I have sitting in front of me a pair of AR3a, the woofers appear in decent condition and they have doped fabric surrounds which don't seem like they need anything doing to them.
The issue is that the mid has been replaced with a pair of cones and the tweeters have been replaced with frankly bizarre looking things, they look kind of like horns but with a protruding dome with a horn like slot down the middle of it with the driver in the middle of this slot.
Firstly, it concerns me when I depressed the woofer to test for leaks that the mid shot right up, surely a cone mid is a pretty poor choice for an acoustic suspension design? Secondly, the tweeter is not sealed, pressing down the woofer results in air rushing through the tweeter, I'm not quite sure where.
Given these two things do I have any choice but to simply keep an eye out for replacement drivers on fleabay?
I may take pictures of them later today.
The issue is that the mid has been replaced with a pair of cones and the tweeters have been replaced with frankly bizarre looking things, they look kind of like horns but with a protruding dome with a horn like slot down the middle of it with the driver in the middle of this slot.
Firstly, it concerns me when I depressed the woofer to test for leaks that the mid shot right up, surely a cone mid is a pretty poor choice for an acoustic suspension design? Secondly, the tweeter is not sealed, pressing down the woofer results in air rushing through the tweeter, I'm not quite sure where.
Given these two things do I have any choice but to simply keep an eye out for replacement drivers on fleabay?
I may take pictures of them later today.
What you've got is a shoddy job of mid/tweet replacement on your hands.
What you also have is an ideal candidate for a Super-Mod. Utilizing Seas mid and tweeter.
Visit here for more info.
Welcome to Carl's Custom Loudspeakers
What you also have is an ideal candidate for a Super-Mod. Utilizing Seas mid and tweeter.
Visit here for more info.
Welcome to Carl's Custom Loudspeakers
There's a great reference document for any 3a restoration work you may do.
Restoring the AR-3a - The Classic Speaker Pages Discussion Forums
IDed the tweeters, they're realistic 40-1377 8ohm drivers, the previous owner had put a bipolar electrolytic cap in series with them which would explain why I could only get erratic readings from the thing with a multimeter.
They were attached with double sided tape, and just jammed in there hence the lack of a seal.
Looks like the first thing I'll do is get a pair of new tweeters, get them nicely sealed in place. Replacing the mids seems like a much more challenging problem, I can't find any anywhere so I guess I'll have to just keep looking.
They were attached with double sided tape, and just jammed in there hence the lack of a seal.
Looks like the first thing I'll do is get a pair of new tweeters, get them nicely sealed in place. Replacing the mids seems like a much more challenging problem, I can't find any anywhere so I guess I'll have to just keep looking.
Have you tried Wembley loudspeaker, which oddly is in Shepherds bush/Acton? I think they deal with AR in the UK, I got the woofers for my 3as resealed there, as well as a few oter things sorted and am very happy with the results. If they don't have the original they will recommend what could do the job.
Good luck, it's worth the hassle, they're great speaker IMO.
Good luck, it's worth the hassle, they're great speaker IMO.
Replacement AR3a speakerunits
AR3a repair at:
https://picasaweb.google.com/103176186685392443797/AcousticResearchAR3aAR11#5649255917072786754
https://picasaweb.google.com/103176186685392443797/AcousticResearchAR3aAR11
AR3a repair and crossover schematic:
AR3a
AR3a repair at:
https://picasaweb.google.com/103176186685392443797/AcousticResearchAR3aAR11#5649255917072786754
https://picasaweb.google.com/103176186685392443797/AcousticResearchAR3aAR11
AR3a repair and crossover schematic:
AR3a
AB Tech Services
Well, one could look at AB tech Services at:
Acoustic Research Parts From the same Manufacturer AR has been using since 1983!
and one could mail the manager Mr Barsotti at AB Tech Services for replacement units when one can afford to buy them ( be patient and buy one unit from time to another):
abarsotti@mindspring.com
The midrange dome sounds ok without too much sound decrease , price 99,60$
the tweeter is sold for 62,50$
Another way is Ebay and buy the midrange speakers there!
Rgds.
Well, one could look at AB tech Services at:
Acoustic Research Parts From the same Manufacturer AR has been using since 1983!
and one could mail the manager Mr Barsotti at AB Tech Services for replacement units when one can afford to buy them ( be patient and buy one unit from time to another):
abarsotti@mindspring.com
The midrange dome sounds ok without too much sound decrease , price 99,60$
the tweeter is sold for 62,50$
Another way is Ebay and buy the midrange speakers there!
Rgds.
Last edited:
Well, considerable time has indeed passed since your OP's, but that's good news you had success with your resto as well!
If one visits classicspeakerpages.net and does some research, one finds the consensus on ABT drivers is they are great looking and fit perfectly.
Sound performance, OTOH, is deficient vs original drivers.
Last edited:
Ah, a bit disappointed at the lack of detail there, my friend. Photos would be nice. I'm always interested in AR designs, which certainly got something extremely right. To a modern eye they look unsophisticated, especially the paper tweeters. But recall the AR-3A was one of the most respected speakers of its time using the now unfashionable acoustic suspension bass.
Without having done any modelling of some of those simple crossovers, it certainly looks like they were quite a lot more time-aligned than other designs. They also seem to have less places for energy to be stored, resulting in a very immediate and lively presentation.
What I'm getting at, is that one approach is to seek out the original drivers and similar crossover components. The other is to fully understand how the design worked, and use modern components with the same properties. For instance it stands out to me that the AR3-A used paper dome tweeters. Now that is interesting. I don't know what the midrange domes were made of, do you?
Attachments
I took some photos at the time, i'll see about digging them up later with a bit of commentary on what I did.
I just installed the new drivers, fixed some wiring faults in the crossovers, cleaned out the pots and put it all together again. The only tricky bit was sealing which required some new gaskets which I just cut from a foam packing bag. The surrounds are cloth not foam so did not need replacing.
I still prefer my big Celestion 662, but they came out surprisingly nice for a pair of their age
I just installed the new drivers, fixed some wiring faults in the crossovers, cleaned out the pots and put it all together again. The only tricky bit was sealing which required some new gaskets which I just cut from a foam packing bag. The surrounds are cloth not foam so did not need replacing.
I still prefer my big Celestion 662, but they came out surprisingly nice for a pair of their age
The Celestion 66, which I know well enough was not a million miles away from the AR-3A. I notice a third order tweeter there. It so depends on the acoustic rolloff of the drivers, but both have something going for them.
For sure putting a dome midrange next to the tweeter is a sweet combination.
For sure putting a dome midrange next to the tweeter is a sweet combination.
Attachments
Well, the inventor of many hifi things and among others the "dome" , mr. Edgar Villchur, who was the founder of Acoustic Research unfortunately died autumn 17. october 2011.
His paperdome and coil in the AR3 and AR3a tweeter is situated with only 3 dots of an unknown glue, and deliver/delivered a wide soundperspective which in the 1950 'es was very difficult to obtain with elipse or round papercone speakers. The midrange has a fabric clothdome and a piece of something like glasswool to reduce reflections. Mr Villchur used a lot of time and messurement to get the three units in the AR3a to work together. Because of this work the crossover became rather simple, and the AR3a produces easily what we all like: "A very presize stereo window".
The sound from AR3a is authoritative and one of the best...I think. Try " Jet Set" with Grateful Dead, then you know what I mean.
Rgds.
You've reminded me of something I've been meaning to do for some time, which is remove the crossovers and draw out the schematic for them, note they're 662 not 66 so they differ to some degree. I've never found full proper specifications of crossover schematic for the 662.
I've had them for a few years now, keeping them in repair has been somewhat more exciting though not challengingly so, one of the tweeters blew so I took it apart and rewound the coil, the mid dome also became misaligned and was easily fixed by centring it. I wrote both repairs up and I believe they're in my post history.
I've had them for a few years now, keeping them in repair has been somewhat more exciting though not challengingly so, one of the tweeters blew so I took it apart and rewound the coil, the mid dome also became misaligned and was easily fixed by centring it. I wrote both repairs up and I believe they're in my post history.
Yes, you are right! mirrored pairs would have been better....I think.
I have a very rare pair spare set of AR3a in light birch veneer, and I like the dark rosewood better. My thought was to built a new pair of AR3a cabinets by use of MDF hardwood and with dark rosewood veneer. At this point it was possible to make them mirrored.
Rgds.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.