Rob Irvin Posted February 9, 2018 Report Share Posted February 9, 2018 Hello everyone.I am new here, and I am glad I found this site! I am in the process of refurbishing several sets of AR's. I just finished a set of 4 ax's, and now am at a loss on my 2 ax's. Can the tweeter be rebuilt(yes, I cleaned the pots).I am trying to keep them as original as possible.If they can not be repaired, I am going to have to replace with the HIVI's. I understand that I will have to replace the inductors and a capacitor. Does anyone have a schematic, as to what has to be done ,and a parts list? These are a 1968 version with the red dome.I would gladly pay for the schematics, and detailed instruction or the name of a place that can rebuild them. Link to comment Share on other sites More sharing options...
Aadams Posted February 10, 2018 Report Share Posted February 10, 2018 2 hours ago, Rob Irvin said: Hello everyone.I am new here, and I am glad I found this site! I am in the process of refurbishing several sets of AR's. I just finished a set of 4 ax's, and now am at a loss on my 2 ax's. Rob Hang in there you have come to the right place. The board is usually quieter on the weekend but someone knowledgeable will respond eventually. You may find a schematic in the AR library section but the 2ax is pretty straight forward and being a classic AR you can get a good bit of guidance from the AR3a restoration guide. RE Inductors: Unless they are damaged or incorrect I don't know why you would replace them------- they should be OK. Adams Link to comment Share on other sites More sharing options...
JKent Posted February 10, 2018 Report Share Posted February 10, 2018 Welcome Rob There were two tweeters used in the 2ax. Earlier ones had a phenolic (orange) dome used in the 3 and the 2a, and later ones had a soft (black) dome. Depending on which one it is you could shop on ebay, contact CSP member Chris1this1 to rebuild the original or check out these new replacements https://www.ebay.com/itm/AR-Acoustic-Research-Replacement-Tweeter-for-AR2a-AR10-LST-Speaker-MT-4121-4/152720222777?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649 Quote RE Inductors: Unless they are damaged or incorrect I don't know why you would replace them------- they should be OK. Yeah. What he said. -Kent Link to comment Share on other sites More sharing options...
Rob Irvin Posted February 10, 2018 Author Report Share Posted February 10, 2018 Thanks everyone that replied! I have seen all the after market replacement types' I only need one tweeter actually .These are 1968 models,and before I replace them,I would really rather have a used original, are get the one I have repaired.It worked up untill a week ago,then quit. The rheostat's are in very good shape, just a little corroded, which I cleaned. I have not done any electrical diagnosis or repair for over 30 years,so now that I am retired,I have plenty of time. The ohm reading is 0.it is the orange dome with date on back.I really want to fix these back to the way they were, and keep them original.Thanks again everyone!Cheers Link to comment Share on other sites More sharing options...
JKent Posted February 10, 2018 Report Share Posted February 10, 2018 11 minutes ago, Rob Irvin said: get the one I have repaired. http://www.classicspeakerpages.net/IP.Board/index.php?/profile/179217-chris1this1/ Link to comment Share on other sites More sharing options...
Rob Irvin Posted February 11, 2018 Author Report Share Posted February 11, 2018 JKent,I just posted a message to Chris,Thank you very much! Link to comment Share on other sites More sharing options...
Rob Irvin Posted February 11, 2018 Author Report Share Posted February 11, 2018 Aadams,I was reading that if I were to use the hivi tweeters,I would have to use another inductor along with the one already there, and add two capacitors to change the polarity to the tweeter. That seemed like an awfull lot to do, and I did not want to change the circuitry.Thanks for your response,Rob Link to comment Share on other sites More sharing options...
JKent Posted February 11, 2018 Report Share Posted February 11, 2018 Rob, RoyC is really the expert on this but you mount the inductor to the back of the tweeter and "if" you want to add a 6uF capacitor you can add it in series, also at the tweeter to bring the value of the tweeter cap down to 3uF. That's what I did and it is easily reversible. Roy told me that if you are using the original pots, the added cap may not be needed. Bottom photo below shows mine with a 6uF cap in series (and a totally unnecessary "bypass cap"), .05 coil on the tweeter and reversed polarity. Again--this is really Roy's thing but he is constantly experimenting and tweaking, and his latest refinement seems to be the .05mh coil, 5uf cap (to replace the original 6uF), L-pads/no resistor, and like-polarity. All of these things affect the relative output of the tweeters and of course the level controls, room characteristics and personal preferences all enter into the mix. ANY variations here will be pretty subtle, so you could pretty simply just add the HiVi tweeter with a coil on the back, as shown in the top photo below. -Kent Link to comment Share on other sites More sharing options...
Aadams Posted February 11, 2018 Report Share Posted February 11, 2018 42 minutes ago, Rob Irvin said: Aadams,I was reading that if I were to use the hivi tweeters,I would have to use another inductor along with the one already there, and add two capacitors to change the polarity to the tweeter. That seemed like an awfull lot to do, and I did not want to change the circuitry.Thanks for your response,Rob Rob I am not what I would call an expert in this area but I once owned a late model 2ax pair and have stayed a few nights at Holiday Inn Express. The HIVI is the most cost effective way to restore your speaker performance if your original tweeters are broken. (And just now I see where JKent has covered the RoyC info.) My opinion is I would have Chris rebuild both of the originals for 3 reasons. 1. These are the same tweeters used in the AR3 which may be of value down the road 2. If your 2axs can be restored to a fine original look 3. Originality is more important than cost. Sound wise I doubt you could reliably tell the difference between the HIVI and the original tweeter in a 2ax, unless you have very young ears and abuse the treble controls. Adams Link to comment Share on other sites More sharing options...
JKent Posted February 11, 2018 Report Share Posted February 11, 2018 Adams is right. If you are concerned about authenticity and possible resale, have Chris rebuild BOTH original tweeters. But if you are just going to keep these to enjoy you won't hear any difference between the HiVi and the original, and the HiVi is much more cost effective. Also--forget what I wrote about capacitors. I wasn't paying attention and wrote about the HiVi mod in AR-3a speakers SO. The HiVi with coil is a very simple drop-in replacement that may cost you about $50 total. Chris can rebuild the originals and from what I'm told, he does excellent work and they will be like new. But all that labor will cost you and in the end the sonic difference may be negligible. So you need to decide which option is best for you. Keep us posted. Kent Link to comment Share on other sites More sharing options...
Rob Irvin Posted February 11, 2018 Author Report Share Posted February 11, 2018 Thanks again everyone. Kent and Aadams,I will get back to you on what I decide to do.The hivi's sound like the way to go, I'll have to wait for Chris to find out what it costs.If it is just the inductor and speaker, and do not have to change the circuitry, that is feasible.Thanks again! Link to comment Share on other sites More sharing options...
Rob Irvin Posted February 14, 2018 Author Report Share Posted February 14, 2018 JKent,I just finished a set of 4 ax's.They turned out very nice.The sound is excellent for book shelf speakers !Now,I am onto the 2 ax's.Again,to make sure a understand.I get the hivi's,and as per your your picture use a piece of cardboard to insulate the inductor from the coil.I soldier the leads as pic shows.and the polarity stays the same,as per the original contact posts? Thanks again ! Link to comment Share on other sites More sharing options...
RoyC Posted February 14, 2018 Report Share Posted February 14, 2018 On 2/11/2018 at 1:25 PM, JKent said: you could pretty simply just add the HiVi tweeter with a coil on the back, as shown in the top photo below. -Kent ...which is what I now recommend as a starting point for all applications. (Kent, the 5uf cap tweak only applies to the AR-3a, not the 2ax. ). Most people seem satisfied with the HiVi tweeter when used with the original capacitor values, as Larry/"Vintage_AR" sells them by the boatload. Most of my HiVi tweaking activities were in response to conversations with some HiVi users, and occurred prior to the availability of the rebuilt tweeter option. As I've stated before, the HiVi tweeter/inductor combo is the least expensive way to get back into the original AR ballpark, but I currently believe the best bet in terms of originality is Chris' rebuilt tweeter. Roy Link to comment Share on other sites More sharing options...
Rob Irvin Posted February 17, 2018 Author Report Share Posted February 17, 2018 Thanks RoyC.I have ordered the parts,just waiting for arrival and installation. Link to comment Share on other sites More sharing options...
JKent Posted February 17, 2018 Report Share Posted February 17, 2018 On 2/14/2018 at 4:10 PM, RoyC said: (Kent, the 5uf cap tweak only applies to the AR-3a, not the 2ax. ) Yes, I did retract that in my last post: On 2/11/2018 at 1:53 PM, JKent said: forget what I wrote about capacitors. I wasn't paying attention and wrote about the HiVi mod in AR-3a speakers but it does make sense to reiterate the point Hope I didn't mislead anyone. Kent Link to comment Share on other sites More sharing options...
Rob Irvin Posted February 24, 2018 Author Report Share Posted February 24, 2018 For those of you that were still wondering,I got the hivis,and did the swap with the one blown tweeter.It makes an interesting contrast with the one speaker with the original.It is very clear and precise sounding.I had the in-house musician give a listen.He liked it,he said it is not as "shimmery"as the original.I am going to have Chris rebuild the original and then reinstall that. I think I will install the hivis into a set of Wharfedales that need a set of tweeters.Thanks for all your help,Everyone.I will be asking for more advice since I have about 20 more pairs of classic speakers.Rob Link to comment Share on other sites More sharing options...
JKent Posted February 24, 2018 Report Share Posted February 24, 2018 Nice. Have you done the push test on the AR and KLH woofers? You may need some of Roy's sealant for the surrounds. -Kent Link to comment Share on other sites More sharing options...
Rob Irvin Posted February 24, 2018 Author Report Share Posted February 24, 2018 I am still working on the speaker with the new tweeter,The resistance is very low across the tweeter posts(0.5)ohms.So I guess I will have to open it up again and check??? Would be nice to have a diagram with Values to check.The bass and midrange drivers are working properly.I think I need to take the filler out and check all connections.I did not follow my fathers rule to do it right the first time.So back too it. Link to comment Share on other sites More sharing options...
JKent Posted February 26, 2018 Report Share Posted February 26, 2018 Rob, We discussed this a little in a PM but I want to follow up here so others may join in. You have the schematic and found everything to be wired correctly but you're dealing with original pots and caps, any of which can be the culprit(s). I would recommend replacing the caps. Buy two 6uF and two 4uF (or 3.9uF) caps from PE or Madisound. twist one lead from a 4 and a 6 together--that's the Common (blue) lead. Then just wire them up the same as the old one. The pots are more "controversial". Some members recommend cleaning them to keep them original. That may or may not work and if they are cleaned they could go bad again. Some pots can be cleaned while others are beyond repair. Personally I like L-pads. If I were doing this job I'd order the following from Madisound: 2) Carli MET 3.9 mfd Non-Polar Mylar Capacitor $1.35 ea 2) Carli MET 6.0 mfd Non-Polar Mylar Capacitor $1.80 ea 4) Yung LP15, 3/4" 15W 8 ohm L-pad $6.60 ea You could also use Solen PB 4 mfd Metalized Polypropylene Fast Capacitors @ $3.20 ea but 3.9 is close enough. Instructions on cleaning pots and wiring L-pads are in these pages. -Kent Link to comment Share on other sites More sharing options...
Rob Irvin Posted February 26, 2018 Author Report Share Posted February 26, 2018 Just ordered the carli met caps.Sent Chris the tweeter.Will let everyone know the outcome with pictures. Link to comment Share on other sites More sharing options...
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