AR2AX WOOFER MASONITE SEPARATION

[oldguide]

Well you guys have done it, I just fell into a pair of pretty nice AR2AX at a price I could not refuse. Cabinets are in excellent condition. Speakers sounded good, pots even seem to work. So now I have 3s, 4AXs and the 2s. I suppose the LST is next?

However, on getting them home and getting the grills off and listening to some low bass I discovered the notorious cone separation issue. The masonite ring that holds the cone to the aluminum speaker housing is totally loose. Luckily the spider seems OK. I searched all the previous posts on this and found Roy's recommendation of Goop to secure the masonite.

Question: how to be sure it is centered? Roy had mentioned looking for previous marks but they are pretty vague and also under the ring. In the interests of do no harm I have not moved the ring other than to see it is loose. Does it make sense to center the ring by GENTLY moving the cone to be sure there is no rubbing? How about aligning it with a gauge so it is equal all the way around (I suspect it would be fairly easy to rig up a jig for this) or are these built so the ring is not equidistant (i.e. the masonite is rough cut)?

As I understand it the two things to avoid are doing anything that might also separate the equally fragile connection of the spider and to not get the masonite ring off center. I suspect the as little "as possible" rule holds for the glue--Goop can get kind of messy but in using it for various repairs I have found a glue brush works great so assume that would be fine here.

BTW I have not removed the speaker because the masonite ring is so loose I was afraid of causing further problems. I will of course be going "inside" to check caps and pots as soon as I can get the ring stable.

As always, thanks for the help.

[Carlspeak]

My advice is, if you've never refoamed a speaker using the battery or the 30 hz. test tone method, then remove the dust cap and shim the voice coil. It is the only sure way to get the cone/voice coil assembly centered.

If you have used the afore-mentioned alternative methods, give them a try using an adhesive that isn't too agressive so you can re-center if you have to.

Good luck!

[RoyC]

I agree with Carl. If the ring is completely free of the woofer basket, centering the voice coil using one of the two methods he mentions is probably necessary. Take a good look at the spider. It is not uncommon to find the glue holding it in place is also failing at the basket and/or cone.

Yeah, Goop is messy to work with. (BTW, I found that Goop can be thinned and cleaned up with toluene.) I've since used Aleene's Tacky Glue to successfully re-attach a ring.

Roy

[oldguide]

Thanks much to both of you for the advice. The speaker has the cloth surrounds, which I went ahead and took care of re the established methods, so the surround is good, it is just the masonite ring.

Judging by what you are both saying it makes sense at this point to remove the woofer and assess its overall status. I had refrained from this thinking it best to get the masonite back in place before removing it.

Sounds like what I had thought was relatively simple is not. Obviously the masonite is not precision cut so trying to center it geometrically is a nonstarter.

Obviously gorrilla glue would be a bad idea (have used it to build laminated canoe paddles and it is a pain to work with).

Interestingly the other speaker woofer is one of the infamous hot cross buns models (non aluminum)and seems fine.

Based on some quickie analysis it looks like this may be one of the early AR2s that was upgraded to an X or perhaps a mismatched pair or a pair that got put together from two different pairs.

I am actually itching to get inside to see what is there and based on what both of you have said might as well go ahead and do that.

One added note from a 2AX newbie--interesting the way they did the tweeter leads as opposed to the three series. Since both were chronologically close why the difference since the tweeters (at least in this one)are identical.

Thanks again.

[oldguide]

Just want to extend many thanks to Roy, Carl and especially Kent whose advice to several recent AR2 projects was a big help to me.

The reattaching of the masonite ring went just fine, thanks to all your advice. Ending up using Goop because that is what I had.

The insides of one speaker were especially interesting. The reason the cabinet looked so good is that it looks like someone rebuilt the two sides of the cabinet exterior, even added a cartoon to identify who did it. The cabinet work was quite good as you cannot tell from the exterior the old and the new panels. They also had replaced the pots with L pads which were in pretty good shape. Strange that in doing all this work the rebuilder did not recap as the originals were still there.

Tried a different method of attaching the caps to the board which is cheap and works pretty well: used plastic plumbers' hanging straps which come in rolls with holes every half inch or so, so you can tighten them around the caps fairly securely and then anchor them wherever you wish.

Also will again endorse electricians' duct seal (which I had from wiring). Just to test it, after I sealed it down I tried to pry the woofer back up with the recommended paint cover remover and it bent from trying to break the seal.

Ended up trying some Jantzen caps which I have used in amplifier rebuilding projects, only these are the less expensive blue ones. Since I have no desire to get into the cap debate or do any cap rolling as I do with electronics, I would just offer these as an alternative to the Daytons, Solens, etc. which they match price-wise. They are available through Parts Express.

In amps the one cap I can say made an audible difference was a Mundorf silver/oil, whose 1 uf model looks like a small beer can in cramped amp housing. Have no interest in trying these in speakers since the price climbs pretty high for a 24uf and they also are quite large. Not really sure they would make all that much difference since they are in two different circuits/schematics.

Thanks again to everyone, this is now the fourth set of speakers you have guided me through.

[Carlspeak]

In amps the one cap I can say made an audible difference was a Mundorf silver/oil, whose 1 uf model looks like a small beer can in cramped amp housing. Have no interest in trying these in speakers since the price climbs pretty high for a 24uf and they also are quite large. Not really sure they would make all that much difference since they are in two different circuits/schematics.

Thanks again to everyone, this is now the fourth set of speakers you have guided me through.

The Mundorf Silver-Oil's are a very popular cap. I put a pair of these (6.8 uF) in a Swiss-made Ensemble Reference speaker - much to the delight of my customer. The 1200 VDC version was rated very high by Tony Gee at HumbleHomeMade HiFi.com.