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Acoustic Research AR-2A restoration help


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#1 Audiophile03

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Posted 15 September 2011 - 03:11 AM

I picked up a pair of these for free at a local pawn shop believe it or not. They are in desperate need of attention. I was wondering if anyone had the spec sheets on these and rebuild procedures, recommendations for these. I am planning on refinishing these to a nice darker stained finish. There were no grills with them. All the speakers sounded great when I hooked them up. I think the speakers just need to be cleaned. I didn't hear any crackling or bottoming out. Lastly, whats the best way to clean the actual speakers? Do they normally look nasty brown and such or is there a way to get them cleaned up and with what cleaner would work best as to not damage the speaker? So now the rebuild begins.....any help would be appreciated!
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#2 Carlspeak

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Posted 15 September 2011 - 12:22 PM

AR didn't seem concerned about the unsightly look of the baffle board because the grille and clothing hid all that. Vintage AR on the WWW probably has new grille with cloth that will fit your speakers. Or, you could make your own if that's what you want to do. If not, remove or cover the drivers and spray paint the BB flat black.

If the rheostats are in good shape, you're good to go with the exception of the outer cabinet finish.
IT'S ALL ABOUT THE MUSIC!

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#3 dynaco_dan

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Posted 15 September 2011 - 03:20 PM

I picked up a pair of these for free at a local pawn shop believe it or not. They are in desperate need of attention. I was wondering if anyone had the spec sheets on these and rebuild procedures, recommendations for these. I am planning on refinishing these to a nice darker stained finish. There were no grills with them. All the speakers sounded great when I hooked them up. I think the speakers just need to be cleaned. I didn't hear any crackling or bottoming out. Lastly, whats the best way to clean the actual speakers? Do they normally look nasty brown and such or is there a way to get them cleaned up and with what cleaner would work best as to not damage the speaker? So now the rebuild begins.....any help would be appreciated!



Hi there

Nice find.

These are a transitional speaker system from their earliest AR-2 to the later AR-2AX, well reviewed and cherished by many.

If you are bothered by the unsightly front baffleboard, then, I would suggest carefully masking off the drivers and painting it.

You need to be careful that you do not stick or touch anything on the dome or cone surround surfaces.

This will lessen any chance of removing and possibly damaging the drivers, unless there is internal service work required.

The magnets are very strong so watch any credit cards, watches and tools.
VERN

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#4 Audiophile03

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Posted 15 September 2011 - 07:12 PM

Well, here is the proposed plan: I am going to strip all the cabinet except the front. I am going to refinish it in a darker wood finish, then as suggested, I will mask of the speakers carefully and flat black spray the front. That should give a quality look, I hope. I found a seller on eBay that sells grills for these but only in offwhite. I may end up picking a set of grills for this depending on how the refinish looks.

#5 dynaco_dan

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Posted 15 September 2011 - 08:04 PM

Well, here is the proposed plan: I am going to strip all the cabinet except the front. I am going to refinish it in a darker wood finish, then as suggested, I will mask of the speakers carefully and flat black spray the front. That should give a quality look, I hope. I found a seller on eBay that sells grills for these but only in offwhite. I may end up picking a set of grills for this depending on how the refinish looks.



Hi again

I cannot stress enough how important it is that you not touch any portion of the dual drivers surface or the tweeters dome.

I bought a pair of duals that were removed from the plastic molded cabinet.

They were bolted together, face to face, without any spacers and the still sticky surrounds stuck together, destroying themselves.

After all these years they are still sticky and extremely fragile, sort of like a wasp nest material.



UPDATE 20110915 4:00 PM

I forgot to mention that if you choose down the road to re-coat only the woofers surround and voice coil dust cover, there is much written about that here.

The correct compound can lightly be applied, once only, so as not to completely seal the speaker.
VERN

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#6 RoyC

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Posted 15 September 2011 - 09:06 PM

Do they normally look nasty brown and such or is there a way to get them cleaned up and with what cleaner would work best as to not damage the speaker?


The brown color of the woofer surround is normal. Do not attempt to "clean" it, as you could compromise the specially treated cloth it is made from. It is not advisable to try to clean any of the drivers.

Roy
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#7 Audiophile03

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Posted 16 September 2011 - 04:18 AM

I did the seal test on both woofers and only one of the woofers returned slowly so it seems I need to re-coat them with Permatex High-Tack 98 gasket sealant which I hope to find in a black color. When I mask off the speakers, I will be sure to use paper over them and just take the very edge of the metal speaker frames.

#8 RoyC

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Posted 16 September 2011 - 04:49 AM

I did the seal test on both woofers and only one of the woofers returned slowly so it seems I need to re-coat them with Permatex High-Tack 98 gasket sealant which I hope to find in a black color. When I mask off the speakers, I will be sure to use paper over them and just take the very edge of the metal speaker frames.


The cabinet could have a leak elsewhere. It could be any of the driver-to-cabinet seals. You really should be absolutely certain it is the woofer surround before applying anything to it, as it is very unusual for AR 10 inch cloth woofer surrounds to require re-treatment. Inspect where the surround frame is glued to the metal basket. The glue is frequently deteriorated in this area. The whole frame can be lifted off the basket when this occurs.

Subsequent testing and feedback suggests the Permatex gasket sealant tends to stiffen the surround with time. It does not come in any color other than red.

If it becomes apparent your surrounds need re-treatment send me a PM. I have a (transparent) sealant compound available that works very well without compromising compliance.

Roy
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#9 Audiophile03

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Posted 16 September 2011 - 04:52 AM

Ok, I will pull the woofers and check to see if the sealant is bad. If not, I will send you a PM. Thanks for the help!

#10 RoyC

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Posted 16 September 2011 - 05:01 AM

Ok, I will pull the woofers and check to see if the sealant is bad. If not, I will send you a PM. Thanks for the help!


You do not have to pull the woofers to check out the possible (and very typical) glue problem. Attached is a photo showing where to look.

Roy

AR 10 inch woofer to frame.JPG
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#11 Audiophile03

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Posted 16 September 2011 - 05:04 AM

I checked the glue where you indicated and it is in great shape...no deterioration.

#12 michiganpat

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Posted 16 September 2011 - 11:27 AM

for the one not returning slowly, play something bass heavy (maybe even a 20-30 hz test tone generated by audacity on your computer), and feel all around the drivers and the back board where the binding posts are for air leaks.....or you can do the same thing manually pushing on the woofer cone....

speakers this old, I'd be pulling the woofers and replacing the capacitors, personally.

#13 Audiophile03

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Posted 18 September 2011 - 05:47 PM

Here are the updates from yesterdays work :D

First I removed the screws from the woofer, the tweeter, and the plastic piece that housed the dual mids. I put the screws to each item in there own cup to make sure I didn't replace them in the wrong place.

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Removing each speaker was a bit of a chore simply because whoever opened this up last time used ALOT of calk to seal the speakers. After digging most of the calk up, I was able to get a long flat head screwdriver wedged under the woofer to pry it out. The tweeter was a bit of a pain also. I was not careful enough and broke 2 of the little wires that connected the tweeter to its terminals but thanks to an AK users prior experience of breaking these, I have an easy solution to fix it.

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After pulling the woofer out, I found that the speaker wires are soldered to the speaker terminal. Thankfully, I had a solder iron on hand. After pulling the woofer, there is a thin piece of material between the speaker and the stuffing in the cab. I had to very carefully pull it out as to not tear it. Next I removed the stuffing from the cab and placed it in a brown paper bag.

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#14 Audiophile03

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Posted 18 September 2011 - 05:48 PM

And here is the guts of the cab revealed

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After removing the speakers and stuffing, now cam time to get rid of this nasty white paint. I used a heavy duty paint remover, plastic scraper, rough sponge to remove excess paint, and an assortment of sanding paper. Here are the pics of progression.

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#15 Audiophile03

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Posted 18 September 2011 - 05:48 PM

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So, after I removed the paint, there was some wierd aqua colored paint on them. Almost done with this first one. I just need to do some touch up sanding with the dremel and then sand down the front of the cabinet.
I am still searching for a company that makes the factory replacement capacitors for these. I have decided also that I am going to replace the woofers, both the mids, and the potentiometer from this site: http://www.abtechser...arspeakers.html which I found in this sites links page. I may think about about updating the tweeter as well but am not sure which tweeter this speaker takes. More updates to come.... :lol:

#16 RoyC

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Posted 18 September 2011 - 06:25 PM

Nice job on the cabinet!

DO NOT replace the drivers! AB Tech is simply selling replacement drivers to fit the cabinet holes. They will not have the same response as the originals, and the result will definitely be inferior to what you already have! They will no longer be AR-2a's. Hmmm, on second thought, forget what I said...send me those crappy old drivers. I'll take them off your hands. :rolleyes:

Be very careful with the tweeters! The leads are made of aluminum and are VERY fragile! If you break a lead it cannot be soldered in the conventional way. Btw, these are the same tweeters used in the AR-3, and are quite valuable.

There are no "factory replacement" capacitors for these. You will have to replace them with modern film or electrolytic capacitors of the same value (4uf and 6uf), and they will work fine. There are a number of places to purchase these, such as Parts Express and Madisound. Do not get sucked in by Ebay AR parts sellers. They are simply repackaging items from AB Tech, and the two vendors I just mentioned...usually at a much higher price.

Send me a PM if you need more info, or do a forum search. These issues have been discussed many times here.

Roy
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#17 Audiophile03

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Posted 18 September 2011 - 08:59 PM

Thanks for the info RoyC. In that case, I guess I will use the same woofers. What about the mids? The cones seems like they are kind of falling apart...a bit weathered. Are those worth replacing from that site I linked previously or another site you might recommend? As far as capacitors, I may have to check out Madisound. Thanks for the direction on those. If I run into any issues, I will send you a PM. Thanks again for your insight!

#18 Audiophile03

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Posted 18 September 2011 - 09:05 PM

Are these the caps?
http://www.madisound...-fast-cap-400v/
http://www.madisound...-fast-cap-400v/

#19 dynaco_dan

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Posted 18 September 2011 - 09:48 PM

Are these the caps?
http://www.madisound...-fast-cap-400v/
http://www.madisound...-fast-cap-400v/



Hi again

You removed the mid range drivers screws, no need to.

The cones looked fine in the photos, unless you touched them after the photos.

There is no equivalent replacement dual mid range drivers available, just on the used market.
VERN

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#20 Audiophile03

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Posted 18 September 2011 - 09:56 PM

Finished getting the cabinet sanded and got the face painted. Now all that's left is staining the rest of the cabinet, replacing the capacitors and potentiometers. I cleaned up the woofers and tweeter pretty well. Also got the tweeter leads fixed. Can't wait to get them back in!

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