EPI 100 restoration project

[DaveStra]

Hello Everyone. I am beginning my winter project of restoring a pair of EPI 100 speakers that I bought at Goodwill this summer. I have never done any speaker work before so I will be coming to the many experts here for advice throughout my project. I have some pictures below showing what the first speaker looks like in it’s present condition. I am going to start out by ordering a refoam kit for the woofers.
My first question is, are the tweeters ferro fluid cooled? If so, should I clean and change out the ferro fluid? And also if so, how do I best go about this?
Thanks ahead of time for any and all advice!

 

[kfa888]

Refoam the woofers. Glue the magnets on the tweeters as they dry and come loose and kill it. Then assess the sound. If the tweeters sound low you might need to work them a little. We'll explain when you get there :>) Recapping is Easy and might be worth it. Make sure the cabs are sealed tight. Those should sound really good when done.

 

[mythless]

I think these are the ferrofluid ones, don't need to change them out if they work alright.

New caps, maybe binding post, new woofer foam and new gaskets are all you need to make them sing.

 

[DaveStra]

Refoam the woofers. Glue the magnets on the tweeters as they dry and come loose and kill it. Then assess the sound. If the tweeters sound low you might need to work them a little. We'll explain when you get there :>) Recapping is Easy and might be worth it. Make sure the cabs are sealed tight. Those should sound really good when done.

Thanks for the reply. Where should I apply the glue on the magnets - in the same place as the brownish red glue currently there as shown in the photo? Also, what kind of glue should I use?

 

[DaveStra]

I think these are the ferrofluid ones, don't need to change them out if they work alright.

New caps, maybe binding post, new woofer foam and new gaskets are all you need to make them sing.

I ordered the foam kit today. Should get here some time this week.

 

[Pete B]

https://audiokarma.org/forums/index.php?threads/epi-100-restoration.874537/

 

[mythless]

Thanks for the reply. Where should I apply the glue on the magnets - in the same place as the brownish red glue currently there as shown in the photo? Also, what kind of glue should I use?

I used regular white glue, 2 coats. just apply between/around the magnet and plate.

 

[Caryw]

Ordered my replacement woofers today. The tweeters still sound as sweet as the did in the 80’s!

 

[DaveStra]

https://audiokarma.org/forums/index.php?threads/epi-100-restoration.874537/

Thanks for the link. Good info!

 

[RTally]

Thanks for the reply. Where should I apply the glue on the magnets - in the same place as the brownish red glue currently there as shown in the photo? Also, what kind of glue should I use?

Apply epoxy around where the magnet (black square object in middle of sandwiched plates) meets the two opposing plates. The magnet was originally glued on both sides to the plates. As the glue weakens over time, the magnet/plate connection looses and the magnet shifts. I use epoxy applied in several strips around the magnet.

I used regular white glue, 2 coats. just apply between/around the magnet and plate.

White glue, or PVA glue, is not the best to use. It does not have sufficient shear strength to prevent the magnet from moving relative to the keeper plates. I prefer to use JB Weld epoxy. One inch long strips between the magnet and the plate should be sufficient. Eight strips, two on each side of the square magnet where it attaches to the inner and outer plates.

 

[Guido57]

I'll second mythless on the caps and RTally on the glue. The white glue is, however, the favorite of many for the surrounds. Some kits come with white glue. Some (SimplySpeakers comes to mind) include a faster drying solvent based glue that can be hard to work with (sets very quickly) in many applications, particularly for the inexperienced, IMHO.

 

[DaveStra]

Apply epoxy around where the magnet (black square object in middle of sandwiched plates) meets the two opposing plates. The magnet was originally glued on both sides to the plates. As the glue weakens over time, the magnet/plate connection looses and the magnet shifts. I use epoxy applied in several strips around the magnet.



White glue, or PVA glue, is not the best to use. It does not have sufficient shear strength to prevent the magnet from moving relative to the keeper plates. I prefer to use JB Weld epoxy. One inch long strips between the magnet and the plate should be sufficient. Eight strips, two on each side of the square magnet where it attaches to the inner and outer plates.

Thank you for the detailed description of where to apply the glue. Now I can picture exactly where and how to apply it. I’ll pick up some JB Weld this weekend.

 

[BilboBaggins]

The JB Weld should work great! You've made a good choice for your first speaker restoration project. These are not complicated, and the reward of completing them is quite high. I have a pair of EPI M100s that I restored.

 

[tiga]

Great speaker to restore. Not too difficult and will have something great when done. Here is my M100 restore thread. My EPI 100M Restoration | Audiokarma Home Audio Stereo Discussion Forums

As soon as I get some time I'm going to bypass the pots on mine.

 

[DaveStra]

R

Thank you for the detailed description of where to apply the glue. Now I can picture exactly where and how to apply it. I’ll pick up some JB Weld this weekend.

RTally - is there any value in gluing the magnets on the woofers in the same way as is recommended gluing the tweeters?

 

[DaveStra]

Great speaker to restore. Not too difficult and will have something great when done. Here is my M100 restore thread. My EPI 100M Restoration | Audiokarma Home Audio Stereo Discussion Forums

As soon as I get some time I'm going to bypass the pots on mine.

Thanks for the link. I will go through it later today when I get a chance. The hard part for me is going to be replacing the capacitors. I’ve never done any fine soldering on electronic parts before. But I’ve done a lot of research and I’m sure I can do it.
Fortunately, my Epis don’t have the pots on them so that is something I don’t have to deal with.

 

[RTally]

R

RTally - is there any value in gluing the magnets on the woofers in the same way as is recommended gluing the tweeters?

It is the woofer magnets that really need to be epoxied. They are much more susceptible to breaking loose because they are heavier than the tweeter magnets.

It would be good to epoxy each driver (woofer and tweeter) though. It does not require that much more effort and it is cheap insurance.

 

[kfa888]

I used JB weld putty. kneed it into a small rope and run it around the meeting joint. Super strong stuff.

 

[nniemiec]

100% have to replace the original binding posts with something more substantial.

 

[Guido57]

^ Like he said.