IMF owners thread!

This board is attached directly to the white foam, via some sort of brown, crusty glue. The foam peels away from the board relatively easily, especially if you use a plastic putty knife. Since I didn't have enough capacitors to do the entire job right now I didn't peel the boards off completely. Does anybody here have suggestions for an appropriate adhesive to re-attach the boards to the foam? I have some good contact cement and I was thinking of trying that. What do you guys use?

No advice on the gluing?
 
The service department at Falcon Acoustics responded today regarding the capacitors. Apparently there is some variability within each model, and often models destined for export are different from those intended for domestic consumption. They very generously offered to send the additional capacitors.

My advice (which echos a previous comment in this thread) is, if you are going to buy a re-capping kit, count the capacitors and send in a list with your order. It will help avoid problems with (often undocumented) variability.

Interesting, but it would explain some of the slight differences that people have sorta commented on regarding the TLS50 and TLS50mk.II, plus the seeming number of changes to the woofer selection and maybe the two different mids?

Wonder if we should have sub-threads about members' TLS50, ALS40, and TLS80 versions, and document the woofers/drivers and the crossovers with pics and parts lists?

No advice on the gluing?

I would think a hot glue probably would work well. I'm not sure a glue like Goop (which is toluene based) might melt the internal foam piece its on. I would be cautious about something like Gorilla Glue because its a urethane glue which would be compatible with the foam but might really stick too well to the circuit board.

I've always wondered why they didn't attach it to one of the wooden walls?
 
Hi, Lepage glue for home use should be good, when I was young it was a glue in a small bottle with a brush inside who seems to be the one IMF have use, maybe ABS glue will do the job.
 
The service department at Falcon Acoustics responded today regarding the capacitors. Apparently there is some variability within each model, and often models destined for export are different from those intended for domestic consumption. They very generously offered to send the additional capacitors.

My advice (which echos a previous comment in this thread) is, if you are going to buy a re-capping kit, count the capacitors and send in a list with your order. It will help avoid problems with (often undocumented) variability.

Hey sorry if I missed whether or not you've fixed your mids yet, but I'm local and happy to do the re-foam for free for you, I'd suggest picking up the reasonably priced kit I used on mine http://speakerrepairshop.nl/index.php?action=article&aid=3036&group_id=10000028&lang=nl#.WKxuwlUrJhE

(Or of course we could team up and do em as a combined effort!)

I have the same mids in my TLS50II and refoamed them last year.

V3sF6dnl.jpg


qdJilaTl.jpg
 
Last edited:
Hey sorry if I missed whether or not you've fixed your mids yet, but I'm local and happy to do the re-foam for free for you, I'd suggest picking up the reasonably priced kit I used on mine http://speakerrepairshop.nl/index.php?action=article&aid=3036&group_id=10000028&lang=nl#.WKxuwlUrJhE

(Or of course we could team up and do em as a combined effort!)

I have the same mids in my TLS50II and refoamed them last year.

OMG that is such a great offer!

I read your refoaming post and it looks like a job that would benefit from an experienced pair of hands.

Unfortunately, these speakers are currently in Baltimore MD. For family and work reasons I am dividing my time between Charm City and Fog City for the next several months. The IMF's are part of the "East Coast Annex" system. I like them so much, however, that I am tempted to schlep them back to SF when I am done on the East Coast. Either that or I might donate them to my brother-in-law in Kentucky.
 
Dyche01, is there someone there in Baltimore who could extract the mids for you and send them to JL? I probably should get mine done too (two pairs).
 
Dyche01, is there someone there in Baltimore who could extract the mids for you and send them to JL? I probably should get mine done too (two pairs).

Well, I could just pull them myself and put them in my carry-on bag next time I go home. It's not brain surgery, and I have carried more suspicious looking things through airport security: http://audiokarma.org/forums/index.php?threads/another-sign-of-obsession.756903/

I am actually on the fence about whether to refoam these guys. The foam surrounds are clearly doped with something that makes them stiffer than they would otherwise be, and I worry that replacing them with undoped surrounds would change the efficiency or frequency profile. @Johnny_Law, what's your experience?

I am tempted to buy the Monacor drop-in replacements, even though they might also sound a bit different.
 
Dyche01, is there someone there in Baltimore who could extract the mids for you and send them to JL? I probably should get mine done too (two pairs).

I'd be happy to host an Elac 4EM/101 re-foam party on my workbench! They are a little tricky - not much room on the frame perimeter and a tight voice coil gap - but no match for patience, calm hands, and a 30Hz test tone.

Well, I could just pull them myself and put them in my carry-on bag next time I go home. It's not brain surgery, and I have carried more suspicious looking things through airport security: http://audiokarma.org/forums/index.php?threads/another-sign-of-obsession.756903/

I am actually on the fence about whether to refoam these guys. The foam surrounds are clearly doped with something that makes them stiffer than they would otherwise be, and I worry that replacing them with undoped surrounds would change the efficiency or frequency profile. @Johnny_Law, what's your experience?

I am tempted to buy the Monacor drop-in replacements, even though they might also sound a bit different.

Hmm. I never listened to them with the original surrounds, because I didn't want to hurt anything. I'm really not sure how they sounded originally and if they sound any different now. I just don't have any data to be of use. :( If we could find a frequency chart for the Elac 4M/101 as originally doped, then I could try to measure mine and we could compare the two? But subjectively with the new foam they sound absolutely fantastic, phenomenal, musical, silky, hold on let me consult my thesaurus, operatic, symphonious! That being said I wonder if the Monacor replacements would also be a deviation from the originally doped drivers? Maybe the practical answer is that the cost to you is fairly cheap to re-foam the originals compared to getting the replacements; if you are unsatisfied, you can then sell the refoamed Elac 4M/101s to recoup the cost of the Monacors...
 
Hi, if you look at the midrange when listening music, the cone do not move much,imperceptible motion to my eyes. My Tls 50 or Prof.Mk III are the same,the woofer have a big travel,but the mids nothing.
 
I'd be happy to host an Elac 4EM/101 re-foam party on my workbench! They are a little tricky - not much room on the frame perimeter and a tight voice coil gap - but no match for patience, calm hands, and a 30Hz test tone.



Hmm. I never listened to them with the original surrounds, because I didn't want to hurt anything. I'm really not sure how they sounded originally and if they sound any different now. I just don't have any data to be of use. :( If we could find a frequency chart for the Elac 4M/101 as originally doped, then I could try to measure mine and we could compare the two? But subjectively with the new foam they sound absolutely fantastic, phenomenal, musical, silky, hold on let me consult my thesaurus, operatic, symphonious! That being said I wonder if the Monacor replacements would also be a deviation from the originally doped drivers? Maybe the practical answer is that the cost to you is fairly cheap to re-foam the originals compared to getting the replacements; if you are unsatisfied, you can then sell the refoamed Elac 4M/101s to recoup the cost of the Monacors...

I might take you up on this! I will be back in SF on the week of March 6. If you are also around, I'll pop the mids into my carry-on bag and we can have a refoam party. I already have plenty of appropriate glue from previous refoaming jobs and I'll order the replacement surrounds.
 
I might take you up on this! I will be back in SF on the week of March 6. If you are also around, I'll pop the mids into my carry-on bag and we can have a refoam party. I already have plenty of appropriate glue from previous refoaming jobs and I'll order the replacement surrounds.

How many days are you in town? I ask because the way I do re-foams is actually a 2-day process - I glue the foam to the cone one day, let it set, then glue the foam to the frame the next day with the test tone. That way there's only 1 fluid seal at a time to worry about coming up. Maybe we could do em both at once, maybe you could glue the foam to the cone before coming out? And where will you be?
 
Just checking in from Ottawa ON .... This thread is a great reference.

Restored one TLS-80 speaker today, second one planned for tomorrow.

Lots of IMF "in the house"

- Super Compact II
- ALS-40
- TLS-50
- TLS-80
- RSPM - IV
 
Hi Speaker_nut, welcome to the thread.

Could you confirm the TLS-80 woofer model number, KEF B139, SP1212 or SP1044? What type of restoration did you do, any crossover work, and have any pics documenting your work (or will have for the second one)?
 
How many days are you in town? I ask because the way I do re-foams is actually a 2-day process - I glue the foam to the cone one day, let it set, then glue the foam to the frame the next day with the test tone. That way there's only 1 fluid seal at a time to worry about coming up. Maybe we could do em both at once, maybe you could glue the foam to the cone before coming out? And where will you be?

Back in SF for the week but, unfortunately, the replacement surrounds that I ordered from the Netherlands haven't arrived yet. I'll probably just do the refoam myself back in Baltimore.
 
Look what followed me home today. A pair of ALS 40 II's.
The cabinets are a bit banged up, and the midrange drivers aren't original. But the price was right, so I thought why not.





 
Hi K-50, congratulation they seems in pretty good shape,but not sure about the midrange doesn't look original. You should probably get a mids from Falcon Acoustics (Monacor) and recap the crossover if it's not done. This will improved the sound greatly. Good listening,Yvan.
 
Hi K-50, congratulation they seems in pretty good shape,but not sure about the midrange doesn't look original. You should probably get a mids from Falcon Acoustics (Monacor) and recap the crossover if it's not done. This will improved the sound greatly. Good listening,Yvan.

Thanks

The fronts look all right, but the tops and sides could really use some new veneer, and, yeah, the mids aren't original. But, as I said, the price was right, so I'm not too bothered by those issues.
I'll probably look into getting the proper mids, and recapping at some point, but the sound pretty damn nice as they are. They have the same detailed highs, and deep, precise bass as my CM2's, but with are fuller or "wider" in the midrange. And they've got some serious low end "Oomph"!
 
I haven't seen much about the ALS40 II's around here, so I figured I would share some experiences recapping a pair.

I bought the replacement capacitor kit from Falcon Acoustics, which arrived in a timely fashion but, unfortunately, it was missing two of the necessary 4µF capacitors. I alerted Falcon but have yet to hear back from them.
View attachment 872080
For reference, a full recap of two ALS40 II speakers requires twelve (12) capacitors:
4x 60µF
2x 12µF
2x 6µF
4x 4µF

The crossover network inside each speaker is divided into two boards, a large one located behind the upper bass driver (see below) and a smaller one located on the back of the terminal binding posts. Each of the large boards has four capacitors (2x 60µF and 2x 4µF) while the small boards have two (1x 6µF and 1x 12µF).
View attachment 872083

Here is the board behind the bass driver:
View attachment 872084

This board is attached directly to the white foam, via some sort of brown, crusty glue. The foam peels away from the board relatively easily, especially if you use a plastic putty knife. Since I didn't have enough capacitors to do the entire job right now I didn't peel the boards off completely. Does anybody here have suggestions for an appropriate adhesive to re-attach the boards to the foam? I have some good contact cement and I was thinking of trying that. What do you guys use?

Although I left the big boards alone for now, I did re-cap the small boards and clean the high frequency attenuator switch with contact cleaner. The through holes for the 6 and 12 µF capacitors are marked below.
View attachment 872101

The ALCAP replacements are slightly bigger than the original ELCAP's but they fit just fine.
View attachment 872102

I am not finished with these speakers, but I already notice a BIG difference in the sound. Before cleaning the switches and replacing the capacitors, both tweeters were essentially dead and the overall sound of the speakers was quite dark. Now the sound is much brighter and the authoritative bass that these speakers can pump out is balanced by a clear top end register.

I finally replaced the rest of the crossover capacitors in one of my IMF ALS40 II's. I often work on one at a time and then compare the two, just to make sure I am not wasting my time with all of this refurbishing. Sometimes I can barely detect a difference, but with the IMF's both rounds of capacitor replacement made a significant difference in the high and midrange sound, in fact more than I expected.

For those who might be tempted to try it themselves, here is a simple, step-by-step guide:

1. You will need: replacement capacitors (natch), phillips screwdriver, plastic putty knife, rubbing alcohol and Q-tips, contact cement (I used Weldwood by DAP), needle-nosed pliers, and soldering gear (iron, solder-sucker, solder, and a good solder flux).

2. If you order the replacement capacitors as a kit from Falcon Acoustics, be sure to tell them how many capacitors your speakers actually have. IMF made different models of the ALS 40 II (some for export, etc.) and the crossovers do not all have the same number of components.

3. The large crossover (which has either 3 or 4 capacitors) sits behind the upper low frequency driver. This driver is not centered and the easiest way to remove it and get it out of the way is to turn the speaker on its side, so that the driver is farther from the floor. This sounds counter-intuitive, but the way the wires run, this position gives the most play and allows the driver to reach the ground without cutting the wires.

One of the best decisions IMF made in building these speakers was to use bolts and threaded inserts to hold the drivers, rather than just driving wood screws into the MDF. The driver might need to be coaxed loose and it will probably take a few small chunks of MDF with it (see second photo below).

upright.jpg driver_out.jpg

4. The crossover board is glued to the acoustic foam inside the speaker so you will have to pry it off. I used a combination of a plastic putty knife and my fingers to minimize damage to the foam. Some of the foam will inevitably come along with the board.

prying_pried.jpg

5. Use the rubbing alcohol and Q-tips to remove the foam and glue residue from the solder joints that connect the capacitors to the traces. You don't need to remove all the crud, just the crud on the contacts that you need to de-solder.

6. Desolder the contacts (I prefer a spring-loaded solder sucker) and use the needle-nosed pliers to pull the old capacitors. Be careful not to pull any of the traces loose. If you do, use super-glue to re-attach them to the board.

7. Thread the new capacitor leads through the holes and double check the values. Pull the leads tight with the needle-nosed pliers and then solder them in place. Use flux to get a good, hot joint. Note that the Alcan capacitors from Falcon Acoustics are larger than the original Elcans, so they might protrude over the edge of the board or rest against the adjacent inductors. I use hot glue to stabilize them.

8. Apply contact cement to the bottom of the board and to the foam. The foam soaks it up a bit so you will have to apply more to the foam than the board. I shifted the position of the board slightly compared to its original position so that I was not applying all the cement over the old, dried up glue. Depending on the contact cement, wait a few minutes for it to dry and then apply the board to the foam. The bonding is more or less instant, but I held it on for a minute or so, just to make sure.

contact_cement.jpg

recapped_xover.jpg

9. Replace the driver and screw it in tight (this is where the bolts and inserts make a huge difference). Be sure to inspect the gasket to make sure that it is in good shape and will make a nice seal.

And then: voila!
 
Last edited:
Back
Top Bottom