IMF speakers and KEF B139 woofers

I have a pair of 25 year old IMF Monitor Mk III transmission line speakers. One of the woofers is damaged. Does anyone know how to get these repaired, or better yet, replaced ? They are KEF B139 flat oval woofers, 13"x9".
There are some units available from time to time here in the UK. What damage do you have? Regards, Richard.
Richard (Vantageaudio) - thanks for your quick reponse. I believe the speakers were overdriven (not by me, by someone who was house-sitting for me). On one of the woofers, the voice coil is out of alignment, and at high (not excessively high) volumes, on certain low frequency notes (on some recordings), it can be heard rubbing against the magnet - rather ugly sounds, not musical at all!! I would like to replace both woofers if I can, but only one if that is all that can be foind. By the way, do you also get other replacement drivers for these speakers, such as midrange (KEF B110), and tweeters and supertweeters ?
thanks for your reply. Matt Bonn (
Hello Matt. We send any drivers we need repairing to an associate company in the UK. They repair pretty much anything speaker related. I can ask them Monday about your specific problem. As far as replacement drivers go we search around our contacts when we need them and have found the B139 and B110 units are out there. Tweeters like the T27 have become very scarce although some versions are available if one exercises patience. If you do repair your units I would recommend you have them repaired as a pair. Hope this helps you, regards, Richard.
Great speakers but easy to damage the woofers. My wife won't let me get rid of my IIIa's because she says they sound like home. They are still in her system in the master bedroom. If you repair them, the cross over is right behind the woofer and I would recommend that you replace the capacitors.
Pls1 - Thanks for your suggestion about replacing the capacitors in the x-over. Do you know where I can get information on the capacitor values and recommended brands to use ? Thanks,
If you replace the capacitors be careful about replacing them with any later, fancy types. The tendency these days is to replace older vintage types with modern capacitor types that are "faster" and able to pass higher energy peaks thru to the tweeter and thus cause damage to the tweeter. Many times we know of people who have replaced their caps with polyprop types and a few weeks later ask why their "...tweets have fried..."!! You should be able to read the brand and value off of the existing one and try and source NOS or equivalent replacement. I've emailed you some info on the B139's. Regards, Richard.
Does anyone have a pair of IMF hpcm(high performance control monitor) for sale.Does anyone remember this model? Wish I kept mine back 17 years ago. Regards.
Sold a pair of IMF super compact IIs last year.

I think IMF still exists or there a company that handles some of their stuff try TDL

Happy Listening
B139 drive units come up regularly on eBay (UK) as they were widely used in the 70s, 80s and early 90s.
Terry (Aberden, Scotland)
Where are you located? I have a spare used one available but only for pickup in NYC.
IMF and later TDL were one of the finest speakers available in Europe (also in the US).
For those who are interested: I have a pair of RSPM MK IV (formely TL80 I think) cabinets, WITHOUT the drivers for sale. They are in pretty good shape, no crossover either though.
I had them loaded with the original B139, B110 drivers, but not the Clestion tweeters. Instead, an original KEF crossover, and some T27. I used the drivers elsewhere. They are located in the US (New York State), I move back to Europe, and since my (ex)company wouldn't pay for this move, I need to sell them. Check ebay, you still can find KEF drivers.
Also, I made a copy of the legendary Bailey's trinagular TL, using the B139 (the one from the IMF...), but midrange and tweeter are Vifa's.
They sound really good, deep and 'black' Bass. Up to you to change to some other drivers for the MH and HF, but actual configuration is nice.
Write me if you're interested.
I built a pair of TL80 out of Gladstone Electronics in 1978 here in Canada.
Still have them but burnt the KEF tweeters that came with kits. Replaced these with Peerless, then with Dynaudio 28mm for the improved dynamics and power handling. They are definitely classics and not for sale. Hang on to these if you own a pair. It is time for new designs to replace these legends and since drivers are rare or unavailable new methods will become the classics of tomorrow.
P.S. Good parts hunting
new email address @
Jean Charlebois

Dear Audiogon:
I`ve bitten the bullet and become a small manufacturer of TLS systems. I lament the closing of Meadowlark TL loudspeakers. Of course this is a loss but we do not know the whole story. Anyway we are start up and will see if we can survive. Let us hope we have a unique marketable product. I know I like the sound and in the end, that is what matters to audiophiles like me.

Jean Charlebois
December 16, 2005