMover

StarMover

AlienToAllThingsAudio
Just got home with a nice pair of AR-2ax speakers from the thrift. The first thing I noticed when I wired them up was corrosion on the pots. White flakes were literally falling off as I was working them. I can hear the mids and tweets sporatically, clearly I need to get inside to really clean the pots.

OK, exactly how do I do that?? These cabs are welded shut. No access from the rear and the grills don't appear to come off without destroying them.

Am I going to have to sacrifice the grills? Cut new ones from 1/8" luan and recover them with similar fabric? Is it the only way? :sigh:

I also hear that AR uses a strong caulk/adhesive to weld the drivers in place. This won't be easy will it? :no:

I would appreciate any advice anyone can give.
 
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Here's a road map in:
http://audiokarma.org/forums/showthread.php?t=71133

Here's your pot cleaning thread:
http://audiokarma.org/forums/showthread.php?t=42588

The grills are either stapled or glued or both, I've seen it every way. Look for tiny little staples along the edge, use an o-ring pick to get them started then pull them out. Use a wide scraper or spatula-shaped implement along the sides and pry up gently - don't want to mark the wood! Might take a while to break the glue loose (if they're glued at all) but it will happen. :thmbsp:

Sometimes the drivers will come out easily, sometimes not. they are sealed in with a heavy putty in older models, simple gaskets in later models.

Good Luck! :music:
 
For grill removal, I've had success using the following method:
Unscrew the AR badge and replace with some type of thin wood screw......don't go too far in, you just want to screw into the masonite frame, not the cabinet itself.Grip the screw with a pair of pliers and pull slowly yet firmly. The frame should pull away. Then use your hand to reach behind it and continue pulling the frame away from the cabinet.
The only problem with this method is that the hole for the badge is now a bit too large and need to be made smaller. I just break off a piece of a wooden match and insert in the hole and then screw the badge into that.
This method has never failed me, but YMMV. Good luck and have patience......your ears will thank you. :D
 
A work in progress

Thanks guys for the help and encouragement.

I got the grills off without damage. They were held on with dots of white hot-melt glue. I took Joe Longwood's advice and used one of those paint can openers they give you at Home Depot to loosen the grill in one spot, it has just enough hook on it to get between the edge of the grill and the cabinet. Once I got a start, I used a one-inch putty knife to work my way around. In some places the grill fabric was stuck to the glue residue on the cabinet, so I had to reach in with a sharp razor and cut it free. I will probabally recover these anyway.

OK, grills off. Drivers look OK (not saying much for vintage AR drivers). The woofer surround looks like hell, but it's intact and flexible. The woofer looked like it was welded in with a heavy putty-like stuff. Again I used the paint can opener to get a little bite between the speaker frame and the cabinet. Now with the paint can opener locked in behind the speaker, I used a 3 inch block of wood against the outside of the cabinet to pry straight out on the paint can opener with a pair of slip-joint pliers...and viola! It popped loose. Not as bad as I remember my first attempt on an AR-2a. I unsoldiered the wires and the woofer is free.

With woofer out and that God-awful fiberglass batting removed (still itching from it :tears:), I now have access to the crossover pannel. Looks like the pots have a top and a bottom and are held together with a kind of springy wire strap. I popped this off and the pot came into two parts. (damn it's actually servicable... they don't make stuff like this anymore) I removed the knob side to reveal green corrosion on the contact point which I cleaned off with my dremel tool fitted with a tiny grinding stone. The other side of the pot with the spring-like winding array looked OK, except for some green corrosion at both terminals. A little vinegar and that was gone. (Wishing now that I was not out of Deoxit) The other pot looks like it has two opposed contact points and has some serious eaten-away metal. I cleaned it and put it back together, but I think it needs to be replaced.

With it all hooked up, the pots were really working now. The mid can be turned up until it's intolerable. I can hear the difference in the tweet when I adjust the pot, but still I don't think the tweet is up to par. Could be the rotten pot or perhaps it needs a new cap? Anyone replaced a cap on the AR? Looks difficult given that little plastic box all the electronics are in. :scratch2:
 
Cool! :music: Sounds like you have the earlier model - fabric surrounds? Red Dome tweeter? Great Speaker!

The recap is easy - that "box" inside is a cap with two taps (the "box" is a solid block of wax, just cut it loose and leave it there) - the values and wiring are written on the face. :yes: Just buy the two values it mentions (In this case I think 4uf and 6uf, IIRC) and wire them in. Super simple, and that plus the rheostats (and a single coil) constitutes the entire crossover.

Get film/foil caps.
 
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Heh heh. Without getting into any deep conversations about degradation over time in the AR dome tweeter, your tweeters may be fine. New caps might very well help.

After that, if you think they sound too rolled off but might be functioning properly, try them for a few days before you go back to whatever speakers you were using. Then see which one sounds wrong. Psycoacoustics can be baffling.
 
Yeah, fabric surrounds, red dome tweeter, mid has a mesh covering. Ordering caps tomorrow. What about wiring out the tweeter pot? What are the ups and downs of that? Oh, and should I replace the batting with conventional fiberglass batting? I could just mail the old stuff to the IRS.
 
Put your working pots on the mids, and if the coils are OK use the "spotty" one on the tweeters, wire the wiper lead to the highest setting terminal. Bypasses the bad connections and leaves the coil in the crossover circuit.

Some folks like the mids wired in "fully on" like that and by-pass the tweeter pot completely. Do whatever sounds good to you!

FWIW, I never adjust mine anymore. I found that the tweeter full-on and the mids just a tiny tic back from that is where my ears are happy.

What are you using for power? The ARs are hungry :D and like a good bit of headroom. :yes:
 
ozmoid said:
FWIW, I never adjust mine anymore. I found that the tweeter full-on and the mids just a tiny tic back from that is where my ears are happy.

What are you using for power? The ARs are hungry :D and like a good bit of headroom. :yes:
Click to expand...

I also like the tweeter (pre new caps) turned all the way up and the mids backed down to about 80%.

I'm driving these with a vintage Pioneer SX-737 I think it offers 60 WPC. I'm gonna replace that batting with new.
 
You're going to love those older 2AX's. I have ~1965 set and another from the 70's. I prefer the 65's. I recapped, used clean set of attenuators to keep crossover original, re-used rock wool and re-doped woofer surround.

When I first listened to them I was dissapointed. They are rolled off and at first don't seem anything special. But wait - give them a chance and odds are you will get hooked. :yes:

I started out using Pioneer SX950 which seemd like plenty of watts. But when I pciked up a Sansui 890DB (about the same 85 watts) these speakers really openned up :banana: I've tried them with Sony 6065, Pioneer 3700, Proton int amp, and nothing sounds even close to the Sui. Maybe my SX950 need re-cap. Bass response just delicious :music::thmbsp: And sweetest midrange I've ever heard. :D

Here's a pic of my babies:

IMGP1142.jpg

IMGP7999.jpg
 
shacky said:
When I first listened to them I was dissapointed. They are rolled off and at first don't seem anything special. But wait - give them a chance and odds are you will get hooked. :yes:
Click to expand...
There is just something "real" about the sound they make - not bright or forward, not in-your-face, but "there" none the less. It does occasionally take a little acclimation to really appreciate this design.

ZERO fatigue, response down to 30 hz... what's not to like? :D
 
shacky said:
You're going to love those older 2AX's. I have ~1965 set and another from the 70's. I prefer the 65's. I recapped, used clean set of attenuators to keep crossover original, re-used rock wool and re-doped woofer surround.

When I first listened to them I was dissapointed. They are rolled off and at first don't seem anything special. But wait - give them a chance and odds are you will get hooked. :yes:

I started out using Pioneer SX950 which seemd like plenty of watts. But when I pciked up a Sansui 890DB (about the same 85 watts) these speakers really openned up :banana: I've tried them with Sony 6065, Pioneer 3700, Proton int amp, and nothing sounds even close to the Sui. Maybe my SX950 need re-cap. Bass response just delicious :music::thmbsp: And sweetest midrange I've ever heard. :D

Here's a pic of my babies:

IMGP1142.jpg

IMGP7999.jpg
Click to expand...


I saw a pair of those once for $8.00 but i didnt get them! :tears: :sigh:
 
StarMover said:
I also like the tweeter (pre new caps) turned all the way up and the mids backed down to about 80%.

I'm driving these with a vintage Pioneer SX-737 I think it offers 60 WPC. I'm gonna replace that batting with new.
Click to expand...
Make sure the woofer surrounds aren't leaking air - if they are, you are missing out on the bass these are capable of. :music:
 
Would it make sense to just refoam these as a matter of principal. The fabric seems pretty flexible, but it looks like hell and is 30+ years old...
 
StarMover said:
Would it make sense to just refoam these as a matter of principal. The fabric seems pretty flexible, but it looks like hell and is 30+ years old...
Click to expand...


I'm not the expert but I would say no way. Might change characteristic of woofer as the clothh surround is light and very flexible. light coat or of liquid rubber will put them back in shape.
 
Refoaming isn't the ticket on the old Alnico woofers. ARs generally never looked very good with the grills off.

I can't tell you what you should use to re-dope the cloth, though. I'm up against the same choice in my Alnico AR-3a woofers.
 
Liquid rubber? Any specific brand? Something you find at Home Depot? You don't mean rubber cement, right?
 
StarMover said:
Liquid rubber? Any specific brand? Something you find at Home Depot? You don't mean rubber cement, right?
Click to expand...
Actually, rubber cement has been used by a number of people here to seal cloth surround woofers. Also, you may want to consider another alternative, which I've used with great success on a number of cloth surround woofers, both AR and KLH. I mixed some siliconized latex caulk (it's white when applied, but dries clear) with water to achieve a paint like consistency. I brush it on, let it dry, and voila!......the woofer is sealed.
Just like Shacky posted, I'm no expert in these matters, but I can tell you what has worked for me, and quite a few others who have used this method.
Tom Tyson, the resident AR expert over at the Classic Speaker site recommends the use of Armorall for coating cloth surrounds.
Also, I believe Orange County Speakers sells a sealer for cloth surrounds.
As you can see, there are a number of choices available, and whichever one you choose will more than likely leave your woofers in better condition than they are now.
Again, good luck with your project. :D
 
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