How to convert DT 880 into DT 990 (and vice versa). DT 770 Info.
Apr 8, 2009 at 7:20 PM Post #61 of 63
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Originally Posted by leeperry /img/forum/go_quote.gif
haha, they say AVS is "the place to become unhappy"....how about head-fi
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OK thanks for the picture, I recabled my 770 so no worries
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but I mean you can do it on the phones unplugged, or you have to play music through them and plug the multimeter on the drivers connectors?

did you have a HUGE diff between the 2
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mono sounds pretty centered here...well the 2 drivers don't have the exact same FR of course.



Unplugged, set multimeter to resistance measurement mode, attach black lead to the sleeve and red to the tip or the ring for the left, right channel. The diff was pretty steep, 30Ohms, smaller variations are normal, I assume.
 
Apr 8, 2009 at 8:05 PM Post #62 of 63
haha, I've learned something today, thanks!
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well they both read 626Ω(the manual gives a ±(1%+3) error margin), I should be fine....as I eagerly hoped
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I guess that's what they mean when they talk about "matched drivers", not FR but impedance-wise.
 
Jul 13, 2010 at 3:57 PM Post #63 of 63
TO revive an old thread I need an answer so I can get my beloved DT880s working once more.
 
http://i38.tinypic.com/28v9ijr.jpg
 
The white webbing around the driver, the black plastic housing/web that has the white acoustic felt on either side, I punctured two of the webbing holes all the way through, so a torn hole now exists. I attempted to fix it with careful use of very diluted elmer's glue, like almos water, and tried to hold the torn pieces in place. Once set and installed, they sound terrible. The balance is all messed up, and in taking apart the OTHER can, I damaged the OTHER black webbing with the acoustic white felt cover on nearside/farside in one area, but have attempted to "fix" anything again.
 
I desperately need to know where to get these parts. Two driver housings/black webbing with white acoustic felt on either side, that holds the driver element in place, and acts as the "baffle" when everything is snapped together. I have no idea how to order just those parts, but until I can, my 880s sound utterl horrible. That webbing and felt is in in 770-990, new and old, so it is certainly a common part. I have the new styled 880s, but an old set of 990s has the same black webing and white acoustic felt on either side, and my 770/80s do as well. I know this semi acoustically transparent "baffle" controls freq. response as much as anything else that is directly involved with the driver element. This part, though, seems to be the same in all 3 models, with the differences being drivers and what is done after the drivers are secure in these housings. (the black plastic web with white acoustic felt on either side.)
 
It is like paper and tears very easily, as well, it is obviously an extremely important part of the design, for there to be even airflow in and out of the cups from around the driver, probably tuned as well. I only need two of them. I do not need the actual driver elements that sit in them, nor any black felt that goes over the driver front. The black platic webbing that acts as the driver element mounting/holding piece, that has white paper-like felt on either side (sandwitching the black plastic web/driver mount). I need those with fresh white felt intact, so I can move the drives from the ones I messed up by puncturing the white stuff, (I figure it is cheaper to get the whole webbing/mount, than anything that could "repair" the white acoustic felty-paper), to fresh ones, and I can then install them and get back to enjoying my 880s. Until that white felt-paper is properly in-place, the design, I think, is going to suffer, as I am sure this semi-acoustically transparent material that surrounds the driver, acts as an air-flow gate from inside the cups, needs to be intact for them to sound correct. They are so out of balance now, I cannot use them.
 
Any help would be truly appreciated. I want to get my 880s back :frowning2: I have removed the snap rings on 990s, 770s, and was alright, I had bad luck slipping three times, two on one side and one on the other, fixing as best as I know how obviously is not good enough)
 

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