Guest rogjack Posted January 24, 2009 Report Share Posted January 24, 2009 I have a pair of AR-2ax speakers that I bought new around 1972. These were built at AR's Houghton Regis factory in the UK not long after they started manufacturing. Prior to that AR speakers were only available as imports and highly expensive.They have stayed with me through the years and numerous moves and now are the fronts for my home theater system. They have never had any parts replaced or maintenance done on them. It was only when I discovered this forum that I realised how degraded they have become. Having now examined them outside the the cinema system I find that the foams on the woofers have both perished and one of the tweeters is dead. After nearly forty years service it's not really surprising so I've decided to rebuild them.Thanks to the information I have found on this forum I feel able to undertake this myself. I have decided to refoam the woofers as the cones are in good condition and they were never driven at high volume. I will also replace the capacitors and the pots which are very scratchy and have a number of dead spots.I am not sure what to do with the tweeter. Whether to replace from ABtech which will be quite expensive since the pound has now collapsed against the dollar or replace both with newer replacements which I may be able to source locally. I understand that I will probably not be able to find an exact match even if I buy ABtech's tweeter. I also appear to have the solid capacitor blocks in my speakers. I assume they will have deteriorated as well. I would appreciate any advice given. The UK AR-2ax has some minor differences to the original model but overall seems the same. Link to comment Share on other sites More sharing options...
genek Posted January 24, 2009 Report Share Posted January 24, 2009 I am not sure what to do with the tweeter.I would check out the Hi Vi tweeter thread below. If your current setup has multiple surround speakers, the reduced dispersion of replacement tweeters vs the originals will probably not be much of an issue, if at all.Capacitor deterioration and failure in 70's ARs is more hit-and-miss than in earlier or later models. Check out this post by Ken Kantor, R&D Director for AR in the early 80's:http://www.classicspeakerpages.net/IP.Boar...ost&p=50756 Link to comment Share on other sites More sharing options...
JKent Posted January 24, 2009 Report Share Posted January 24, 2009 Welcome to the CSP!First thing to do: Download and study the excellent "AR3a Restoration Manual". Much of what is written about the 3a applies to the 2ax.I think the only difference between your 2ax and the one made in the USA is the European cabinet design and the stuffing material.Are you SURE you have a dead tweeter? If your cap is dead or the pot hopelessly corroded, that may be the problem. If you DO need new tweeters, you should consider the HiVi/Swans that Gene suggested. They are probably available in Europe and cost a fraction of the price of the AB Tech tweeter. Their European HQ is in Germany:http://www.worldclass-speaker.com/RoyC has studied the Q1R and written about it. Look through the threads. Here is one, but there have been several:http://www.classicspeakerpages.net/IP.Boar...?showtopic=5109If you decide to replace the caps, you can leave the old ones in place and just bypass them. The pots can either be cleaned, as shown in the 3a manual, or replaced with reliable and inexpensive L-pads. Here is a thread regarding my 2nd pair of 2ax speakers--slightly older than yours, with cloth surrounds, but otherwise the same. I replaced the tweeters with newer 2ax tweets, replaced the pots with L-pads, added a resistor to compensate for the differences between pots and pads, and replaced the caps. Thanks again to RoyC for all of his advice and guidance on this project:http://www.classicspeakerpages.net/IP.Boar...amp;#entry73980My first AR 2ax project did involve new foam surrounds. On those I cleaned the pots and replaced the caps:http://www.classicspeakerpages.net/library...res_from_jkent/Good luck with this worthwhile project!Kent Link to comment Share on other sites More sharing options...
Guest rogjack Posted January 24, 2009 Report Share Posted January 24, 2009 Thank you all for the information, I have the 3a manual printed out now. I'm pretty sure the tweeter is dead, I removed it and checked with a meter, there's no reading at all. The woofer gives a reading of 7.7 though it's probably not accurate.I found a source for the L-pads and have ordered them. Capacitors shouldn't be a problem.I'll start looking for new tweeters now. Link to comment Share on other sites More sharing options...
onplane Posted January 24, 2009 Report Share Posted January 24, 2009 Having now examined them outside the the cinema system I find that the foams on the woofers have both perished and one of the tweeters is dead. After nearly forty years service it's not really surprising so I've decided to rebuild them.Before you buy anything, would you please share with us how you know the tweeter is "dead". 9 times out of ten the tweeters are "fine" and it's the pots that are bad.Did you try the battery test or attempt to measure the DC resistance of the tweeter by itself.Now, in all fairness, when I say the tweeters are "fine", I mean you can coax sound out of them. There is plenty of speculation that those old tweeters are weak in output, but ... there are solutions (see the Tweaks and Mods board).Regards,Jerry Link to comment Share on other sites More sharing options...
Guest rogjack Posted January 24, 2009 Report Share Posted January 24, 2009 Before you buy anything, would you please share with us how you know the tweeter is "dead". 9 times out of ten the tweeters are "fine" and it's the pots that are bad.Did you try the battery test or attempt to measure the DC resistance of the tweeter by itself.Now, in all fairness, when I say the tweeters are "fine", I mean you can coax sound out of them. There is plenty of speculation that those old tweeters are weak in output, but ... there are solutions (see the Tweaks and Mods board).Regards,JerryDC resistance is zero. No reaction to battery test. I agree that the output is weak, that's probably why I hadn't noticed it had failed before. Link to comment Share on other sites More sharing options...
onplane Posted January 24, 2009 Report Share Posted January 24, 2009 DC resistance is zero. No reaction to battery test. I agree that the output is weak, that's probably why I hadn't noticed it had failed before.Zero indicates a short circuit!! Are you sure the wires under the tape aren't crossed???You should get a reading of (now I don't remember for the 8 ohm version) 5 ohms???Ususally a tweeter fails due to too much power getting to the voice coil and it opens up (no reading at all indicating that the circuit is NOT complete).Regards,Jerry Link to comment Share on other sites More sharing options...
Guest rogjack Posted January 24, 2009 Report Share Posted January 24, 2009 Zero indicates a short circuit!! Are you sure the wires under the tape aren't crossed???You should get a reading of (now I don't remember for the 8 ohm version) 5 ohms???Ususally a tweeter fails due to too much power getting to the voice coil and it opens up (no reading at all indicating that the circuit is NOT complete).Regards,JerryIf I try a circuit test (the one that beeps) I get a reaction from the woofer (working) I get no reaction from the tweeter. On ohms theres no result at all, perhaps I shouldn't call that zero! Link to comment Share on other sites More sharing options...
onplane Posted January 24, 2009 Report Share Posted January 24, 2009 If I try a circuit test (the one that beeps) I get a reaction from the woofer (working) I get no reaction from the tweeter. On ohms theres no result at all, perhaps I shouldn't call that zero!Well, unfortunately "open" is a clear sign of a dead tweeter!Like Gene said, check out the thread on the Hi Vi tweeter. For me it's an easy call. The Hi Vi fits in the opening and has plenty of sensitivity for the 8 ohm systems. You can always throttle back a tweeter with the pot, but it's hard to cure the opposite problem.Next, because all of these tweeters are different, you really should get a pair. Otherwise, you'll find it hard to match the speakers to each other.Regards,Jerry Link to comment Share on other sites More sharing options...
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