MarkF Posted March 25, 2005 Share Posted March 25, 2005 I am in the process of getting a pair of Electro Voice t-350's tweeters re diaphragmed by Electro Voice service center in Arkansas. I had them re diaphragmed by an authorized service center in Minneapolis and both voice coils rubbed and severely limited the frequency response. Apparently it is very difficult to align the diaphragms in T-350's. Once they are properly installed, I am hopeful they will add a significant difference to the 6k - 15kcps range. I expect to have to use an L-pad. For the mids I am using Altec 288-16K drivers and 805b horns. I have also used 1005 horns but lost a little imaging in the process. For the network, I am using ALK's network. I would be curious if anyone else has incorporated the T-350's and what their opinion is. Quote Link to comment Share on other sites More sharing options...
D-MAN Posted March 25, 2005 Share Posted March 25, 2005 I had them years ago on pair of Klones, and they certainly outperform the EV t-35 which I replaced with them. They cost $75 or $80 each back then. I liked 'em. DM Quote Link to comment Share on other sites More sharing options...
BEC Posted March 25, 2005 Share Posted March 25, 2005 ---------------- On 3/25/2005 12:36:38 PM MarkF wrote: I am in the process of getting a pair of Electro Voice t-350's tweeters re diaphragmed by Electro Voice service center in Arkansas. I had them re diaphragmed by an authorized service center in Minneapolis and both voice coils rubbed and severely limited the frequency response. Apparently it is very difficult to align the diaphragms in T-350's. Once they are properly installed, I am hopeful they will add a significant difference to the 6k - 15kcps range. I expect to have to use an L-pad. For the mids I am using Altec 288-16K drivers and 805b horns. I have also used 1005 horns but lost a little imaging in the process. For the network, I am using ALK's network. I would be curious if anyone else has incorporated the T-350's and what their opinion is. ---------------- The problem of the rub you describe sort of surprises me. On all the T-350s that I have done, it would be impossible to misalign the voice coils since they have a machined centering ring in the diaphragm mount. Also, if for some reason the ring or VC gap was off, nothing could be done about it. There, of course, could be some versions that were made differently than the ones I have rebuilt for customers. Sounds to me more like the voice coils were mishandled before installation. Bob Crites Quote Link to comment Share on other sites More sharing options...
J.4knee Posted March 26, 2005 Share Posted March 26, 2005 I would like to add the T350's to my La Scalas to extend the high freq response. I believe they about 5 db more efficient and require adding an Lpad or similar remedy to match them to a stock La Scala/Belle or K-Horn. Quote Link to comment Share on other sites More sharing options...
djk Posted March 26, 2005 Share Posted March 26, 2005 "On all the T-350s that I have done, it would be impossible to misalign the voice coils since they have a machined centering ring in the diaphragm mount" None of the early EV tweeters are built this way, and the replacement diaphragms must be hand centered while playing noise. Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted March 26, 2005 Share Posted March 26, 2005 I was taught by a local PA technician to play a 1 kHz tone through any speaker as I was tightening the bolts surrounding the magnet assembly. This helps center the voice coil in the gap and insures longer life. DIY'ers who do not follow this procedure will probably experience less than optimum response/life from their replacement diaphrams. Michael Quote Link to comment Share on other sites More sharing options...
BEC Posted March 26, 2005 Share Posted March 26, 2005 ---------------- On 3/26/2005 3:41:57 AM djk wrote: "On all the T-350s that I have done, it would be impossible to misalign the voice coils since they have a machined centering ring in the diaphragm mount" None of the early EV tweeters are built this way, and the replacement diaphragms must be hand centered while playing noise. ---------------- Early would be some time in the 60's. If the T-350's were made that early, they like the early T-35's would have had the diaphragm "sandwich" which centered the diaphragm using the holes in the gasket. Those are a real PITA to replace now since the gasket pack with diaphragm is no longer made. You have to separate out the old diaphragm from the two gaskets and glue another diaphragm in place reusing the old thick paper gaskets. Dennis, Could you explain how those old diaphragms in the tweeters could be centered with noise. Even if one had the proper part, that is the diaphragm pre-glued in the gaskets, there is no play at all in the holes where the screws go through the gasket. I repair a lot of them, but for me it is always "trial and error". I would love to work out a consistent method for those things. Bob Quote Link to comment Share on other sites More sharing options...
MarkF Posted March 26, 2005 Author Share Posted March 26, 2005 The T-350's I have have the two gaskets and teh diaphragm is sandwiched in between. I have been told by the EV service center they have some type of jig to align them. They say they have one person who is the expert at doing this. Quote Link to comment Share on other sites More sharing options...
djk Posted March 27, 2005 Share Posted March 27, 2005 Are the old style ones with the paper gaskets even available still? I would buy them if they were. The last one I did I used the new style one and just ran a warble tone through it, shut the tone off, held the diaphragm down with my fingers, ran the tone up and checked it, repeated as needed, and then tacked the diaphragm down (avoid gluing your fingers too), threw the second gasket in, and bolted it together. If I had to do it on any kind of a regular basis I would make a jig, make a shim like the newer Altec drivers use, glue it up, wait 'till dry, remove shim, re-assemble. Quote Link to comment Share on other sites More sharing options...
BEC Posted March 27, 2005 Share Posted March 27, 2005 Dennis, The old style diaphragm pack inside the cardboard gaskets is not available. The diapragm is still available (8 and 16 ohm) but not the gaskets. If there were a bit more demand to justify the cost, I would have the gaskets made (about $500.00 for the dies) and build a jig to make up the diaphragm packs in advance. I am pretty sure that EV (Now Telex) could build them again if they wanted to here at their plant at Morrilton, AR. In fact, I think from talking to the manager there, they could build anything they have ever built. Just that they want assurance of economic success up front. For instance, he told me he would build T-35As for me if I would commit to purchase of a very large number of them. Bob Quote Link to comment Share on other sites More sharing options...
djk Posted March 27, 2005 Share Posted March 27, 2005 "I would have the gaskets made (about $500.00 for the dies) and build a jig to make up the diaphragm packs in advance" This may be a good job for a laser, only a $30 set-up fee. Quote Link to comment Share on other sites More sharing options...
MarkF Posted December 1, 2005 Author Share Posted December 1, 2005 Bob, I had new diaphragms installed by Electro Voice in AR and one was apparently jostled in transit and the DCR is way high compared to the other, so one is likely misalligned. If I sent them to you could you align them? If so, what would the cost be? These T-350 are in excellent condition and I would love to use them in an extra pair of LaScalla's I have. After waiting for several months I installed the JBL 2404h tweeters in my Khorns. Mark Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted December 1, 2005 Share Posted December 1, 2005 anyone ever try the ST 350 B's ...?? Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted December 2, 2005 Share Posted December 2, 2005 Bob, Aren't the T-35A a smaller magnet version of the T-35? same diaphragm same sound but less efficient? I bought a pair of them accidentally when I first got into this stuff, the magnets were obviously smaller than the regular t-35 or K-77. I asked some guys who were into this stuff, they convinced me that nobody could tell the difference between the T-35, T-35A and T-350 as long as the volumes were equalized. I decided that there wasn't much point in increasing efficiency when we were already cutting the volume with devices in the network. What do you think? Quote Link to comment Share on other sites More sharing options...
BEC Posted December 2, 2005 Share Posted December 2, 2005 Tom. All the variations of the T-35 and T-350 do use the same diaphragm although some of the very old ones use a 16 ohm version of the diaphragm. The T-35s with the magnet smaller than the one in the alnico K-77 are not very well though of, but I haven't really tested one of those. The ST-350 and T-350A and the T-350 also use the same diaphragm. The only one of all these that really stands out as being better is the old alnico T-350 with the really massive magnet. I hope in another month or so, I can provide a replacement for the T-35 and K-77 that is clearly better. Bob Crites Quote Link to comment Share on other sites More sharing options...
Frzninvt Posted December 2, 2005 Share Posted December 2, 2005 I was told that the T-350 does not extend higher in range than the T-35 but it was more efficient, not a lot to gain here I think. If you want better tweeters I would get JBL's or Beyma's instead. Quote Link to comment Share on other sites More sharing options...
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