babadono Posted February 28, 2018 Share Posted February 28, 2018 Anybody got technical data on these drivers like a freq response and impedance curve? Quote Link to comment Share on other sites More sharing options...
Chris A Posted February 28, 2018 Share Posted February 28, 2018 Here is a measured impedance phase and magnitude curve for the TD-4002 on a K-402 horn: Here is a corrected frequency response on a K-402: Chris 1 Quote Link to comment Share on other sites More sharing options...
babadono Posted February 28, 2018 Author Share Posted February 28, 2018 Chris, How'd I know it'd be you with this info? So at the frequencies this driver is used on 2 way Jubilees no impedance below about 10 to 11 ohms. Thanks much. Quote Link to comment Share on other sites More sharing options...
babadono Posted March 14, 2018 Author Share Posted March 14, 2018 @Chris A What about a simple DC measurement? Mine are reading a little under 8 ohms. My concern is maybe the diaphragms got replaced with a non beryllium type and i got taken when i bought these used drivers. Is there a way to know for sure? Quote Link to comment Share on other sites More sharing options...
Chris A Posted March 14, 2018 Share Posted March 14, 2018 You could take it apart and look at the diaphragm itself, looking for any identifying marks. Other than that, you're probably going to need to take a frequency sweep or impedance sweep. Chris Quote Link to comment Share on other sites More sharing options...
Schu Posted March 14, 2018 Share Posted March 14, 2018 Physical inspection... Quote Link to comment Share on other sites More sharing options...
mark1101 Posted March 14, 2018 Share Posted March 14, 2018 I took mine apart to verify. Pretty easy and the beryllium is obvious.. Quote Link to comment Share on other sites More sharing options...
babadono Posted March 14, 2018 Author Share Posted March 14, 2018 1 hour ago, mark1101 said: the beryllium is obvious.. How so? Please educate me. Quote Link to comment Share on other sites More sharing options...
mark1101 Posted March 14, 2018 Share Posted March 14, 2018 Basically, you just need to do some quick research to see what a TAD beryllium diaphragm and the alternative aluminum (usually Radian) looks like. You can find these pics all over the place. Then just take the cover of the driver off and peak inside. They look completely different and there will be no mistake. Quote Link to comment Share on other sites More sharing options...
mark1101 Posted March 14, 2018 Share Posted March 14, 2018 Here is a beryllium.........with a dent! Quote Link to comment Share on other sites More sharing options...
mark1101 Posted March 14, 2018 Share Posted March 14, 2018 Here are Radian aluminum. Quote Link to comment Share on other sites More sharing options...
babadono Posted March 14, 2018 Author Share Posted March 14, 2018 Ok so beryllium is a dark smokey gray color and aluminum is well ....aluminum color? Thanks mark1101 I remember working with hybrid integrated circuits back in the day at Hughes Aircraft that were built on beryllium substrates and that stuff was white as freshly fallen snow. Quote Link to comment Share on other sites More sharing options...
mark1101 Posted March 14, 2018 Share Posted March 14, 2018 Yes the beryllium is much darker. Hope you have the good ones. Quote Link to comment Share on other sites More sharing options...
Coytee Posted March 14, 2018 Share Posted March 14, 2018 Do they make a BE that does NOT have the screen covering it? In other words.... if it has the perforated screen cover, it's BE and if it doesn't, it's not. Is that an accurate statement? Quote Link to comment Share on other sites More sharing options...
mark1101 Posted March 14, 2018 Share Posted March 14, 2018 I never took mine apart any further (cover only) but I am guessing that is a protective screen for whatever diaphragm you use. I could be wrong. Quote Link to comment Share on other sites More sharing options...
babadono Posted March 14, 2018 Author Share Posted March 14, 2018 I only had the cover off of one of mine once back when i got them from TrueHeartSound on e bay. I should have taken pictures. Now that I'm finally going to put them in something I guess I'll take another peek. What I do remember is the cheesey soldering from the binding posts to the diaphragm that made me think they have been worked on/replaced. Could TAD have done such a ugly job on a driver they ask $3k for? Not looking for an answer to that question, just sayin'. Quote Link to comment Share on other sites More sharing options...
pzannucci Posted March 16, 2018 Share Posted March 16, 2018 Just remember to be careful with beryllium. Hopefully no issues with dust or anything once molded into a diaphragm. . Quote Link to comment Share on other sites More sharing options...
Coytee Posted March 16, 2018 Share Posted March 16, 2018 On 3/14/2018 at 4:26 PM, mark1101 said: but I am guessing that is a protective screen for whatever diaphragm you use Though I've never removed mine but I once saw (on Ebay) an OEM replacement..... looks to me like the honeycomb cover is actually part of the diaphragm assembly. (I did once take the front off to see the diaphragm, I just didn't remove the diaphragm assembly itself) 1 Quote Link to comment Share on other sites More sharing options...
Dave A Posted March 16, 2018 Share Posted March 16, 2018 2 hours ago, pzannucci said: Just remember to be careful with beryllium. Hopefully no issues with dust or anything once molded into a diaphragm. . Yes and I wondered if this is why the perforated metal cover. Some time back I did a job for UAH in Huntsville Al. A past project came up and the guy was talking about a machining job involving Beryllium. The job paid extra for the known hazards and apparently the warning to the wise went unheeded. ALL the machinists later died of cancer and Beryllium is a known severe carcinogen. There will never be any Beryllium diaphragms in this household. Quote Link to comment Share on other sites More sharing options...
mark1101 Posted March 16, 2018 Share Posted March 16, 2018 Coytee, I think you are right. Quote Link to comment Share on other sites More sharing options...
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