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AR2a midrange cone strengthening?

R

retreatwi

Active Member
I have a really nice pair of AR2a speakers. I have another pair that aren't so nice and the paper midrange cones have crumbled. I am wondering if there is any preventative maintenance that can be done to keep the cones from crumbling.

I was thinking painting on diluted Aleen's tacky glue would give them a stronger surface.

thanks.
 
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I would recommend lacquer or Sally Hansen "Hard As Nails" from the nail polish section at your nearest drug store covering the body of the cone (not the dust cap nor surround regions). Either will strengthen and bind the paper cone fibers to last indefinitely. If you use the "Hard As Nails", then be sure to apply it in a thin coat in a very well ventilated space as the fumes are really irritating and borderline toxic! For the outer surround region that borders the cone edge I would recommend Elmer's Acid Free Rubber Cement applied with a tiny hobby paint brush in multiple thin coats. This will not only protect the surround region as it flexes and keep it intact indefinitely but this will also provide a needed bit of edge damping as well.

I've been applying these treatments to older paper cone drivers for years, many of which were on the verge of crumbling away, and all of them are still intact and going strong. The effect on perceived sound quality is minimal and it keeps the drivers alive and kicking! (lol)
 
2a mids AR_heathkit.png 2a mids AR_heathkit backs.png Good advice from stickman.
Just an FYI-Heathkit also had a version of the 2a's, and their paper cones held up much better.
I restored a set of 2a's and needed replacement's, which I found on fleabay. One pair were like new, the Heathkit versions. The paper was a bit thicker, no ripples.
Glenn
 
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That's great info. Thanks. Is there any chance you can post a picture of a driver that has had the Hard as Nails treatment?
 
I agree with the above advice. Try to minimize the mass being added. It may be less of an issue with a midrange vs. a woofer, which would have its T/S parameters changed with added mass. But I think the effect would not be zero even for a midrange. Something clear that penetrates and dries light and strong. White glue would probably not be my first choice.
 
Would this treatment upset purists and effect the speakers value? I would think people would be happy that the mids were saved from deterioration.
 
I agree with you. Make it as unobtrusive as possible and IMO it enhances the value rather than detracting.
 
The problem with the old AR cones is that paper is so dry & fragile, almost any pressure, even from a soft hobby paint brush may cause the cone paper to rip.
On the pair I needed to replace, you could almost just blow on them and they would crack.
 
I think that when it comes to the 2a midrange drivers, there are not many purists. They are not rare, nor are they highly regarded from a marketplace standpoint. So, I think you are much better off repairing/renovating them than leaving them as is (assuming you want to use them). Otherwise, they will just get worse and the negative affect on their performance will be worse than any decently-done repair. BTW, I love my 2a's...my favorite AR woofer. Unfortunately, I've had to replace the tweeters; their output had deteriorated to the point that I finally replaced them with the well-documented HiVi and inductor solution. Replaced the pots with Lpads at the same time. They were still very spotty after several thorough cleanings.
 
I've sold 3 AR2 singles, talked to purists regarding non-factory changes. Got a pretty fat payday on those too. Whether it's an improvement or not, they do not want any changes. Other than updated caps, of course.

Biggles
 
That is significantly more the case with the AR2 - a collector favorite (I assume because of historical role, rather than sound quality) than with the 2a. I guess it comes down to whether the buyer is a collector or a user. Also, one could mitigate any value loss issues by picking up a pair of un-improved 2a assemblies and installing them if/when you sell the speakers (and assuming that any improvement in market value more than offsets the cost of the un-improved assemblies). Full disclosure...I am not a collector, and I don't really understand buying speakers to own, but not use. Bottom line, these speakers are getting very old....without maintenance, they are going to become un-usable over the coming years. So, for "factory purists", I guess their only option will be to collect and look at them...rather than use them.

A good illustration of this would be the AR pots. Yes, they can often be cleaned/repaired and kept original. But, it is also common that they are beyond redemption. I just don't see how/why a pair of AR3a's (for example) with original pots but no output from the mids and tweeters because the pots are shot, vs a pair in which the pots have been correctly replaced with modern pots or L-pads, can be worth more.
 
It's a crazy situation. For me, I want them to sound and perform their best for as long as I can get them to. It's a completely different animal for purists. They rarely have concern for performance, or performance longevity. Why do I concede to their wishes? Because they're the ones willing to spend the big money, that's all there is to that. Here, put this in your cap. I was recently contacted by a gentleman with a pair of 1952 JBL's, they had the N1200 crossover. His tweeter output was down to a spittle, he needs new caps. Ultimately, he was unwilling to have me update his capacitors because I would have to melt out the wax to get to his caps. He feels he will no longer be able to sell them as original, a possible loss of value. So, he opted to keep his original capacitors and not be able to listen to his speakers. He's considering selling them and buying a pair he can actually update without all that anxiety entanglement. Nope, I don't get it either.

Biggles
 
I certainly recognize that collectors have different buying criteria. For example, I recently sold a set of JBL potato masher tweeter/horn assemblies to a collector in Japan for $750. But in the AR world, prices have never moved into high-end JBL territory (other than maybe for the AR1s!). My point is that most ARs are bought to listen to, that any value degradation will be relatively small, and that in this specific case the improvement is fairly easy to reverse.
 
Back in the seventies, I upgraded my AR 2 and 2a to AR2x and 2ax with the insert that AR used to sell. I took the midrange/tweeters and put them in Quaker oatmeal boxes (with the fiberglass stuffing from the subenclosures), and a friend used them as full ranges with a tube HK reciever I dug up. They sounded surprisingly pleasant, and didn't blow up.
Of course, we had different expectations, no money, and any 2s and 2as that are still around are now more than twice as old as they were in 1976, so maybe they are more fragile. Even back then, the fiberglass stuffing has warped the cones.
 
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