Fostex 127E phase plug install

[kazoo]

Well I had one of the kids pinch the dust caps on one of the 127E BIBs so decided to cut out the dust cap and istall a phase plug. Here is a little write up to explain it if someone else needs to try it. I looked at Planet 10's site for the warnings and some ideas of what I was getting into. Also look at the diagram on his site of the speaker to see where the voice coil wires are and how they are routed. To let you know it was not too bad cutting the cap out, so here we go.

If you look at the front of the speaker you will notice the white glue that holds the voice coil wires to the cone. If you follow them at a slite angle towards the dust cap that is where the voice coil wires should be. I started cutting the top of the cap using a very sharp razor knife. I kept cutting at it until i reached the black glue line that holds the cap on. The only part I did not cut all the way down to the black glue line is where the voice coil wires are. I left a big chunk of the dust cap there so I would not cut the wires. Once you get to the point that there is hardly any dust cap left except for part of it by the voice coil wires you can pull the cap carefully off the speaker and it should let go easy. All you should have left behind is the hard paper tube that has the voice coil wire wrapped around it with alot of paper fuzz on it. Now what I did so I could see the wires is I started scrapping at the tube using the knife where I thought the wires were. If you do this gently in a little while you will see a copper wire start to shine through the paper and you will see the edge of it. Then do a little more clean up around the wires leaving little bumps where they are so they don't get cut. Now you are done. Put in the phase plug and see what they sound like. Attached are some pictures of the final results. I forgot to take pictures during the process but the final pictures will show where the voice coil wires are and what they will look like after you cut around them. If you have any questions let me know especially if I need to explain something more clearly and as always do this at your own risk.

[kazoo]

Picture 2

[kazoo]

picture 3

[kazoo]

picture 4

[Svein_B]

Nice (and brave) surgical procedure !

Did you use the Planet10 phase plugs for the FE103/108?

According to Planet10:

The void between the dustcap & the voicecoil former is filled with a black glue -- in all 4 cases some of this gets on the inside of the voice coil former as well. This overspill rubs against the phase plug so it's removal is necessary. ...

From your picture 2 above, i do not see any traces of glue on the inside of the voicecoil former. Was there no such problem on your drivers? - maybe it depends on production series?


SveinB

[Scottmoose]

Very interesting. You're a braver man than I am! Though... if we can solve this black glue business, I might try it on my 126s, which are already heavily modified by Dave, to the extent where they give Sigmas a fright.

[kazoo]

Originally posted by Svein_B
Nice (and brave) surgical procedure !

Did you use the Planet10 phase plugs for the FE103/108?


According to Planet10:


From your picture 2 above, i do not see any traces of glue on the inside of the voicecoil former. Was there no such problem on your drivers? - maybe it depends on production series?


SveinB

Hi Svein_B
No, I do a little wood working so I made my own phase plug but to Planet10's specification. In one of the post he mentioned how he measures them so they look the way they do. I bet that if you told him you need one for this speaker or a custom one he would create one for you. I hope I am not stepping on Daves toes with that comment.



When I did this I did not see any glue on the inside. It could be a certain run of speaker or maybe they redesigned them so it would not happen. One thing I did notice is that there should be no way glue gets inside the the tube that holds the voice coil wire. The reason I say that is becasue when I was cutting the cap off to the black glue line I was also cutting a little of the paper tube that holds the voice coil wire. If you notice the bumps on the pictures that is where the wire goes up and over the tube. So from that I guess I cut about an 1/8" off the tube. So unless they really got sloppy with the glue they would have to go over that lip and inside. But I did not see any glue on the inside. So I guess they must have fixed it.

[kazoo]

Originally posted by Scottmoose
Very interesting. You're a braver man than I am! Though... if we can solve this black glue business, I might try it on my 126s, which are already heavily modified by Dave, to the extent where they give Sigmas a fright.

Hi Scottmoose,
Like I mentioned in the post above I did not see any black glue inside the voice coil tube. I tried to order some of the modified 127s from Dave for the Fonken project but put them in the BIBs to break in until I made them. But I did not get a response so ordered the stock ones from somewhere else. Like I mentioned I had to do this because the cap was crushed and I could not stand looking at it. I bought these about 3 months ago so Fostex could have changed their production.

[Scottmoose]

Interesting. I'm surprised you didn't hear from Dave though -your email must've got lost somewhere along the line. My 126s are from a recent batch Dave ordered so it might well be possible with these too. I'll look into it.

[vinylkid58]

I'm going to try this with my 127's also. Our Sheba puppy decided to give the dust caps a little nibble. They are still intact but look awful. I'm also working on a pair of Fonkens; they are slightly different from the box plans on Dave's site.
Excellent job installing the phase plugs BTW, and thanks for the info.
Keep us posted on your Fonken progress.

Jeff