IMF owners thread!

Life might just be too short to refoam the midrange driver on my ALS 40 II's, so I ordered the Monacor replacements from Falcon Acoustics. I worried that the Monacors might not be the same quality as the original drivers, so I was a little surprised by how substantial they look and feel.
driver_sm.jpg

I popped the old driver out of the speaker. The main impediment to removal is that the corners of the flange are stuck to the wood with little dabs of glue (blue arrows below). The best approach would probably be to slide a utility razor under all four corners, but a (carefully wielded) knife blade worked (yellow arrow).

Unlike the bass driver, which is mounted with bolts and threaded metal inserts, the midrange driver is attached by screws driven straight into the MDF.

pry_pull_sm.jpg

In a side-by-side comparison you can see how substantial the replacement driver is compared to the original. The magnet is much bigger; the basket feels much more damped; and the surrounds are NOT made of crappy foam.
compare_sm.jpg

If you do this replacement yourself, beware. The holes on the flange of the Monacor are not in exactly the same place as on the original driver. They are close, but the mismatch is enough to make it tricky getting the screws back into the MDF.

Once installed, I have to say that the replacement driver actually looks better than the original -- more like it belongs in this speaker.
finished_sm.jpg

I gave the speaker a listen and HOLY MOLEY, it sounds a amazing. From the beginning I have been impressed with the IMF's clear and thunderous bass but, apart from that, they sounded a bit dull and lifeless. After the re-cap and midrange replacement, however, they are starting to raise the hairs on the back of my neck.
 
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Here is a question: What do you guys think about turning the ALS 40 II's on their sides? Is this done? I assume that the best orientation would be with the tweeters on top and toward the middle.

Any thoughts? Experiences?
 
Sorry if I've asked this before, can't find it, can the bass drivers from the CM3 equatable to any of the KEF drivers? Trying to clean house, but also would not mind boxing up the drivers if I could use them in the future, and given the cost of the Kef drivers in The Studio or the CSM's might be an option.


DYCHE what are your impressions of that moncor mids? I have them in The Studio's and when I swithed to TDL RSTL's I noticed a perceptible loss of mid-range richness....
 
Sorry if I've asked this before, can't find it, can the bass drivers from the CM3 equatable to any of the KEF drivers? Trying to clean house, but also would not mind boxing up the drivers if I could use them in the future, and given the cost of the Kef drivers in The Studio or the CSM's might be an option.


DYCHE what are your impressions of that moncor mids? I have them in The Studio's and when I swithed to TDL RSTL's I noticed a perceptible loss of mid-range richness....

I could be wrong, but isnt the woofer from the CM3 just a KEF B200?
 
Sorry if I've asked this before, can't find it, can the bass drivers from the CM3 equatable to any of the KEF drivers? Trying to clean house, but also would not mind boxing up the drivers if I could use them in the future, and given the cost of the Kef drivers in The Studio or the CSM's might be an option.


DYCHE what are your impressions of that moncor mids? I have them in The Studio's and when I swithed to TDL RSTL's I noticed a perceptible loss of mid-range richness....

I LOVE the Monacor mids. I compared a Monacor driver head-to-head with the original ELAC 4EM/101 driver, both mounted in ALS 40 II speakers. I used an alternating (left-right) pink noise signal and the two drivers sound very similar, which is good I suppose. The Monacor seemed to put out a bit more energy in the lower midrange than the ELAC. I also noticed a difference in angular dispersion: at some angles the speaker with the Monacor sounded distinctly better, while at other angles the two speakers sounded indistinguishable.

For some reason, obsessive-compulsive disorder maybe, I decided to refoam the old ELAC 4EM/101's, even though I have no good use for them.

I already had the kit from the Netherlands.
composite_sm.jpg

After reading previous posts (from johnny_law, I think) about refoaming these drivers, I was prepared for a bit of a hassle. In the end, however, it wasn't a bad job at all. After peeling off as much of the rotted foam as I could by hand, I daubed rubbing alcohol all along the outer edge of the paper cone. This made it much easier to pry the residual foam off the paper. After removing the bulk of the foam, I carefully scraped off the residual using a sharp knife.
defoamed_sm.jpg

Like most people, I started by gluing the surround to the cone and letting that dry overnight.

inner_glued_sm.jpg

Next, I glued the outer edge of the surround to the basket. I used a weight to help center the voice coil while the glue dried.
glueing_comp_sm.jpg

After letting the surrounds dry overnight, I re-attached the white cardboard outer rings.
finished_sm.jpg

I gave them a listen and they sound pretty good. I might sell them on eBay or bundle them with the IMF speakers if/when I eventually sell them.
 
Hi,so no news for a long time, every one appreciate there's IMF, WHAT A GREAT SPEAKERS,John Wright was a genius + a formidable audiophile,should someone continue is magnificient work.Transmission line is the way to go! Keep it going,FOREVER addict to this great concept ,best bass ever!,natural and effortless sound.
 
Life might just be too short to refoam the midrange driver on my ALS 40 II's, so I ordered the Monacor replacements from Falcon Acoustics. I worried that the Monacors might not be the same quality as the original drivers, so I was a little surprised by how substantial they look and feel.
......... ........... .....

I gave the speaker a listen and HOLY MOLEY, it sounds a amazing. From the beginning I have been impressed with the IMF's clear and thunderous bass but, apart from that, they sounded a bit dull and lifeless. After the re-cap and midrange replacement, however, they are starting to raise the hairs on the back of my neck.


Just a minute to thank you for the great pictures and feed back, I have TLS50s and 80s both sets of midranges are getting ugly and as always making such a change is always a dicy decision has anyone else used these? they are recommended it seems by some pretty reputable sources as a good replacement but given the high regard the Monacor msh-115 has been quite highly regarded as a midrange in DIYAUDIO blogs for over a decade but adding a good driver doesn't mean magic happens as we all know properly fitting the system the cross over the synergy with other drivers.. has anyone had somewhat of a before and after feed back on these?

EDIT:
It would seem i missed YOUR side by side.. has anyone else i suppose would be the question now lol
 
Hi,keep it original , invest in better capacitor's to achieve a better midrange frequency only if your mids are not available, you have no choice but find replacement, keep it like John Wright design it, that's my POV.
 
Hi,so no news for a long time, every one appreciate there's IMF, WHAT A GREAT SPEAKERS,John Wright was a genius + a formidable audiophile,should someone continue is magnificient work.Transmission line is the way to go! Keep it going,FOREVER addict to this great concept ,best bass ever!,natural and effortless sound.

I think there was talks of Falcon Acoustics putting out new IMF models. Jerry Bloomfield does own the IMF Electronics company name after all, and is reproducing now the Kef B110 and B139. They build crossovers and have made cabinets for other speakers, so I think something could be in the works.
 
Just a minute to thank you for the great pictures and feed back, I have TLS50s and 80s both sets of midranges are getting ugly and as always making such a change is always a dicy decision has anyone else used these? they are recommended it seems by some pretty reputable sources as a good replacement but given the high regard the Monacor msh-115 has been quite highly regarded as a midrange in DIYAUDIO blogs for over a decade but adding a good driver doesn't mean magic happens as we all know properly fitting the system the cross over the synergy with other drivers.. has anyone had somewhat of a before and after feed back on these?

EDIT:
It would seem i missed YOUR side by side.. has anyone else i suppose would be the question now lol

I will happily sell you a pair of refoamed ELAC 4EM/101 drivers. :rolleyes:
 
Hi, but his he (Jerry) at the same level as John Wright? I'am very sceptical,the need for an other genius to go forward........did they made in improvment on the B110 and B139, I will have love to see a better casting for the basket, we are year 2017 after all.
 
Hi, but his he (Jerry) at the same level as John Wright? I'am very sceptical,the need for an other genius to go forward........did they made in improvment on the B110 and B139, I will have love to see a better casting for the basket, we are year 2017 after all.

At the same level? I would think so. Jerry has access to a myriad of experience in the industry and has been around for a long time. I would have full confidence in him being able to design new IMF speakers should he choose to.
 
Hi, I don't say he could, but do he have the time to past many hours an anechoic chamber like John Wright have done and create new components from scratch not copying some products wich all ready exist. Experience come from trying , make mistake error, if previousl'y Jerry will have work develloping IMF,TDL I will have incline to what you say,but please Jerry is not John, even today IMF never have been surpasse in transmission line speaker.Best regards my POV, Yvan.
 
Hello to everybody here,
Stumbling upon this forum site is a real joy and before joining I read every single post in the IMF owners threads - such a mine of useful information - I must first say a huge thank you to everyone who contributes.
I am currently celebrating (if that is the correct word) owning the same pair of IMF TLS80's which I bought new on 23 September 1977 and they are still giving me the same excitement now as when new, especially in this new age of digital HD Audio files.
If there are any members out there that have similar stories or would like to talk more about my experiences I welcome all comments and look forward to making more friends who appreciate not only IMF speakers and other British equipment, but also listening to music of all genres.
Graphicalman
 
Hi,welcome to the forum ,IMF was a great speakers maker,transmission line have a very distinctive sound,on yours did you modify or change your capacitors ? I suppose Your model are the Mk II,do you have the stand with it ? Myself I own the prof.Mk III, now heavily improved and just order Mundorf foil coil (8) inductors (aircore), I' have spend good amount of money to improved these speakers and very satisfy with the result, will have to put the x-over outside because of the size of components.I'M listening mostly Classical musics (big orchestra),love the way my speakers sound, very dynamic
and détail, no harsh.
 
Hi and thank you for the welcome.
My TLS80's are all original MK I's with stands and no modifications have been carried out. I still have the original purchase receipt (£400) from when they were delivered back in 1977. They have never given me reason to doubt their performance or seek out a replacement in all those years and having never moved house they are still standing in their original locations. In 2016 I returned all of my Quad equipment to the manufacturers in Huntingdon for a complete overhaul and a 40 year upgrade (well over due) and that made a massive difference restoring my system back to full quality. Reading through the IMF pages I see that there are a lot of people talking about "recapping" which so far I have not felt the need to question as my speakers do not seem to have suffered any loss of quality. Perhaps it is an interesting topic for discussion, but without listening to others I cannot really make any constructive comment. I too listen to a lot of Classical music, some orchestral, some piano, but mostly have an interest in organ works, especially if it involves unusual combinations of instruments, for example "Antiphone Blues by Arne Domnerus" which I have on vinyl from back in 1975 and also a digital version - my personal preference is for the vinyl version, but that is another story. It may be an interesting topic to you, but I only live 18 miles from the KEF factory who made the drivers fitted to my TLS80's.
Thanks for making contact, it is so nice to hear other people's experiences, especially from other countries.
Graphicalman.
 
Hi and thank you for the welcome.
My TLS80's are all original MK I's with stands and no modifications have been carried out. I still have the original purchase receipt (£400) from when they were delivered back in 1977. They have never given me reason to doubt their performance or seek out a replacement in all those years and having never moved house they are still standing in their original locations. In 2016 I returned all of my Quad equipment to the manufacturers in Huntingdon for a complete overhaul and a 40 year upgrade (well over due) and that made a massive difference restoring my system back to full quality. Reading through the IMF pages I see that there are a lot of people talking about "recapping" which so far I have not felt the need to question as my speakers do not seem to have suffered any loss of quality. Perhaps it is an interesting topic for discussion, but without listening to others I cannot really make any constructive comment. I too listen to a lot of Classical music, some orchestral, some piano, but mostly have an interest in organ works, especially if it involves unusual combinations of instruments, for example "Antiphone Blues by Arne Domnerus" which I have on vinyl from back in 1975 and also a digital version - my personal preference is for the vinyl version, but that is another story. It may be an interesting topic to you, but I only live 18 miles from the KEF factory who made the drivers fitted to my TLS80's.
Thanks for making contact, it is so nice to hear other people's experiences, especially from other countries.
Graphicalman.

While it may seem like your speakers have not suffered any loss of quality, I guarantee they have. Likely what has happened is your ears have become accustomed to the slight degradation in sound over the years. It is impossible to take your speakers and compare them to how they sounded when new, so the way they sound now is no indication they are working perfectly.

Like your Quad equipment, spending some money on your IMFs will result in an improvement to their current sound and will bring them back to what they sounded like many years ago. The culprits are the ELCAP capacitors on the crossovers that are original to your speakers - they do not age well. Electrolytic capacitors in general are only good for about 20-25 years. I have replaced ELCAPs in about a dozen or so speakers and every speaker I restored realized a noticeable improvement. So, with experience, I am informing you that this is something you should do if you want your IMFs to sound 100%.

The reason this happens is because the old ELCAPs are a wax paper with electrolyte, and they dry out over the years. This results in the capacitor no longer being within its original specification which causes the crossover to function abnormally.

The great thing is that there is an outfit called Falcon Acoustics and they supply capacitors that are nearly identical to the originals, so they will retain the original voicing of the crossovers. They are at http://www.falconacoustics.co.uk. If you have any questions about the process or how to go about this feel free to ask.
 
Wow, that was a quick response.
I totally agree with you on hearing and have looked at the Falcon Acoustics website - in fact they are only a couple of hours drive from myself - I also noticed that the expense for the components is really affordable - perhaps this is something that I should undertake, however I will need a lot of advice on how to proceed and what it actually entails doing this modification/upgrade.
Now that you have triggered my curiosity about what improvements I will reap I can see that this is a project that will have to be undertaken, even if only just to satisfy my curiosity and to prove yourself correct.
Any guidance that can be given will be warmly accepted, thank you.
Graphicalman.
 
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