KenB Posted March 31, 2020 Report Share Posted March 31, 2020 Hi....I am new....I recently resurrected a pair of AR2’s that had been sitting idle on a basement for more than 20 years. They look to be ‘original’. One unit only has 3 sides finished. They have the dual angled tweeters and based on what I have read they should be positioned on a bookshelf (on their side). I removed the woofer and the units have the old military oil filled capacitors and the rheostats were undamaged (but needed cleaning). I reassembled the units and they really sound lovely. However, I would like to replace the tweeters....which would be doable without changing the historical character by removing the existing tweeter basket and replacing it with a ‘baffle’ carrying the ‘modern’ tweeter and not touching the crossover. Sooooo does anyone know what the combined impedance of the existing double tweeter is? Also, what would be a good replacement.....I was thinking of either the PRT or the Dayton DCF28-8 if the impedance is 8 ohms. Thanks KenB Quote Link to comment Share on other sites More sharing options...
Aadams Posted March 31, 2020 Report Share Posted March 31, 2020 Your tweeters are really mid range drivers. The solution would be an added super tweeter array that was made to achieve the result you seek. I am pretty sure the solution you have proposed does not exist here. You will be a pioneer. Welcome to CSP btw. Adams Quote Link to comment Share on other sites More sharing options...
samberger0357 Posted March 31, 2020 Report Share Posted March 31, 2020 I believe CSP member Sonnar has done some changes to his AR2's of the type that Ken is considering. Perhaps he will see this thread and comment. I have used both JansZen 1-30 's electrostats and Micro Acoustic microstatic tweeters with my AR2's, and both additions were worthwhile. I presume some Realistic bullet super tweeters would works well also. Quote Link to comment Share on other sites More sharing options...
ra.ra Posted March 31, 2020 Report Share Posted March 31, 2020 1 hour ago, KenB said: I reassembled the units and they really sound lovely. However, I would like to replace the tweeters.... Hi Ken, welcome to the forum. I'm a bit confused by these statements - - - if they already sound lovely, why are you interested in modifying your AR-2's? If you want a historically accurate "upgrade", you might consider the original conversion promoted by AR, which would turn your AR-2's into AR-2x speakers. Replacing with a modern tweeter will most likely require unknown crossover modifications. Quote Link to comment Share on other sites More sharing options...
JKent Posted March 31, 2020 Report Share Posted March 31, 2020 29 minutes ago, samberger0357 said: I have used both JansZen 1-30 's electrostats and Micro Acoustic microstatic tweeters with my AR2's, and both additions were worthwhile. I presume some Realistic bullet super tweeters would works well also. Agree. Those are simple add-ons. The only downside: all the suggested tweeters are a bit expensive. I wonder if these are similar to the Realistic ones https://www.parts-express.com/pyramid-tw28-375-aluminum-bullet-horn-tweeter-pair-with-swivel-housing--270-105 Here's a thread about DIY supertweeters that also mentions other options.http://www.classicspeakerpages.net/IP.Board/index.php?/topic/10548-diy-supertweeters/&tab=comments#comment-124149 PE has a lot of tweeters that look promising but I would do something external and not mess up nice original AR-2s. Some of the horn tweeters could just be placed on a shelf without any enclosure and if you use a piezo you don't even need a filter (I don't prefer piezos but with others you need to add a capacitor. Quote Link to comment Share on other sites More sharing options...
samberger0357 Posted March 31, 2020 Report Share Posted March 31, 2020 4 minutes ago, JKent said: Agree. Those are simple add-ons. The only downside: all the suggested tweeters are a bit expensive. The MA"s can usually be found for what I would consider a reasonable sum plus they're less prone to failure then the much more expensive 1-30's. Quote Link to comment Share on other sites More sharing options...
genek Posted March 31, 2020 Report Share Posted March 31, 2020 Larry at Vintage-AR has one of those phenolic tweeters that he has treated to make it an AR-4x replacement unit. The 4x tweeter is the same one that was used in the 2x, so at $22.95 each they would probably be the most cost-effective way to accomplish a 2-2x conversion. Quote Link to comment Share on other sites More sharing options...
KenB Posted March 31, 2020 Author Report Share Posted March 31, 2020 I would like to place them vertically rather than horizontal and I understand that horizontal dispersion is limited in this position. I am thinking that I could configure this as an AR2X....AR had sold a kit to actually do this conversion. However I am thinking that a modern tweeter such as the PE PRT tweeter would fill that task. The open question that I have is the impedance of the existing tweeter/midrange arrangement. I guess when all is said and done I would like to have a 10 inch version of the venerable AR4X? Quote Link to comment Share on other sites More sharing options...
Aadams Posted March 31, 2020 Report Share Posted March 31, 2020 4 minutes ago, KenB said: I would like to have a 10 inch version of the venerable AR4X? You would be looking for an AR14. Quote Link to comment Share on other sites More sharing options...
JKent Posted March 31, 2020 Report Share Posted March 31, 2020 Just to rain on your parade.... There are online high frequency hearing tests that will tell you whether you can hear those tweeter frequencies. All speaker specs tell you about the frequency range of 20 to 20k Hz. Can you hear 20k? No. And depending on your age and other factors you may not hear 15k. Or 12k. Or even 10k. So what will this mod do? Quote Link to comment Share on other sites More sharing options...
ra.ra Posted March 31, 2020 Report Share Posted March 31, 2020 Regarding the AR-2x, it was available in at least two variations, with different tweeters, woofers and crossovers. If you use the AR-4x tweeter, your tweeter cap should be replaced with a 20uF. You'd probably need something similar if using the PRT tweeter. But if you use the original AR-4 tweeter (or AR-2ax mid), I think you can simply re-use the original AR-2 oil caps. These AR-4 (2ax) drivers are typically available at reasonable prices. With any of these replacements, the speakers could be used in vertical orientation. Quote Link to comment Share on other sites More sharing options...
genek Posted March 31, 2020 Report Share Posted March 31, 2020 The biggest change would be making it possible to place the speakers vertically. Even people who can't hear up to the 14k top end of the AR-2 can probably tell the difference when those cross-fired tweeters are firing up and down rather than left and right. Of course, once you do that, you are faced with the question of what to do with that unfinished pine cabinet face. Quote Link to comment Share on other sites More sharing options...
ra.ra Posted March 31, 2020 Report Share Posted March 31, 2020 31 minutes ago, KenB said: I could configure this as an AR2X....AR had sold a kit to actually do this conversion. Yes, see the fine print on AR's literature attached in earlier post. Quote Link to comment Share on other sites More sharing options...
KenB Posted June 14, 2020 Author Report Share Posted June 14, 2020 Hi folks....my AR 2 project is complete...I used Dayton DC 28 soft dome tweeters from Parts Express. I did not modify the crossover but reversed the polarity on the tweeters after listening to them. The tweeters are mounted on a 1/2 plywood panel that fits the opening where the original tweeter/midrange sat and I kept the originals for posterity. The original pots were good (12 ohms btw) and I used the goo from the guy on eBay to refresh the cloth surrounds. The speakers sound terrific and can be put back in original condition if ever I want to😎 Quote Link to comment Share on other sites More sharing options...
KenB Posted July 12, 2020 Author Report Share Posted July 12, 2020 So I took aadams note to heart and found the circuit for the AR14 crossover.....replaced the 6db crossover with the 2nd order crossover from the AR14, but slightly modified....instead of the Switched RL contour used in the AR14 I used the 12 ohm ( yes in my case it was 12 ohm) rheostat with the 2mfd capacitor contour as a level control in place of the 2 ohm resistor in the AR14 tweeter crossover.....with the rheostat at 6 ohms the Dayton’s DC28 tweeter sounds balanced with the original AR2 woofer.....all in all the new system sounds really really good😀 Quote Link to comment Share on other sites More sharing options...
Giorgio AR Posted December 24, 2021 Report Share Posted December 24, 2021 Thanks Robert, this is your last post on our site... the day before we exchanged our views on the AR7... I would like to let you know that even now you have helped me ... I have purchased a splendid pair of AR2x, of which I know the history from the birth of AR2, the evolution with the various steps, I was looking for photos of the evolution of this model in my photographic archive and now I have found two other precious ones ... Ciao e grazie Robert Giorgio Quote Link to comment Share on other sites More sharing options...
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