EPI 120B

[Motnick]

I recently picked up a set of EPI speakers which I believe to be model EPI 120b. They seem very similar to the EPI M100, but with a 10" woofer and slightly larger cabinet.

I have noticed that these speakers are not as loud as my Polk Audio S8 speakers at any given volume. One set on channel A, and the other on channel B. This is not an issue, but made me wonder if these speakers are not efficient enough for the receivers that I have? So far I have used them with a Technics SA-200 (25w), and a Sankyo SRC-4040 (40w). I bought these thinking that they would be a nice match with my Pioneer SX-737 which I have been working on restoring, but I am worried that these may be a bit too much for that receiver as well.

The seller claimed that the woofers had been recently refoamed, but that they had not been recapped. I was thinking of replacing the caps and also updating the speaker wire jacks to something better. Maybe this will help, or are the S8's the better match for the receivers that I have currently?

Lastly, these have a pot for adjusting the tweeter which seems to function fine, but I have read some threads suggesting that these should be removed. Is this something that I should do while recapping?

 

[lokerola]

I'm no expert on matching speakers to amps, but I recently refreshed my set of M100's and they sound great paired with my new Yamaha A-S801 (100watts x2). I bought replacement backplates and tweeters from humanspeakers.com. The new backplates came with banana plug connections, new wires, and new caps. You should browse a bit over on the HS site.

Here's my refresh thread. I didn't have the adjustable tweeter pot, so I can't advise you there. I can tell you that doing all the following made the speakers sing:
1. Brace installed in between the woofer and tweeter
2. Polyfill to replace the fiberglass
3. New tweeters
4. New backplates with new caps, wiring, and plugs
5. New speaker gaskets

http://audiokarma.org/forums/index.php?threads/help-with-possible-epi-m100-tweeers.779360/

 

[classic carl]

Huw at Human Speakers recommends that the tweeter pot be bypassed. I removed them from my EPI 200C and EPI 180 cabinets during recapping.

The receivers you have should drive the EPIs just fine. They like more power, but are rated at 25 to 80 RMS.

 

[Boto]

Huw at Human Speakers recommends that the tweeter pot be bypassed. I removed them from my EPI 200C and EPI 180 cabinets during recapping.

The receivers you have should drive the EPIs just fine. They like more power, but are rated at 25 to 80 RMS.

I have a pair of A240's and did something similar. They have a 3 position switch and resistors to attenuate the tweeter. When I rebuilt them I completely eliminated that part of the crossover and just run them wide open.

 

[Motnick]

Thanks for the feedback guys! I think I will go ahead and recap these EPI's then and see what happens. They sound pretty good as is, but from reading other threads here on the forum it looks like the recapping will benefit these a bunch. Once the SX-737 is all done, I'm about half way through it now, I will know for sure how these speakers will match up.

It looks like the Dayton poly caps (10uF/250V) from Parts Express is the best bet, and are what most others are using to perform their EPI recaps?

I think I will bypass the tweeter pots also as I won't use them anyhow.

 

[Boto]

Thanks for the feedback guys! I think I will go ahead and recap these EPI's then and see what happens. They sound pretty good as is, but from reading other threads here on the forum it looks like the recapping will benefit these a bunch. Once the SX-737 is all done, I'm about half way through it now, I will know for sure how these speakers will match up.

It looks like the Dayton poly caps (10uF/250V) from Parts Express is the best bet, and are what most others are using to perform their EPI recaps?

I think I will bypass the tweeter pots also as I won't use them anyhow.

I've used the Dayton 1% caps in the couple of EPI and Genesis speakers that I worked on. They are reasonably priced and sound great. I also used some Solen's in a pair of ESS speakers that I rebuilt. I was very happy with those also.

 

[Motnick]

I think I'll pull the woofers out and see what I find inside. Then put together an order with Parts Express. I'll let you guys know how it turns out. Thanks!

 

[classic carl]

I think I'll pull the woofers out and see what I find inside. Then put together an order with Parts Express. I'll let you guys know how it turns out. Thanks!

I always recap one speaker first and then A/B them to compare the old and new caps before recapping the second xover.

 

[ra.ra]

I always recap one speaker first and then A/B them to compare the old and new caps before recapping the second xover.

That's never a bad idea, but I'm just curious..... after the A/B comparison, have you ever gone back and removed the new cap and re-installed the original because the "new" was not a noticeable improvement?

 

[classic carl]

That's never a bad idea, but I'm just curious..... after the A/B comparison, have you ever gone back and removed the new cap and re-installed the original because the "new" was not a noticeable improvement?

No. If I don't hear a noticeable difference from rock, I play some jazz and the change is not subtle. The sound from a trumpet or sax really make the biggest diference. It's like a veil was removed from the speaker

 

[Motnick]

All of the parts that I had ordered to rework these speakers arrived a few days ago, and I had some time to open up the first speaker today. I'm following the advice to recap one speaker at a time in order to be able to see the difference before and after.

Here is the crossover that I found inside.

The woofer.

The tweeter had some corrosion on the connections. I was able to clean it off with some deoxit and a rag. 10/19/76 is written on top of the tweeter magnet.

I put the old cap into my HF test meter. I hope this doesn't mean that I'm wasting my time here?

I decided that although I wanted to remove the tweeter pot from the circuit, I still wanted the speakers to look untouched from the outside. I also didn't want to get rid the of old crossover board since it has all of the epi stuff printed on it. So I rotated the pot so that the connections would be out of the way and left the pot in place on the board. I followed the circuit diagram on the HS website for speakers without a tweeter pot. This moved the cap from the Neg. side of the circuit to the Pos. side. Does it matter which side of the circuit that the cap is on?

The only noticeable difference from the outside of the speakers is that I changed out the speaker wire connector, but I think it will be a worthwhile improvement.

The cabinets were stuffed with insulation completely. Luckily it's two big pieces that were easy to remove. I should be able to get them back in without issue.

These cabinets already have a brace between the front and back of the cabinet. So I shouldn't need to do anything there. It's right between the woofer and tweeter.

The tweeter screws were stripped out so I ran to the hardware store and bought some 6/32 machine screws, fender washers, and nylon lock nuts to hold the tweeter into the cabinet instead of the wood screws. It's a little tougher to get the tweeter in and out now, but it's not too bad with the woofer removed.

I noticed that the tweeter has a foam gasket seal, but the woofer seemed to be sealed in place with plumbers putty. Any suggestions on how to properly seal the woofer to the cabinet? Shouldn't the woofer have a foam gasket as well?

 

[lokerola]

All of the parts that I had ordered to rework these speakers arrived a few days ago, and I had some time to open up the first speaker today. I'm following the advice to recap one speaker at a time in order to be able to see the difference before and after.

Here is the crossover that I found inside.

The woofer.

The tweeter had some corrosion on the connections. I was able to clean it off with some deoxit and a rag. 10/19/76 is written on top of the tweeter magnet.

I put the old cap into my HF test meter. Hope this doesn't mean I'm wasting my time here?

I decided that although I wanted to remove the tweeter pot from the circuit, I still wanted the speakers to look untouched from the outside. I also didn't want to get rid the of old crossover board since it has all of the epi stuff printed on it. So I rotated the pot so that the connections would be out of the way and left the pot in place on the board. I followed the circuit diagram on the HS website for speakers without a tweeter pot. This moved the cap from the Neg. side of the circuit to the Pos. side. Does it matter which side of the circuit that the cap is on?

The only noticeable difference from the outside of the speakers is that I changed out the speaker wire connector, but I think it will be a worthwhile improvement.

The cabinets were stuffed with insulation completely. Luckily it's two big pieces that were easy to remove. I should be able to get them back in without issue.

These cabinets already have a brace between the front and back of the cabinet. So I shouldn't need to do anything here. It's right between the woofer and tweeter.

The tweeter screws were stripped out so I ran to the hardware store and bought some 6/32 machine screws, fender washers, and nylon lock nuts to hold the tweeter into the cabinet instead of the wood screws. It's a little tougher to get the tweeter in and out now, but it's not too bad with the woofer removed.

I noticed that the tweeter has a foam gasket seal, but the woofer seemed to be sealed in place with plumbers putty. Any suggestions on how to properly seal the woofer to the cabinet? Should the woofer have a foam gasket as well?

Sweet, you're making some good progress! I am no expert at restorations, but my understanding is that both the woofer and tweeter are supposed to be sealed. I bought some compression-type foam gasket sealer at Lowes and sealed up all my speakers with it. If the putty still seals I think you could use that too. As long as they're all sealed up.

 

[Motnick]

I got the first speaker all back together this morning. I just need to find a good way to seal the woofer back to the cabinet.

What I noticed straight away is that all of the vocals seem to be coming from the recapped speaker. It's almost like I'm listening to the stereo with the balance shifted toward the recapped speaker.

I wasn't sure that I would be able to notice such a dramatic difference, but I am pleasantly surprised! This was well worth the effort. I think I'll give them a listen for awhile more like this before I recap the second speaker.

 

[Motnick]

I also got curious about all of the audiolight price tag style stickers all over the woofer. They didn't look old enough to have been there since 1976. A quick google search of audiolight shows a speaker shop on Grand River in Detroit.

I had assumed that the person I purchased these speakers from had refoamed these woofers himself, but it looks like he must have had the audiolight shop do them for him.

 

[classic carl]

All of the EPI woofers that I've done had foam gaskets on them. Plumbers putty will work also, but you can buy foam gasket material and cut to fit.

 

[Motnick]

All of the EPI woofers that I've done had foam gaskets on them. Plumbers putty will work also, but you can buy foam gasket material and cut to fit.

Are the foam gaskets available for purchase somewhere? I didn't find them on the Parts Express website.

 

[lokerola]

Are the foam gaskets available for purchase somewhere? I didn't find them on the Parts Express website.

Yea, I noticed the same thing. I thought there would be lots more options for speaker gaskets, but there aren't (that I found). I ended up perusing the hardware store and bought a few different gaskets and used the one I thought gave the best seal. I "McGyvered" it for sure; I probably could have found custom speaker foam cut at just the right diameter, but the speakers are sealed and it only cost me about $5.00 to do it.

 

[Boto]

Are the foam gaskets available for purchase somewhere? I didn't find them on the Parts Express website.

Parts express sells material to make your own:

https://www.parts-express.com/parts-express-speaker-gasketing-tape-1-8-x-3-8-x-50-ft-roll--260-540

You can get similar tape from a hardware store.

 

[lokerola]

Nice.

 

[ra.ra]

Using 1/8" foam sheet available at most craft stores, first pic shows layout for six tweeter and two 8" woofer gaskets; second pic shows interim process; and third pic shows installation. All different AR speaker projects shown, but similar process for EPI.