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Acoustic Research AR-2A restoration help


Audiophile03

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baffle looks good, honestly, the stain color doesn't do much for me. I think I would have just gone with a clear or light tint over the pine plywood, or just a few coats of furniture wax.

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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!

Hi there

Something that came to me this morning is an experience that I had a few years ago when I received a pair of damaged AR-2 speakers.

The woofers were the aluminum alnico magnet version and they had a setback from the baffleboards front, more than usual.

There is a ring of plywood slightly larger than the woofer frame nailed inside the enclosure with small finishing nails.

The T-Nuts were mounted into this sub frame, not the baffleboard.

With a tremendous amount of physical shock from the cabinets landing on it's backside the nailed adapter ring detached itself.

Of course the woofer bounced around destroying the woofer, dual drivers crossover and separating the cabinets edges, which had to be the strongest construction ever.

I have never read anywhere else about an issue with this adapter ring.

If the adapter ring had been glued and screwed, it would have stayed there and would never have been an issue.

I wonder how many speakers have a very slight detachment allowing air leaks.

I remember one member writing on the thickness of the baffleboard measured at the woofer opening.

Up till that point he likely never had any bad experiences or even heard of any.

If the thickness of your woofer opening baffleboard is in excess of 3/4" it should be glued to seal it.

Even a few screws from the inside would be better as well.

This particular adapter issue may have only been the AR-2 and not any other speaker system.

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Thanks for the heads up on this issue. I will have to look at both cabinets and make sure this is not an issue. I know that on the finished cabinet, it sealed quite well. I did the push in woofer test and it rebounded slowly.

Hi there

Just to add to my previous issue message.

When they originally installed the woofers into the baffleboard recess and bolted it in, they used the dark thick putty.

Even if there may be a gap between the baffleboard and the adapter ring it would still be puttied.

Another suggestion is to not use a power sander, too aggressive and it can remove the edges or gouge into the surfaces.

A brick size block of hardwood for backing sandpaper and less coarse sandpaper will allow adequate surface removal and still keep the surface flat and the edges sharp.

Even the pine finish done in a clear coat can be very nice looking and affordable.

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  • 2 weeks later...

Nice job on those! I was away most of September so never gave my 2 cents on the project.

A couple of thoughts (after the fact):

  1. Those are the "utility" cabinets and were meant to be painted, left as-is, whatever. They offer an opportunity to be creative, and you did a nice job.
  2. I have a similar pair of 2a's (but with mahogany veneer) and always thought the 2a's were often overlooked and under-rated. They sound great--better, IMHO than the 2ax
  3. Those original caps are oil-filled, possibly mil-spec and could have been left in place. Bet they are still within spec. Did you use the new Solens or leave the originals?
  4. The flimsy cloth-like stuff was Kimpac and was used to keep fiberglass out of the woofers. It does deteriorate, so it's OK to replace with cloth
  5. why not make your own grilles?
  6. Kind of late now, but a lot of info in the AR3a restoration booklet is relevant to the 2a. http://www.classicspeakerpages.net/library/acoustic_research/original_models_1954-1974/original_models_schematicss/restoring_the_ar-3a/
  7. Nice job on the tweeter leads! Been there, and they are tricky to repair
  8. On the speaker with the fast-returning woofer, that is probably due to an air leak through the cut in the mid's cone. Have you repaired that? You can glue it with a bit of Aleene's Tacky Glue (available in craft stores like Michael's and in the fabric dept of Walmart). If the hole is too big for just a dab of the glue, tear a small patch of tissue paper or, even better, that thin strong paper used to clean eyeglasses and camera lenses. Glue it on with Aleene's.
  9. Did you check the pots and clean them?

Kent

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Yes, I checked the pots and they were quite clean which leads me to believe that they were very well taken care of despite the outward appearance or they have been opened before. I exercised the pots on both cabs and there was no static or cutting out in the speakers, luckily for me. I thought about making my own grills only because the ones offered on eBay which is linked here:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=160636956474&ssPageName=ADME:X:eRTM:US:1123#ht_500wt_1180

only come in that off white color, and I think it may look better with a black grill. I guess we will see though, haven't quite made up my mind yet. As far as the Kimpac, it was quite intact in both cabs, so I just re-used them. Concerning the fast returning woofer, it returns slowly now like the other cab. I think the woofer was not quite sealed all the way despite the large amounts of sealant that I found after removing the woofer. I will have to go to Walmart and get me some that glue you are talking about just to get it sealed up. The two mids though are kind of sealed in that plastic piece there are mounted too so I don't think that contributed to the leaking woofer issue. I kept the original caps in because they sounded great before I took the cabs apart so I found no need to replace them.

Thanks for the info and kind words Kent!

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Sounds good.

Some comments on the grilles:

The ones you linked to are for the AR2ax and will NOT fit the AR2a.

You might try emailing that ebay seller (vintage AR) and ask if he will sell you AR2a grille boards (without the cloth). Then you could cover them with the grille cloth of your choice.

Or ask him for complete AR2a grilles. They are consistent with the original appearance, but not all 2a's had the natural linen grilles. Here's a shot of mine, with funky original 60s grille cloth.

If you decide to make your own, you could use thin (1/8") Masonite. I can give you the measurements. On the 2a, the grilles are the same width as the opening in the frame, but they are longer than the length of the opening. You bow them and slip the top and bottom into the slots behind that front frame.

Kent

post-101828-0-98737100-1318306636_thumb.

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I mailed him a little while back and he said he could send me the AR-2A full grill setup with cloth and logos but after considering a different color, I mailed him asking him what he would charge for just the grills and logo's with no cloth. I hope to hear from him soon. Hopefully it will be a bit cheaper without the cloth. By the way, those are some good looking AR's you linked there :D

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  • 3 weeks later...

Finally got my AR's covered today. I cut the frames and my lady cut and mounted the cloth to the frames. All I need left is to order the emblems for the grills then they will be finished. By the way, the fabric I used was an 18ct Lambswool that is colored a slight off white with bits of slightly darker stitching to give it a hand stitched look all for around $5.50 on sale from JoAnne's. I bought a large sheet of fiberboard from Home Depot for $7.00. So, all in all, I spent around $12.50 or so to make some very good looking grills.

livingroom6h.jpglivingroom7.jpg

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