Jaws Posted September 10, 2011 Report Share Posted September 10, 2011 I've got the AR bug now, yay! Having cut my teeth restoring a pair of AR-7, I picked up a pair of late AR-2ax on ebay for UK£70. I did the woofer re-foam, replaced the caps with Claritycaps, cleaned the pots and fired them up. The first one worked just fine, and I had it producing wonderful sounds for a day, whilst I worked on the other speaker. Unfortunately next time I tried it the was no sound from the tweeter, and it's gone open circuit (measured at the tiny wires on the front with other connections undone). I guess the excitement of being used after years of neglect popped it :-(After reading these excellent forums I've ordered a pair of HI-Vi Q1R replacement tweeters from Parts Express. Various posts from Roy C, Kent, and others recommend adding an inductor in parallel and a resistor, and I want to check the values before ordering them. I don't have access to a stock of components or any sophisticated test gear (other than my ears) to experiment with, so can someone please answer these questions:1. Is the inductor value 0.05mH?2. What should the resistor value be?3. What type should the resistor be (I'm guessing wire-wound)?4. Is the resistor in series with the tweeter/inductor or in parallel?The serial number of one of the speakers is AX257976, and it has the US address on the label (what's left of it). The other one's label is missing. Link to comment Share on other sites More sharing options...
RoyC Posted September 11, 2011 Report Share Posted September 11, 2011 Jaws,The inductor is 18ga, .05mh. You do not need a resistor at all. If you anticipate replacing the original 4uf tweeter cap, replace it with a 2.5uf to 3uf cap if you want the tweeter to sound a bit more like the original.Roy Link to comment Share on other sites More sharing options...
Jaws Posted September 12, 2011 Author Report Share Posted September 12, 2011 Thanks Roy,Time for some experimentation methinks. Luckily I've still got one working tweeter for comparison. Jaws Link to comment Share on other sites More sharing options...
oldarnut Posted September 17, 2011 Report Share Posted September 17, 2011 Is the Hi-Vi Q1R at 6 ohms the recommended replacement for the AR1ax, AR5, ARLST2 that are 8 ohm systems as well as the AR3a, ARLST 4 ohm systems? Link to comment Share on other sites More sharing options...
RoyC Posted September 18, 2011 Report Share Posted September 18, 2011 Is the Hi-Vi Q1R at 6 ohms the recommended replacement for the AR1ax, AR5, ARLST2 that are 8 ohm systems as well as the AR3a, ARLST 4 ohm systems?I assume you mean the AR-2ax (not "AR1ax")...The HiVi will work fairly well in the 2ax, 5, and 3a with a .05mh parallel coil. If the goal is to get as close as possible to the tonal balance of the original tweeter, the tweeter capacitor value should be reduced to between 2.5uf and 3uf in these three models. I am presently experimenting with the HiVi Q1R's sibling, the "X1" in the 3a. This tweeter has lower impedance, and is more sensitive than the Q1R, yet still has a large, convenient mounting flange. The replacement's resistance (dcr) is not a big issue if the sensitivity is sufficient, and appropriate crossover adjustments are made.It has recently come to my attention that the HiVi tweeter will NOT work in the LST or LST 2 as a single replacement driver! It may be used if ALL of the tweeters are replaced in the LST 2 and LST cabinets, but crossover changes are required. I am communicating with some people who are currently dealing with replacement tweeter issues in both. More info should be available soon.Roy Link to comment Share on other sites More sharing options...
oldarnut Posted September 18, 2011 Report Share Posted September 18, 2011 Thank you, Roy, for the reply. I have four AR3a's and a pair of ARLST2's--all with good woofers, mids, but tweeters that have very low output, don't work at all, or were replaced years ago with KEF, Yamaha, and Radio Shack tweeters. I can vouch for your statement in your last post that the LST2 needs all tweeters to match. The KEF and Yamaha tweeters, compared to the single OEM AR unit in each of my LST2's, are mismatched so much that the OEM tweeters can't be heard at all without a toilet paper roll held next to them. Let's see--That's 10 replacements I'd need to handle all of them. I believe that's enough for the PE quantity discount! Link to comment Share on other sites More sharing options...
RoyC Posted September 18, 2011 Report Share Posted September 18, 2011 Thank you, Roy, for the reply. I have four AR3a's and a pair of ARLST2's--all with good woofers, mids, but tweeters that have very low output, don't work at all, or were replaced years ago with KEF, Yamaha, and Radio Shack tweeters. I can vouch for your statement in your last post that the LST2 needs all tweeters to match. The KEF and Yamaha tweeters, compared to the single OEM AR unit in each of my LST2's, are mismatched so much that the OEM tweeters can't be heard at all without a toilet paper roll held next to them. Let's see--That's 10 replacements I'd need to handle all of them. I believe that's enough for the PE quantity discount!Before ordering all of those tweeters, send me a PM. There appears to be an LST family "replacement tweeter support group" forming. Among other things, information regarding crossover changes is being discussed.Roy Link to comment Share on other sites More sharing options...
dynaco_dan Posted September 18, 2011 Report Share Posted September 18, 2011 Thank you, Roy, for the reply. I have four AR3a's and a pair of ARLST2's--all with good woofers, mids, but tweeters that have very low output, don't work at all, or were replaced years ago with KEF, Yamaha, and Radio Shack tweeters. I can vouch for your statement in your last post that the LST2 needs all tweeters to match. The KEF and Yamaha tweeters, compared to the single OEM AR unit in each of my LST2's, are mismatched so much that the OEM tweeters can't be heard at all without a toilet paper roll held next to them. Let's see--That's 10 replacements I'd need to handle all of them. I believe that's enough for the PE quantity discount!Hi thereMy eyebrows raised at the, "low output," comment.The AR-LST complete speaker system will still work, mind you, at a much reduced output, even when the fuse is blown.If that is something that you have not checked yet.I have never heard of the AR-LST-2 doing it, but it's worth a check also. Link to comment Share on other sites More sharing options...
RoyC Posted September 18, 2011 Report Share Posted September 18, 2011 Hi thereMy eyebrows raised at the, "low output," comment.The AR-LST complete speaker system will still work, mind you, at a much reduced output, even when the fuse is blown.If that is something that you have not checked yet.I have never heard of the AR-LST-2 doing it, but it's worth a check also.Vern,The way the LST and LST 2 are configured, any modern tweeter installed in the same cabinet will easily overpower the unique original tweeter, which has very little output below the very high crossover frequency. This is also why crossover changes, such as parallel inductors and capacitor value adjustments, are required to tame (ALL) modern tweeters for use in AR's single tweeter models of that era.Roy Link to comment Share on other sites More sharing options...
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