Thumpelstiltskin Posted March 8, 2005 Share Posted March 8, 2005 I saw these on Ebay. It's a pair of K-77 tweeters that have an extra magnet. The guy says he hasn't measured them, but insists they sound better. Is it possible that an extra magnet could improve the K-77? Modified K-77 Quote Link to comment Share on other sites More sharing options...
djk Posted March 8, 2005 Share Posted March 8, 2005 The EV T350 is the big magnet job that goes for big $$$, this is the magnet from the ST350B. The bigger magnet gives both more high end and more efficency. Quote Link to comment Share on other sites More sharing options...
BEC Posted March 8, 2005 Share Posted March 8, 2005 I have built some of them. Bob Crites Quote Link to comment Share on other sites More sharing options...
Frzninvt Posted March 8, 2005 Share Posted March 8, 2005 You have showed me those before Bob, if you ever feel like building some I would probably be interested in 3 of them. One for my center and the others for my mains. I will keep an eye on Digjr's auction though. Quote Link to comment Share on other sites More sharing options...
ZAKO Posted March 8, 2005 Share Posted March 8, 2005 DJK....How does a larger magnet on the T35 give you higher end response. Show me. Publish some graphs. Quote Link to comment Share on other sites More sharing options...
Hardhead Posted March 8, 2005 Share Posted March 8, 2005 Take special notice of the phrase "Sale is final unless tweeters arrive dead." That tells me all I need to know about how they would sound. What does it tell you? Quote Link to comment Share on other sites More sharing options...
boom3 Posted March 8, 2005 Share Posted March 8, 2005 I can see higher efficiency, although the T-35/K-77 is already about at the top of that parameter. That would drive another crossover change to mate with the mid horn. I could see a bucking magnet to cancel the magnetic field to prevent CRT distortion. But unless he is changing the diaphram and/or phase plug, he is not going to get smoother, higher highs. Quote Link to comment Share on other sites More sharing options...
digjr Posted March 8, 2005 Share Posted March 8, 2005 Maybe it implied that if the buyer chose not to insure or someone didn't know what they were buying. Sometimes it better not to make assumptions until you have a chance to hear them first. This is one of those times. Quote Link to comment Share on other sites More sharing options...
D-MAN Posted March 8, 2005 Share Posted March 8, 2005 Bigger magnets (higher flux density) means more positive control of the diapragm and increased excursion per given input, so better performance and higher efficiency are natural outcomes all things being equal. The EV T350 is a fine tweeter. Its louder, goes higher and is more efficient. Dispersion pattern is also larger due to the large horn structure. The difference in sound was about twice the output in everyway (as I remember it) as the T-35, which the T350 replaced in my horns in the late 70's. DM Quote Link to comment Share on other sites More sharing options...
BEC Posted March 8, 2005 Share Posted March 8, 2005 ---------------- On 3/8/2005 9:28:49 AM Frzninvt wrote: You have showed me those before Bob, if you ever feel like building some I would probably be interested in 3 of them. One for my center and the others for my mains. I will keep an eye on Digjr's auction though. ---------------- Charles, I feel like building them, but the one part of that tweeter that I did not produce myself, has been in such short supply that I have only built a few complete units. I have all the other parts to build 100 of them. Bob Quote Link to comment Share on other sites More sharing options...
Hardhead Posted March 9, 2005 Share Posted March 9, 2005 Sometimes it's better not to make assumptions about what something sounds like until you've had a free listen. This is one of those times. My dog Maggie can "modify" a K-77 by squatting over it, but that doesn't mean it will sound better, unless, of course, anyone wants to take my word that "I am quite confident that this setup will impress all!" "Caveat emptor" is a very loose translation of what P.T. Barnum said. Quote Link to comment Share on other sites More sharing options...
Thumpelstiltskin Posted March 9, 2005 Author Share Posted March 9, 2005 ---------------- On 3/8/2005 1:35:17 PM digjr wrote: Maybe it implied that if the buyer chose not to insure or someone didn't know what they were buying. Sometimes it better not to make assumptions until you have a chance to hear them first. This is one of those times. ---------------- Hey digjr, Are you the one (digjr22) selling these tweeters on Ebay? Are they basically a T-350 magnet on a T-35? Quote Link to comment Share on other sites More sharing options...
djk Posted March 9, 2005 Share Posted March 9, 2005 "How does a larger magnet on the T35 give you higher end response. Show me. Publish some graphs." The ST350A had a big ring magnet. When they redesigned the T35 for Klipsch they had to make the 8oz square magnet so as to fit the space available. It may have just been an inventory choice to dump the big ring and go with the small square magnet and someone thought it looked too wimpy. I suppose it is possible that EV didn't have a clue when they put the larger magnets underneath all those different models. In a way you might be right, magnet size means nothing, its flux density in the gap that makes it work. Your real question should have been: does stacking a pair of magnets really increase the flux density? The answer is : no, not by much. But... They had to make a new longer pole piece to make it work, and that will make a much bigger difference. The high end in the EV tweeter varied so much I always had to wonder whether it was gap volume issues or mass variations? Quote Link to comment Share on other sites More sharing options...
digjr Posted March 9, 2005 Share Posted March 9, 2005 Boy, this one stirred the pot. First, I have nothing to gain by trying to bull**** anyone. Why would I disable a couple of good T35's and ST-350's unless I thought someone else might be as interested and satisfied as I am. The resulting leftover pair are single magnet ST-350's that have no sales value. It makes no sense to end relationships over something so minimal. My reserve is the same as any of the K77/T35's I listed and sold before so it's not like I'm trying to take advantadge of anyone. To Hardhead, man you are one bitter person! You added nothing of value, just insults and naysaying on a topic that you clearly have not investigated. If I had an extra tweeter I would send it to you so you could at least have a valid opinion. To Thumpelstiltskin, yes I am one and the same. Yes the magnet assemblies are from a pair of ST-350's, thank you for the question. THE END. Quote Link to comment Share on other sites More sharing options...
ZAKO Posted March 9, 2005 Share Posted March 9, 2005 DJK....Correct...But remember increasing flux may not only increase HF but if overdone will increase distortion. Instead of concentrating on magnet. It would be interesting if a better diaphram/voicecoil could be manufactured for the K77, T35, T350. Quote Link to comment Share on other sites More sharing options...
BEC Posted March 9, 2005 Share Posted March 9, 2005 Maron, What would you suggest for a diaphragm material? I have done some experimenting with the K-76 tweeter using a soft poly dome diaphagm, phenolic, and titanium. The phenolic and titanium are much better than poly, but there is very little difference between the phenolic and titanium diaphragms in that particular tweeter. I have been meaning to try titanium in a K-77 but was not particularly encouraged by the results in a K-76. Bob Quote Link to comment Share on other sites More sharing options...
boom3 Posted March 9, 2005 Share Posted March 9, 2005 I think the K-77 has been taken about as far as it will go. There is little to be gained in higher efficiency from greater flux density since we already have a system that is at the top of efficiency for home systems. Bob Crites testing of the various diaphrams is very valuable, especially for us out here in Aftermarket Land, but the gains made with K-77 are, to me, just not worth the effort. I think that reproducing the K-79 would be a better choice. I know that when I get a pair of K-horns my first mod will be to swap the K-77s for K-79s or a tweeter of equal merit. Quote Link to comment Share on other sites More sharing options...
Hardhead Posted March 9, 2005 Share Posted March 9, 2005 If trying to alert people to the dangers of buying "modified" merchandise on eBay is being bitter, then I'm proud to plead "Guilty as charged!", and when given the opportunity I will continue to advise people to keep their wits about them. In retrospect, I do think the analogy of Maggie peeing on a tweeter was a bit much, however, and I apologize for not making my point better. My point was that any amateur, bumbling or not, (even me or my dog) can modify something and not have the foggiest idea of what he's doing and think it's the greatest thing on God's green earth, whether or not it is. If the person who "modified" those tweeters were in any way qualified to modify them, I believe he would have stated his qualifications to do so in the eBay writeup. That would have been smart and good business practice. The fact of his not having any instruments to measure the change is a red flag--as is his refusal to stand behind the product. It's possible to take advantage of someone without having that intent; just being in something over one's head is enough. Quote Link to comment Share on other sites More sharing options...
Thumpelstiltskin Posted March 9, 2005 Author Share Posted March 9, 2005 Sorry dgrjr. I just wanted to know if your tweeters were something I "needed" for my Cornwalls and didn't mean to get all this trash started. You didn't make any unreasonable claims in your ad, so don't let anyone get to you with their rude comments. Good luck with your auction. Rick. Quote Link to comment Share on other sites More sharing options...
ZAKO Posted March 9, 2005 Share Posted March 9, 2005 "BEC....In order to best the K77/T35 The diaphram would have to be mutch lighter but stronger. The diaphram would be very very costly and no one on this forum would stand for that. A tweeter of that caliber costs $995. It to is a diffraction horn type like the T35. But we are talking about using most of the T35 body & just changing the vc/diaphram. I shudder to say....beryllium....That is beyond my experteze. (and yours) to manufacture cheaply. But the TAD ET703 is the one to partially copy. And morf into the T35. The "Be" is tough to manufacture. Tiannium is not easy either as you have found out. The idea to reduce mass & keep ridigity Is hard at the upper HF. Quote Link to comment Share on other sites More sharing options...
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