Guido57

There were a few versions of this woofer. I believe the latter versions did not have the heatsink. The surround material also changed over time. My original surrounds appeared to be foam that had a weird failure: they devolved into a non sealing goo that kind of held its shape. Couldn't see the problem without taking off the grill, same with the satellites' midrange. New surrounds and caps for all. Note: IMHO a set in good shape sounds a lot like NLAs.

Where did you get your first set of replacement surrounds? A known vendor like Rick Cobb, Simply Speakers, Midwest Speaker, etc. or an ebay seller sourcing surrounds from China? (Rick Cobb is on ebay but has a good reputation for selling quality surrounds and has a pretty very loyal following.) Note: there are two types of polyurethanes used for most foam surrounds: polyester and polyether. Polyester is stronger against physical damage while polyether is more resistant to UV and humidity.

Basic restoration is done, with Lpads replacing the pots/rheostats. Wanted to post the before and after pictures of the mutilated one next to each other. I find I like the Lpads a little lower than halfway. I'm very pleased with the sound and find the bass response better than I expected. I will be listening to these exclusively for a least a week before I do any direct comparisons. Both cabinets are now stripped to bare MDF, with my final choice of finish depending on how they fare in comparison to some other speakers.

My issue/question is referring to understanding a potentiometer as a voltage divider in layman's language. Maybe I'll just have to buckle down and read a bunch of electronics tutorials. However I did eventually find an old AK post by Zilch that answered the question for my application.

I've been re-reading Pete B's EPI Restoration thread. He mentions rheostat, my speakers has potentiometers. "Potentiometers are often used to vary voltage and rheostats are used to vary current." In my limited understanding current is volts times amps and is measured in watts. It may take some time before I understand the significance of this. My question at the moment is would the potentiometer change the resistance, and therefore the crossover point? What goes on in a rheostat circuit is much easier to understand than the voltage divider action of the potentiometer.

Rebuild is complete to functioning level. I went with Hu's method of crossover: new binding posts and polypro cap. Pictures show'shelf for setting new baffle, baffle in place and completed rebuild. Short listening session makes me think I'll follow what Pete B did restoring a pair of 100's: putting an L-pad to modulate the tweeter. I feel the tweeter is much too loud in comparison to the woofer and an L-pad is more appropriate to the quality of the speaker's sound than the original potentiometers. Vocals are heavenly but low end is weak. I would think pots were used because they're cheaper than L-pads. While removing the mutilated baffle I also stripped the vinyl. Ruts, dent and dings were filled with Durham's Rock Hard Water Putty. Really smashed edges and corners were rebuilt with QuickSteel epoxy putty. The cabinet of the mate will get the same treatment eventually. Actually listening to vocals makes me wonder if Advent would have been better off buying or licensing this tweeter. Maybe I need to listen to some cymbals first.

Update: The tweeters sounded muted when compared to other speakers. Removed the resistor and still had the problem. On advice from someone on AK I pushed the sides of the inverted domes lightly and the tweeters came to life. https://audiokarma.org/forums/index.php?threads/epi-100m-masonite-tweeters.911400/reply&quote=13713607 I could now hear what gave these speakers their reputation. One of the pots was giving really high ohm readings, so I hit all the rivets connecting the pots' tabs and now get a uniform 24.2 ohms for the outer tabs on both. All done with the one usable box. Cabinet with the mangled baffle is still in process.

If you already bought the simply speakers kit get Ailles Tacky glue, it works well with Advents and may be found at craft stores or Walmart. I may not have the correct spelling. Their Advent surrounds seem fine to me. All of the grills I have appear to be Masonite frames.

Finished with a new surround on one of the woofers and installed it into the complete cabinet. The sound is good. Next step is putting a new baffle in the hacked up cabinet. When I have a working pair I'll do some more critical listening and compare them the other speakers I have. Huw's response to questions on the crossover: "It's normal, the pot is just something they had to have back then for fashion's sense. All the way up is "flat". The order components are in when they are all in series does not matter."

Oops, my bad. I meant to say series, not parallel. The resistor is in there to attenuate the tweeter while I'm evaluating, cleaning and rebuilding; the pot is currently removed for the process. It's 1.5 ohm because that's what I had on hand. Everything is on quick connects for now. The mystery to me is the cap is on the negative side of the tweeter with the pot between the driver and the cap.

I would like to add that there are tweeters out there that are claimed to be drop in replacements for the Advent tweeter and would like to caution against such claims.

In the later 1970's one of the speakers I wanted to audition was the EPI 100. Unfortunately, the salesman at the only place I could find them did not want to hook them up and tried shoveling so much bullshit on me in an effort to get me to buy their house brand I left and never went back. These came up for free on the local Craig's List, obviously a fixer upper pair. The previous owner still had the woofer for the mutilated cabinet so I decided to give it a go. The butyl surrounds on the woofers have definitely stiffened and I decided to replace them with fillet foam surrounds that are still on their way. A listening test to the complete speaker showed the degradation from age and their storage in an unheated garage. As a first step I put on new binding posts and replaced the crossover with the common EPI setup of a 10 uF capacitor parallel to the tweeter while adding a 1.5 ohm resister. This brought the tweeter back nicely. I will replace the baffle on the mutilated one and already have a tweeter for it. Once I've got the basics together I'll decide on the next step. One thing I don't understand is the capacitor was attached between the rheostat and the negative terminal of the speaker, with the negative terminal of the tweeter connected to the middle terminal of the rheostat, and I was quite surprised they are 25 ohm.

The crossovers are held by both staples and hot glue. At least they were on mine. If you just punch them out you may take some fiberboard with them. I pulled the crossovers instead of working through the woofer hole just because I though there was too much going on in a limited space for my soldering skills at the time. Note: my OLA's had their crossovers mounted on a metal plate and isolated by spacers( at least that's how I remember it). Whether or not putting the original tweeters is a step back is a matter of opinion.

I was never sure how significant the dust cap is to the sound of these tweeters, but I like the look you got with this repair.

I too would like to see those details but since it was posted by a guest, Guest Ken Perkins, it's quite possible he has not been to this forum since his original post. I'd like to note that at least one company has presented a replacement tweeter for the Legacy and other later Advent as a fitting drop in replacement for the fried egg tweeter in the Large Advents with no crossover modifications. I find this to be highly dubious.

Pete, I'm wondering if you might consider bringing these to the winter Frankenfest. When I was speaker shopping in the 70's the only place around here that had the EPI 100 didn't have them hooked up and the sales person I was dealing with did not want to take the trouble to connect them. Considering the line of BS he laid on me in reference to the speakers on display I never had the urge to go back. I finally ended up with NLA's and have never heard the 100's, though I have heard a pair of Genesis 1's.

I believe so, I think this was covered over on Audio Karma.

I think PeteB preferred Rev.2 and also pointed that the "dot" inductors could be problematic.

Nice find! Just for grins, could you post a picture of the crossovers when you open them up as there are several iterations of the crossovers in these speakers. Just curious.

I've lined up a couple of curiosities to display. I'll be there if my work schedule allows.

One might rebuild the ripped section of the baffle with something like Elmer's Damaged Wood Repair. It's an epoxy product that once cured will be stronger than the original particle board and can be worked (sanded, drilled, etc.) like wood. It has worked well for me on speaker baffles and more demanding applications.

Just curious; has anyone tried GooGone to clean up speakers for foam replacement? I've used this on other types of projects where acetone and alcohol evaporated too quickly to work but I've never tried it on speakers.

Regarding the Genesis inverted dome check out Human Speakers web site which puts the crossover at 1800. I think (speculate) there currently are more dome tweeters available to reach below 2000 than back in the day.

In order: Need to clean? No, not strictly, but it doesn't hurt to hit them with Deoxit. If you mean where the wires from your Sansui are attached; masonite originals were hot glued on so you can re-glue them. Metal originals were held by staples and glue, re-glueing should suffice but you do want a tight seal. The grill covers may have been yellowish to begin with. They seem to be some type of burlap and the shade did vary over the years. Search the forums and you'll find discussions on replacing the material, I've yet to see anything about cleaning it. Lots of threads on Advents more current than this one. Try http://www.classicspeakerpages.net/IP.Board/index.php?/profile/180451-rickb/