Opet McIntosh i opet PHILIPS. Ovaj put legendarni visokotonac T8 sa Mekovom maskom.
1" Dome Tweeter 036-068 This soft fabric dome tweeter is made by Philips and is similar to the round Philips AD 0141HE-T8 but is custom made for McIntosh. The rectangular shape is custom made for Mcintosh. This allows closer spacing of the tweeters then used in multiples for the column systems.
The black plastic front plate has a phasing disc in the center that smoothes the response, improves directionality and also protects the dome from being damaged. A recessed area near the bottom is for an aluminum silk-screened decal with the McIntosh name in gold lettering.
The soft dome, voice coil, tinsel leads and terminals are one subassembly called a "butterfly." The tinsel leads are brought out to terminals on either end of the subassembly. Some versions had solid wire instead of tinsel wire. A red mark can be seen on the upper left part of the assembly that indicates the positive terminal. The fabric of the dome and surround has a black colored coating to seal the interstices of the material. A second custom coating under the dome was made only for McIntosh. This completely damps out the fundamental resonance.
Two holes in the butterfly locate with pins on the magnet structure. These assemblies are interchangeable and a damaged butterfly assembly can be easily replaced by removing three screws from the front plate and adding the new one. The rainbow colors are from the plating process.
The magnet assembly is made of three parts. The back plate and pole piece is made from one piece of cold formed steel. The magnet is barrium ferrite. The front plate is stamped steel. The two locating pins and three screw holes can be seen in the picture. The center of the pole piece is recessed for an increased air volume behind the dome.
We sampled a version using Ferrofluid in the magnetic gap. This raised the resonant frequency and limited the useful low frequency response of the tweeter and that was not acceptable. Later, we found that the ferrofluid had dissolved the adhesive that held the voice coil to the dome assembly. The problem was said to have been corrected by Philips in later production.
Ferrofluid is a mixture of finely ground magnetic particles suspended in a viscous fluid. It is kept in place by the magnetic field in the gap. It is used to keep the voice coil temperature down and transfer the heat to the magnet structure. It was not used with this tweeter or any other tweeter until 1993, starting with the 036-095.
A McIntosh part number label is added to the tweeter after is has been tested. The tweeter is 3-11/16" X 3-1/8" and 1" deep. Weight is 262 grams or about 9.2 ounces. It is used in the XRT18 and XR290. This tweeter was no longer used for designs made after 1992.