3.6R XO upgrade by EAR

I used to have magnepan smg3a for 8 years, I modified them from the begining and had a beautifull sound. Now I have magnepan 3.6 and I also modified them. This is a photo of my room with the 3,6 modified.

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I took the desision to modify the XO and the internal wiring as soon as I took a look at them. The original caps, inductors, internal wiring and binding posts are horrible.

For caps I use Ansar Supersound because they are cheap, good sounding (standard in PROAC) and can be ordered at any requested value up to 200mf of even more... I ordered a value 17,1mf and looking at it still makes me laugh!! For woofer inductors I use North Creek Music Coils 10 awg because they have a very low DCR and very thick wire of pure copper. Also made at the exact requested value!! For midrange and tweeter inductors I use Goertz CFAC 12 awg because of the extra sonic improovements of foil in frequecies > 200Hz. These were de-winded to the requested value. For internal wiring I use Goertz M1 13 awg because it is an easy to fit in mags cable, good sounding and cheap!! For resistors I use North Creek North Power resistor 10 watt because of their sonics and 100watt for 5 seconds capability. The resistor I am using is 1,82 Ohms. This is really a must, because by placing so much better caps (lower resistance) treble power is increased. Speaker cables do not exist, because each amp is right behind each speaker.

For comparison of the standard XO and North Creek - Ansars just take a look:

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The first step was to replace just the external XO for 1 reason: to burn up the shunt caps.

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The sonic improvement from this change is enormous in bass, but moderate in the rest. This is due to the remaing of the internal XO.

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The second step wat to build the external crossover box. All parts are placed in an external box handmade by 8mm black plexiglas. Dimentions are 43cm-35cm amd 16cm heigh. All parts are not placed on the bottom of the external XO box. Instead they rest on a vibration absorbing material which is hold by a double sided friction tape on a piece of plexiglas vertically glued at the bottom of the box. The glue used for plexiglas to plexiglas is chloroform. Then all materials are tied up with nylon cable ties. The rest of the internal XO box surface is covered with sound-vibration absorbing materials.

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To remove the internal wiring and XO I took off the second (rear) fabric from the 3.6:

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The next step was to connect the GOERTZ cable to the planar cables (bass and mid sections). The connection was made by removing the screw witch holds a piece of metal witch holds the wires of the panel, and by placing the Goertz cable under the metal and tighten it over the wires of the planar with the screw passing from a hole on the GOERTZ.

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Then I replaced the rear fabric and the ribbon and connected the ribbon ends with the goertz cable by the same way.

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Removing the screw wich holds the ribbon and placing the goertz cable in contact with the ribbon is a very delicate job, demands extreme caution!!! I believe that this is the best possible connection between internal wiring and ribbon-bass-mid wires because the goertz cable is pressed in contact with the wires.

The parts in the external XO box are not connected by solder, but with heavy duty dual screw electrical connectors. The XO box is screwed on the speaker. This is the XO at the final stage:

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By placing the cover over the external XO box, no wires are visible and the whole construction looks cool!!

I also ordered a copy of the original 3,6 woods but in a different color to match my furniture. The copy will be slighty different: there will be more space for the ribbon (wider by 2 cm) and I will place in each side a 1cm thick sound absorbing material to reduce the side reflection from the ribbon (which is noticable when removing the woods).

Sound improvements: responce: from what I cannot hear (~18k is the highest frequency my ears can sense) to 30 Hz FLATTTT...even at 20Hz all furniture in my room are vibrating... Overall the sound is so much better that I can not possibly describe it, you have to hear it, sorry folks!!!

Costas from sunny GREECE!!!!!!!!!!!!!!!!

email me for any questions and don't forget to visit my site to see my aquarium & my parrot