Mexicomike Posted January 25, 2009 Report Share Posted January 25, 2009 Hi John, the Red Tree House is in Condesa, a nice area of the city that's very soho-like. There are a lot of nice restaurants and it's a neat place to walk around. We live in Polanco which is the "next" district over. It's a long walk or a short (distance, maybe NOT time) ride. We will be out of town during the weekend of the 14th and the following weekend including Fri the 20th. But we might be able to get together for a drink or dinner on 11, 12 or 13 if it works with your schedule. We could come over there...Re the tweeters - I don't know what they cost which will have a lot to do with this. Frankly, I am not sure I want to spend hundreds of dollars for an experiment that involves my LSTs that don't (in my opinion) need any improvement anyway. But I can't think of how to try them without buying at least 4. If I just bought one and mounted it, I don't know how that would interface with the others and if there is a dispersion issue, it probably wouldn't be too apparent because the other 3 oem drivers would cover that to some extent. I'd welcome suggestions from anybody on how to test this with less than 4 drivers per speaker. Of course one solution would be to buy 4, install them, listen and then, if they do sound "better," buy 4 more when I'm in the states or have them shipped down with the cookies! I could buy two and put one in one of my AR3As and compare it to eom in the other 3A so that's an option as well I guess but it seems that there is already data showing that the new tweeter does NOT disperse as well as the oem so I don't know if there's any point in trying it with a 3A.John, I'm not sure your question re the inductors was addressed to me but... Re Xovers on my LSTs and 3As...Over 50 emails went back and forth between me and 4 of the folks on this site who were very involved in the AR3 restoration guide regarding caps/resistors, etc. The goal was to try to get the speakers as close to original as believed to be possible. The emails even went so far as China, where one of the folks was on a business trip! Actually, there were two series of email discussions - the 3A discussions and, several months later, the LST discussions. At the time of my 3a restoring, the site's 3A restoration guide was not yet available.I went with all Polpropylene caps with the same Ohm rating as the originals with resistors added to adjust for ESV. NOT everyone involved agreed/agrees that adding resistors is necessary. I don't know the slightest thing about any of this from a theory aspect but I still have pretty good ears, I can follow instructions, and I'm very good with a soldering iron! So basically I just did what I was told! The only change to oem specs was that one of the LSTs had 5000 Ohms of capacitance in its transformer circuit while the other, a few serial numbers later, had the newer version - 2500 ohms. So I installed 2500 Ohms worth of new caps in both speaker's transformer circuits. There were no changes to the inductors. Any additional wiring needed to connect the new caps was done with 14ga "normal" copper wire. I did not rewire any other existing circuitry with "better" wire. Link to comment Share on other sites More sharing options...
RoyC Posted January 25, 2009 Report Share Posted January 25, 2009 Oh, no way. I'm socking away spare parts against the day my working original tweeters give up the ghost. So far I've laid in a pair of 10pi/11 domes with Ken Kantor's recommended 0.07mH coils and a pair of the 218V domes with Carl's adapter plates and 0.15mH coils. I might have ordered up a pair of the Hi Vi's if not for the fact that Carl says their only advantage over the ones I already got from him is that they don't need adapters.Gene,Sounds like you are in good shape for the future:-)! Actually Ken's recommended .07mh coil was only for the AB Tech tweeter, which is different than the much better built, and more appropriate, 10pi/11 AR dome. That AR tweeter was used with a .1mh coil and a larger 10uf capacitor in the 10pi and 11. In the AR-3a Limited a very similar AR tweeter was used with a .16mh coil and a 4uf capacitor (and L-pads). I tried it in the Limited, and thought it sounded very good. (According to Minh L., our resident AR-3a Limited expert, the cloth dome AR tweeter used in the 3a Limited was essentially a clone of the 10pi/11 tweeter.)In the late 70's AR was supplying these tweeters as drop in replacements for the 3a and LST....So, in an original 3a, try them first with no coil to see how they sound to you. If they need taming, I doubt you will need a smaller coil than the .15mh you already have on hand.Roy Link to comment Share on other sites More sharing options...
JKent Posted January 25, 2009 Report Share Posted January 25, 2009 Re the tweeters - I don't know what they cost which will have a lot to do with this.http://www.parts-express.com//pe/showdetl....tnumber=297-417http://www.madisound.com/catalog/product_i...roducts_id=1493About $23 but Out of Stock at both PE and Mad! Guess the CSP members have generated a lot of demand for these! Link to comment Share on other sites More sharing options...
Mexicomike Posted January 25, 2009 Report Share Posted January 25, 2009 Well, we spent more than that on dinner for the two of us in NYC anytime we drove in from Long Island! Heck, having 8 matching paperweights isn't bad at that price! Link to comment Share on other sites More sharing options...
RoyC Posted January 25, 2009 Report Share Posted January 25, 2009 However I do accept the fact that, as Roy says, the tweeters (and the mids as well, I assume) may not be performing as they once did. As as often been discussed, this is difficult to determine unless they are clearly damaged or not working because there is no brand new set of LSTs to compare them to. But they throw an absolutely marvelous soundstage and tweeters that do not disperse as well might not be an improvement at all, even if they are capable of better high freq response that the current tweeters. As I said, it would be interesting.Hi Mike!I am enjoying all this talk of Mexico, considering the current 20 degree F temperature here in the frozen wasteland of upstate NY!Anyway, the good news is ONLY the old hard dome tweeters are in trouble. The mids seem to be holding up quite well! Their construction is very different, much more "modern"...no foam to deteriorate. In fact I recently tested a bunch of AR midranges, including some that were pulled from Cello Amati speakers (identical to the 3a/LST/11/10pi mid, but without the metal grille/fiberglass arrangement). Electrically, these mids from the 3a onward really don't vary much at all, and are pretty much interchangeable. We are in better shape in the midrange department.Regarding your LSTs, I would not rush to disrupt them. Since you are satisfied with the way they sound, variations on the part of the Q1R may not be for the better when multiplied by that many tweeters . It is probably not yet worth the risk or expense, unless you see it is as an easy thing to experiment with. Also, when Ken K. was working with us he suggested that the recommendations made for the AB Tech tweeter for the 3a may not be as applicable to the LST. Based on his comments, other crossover tweaks may be needed to work with the LST level control arrangement. If anything I would play around with the 3a to begin with just to get a feel for the differences.On the other hand, it would not be concern over "holes" in dispersion that would stop me from trying the Q1R. Your old tweeters probably already stray from original specs in more significant ways. Most of the ears in this forum are not hearing much of anything at 15khz...widely "dispersed" or not:-)! Heck, there is not much musical information up there to begin with. Once again, it is fun to speculate about the sonic differences of charts and theory, but there is no substitute for experiencing it. I contend most of the original 3a/LST tweeters are not producing much output at very high frequencies today, dispersed or otherwise...yet folks are still very much enjoying them.Hmmm, this may indeed require a charter flight to Mexico by the CSP gang:-)!Roy Link to comment Share on other sites More sharing options...
RoyC Posted January 25, 2009 Report Share Posted January 25, 2009 http://www.parts-express.com//pe/showdetl....tnumber=297-417http://www.madisound.com/catalog/product_i...roducts_id=1493About $23 but Out of Stock at both PE and Mad! Guess the CSP members have generated a lot of demand for these!Hey Kent,I know where at least some of them went. I was contacted by Larry L ("Vintage AR") this morning to compare some notes. He is planning to offer "drop-in" kits centered on the Q1R, which will include mounted inductors (another convenient feature of this tweeter is the shielded magnet, which has little effect on the added inductor), wiring for front-wired and back-wired applications, screws for the small holes, and drilled faceplates for the 3 original AR screws.We should be getting more real world feedback soon...Roy Link to comment Share on other sites More sharing options...
RoyC Posted January 25, 2009 Report Share Posted January 25, 2009 Roy, I see from your post #8 that you have experimented with ribbon tweeter replacements for the 3/4 inch dome. It looks like a Hi-Vi model.I did a Super-Mod last year for a customer using a Fountek Neo CD3 ribbon tweeter which worked out quite well. The impetus behind the choice of a ribbon was the customer's desire to extend the high frequency response into the 'super-tweeter' range well above 20 kHz and, have improved off-axis response over dome types. The link below is to Fountek's information on this tweeter.http://www.fountek.net/products/neocd3.pdfTheir data shows very good horizontal off-axis response but poor vertical off-axis response which, I believe, is typical of ribbon tweeters. The diameter of this one is 4 3/8 inches. I don't remember if I fabricated an adapter plate or not. I searched my test database but couldn't find any of my own off-axis testing. These tweeters are a bit power shy. Fountek recommends a 3rd order xover at 2500 hz. I used a 2nd order at 5 kHz.Prior to getting the Fountek tweeter I initially got a pair of Arum Cantus G2 tweeters. These tested terrible and were subsequently sent back.Carl,Thanks for the "diffraction" link...interesting stuff.Yes, the tweeter in the photo is the HiVi RT1C-A, http://www.madisound.com/catalog/product_i...roducts_id=1486I used a simple 2nd order crossover at around 5 kHz as well, but have no measurement data. Now that you mention it, the subjective differences off axis seemed to be more upon standing and moving around the room. I could very well have been hearing vertical dispersion issues as much as anything else. I only used them for a few weeks....You are welcome to them for postage from NY to CT. They are presently sitting on a shelf.Roy Link to comment Share on other sites More sharing options...
Guest John Faulkner Posted January 27, 2009 Report Share Posted January 27, 2009 RoyI keep reading about the need for shunt inductors on replacement (non-OEM) tweeters. What is the reasoning for this? I am going to replace the tweeters in a pair of AR-3 cabinets with 303a tweeters. I am also replacing mids with ar-3a mids and rebuilding crossovers to AR-3a specifications. I have read about shunt inductors of 0.05, 0.07, 0.10 and 0.15 mh - which should I use and how much difference does it make? I have the 51 turn coils from the original AR-3 crossovers, listed in an AR crossover inductor table as being 0.044 mh, so my thought is to use them across the tweeter leads (but mounted on the new crossover boards I will build). The value is a little on the low side but they will cost me nothing and I have them here. Any thoughts on my plan?thanksJohn Link to comment Share on other sites More sharing options...
RoyC Posted January 27, 2009 Report Share Posted January 27, 2009 RoyI keep reading about the need for shunt inductors on replacement (non-OEM) tweeters. What is the reasoning for this? I am going to replace the tweeters in a pair of AR-3 cabinets with 303a tweeters. I am also replacing mids with ar-3a mids and rebuilding crossovers to AR-3a specifications. I have read about shunt inductors of 0.05, 0.07, 0.10 and 0.15 mh - which should I use and how much difference does it make? I have the 51 turn coils from the original AR-3 crossovers, listed in an AR crossover inductor table as being 0.044 mh, so my thought is to use them across the tweeter leads (but mounted on the new crossover boards I will build). The value is a little on the low side but they will cost me nothing and I have them here. Any thoughts on my plan?thanksJohnJohn,A parallel inductor makes a modern tweeter roll off more quickly at lower frequencies (into the midrange area), which more closely matches the natural response of the old tweeter.I think the .044mh inductor will be on the low side. You will likely not get enough output from your 303 tweeters with that one. Carl worked with a similar tweeter and found .15mh to work satisfactorily.Check your forum messages.Roy Link to comment Share on other sites More sharing options...
johnieo Posted January 29, 2009 Report Share Posted January 29, 2009 John,You will need two 51-turn (0.044 mH) coils for the rebuilt AR-3a crossover. Were you planning on using that pair for the tweeter pad and purchasing new ones for the crossover? Or do you have two pair? One should not replace the coils, as their resistance is part of the crossover design.As Roy noted, the ferrofluid cooled replacemnts have much more output below 5 kHz than did the original. As well, many show a strong resonance peak at 2 or 2.5 kHz. You will see a coil in parallel with the tweeter in many designs, such s the AR-11, 10pi, 9, Ar-3a Limited, and so on that used Ferrofluid tweeters.Cheers,John O'Hanlon Link to comment Share on other sites More sharing options...
Guest pbda Posted January 30, 2009 Report Share Posted January 30, 2009 This is an excellent discussion. My LSTs are with Carl at the moment having their crossovers modified as per KlausDK's mods and - ahem - having four blown tweeters replaced (my fault). As Warren Zevon sang: "I don't want to talk about it."Carl and I discussed at some length the pros and cons of replacement tweeters vs. originals, and I had similar conversations with Larry Lagace. The Hi-Vi tweeter sounded really promising, but in the end I was concerned about the loss of soundstaging, which to me is one of the LSTs particular strengths. In the end I decided to go with the original units, and was fortunate to find four of them to use. I may not be so lucky next time. Link to comment Share on other sites More sharing options...
Guest benz1954 Posted August 16, 2009 Report Share Posted August 16, 2009 MexicoMike! !Buenos Dias! Hey, I wondered about your name, and now I know: that's where you live. Where in Mexico? I too had problems getting packages to me. I've lived in Mexico (1960, 1986) where things were sometimes problematic. In Papua New Guinea, the most problematic for mail, eventually things did get to me--too long in getting to me but they did get to me without fail. Resorting to DHL (then with an out-office in the small city where I was working--Lae--at a state university), it was easy to move things in and out. So I mention this to suggest to you that UPS, FedEx or DHL would be -- as you mention -- not terrible cost effective, but highly dependable and -=- at least here in the US -=- with an automatic US$100 insurance deal wrapped up in the delivery. Based on my experience with the 3a, I'd say the extra cost will be forgotten in minutes after installation and tuning of pots. I'd be especially pleased to hear about your experience with the Hi-Vi Q1 R tweeters and...if you go for it...don't forget the inductor coils. Check with RoyC too; he is immensely helpful.Oh, and if it doesn't work out? Just send those LST dawgs to me What value inductors did you use with your HiVi tweeters? Link to comment Share on other sites More sharing options...
Tekker Posted December 5, 2009 Report Share Posted December 5, 2009 I'm fairly new to the discussion group. About a month or so ago I breezed through this thread trying to catch up, but Kent offered me the link for a reread. Wow, this is good stuff.I've recently found someone to wind new voice coils for my old AR3a tweeters, and I think they sound great. If any of you care to make use of his service, I'd be real interested to hear your opinions. He had an ad on Ebay for a short time going by chris1this1. He can be reached at reverbdmit@aol.com. He's an AR enthusiast himself who didn't want to go the replacement route.Bill. Link to comment Share on other sites More sharing options...
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