Restoration of Acoustic Research AR3 Speakers
George H
Active Member
I only used the TV Radio cement, it fills gaps readily and dry's in about two hours. The advantage to securing the first layer down is stabilization, and allows the second layer to stay on top of the first without spreading the first, which did happen on my practice windings. I used no tensioning other than a strap of tape over a square of sandpaper on it's non-abrasive side over the incoming wire. Couldn't find any quicker way.
George H
Active Member
Add one odd thing with this tweeter rebuild effort. The two rewinds turned out good, a little imbalanced though, the right is lower output than the first one, same turns (+ or - ) 1 or 2 turns, but the pots on the back do adjust them up evenly, I just should have had one more digit accuracy on my meter, I guess?
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Scott75s1974
Well-Known Member
Thanks for this great thread. I'm glad it worked for you. Any images of the foam supports and thoughts about gluing that up?
George H
Active Member
I guess you have already removed the domes carefully with a scalpel or Exacto knife. It cuts fairly easily but follow the coil not the dome with the blade. The foam I picked out did not appear foamy, it was just a very light early type of resin substance, kind of crumbly, they had not invented urethanes or platinum activated 2 part polymers in the 60's but what ever it was, was a good adhering and flexible compound, and was tinted or 'was' yellow. Thought about dipping a yellow sharpie in the shoe glue to make it look original, but I had more important concerns, like, did I clean the frame 'v' s enough with alcohol to make a good bond. etc.? The Loctite was a good candidate after a few tests, it stuck well to the frame and I hoped it would also on the domes, and had a little flexibility. I tried not to handle those domes too much they are like an egg shell. Only touched the domes when I needed to, like when feeding the leads through them. The spacing of those two leads has to be lined up accurately, when winding the coils, so the start and finish of the leads are the same distance apart, after winding, as the holes are in the domes. The tricky part was aligning the new coils with the flying leads going all over the place, and centering on the coil on the dome. I put the coil on flat surface, and applied strips of tape in four spots to the dome. Blue painters tape worked well. When I was happy with the symmetry of the positioning I pressed the tape down on the dome, down the coil sides, and up into the underside of the coil to capture the two. I repositioned for what seemed like forever until I was happy with the look of it, the lead placement and fit coming through the dome are where you need to do a little massaging to get the dome/coil fit up right. Then applied a thin bead of the GC TV/Radio cement with a toothpick, to the inside edge of the dome and coil, trying to get the tiny gaps filled all the way around. I then put the lot up on a flat surface, checked the alignment again and dead weighted them with a chassis knock out type plug, that had spring legs that covered the domes curve, and allowed a flat place for weight to be placed on top of the flat part of the plug. Let it cure for a few hours. The 1 LB brass chunk I had was perfect but wouldn't use much more weight that 1 lb. After curing, I pulled the tape off and put some cement in the areas that were under the tape and dead weighted again. They are done. The leads are a real pain while trying to position the whole affair. Hold the assembly coil/cone to the light to see if all gaps have been filled. Touch up with the cement and let cure for a few more hours. And be careful with those leads...don't ask me why! if they bend too many times they get shorter. 
There were some pics of the dead weighting setup in a previous post and will take some pics of the finished suspensions, it is just 4 dabs of clear goop drops pushed into the v's and taped crossways with magic tape. Let the Loctite cure for 24 hr's under the tape. I added a diffusor to these years ago on a tip, don't think they are needed but here is the tweeter and the clear suspensions
There were some pics of the dead weighting setup in a previous post and will take some pics of the finished suspensions, it is just 4 dabs of clear goop drops pushed into the v's and taped crossways with magic tape. Let the Loctite cure for 24 hr's under the tape. I added a diffusor to these years ago on a tip, don't think they are needed but here is the tweeter and the clear suspensions
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George H
Active Member
pic of a tweeter. Sooo Next day.... turned the volume up and they are noisy, not in a good way. I should have shimmed the coils after all, they are crackling at about 30% volume so that will be destructive at higher levels. I felt like they had good clearance but as little as those coils move it turns out to be a rather a big faux pas on my part. That goo on the old ones was there for a reason, I guess. Will remove them again and put some teflon tape on the outer diameters of the coils and we'll see. I knew it was too good to be perfect on the first try. I'm going digging again. 10 minutes later....I just turned down the pots and the crackling went away... I just had them too loud? I'm still curious, but will give them awhile to break in before opening it up again.
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Hi all, I have a pair of AR3's from my college days that I picked up used in 1975. I used them for about 10 years and they have been stored since that time. cabinets are a bit rough but could be restored. If there is anyone interested I'm selling them. I am in the Raleigh NC area. They are roughly 50lbs each so a bit expensive to ship. I can provide pictures if there is any interest.
George H
Active Member
I am in Tidewater, VA wouldn't be to far for a drive down. I am interested in some photo's, have you managed to get the grills off? I'm trying to sell Fisher Xp66's and a Big Advent set out in my garage myself. I've always liked these 3's. And I agree, they would not survive a Fed Ex or UPS trip up. George
George H
Active Member
Yes on the surrounds material. i returned to the surrounds compound that I used and started thinking of any other thing I had experienced that had good adhesion and never fully hardened or dried. There was a weatherstrip adhesive I used years ago, 3m makes it, and guess what color it is.... yep! Yellow. I picked out the shoe glue carefully with dental picks, cleaned as well as I could, and dabbed a small amount of the 3m adhesive into the 'V''s two at a time, taped up, let cure 24 hrs , and then did the other two, all in an effort to keep the coils centered. They sound no different though. Also reworked the mids I had rewound 5 years ago with the same stuff. Don't hear a lot of difference , but they are more flexible for sure, maybe the higher volumes will sound better?
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George H
Active Member
3 Month's after the surgery...the patients have survived.....
After 3 month's of listening to the AR-3's, with all kinds of music and volume levels, they just sound so full of natural sounding response from all three drivers. This was totally worth letting my obsessive nature venture into finally hearing these speakers true voices for the first time. It gave me great pleasure in doing so.
After 3 month's of listening to the AR-3's, with all kinds of music and volume levels, they just sound so full of natural sounding response from all three drivers. This was totally worth letting my obsessive nature venture into finally hearing these speakers true voices for the first time. It gave me great pleasure in doing so.