Restoman Posted November 22, 2010 Share Posted November 22, 2010 Focusing on the EV T25A compound diffraction driver 16 ohm. One side was blown and one side is still good. See pics of diaphragm removed. I have no choice but to replace it with EV part No. 89521A which is the same dimensions but 8 ohm impedance. I will need to repair the blown one and then compare it to how the other original mid horn sounds with the original driver. Note---you must save the original diaphragm gasket so you can use it as a template to fabricate another one. My originals still had "May 1955" stamped on them. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted November 22, 2010 Share Posted November 22, 2010 The way the lead wires come off the voice coil at an angle implies it's the wrong diaphragm. I once got a group of solder-post K55V drivers that were buzzing. The leads came off at an angle like that. It turned out that they had K55M diaphragms in them! The lead of the correct diaphragms came straight off at a right angle. The picture shows the correct diaphragm but an open connection at the voice coil on this particular one. Al K. Quote Link to comment Share on other sites More sharing options...
Restoman Posted November 25, 2010 Author Share Posted November 25, 2010 I think you are correct---it does not look correct to have the leads coming off at an angle. What is interesting is the other side is the same and based on my DC resistance measurements it is the correct 16 ohm impedance. I have the Electrovoice T25A drivers but they also used the T10A which looks exactly the same except for power rating: 30 Watts versus 25 Watts respectively. With such a small difference I don't know why they even bothered to have the 2 models of drivers. What is even more interesting is that my drivers have the threaded snout on both the rear and the front for mounting on the big 848HF fiberglass re-entrant horn. The older T10A and T25A drivers did not have the 1 3/8 X 18 threaded snout on the rear and they were mounted on std horns at the rear of the horn. I have a pic of the horn with the driver and small forward horn Quote Link to comment Share on other sites More sharing options...
Restoman Posted November 25, 2010 Author Share Posted November 25, 2010 View of the EV15WK driver being cleaned up and fixing the double gasket on the basket. When you remove these from the K-horn bass bin you better eat your wheaties------Magnet is 37 lbs. and it is very hard to squeeze it in and out of the mounting position. Quote Link to comment Share on other sites More sharing options...
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