Fostex 127E phase plug install

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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.
 

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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
 
Svein_B said:
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.
 
Scottmoose said:
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.
 
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
 
The dust caps on the 126s and 127s must be very inviting. I didn't even have 5 hours on my speakers before my son's friend popped one in.

I poked a hole in the tip with a pin and pulled it back out with a piece of wire. Then I sealed the hole with glue. Now I really need to do the puzzlecoat mod and hid the discoloration.

pete
 
widman said:
The dust caps on the 126s and 127s must be very inviting. I didn't even have 5 hours on my speakers before my son's friend popped one in.

Kids just love to poke at speakers for some unknown reason. I've seen this happen to all kinds of drivers; even dome tweeters, which don't take kindly to such abuse. Some kind of protective covering is a must with small children around, or puppies.😉

Jeff
 
Originally posted by kazoo 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.

The new FE108eS plugs are actually the same as the prototypes for the FE127. The plug needs to be a bit longer than the stock 103/1197 plug.

I'm excited that you found success. I may try this again. I'm pretty gun-shy after loosing 4 out of 4, but -- even with the scraping from the black goop at high levels -- the plugs make an improvement. It was clearing up that last scrapping problem that lead to the death of our 127s. I'm glad their death has produced some positive results.

dave
 
kazoo said:
I tried to order some of the modified 127s from Dave ... but I did not get a response

That would only have been because the mail didn't get thru. It is a crime that SPAM & the resultant antiSPAM have made email an unreliable communication medium sometimes.

I have modded FE127 in stock & ready to ship. 126s might take a bit longer, i'm working thru the next batch.

dave
 
widman said:
The dust caps on the 126s and 127s must be very inviting. I didn't even have 5 hours on my speakers before my son's friend popped one in.

It's true with every speaker... Mine have also suffered sometimes.

But I think it's an educational problem. My daughters did touch them only once. After explaining 'em firmly why they shouldn't, they never did it again.

The general problem is with my friend child or my daughters friends... :bawling:

I found one solution : the tweeters are soft domes and I have phase plugs in the boomers 🙂 It only let some fingerprints on them when they touch it...

I poked a hole in the tip with a pin and pulled it back out with a piece of wire. Then I sealed the hole with glue. Now I really need to do the puzzlecoat mod and hid the discoloration.

Did you try a vaccum cleaner? It works very well on mine old speakers. You gently approach the bare tube closer and closer without touching the speaker until the cap comes back.
 
There are quite a few threads about popping out a crushed dust cap and I tried some of the suggestions. The dust cap on the FE126 is fairly stiff and wouldn't pull back out with either a vacuum or tape.

I agree on the education point. Both my kids understand that speakers are for listening, not touching.


pete
 
Re: audio sound difference?

gychang said:
opinions on the sound quality after the mod?

thanks,

gychang


Hi gychang,
At the time I did the dust cap removal, I had only about 150 hours of playing time on them. To my ears the phase plug smoothed out the higher frequencies. It made the speaker easier to listen to. They are in the BIBs right now and sounding pretty good.
 
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