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Post by knucklehead on May 13, 2017 21:57:23 GMT -5
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Post by dcg44s on May 13, 2017 22:17:59 GMT -5
I've been working over a pair of Acoustic Research AR-2ax speakers I recently came across in a second hand store, a few weeks ago. I'm almost done with them. I just finished installing the new capacitors. I pulled the old ones out. Interesting - they are made from waxpaper tin foil, probably aluminum - and a light oil. Many layers and lots of oil. But new they ain't so I took them out. I was going to hot glue the new caps on top of the old ones. I had doubts as to whether the glue would hold on to the wax paper with oil on it. So the new ones are in and the old ones are out. At any rate those were somewhat in the way. This way I got nice clean Masonite to glue to. The final step is to replace the fiberglass that was in them. Ever seen fiberglass that's been pounded by sound waves for 50 years? Dust! I wanted to use a polyfil but was advised to use new fiberglass. Just make sure it is the same weight as the old fiberglass - 30oz. The grills won't be redone - they are in decent shape - as are the cabinets. Check out the pics for that. I had to pull out the rheostats that control the tweeter and mid range drivers. Oddly enough it was suggested I use a combination of vinegar and salt. So I did. They work great now and the tweeter on one speaker has a slight dead spot - maybe 10 degrees. No big deal. I put some furniture cleaner/polish on one of them. You can see the change clearly. I'm not going to re-veneer them - they look decent and that's enough! One has a couple of deep scratches on the bottom and the corners are dinged up a bit, but all in all they look pretty danged good for how old they are - older than some of the Lounge members! My best guess is they were made somewhere around the late 60's. AR quit making this model in 72. I had a pair of AR-2 speakers way back when - bought them while I was still employed by Uncle Sam's navy and paired them up with a Sansui 500a that I bought in 1966. The Sansui was new and the speakers were used. So now I almost have the same setup - a Sansui 500a and the AR-2ax combo. Last pic is of the ARs and the Sansui - finally together. Even without the stuffing (have to go buy that) they sound good. A bit boomy on the bass and some cabinet resonance but I suspected that would happen. I'll get some fiberglass batting tomorrow and stuff em like a turkey! This has been a lot of fun for me to do this. The last pair of old speakers I had I gave to my son. Some Harman Kardon HK-20 speakers. I recapped them and they sounded ok. They aren't near what these are ARs are but those were a $15 special at a Goodwill store. So don't be afraid to buy those old speakers you might find in your travels, even if they aren't working. They often sound just as good as today's speakers. They just need some TLC. This project cost me $90 at the second hand store. The caps were $24 shipped. Maybe one of these days I'll connect one to the main setup and see if they can handle a song tower comparison. It results might be closer than you think. The setup is temporary while I go about taking out that 4' light and the shelf above it and make more room for some listening space. It all takes time - I have 'stuff' to do. Like golf! My major pastime. That and audio stuff. Can you edit or repost?The pics didn't come through. |
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Post by knucklehead on May 13, 2017 22:53:24 GMT -5
Yeah - I'll do that. Don't know what happened.
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Post by repeetavx on May 13, 2017 23:12:36 GMT -5
I'm almost done with them. I just finished installing the new capacitors. I pulled the old ones out. Interesting - they are made from waxpaper tin foil, probably aluminum - and a light oil. Many layers and lots of oil. But new they ain't so I took them out. I was going to hot glue the new caps on top of the old ones. I had doubts as to whether the glue would hold on to the wax paper with oil on it. So the new ones are in and the old ones are out. At any rate those were somewhat in the way. This way I got nice clean Masonite to glue to. Metal in Oil is how the best ones are made. |
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Post by knucklehead on May 13, 2017 23:30:53 GMT -5
True. They are 50 years old as well and even the best made capacitors age. I had the chance to listen to these speakers prior to pulling the old caps and replacing them with new 1% caps with higher voltage capacity. It seems like the music is clearer with the new caps. I noticed an improvement mainly in the highs - which are very good now.
The mighty 18wpc from the Sansui seems surprisingly like more. I can play these speakers to fairly high SPL with no audible distortion. They are 88db efficient so not great but there are less efficient speakers.
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Post by tweed on May 14, 2017 8:14:37 GMT -5
Nice find and job bringing them back to life knucklehead!
I recently picked up a Marantz 2230 and Klipch speakers for my retro office system. Also found some Dynaco A25's that will be delivered in July that I plan to clean up a bit and add them to the system.
It's fun to bring back the old days.
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Post by vcautokid on May 14, 2017 8:28:21 GMT -5
Very nice work there knucklehead. Oil filled Capacitors are the tops you can get as per the few I spoke too, and Jensen was one make of these Capacitors. Of course others are ther too. I like how you are bringing back these classics. Nicely done sir.
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Post by Boomzilla on May 14, 2017 8:47:46 GMT -5
ARs are GREAT old speakers. I once had AR-11s and enjoyed them greatly.
Old Dahlquist DQ-10a speakers are also great.
Snell A models
Acoustat 1+1s
Klipschorns of any vintage...
Avalon Symbols
Revel F30s
Just a few of my fave vintage speakers...
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Post by vneal on May 14, 2017 10:15:34 GMT -5
Klipshorns
LaScallas
Dalquist
old Snells
old McIntosh equipment
yes!
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DYohn
Emo VIPs 
Posts: 18,491
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Post by DYohn on May 14, 2017 10:30:26 GMT -5
re: capacitor types. For crossover filters, metalized poly or metalized film/foil caps have the lowest ESR (lower than oil-filled) and will introduce less power loss. Although some designers will use electrolytics to save money for large value caps in woofer filters I say don't do it as they can introduce harshness and a "ragged" sound. If you do use an electrolytic make sure it is bypassed with a good quality film cap to minimize this effect (and make sure it is non-polar.)
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Post by knucklehead on May 14, 2017 11:30:11 GMT -5
I used metalized poly caps from Dayton Audio: www.parts-express.com/dayton-audio-pmpc-40-40uf-250v-precision-audio-capacitor--027-226 in 4mfd and part # 027-236 in 6.2mfd 250v, vs 50v for the originals. I played them for quite a few hours with the original caps while waiting for USPS to get their act together. It gave me time to get an idea of what the speakers sound like with the old caps. It seemed like the highs were missing something. After installing the new caps the difference was immediate - the highs were much clearer and extended and the mid range seemed to bloom - excellent sounding. Confirmed by my brother who also noted the highs were better with the new parts. It's been noted by many that are AR nuts that it's difficult to find an original cap that is working within the tolerance range they were built to. The bass is a bit more than I like but since there is currently no stuffing in them I expect that. Once I get the new fiberglass in place I'll button them up for good and finish cleaning and polishing the cabinets. I'll make a run to Home Depot later today to pick up a couple pieces of fiberglass insulation. I can't stand the thought of handling that 50yo insulation that is original. It's almost dust. I sat down last night and played a cd of CSNY's Deja Vu. These speakers can really sing, and that's with the Sansui pushing a max of 20wpc. A powerhouse it ain't. It reminded me of the why I wanted a pair of these back in the late 60s early 70s when I owned the AR-2s, I had listened to a pair of these at Magnolia HiFi back when they were a 'real' audio shop. It was a great place to shop for audio gear, or just to take a look/see at the latest gear, but that's a story for another day. They were set up in a well treated listening room and the sound of these speakers were stellar. So was the price. They cost over half a month's pay IIRC. I learned to live with what I had and slowly forgot about these. The AR-2 was a decent speaker but didn't have the full range covered like the 2ax does. Some times you have to 'settle' for what you have instead of what you want. The Sansui and AR-2s made good music together. If you find a pair of these for cheap in your travels you might want to pick up a pair. Look for the large red dome tweeter and cloth surrounds on the woofers IF you can remove the grills. The factory stapled the grills on in their first production runs, and later decided to hot glue them on. Mine were hot-glued on.. I hit the sweet spot for this particular model. AR did some mixing and matching so not all of the 2ax speakers are equal. I got lucky. The grills had never been off and it looks like nobody had ever removed the woofers for repairs or just to take a look. |
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Post by tweed on May 15, 2017 10:43:50 GMT -5
Had the Dalquist DQ-10's although at this point it seems like another lifetime ago. Really did like them.
Let's not forget about the large Advents and the stacked Advents ;-)
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Post by knucklehead on May 18, 2017 16:58:05 GMT -5
I finally got the time yesterday to hit Home Depot for some fiberglass stuffing. No way was I going to put that broken up old crap back in the speakers. Since the original 'stuffing' called for 30 ounces I used 2 2/3 bags of this fiberglass - which weighs .7 pounds.  So here's what it looks like with one .7 pound package stuffed inside. You can see the recycled monkey schitt ready to be compressed - I rolled it out much like you would clay. Very similar consistency. All six of the blind nuts were still stuck into the back side of the baffle so I didn't have to mess around with those. Another 1 2/3 package of fiberglass and I'm ready to button these up. Should be good for another 50 years!  So now they're buttoned up and ready to go. I cleaned them up and put furniture polish on all four veneered sides and they look great. There are some scratches in the veneer but they won't be fixed while I own them. They look great the way they are. I never planed on making them look perfect, I just wanted a pair of speakers that would compliment my vintage Sansui receiver. Here's what they look like almost finished - after I locate a pair of badges for them they're done! Time to enjoy them.   Adding the fiberglass took all the boomy bass out of them. The bass response is very good and very well controlled. The furniture polish really spiffed these up very nicely. For a pair of 50yo speakers it seems these have had a sheltered life. What really helped in refurbishing these speakers is that they had never been opened since leaving the factory back in 68-69 - my best guess as to when these were manufactured. One still has the sheet of paper on the back with the serial number, which is right in the 111,000 range. The other one has no serial number - that sheet of paper is long gone but it is identical to the one that does have it. I'd guess that these were paired up for a lifetime. I'll keep them together for mine! I'm going to put them in the living room this coming weekend in place of the song towers just to get a feel for how good these are. I don't expect them to perform quite as well as the song towers but you never know. They should sound pretty good being fed by the ST-120 amp. They sound pretty danged good with the 20wpc from the Sansui. Next time you see a pair of vintage speakers take note of what they are. Some of these old speakers can and do sound just as good as what's available new. With the fiberglass expense added into the mix I'm into these for about $140. What a deal! The grills are the originals. Only the cool looking AR badges are missing. I'm going to order a new pair off ebay in the next few days, that will jack the amount I'm into these up another $25 or so dollars. No big deal, and as good as these look and sound it'll be worth every penny. |
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Post by 405x5 on May 18, 2017 21:17:30 GMT -5
The AR2ax were my first new pair of serious loudspeakers.
I went to these after being brought up on my dad's 2a's.1963.
The sound was excellent.....but those volume pots for the tweeter and midrange were nothing but constant trouble.
Always scratchy and intermittent.
Had those for nearly 5 years, then happily parted.
The gang over at The Classic Speakers have a good handle on those and all AR's, so if one is inclined the solutions can be found there.
Bill
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Post by knucklehead on May 18, 2017 21:45:14 GMT -5
I've been a regular visitor on Classic Speakers these past few weeks. As for the noisy mid and tweeter rheostats, they can be noisy. For now mine are very quiet. I have one dead spot on one tweeter pot but it's so far from where I like them that it isn't a problem. At any rate I can always replace the rheostats with some L-pads with similar specs. I wanted to keep these as original as possible in all respects. I've been listening to them today for an hour or so. I was playing an LP from the late 50s by The Platters - Greatest Hits. Sounds good!
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Post by 405x5 on May 19, 2017 8:25:24 GMT -5
I've been a regular visitor on Classic Speakers these past few weeks. As for the noisy mid and tweeter rheostats, they can be noisy. For now mine are very quiet. I have one dead spot on one tweeter pot but it's so far from where I like them that it isn't a problem. At any rate I can always replace the rheostats with some L-pads with similar specs. I wanted to keep these as original as possible in all respects. I've been listening to them today for an hour or so. I was playing an LP from the late 50s by The Platters - Greatest Hits. Sounds good! Then you are in the right place! Those guys have every trick in the book 📚 down to keep those puppies in top shape. In the Allison section you can see my stuff (to much)! Bill |
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