wilson Posted March 22, 2011 Report Share Posted March 22, 2011 Hi folks - am I correct in thinking that the 2ax and the 5 use the same tweeter and that they come in an early (1.25" dome) and a late (.75" dome) version?I have a set of each to choose from to go into a pair of 2ax's that I will restore. Is one preferable? I also assume that tweeters from a 3 would be a different impedance?The reason I ask about the 3 tweeters is one of my donor pair of 2ax's was sold to me as having 3a tweeters - but I suspect that the seller was confused about early vs late tweeters. Or maybe I'm the one that is confused. Thanks for your help. Link to comment Share on other sites More sharing options...
RoyC Posted March 22, 2011 Report Share Posted March 22, 2011 Hi folks - am I correct in thinking that the 2ax and the 5 use the same tweeter and that they come in an early (1.25" dome) and a late (.75" dome) version?I have a set of each to choose from to go into a pair of 2ax's that I will restore. Is one preferable? I also assume that tweeters from a 3 would be a different impedance?The reason I ask about the 3 tweeters is one of my donor pair of 2ax's was sold to me as having 3a tweeters - but I suspect that the seller was confused about early vs late tweeters. Or maybe I'm the one that is confused. Thanks for your help.The AR-5 shares only the .75" dome tweeter used in the later AR-2ax and LST 2. It is physically identical to the .75" dome tweeter used in the AR-3a and LST, but has a higher impedance.The 1+" red/orange dome tweeter used in the earlier 2ax was also used in the AR-3 and AR-2a...but not the 5.Roy Link to comment Share on other sites More sharing options...
dynaco_dan Posted March 22, 2011 Report Share Posted March 22, 2011 Hi folks - am I correct in thinking that the 2ax and the 5 use the same tweeter and that they come in an early (1.25" dome) and a late (.75" dome) version?I have a set of each to choose from to go into a pair of 2ax's that I will restore. Is one preferable? I also assume that tweeters from a 3 would be a different impedance?The reason I ask about the 3 tweeters is one of my donor pair of 2ax's was sold to me as having 3a tweeters - but I suspect that the seller was confused about early vs late tweeters. Or maybe I'm the one that is confused. Thanks for your help.Hi thereThe AR-3 and early AR-2AX's uses the same physically identical size and impedance tweeters.The AR-2AX was rated 8 ohm and the AR-3 was rated at 4 ohms, both had a 1 3/8" diameter dome, this was confirmed recently by, Roy F. Allison, formerly of Acoustic Research.Prior to this confirmation, we all had assumed that they had used, an 8 ohm for the AR-2AX and 4 ohm for the AR-3.The AR-2AX'a tweeter only was changed over to the 3/4" at a later date, someone else may have that date.The interchangeablity will be somewhat controversial, more feedback to come from members, to be sure.The original tweeter do not have the same power handling ability or dispersion of the 3/4".Tweeter pop-off may also be an issue.With the 3/4" tweeter, disintegration of the foam under the hard dome is an issue now.The 3/4" AR-2AX tweeter is rated at 8 ohms, compared to the 4 ohms rating of the AR-3a.Alternative tweeters, pot tune-ups and re-capping will be discussed here as well.There is already writeups about the pros and cons of interchanging these two tweeters. Link to comment Share on other sites More sharing options...
wilson Posted March 22, 2011 Author Report Share Posted March 22, 2011 Thank you - that helps. What are the symptoms/ how do you check for disintegrating foam under the dome in the smaller tweeters? Is this not an issue with the older red tweeters?I currently have 6 tweeters (5 new and 3 old) for this project and I would like to pick the best 2.I had previously believed that either they (tweeters) work or they don't - I had not been aware of the degradation of foam. Link to comment Share on other sites More sharing options...
RoyC Posted March 22, 2011 Report Share Posted March 22, 2011 Thank you - that helps. What are the symptoms/ how do you check for disintegrating foam under the dome in the smaller tweeters? Is this not an issue with the older red tweeters?I currently have 6 tweeters (5 new and 3 old) for this project and I would like to pick the best 2.I had previously believed that either they (tweeters) work or they don't - I had not been aware of the degradation of foam.Only the .75" dome has foam under it. The foam used as the suspension (3 orange blobs), as well as the same foam used for damping under the dome, is decomposing. The most obvious symptoms are output inconsistencies and differences between specimens.Roy Link to comment Share on other sites More sharing options...
dynaco_dan Posted March 22, 2011 Report Share Posted March 22, 2011 Thank you - that helps. What are the symptoms/ how do you check for disintegrating foam under the dome in the smaller tweeters? Is this not an issue with the older red tweeters?I currently have 6 tweeters (5 new and 3 old) for this project and I would like to pick the best 2.I had previously believed that either they (tweeters) work or they don't - I had not been aware of the degradation of foam.Hi againWe all were not aware of the tweeter foam disintegration, the same as woofer surround rot and AR turntable mat rot.Time was all we needed to show up that issue.I guess the foam under the 3/4" domes may have been more consistant to install, than fiberglass.Perhaps fiberglass fibers would migrate into the tweeters magnetic gap and foam won't, or so we thought.More advice will be forthcoming from the more knowledgable members, as they see your topic. Link to comment Share on other sites More sharing options...
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