Powerglide Posted October 20, 2024 Posted October 20, 2024 Ever since restoring a pair of AR2-ax’s I’ve kept an eye out for some AR3’s. They don’t come up for sale very often in this neck of the woods and when they do they seem to fetch crazy money. There were 3 models - The original AR3 and then the AR3-a, the final model to the trilogy was the AR3-a Improved that were assembled in England and Holland and not marketed in the US. Basically the AR3-a Improved used the same drivers as the other two but the cross over was slightly different to accommodate for a toggle switch instead of potentiometers. The word ‘’improved’’ was more directed at the cabinet, it was meant to have a more modern look and the slimmer leading edge that reduced diffraction, I don’t know about that! That was the end of the 3’s as AR launched their next flagship model the AR 11 which had a similar XO and toggles as the Improved. I picked these up relatively cheap as both tweeters were not functioning and the cabinets were in poor condition. Somebody decided to refinish them with pre glued iron on veneer and some kind of varnish. I gingerly fired them up, one tweeter was working and the other had a broken filament which with a little wiggle produced sound. One of the woofers was scratchy, I was confidant it’s just the voice coil rubbing I could feel a scrape as I depressed the cone. The surrounds had been replaced but the dust caps were original. Guessing the same bloke who had a go on the cabinets. Pulled the drivers and ripped off the veneer. You could tell the glue had never reached the correct temperature to adhere properly, it had also been laid over poorly prepped boxes, like trying to vinyl wrap over rust. Structurally the boxes were OK, I ran some resin into the only open joint and rebuilt the missing bits with some auto filler block sanded to form new corners and edges Some of the ‘’diffracting’’ front edges were missing and they were a different species, I’m guessing Teak. Anyway I decided to remove them altogether. I’d never veneered a finished product before so did a bit of internet surfing, found a blog by an old piano maker who swore by this method which I found a bit unbelievable. I tried a few samples with different glues and applications and it stuck firm, I laid out some Walnut veneer and cut it a few mm oversize. Applied a thin layer of PVA over both surfaces leave to dry Sit the veneer in position and apply a hot iron which reactivates the glue, within two seconds you get an instant hold, I used a fair bit of force and kept ironing till the veneer sat flat. Probably 3 minutes a side, quick and easy to match up the grain. I ran some solid edge strips and glued them in position. Sanded them up continually checking for bubbles or loose edges of veneer, needed to heat up again in a few spots ready for polyurethane Couple of coats of clear Hand sanded the baffles and painted with a matt theatre black acrylic. I was going to mask the walnut and cut the black into it but opted for a trim bead - held into position with Sikaflex Removed the old/new woofer surrounds and cleaned up the frames One of the terminal posts needed pop riveting back in position, bit nervy drilling the old one out Removed the dust caps, shimmed and fitted correct surrounds When I did the 2ax’s the consensus on the tweeters was refurbished originals was best, however now even the die hards admit that modified HI-VI’s preform better for a fraction of the cost, especially on side of the world. To use the HI-VI’s through the Improved crossover, without having to alter it, a .1mh coil is added to the tweeter, the goal is to reduce the parallel coil value. I don’t know the maths, here’s the schematic The old stuffing was deteriorating so I replaced with earth wool Installed the drivers Still an ugly speaker, a face only a mother could love! Just waiting on some new dust caps to arrive, should be Tuesday (sat the old ones back in for the last photo) Because they are suspension drivers I shouldn’t run them until the caps are fitted, everything needs to be sealed for them to operate correctly. Fingers crossed the scratchy woofer was just a poorly aligned surround, they feel smooth as now. 3 8
evil c Posted October 20, 2024 Posted October 20, 2024 (edited) Fantastic project, first high fidelity speakers l heard were the AR2aX and by chance l managed to get the same pair around 30 years later. They also were in poor shape, and l ended up replacing both tweeters with Hivi dome tweeters from Parts Express. I had the woofers rebuilt, and wasn't a big fan of the inferior L pad/ speaker knobs so scrapped them. Put in Gold plated 5 way speaker posts , and sliding controls to replace the corroded plate L pads. Also new coils and crossover parts. I learnt a lot through Classic Speaker Pages, with lot of U.S. guys heavily into restoration. My brother has them now, and loves them and runs a Melody SP1 tube amplifier very successfully together. Very impressed with your results so far! Hope it all comes together for a great result! Edited October 20, 2024 by evil c 1
Willco Posted October 20, 2024 Posted October 20, 2024 Kudos on the excellent work-yes lot of us cut our teeth on the Acoustic Suspension world of Henry Kloss /Edgar Villchur /etc in the late 60's early 70's--I was taken with the early Magazine ads of Von Karajan savouring his AR3A's--I had two sets of them but earlier versions than yours shown--mine had the 40mm wide frame surrounds pre the Improved version. To hear the Bass from those was wondrous emitting from such a "small" enclosure--not a perfect speaker but opened many door to the otherwise formidable choice of Klipschorns, VOT's and ilk with overbearing real estate. I presume you recognise those Midranges can be fragile to overdriving, the fine external wires under the black tape though can easily be rejoined if over extended. I think the AR3A and Improved models were the most successful of the Brand--I had a AR2AX set with the inverted Midrange cones at 90deg inserted in the baffle--sorta worked but no 3A! and same can be said for the LSTs both versions -too many drivers and once again those pesky Mids popping their cherry on the magic moments--not a wise buy sadly. Top work there my man --looking superb --are you going to replace the grill cloth?--I haven't seen a factory black version --are the fabrics original Guildford of Maine?-mine were all the eggshell beige course weave--if you go the whole hog--I'd certainly recommend this product . Good Listening and great work, Willco
Pebbles Posted October 20, 2024 Posted October 20, 2024 2 hours ago, PKay said: What a great resoration. +1
Powerglide Posted October 20, 2024 Author Posted October 20, 2024 1 hour ago, Willco said: are you going to replace the grill cloth?--I haven't seen a factory black version Haven’t thought that far ahead, they sat on the shelf for a year before I decided to rip into them. I’ve only seen one other set of black grills, not in the flesh and not sure if they were factory. These ones are the Irish Linen and have been spray painted !!! It’s actually a good job and could be factory? but surely it would compromise the sound. I still have my AX2’s, couple of sneaky cameo’s in two of the pictures above. They have the original open weave grilles, still they trap a lot of the highs much better removed. They were the first speakers I had a go at restoring. https://www.stereonet.com/forums/topic/298510-acoustic-research-ar-2ax-referb/ 1
Steff Posted January 7 Posted January 7 AFAIK that glue/dry/iron veneer method isn't all that obscure, have definitely seen some furniture repairers on youtube use it regularly. The boxes look really neat again, good luck with the sound results!
Powerglide Posted January 7 Author Posted January 7 Thanks @Steff Unfortunately when I fired these up the woofer still had a vibration at certain frequencies. I was still hopeful that some rubbish had found its way into the voice coil. I pulled the woofer and removed the surround, again! Flipped it upside down and ran a tone generator through it at the offending Hz. Slapped it like a baby choking, gently blew a bit of air around still no joy. Sent it away to an expert, had some internal corrosion and the voice coil needed replacing. I didn’t notice when I picked it up but he has put some kind of dope on the cone which made it a few shades darker. I’ll be taking the other woofer to him to get the same cleaning service once they get back from the Xmas break. Up and running and sounding great, excuse the mess, fooling around with a few different amps and carts 4 2
MarcAL Posted January 7 Posted January 7 Very nice restoration work there Alan. You went the whole distance and then some. Hope to hear them sometime perhaps. 1
Recommended Posts