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IMF owners thread!

tmarx said:
Thanks Jeff. I had a look inside one speaker last night. One of the things I want to do as part of my overall "refurbishment" is to flip the vertical orientation all the drivers 180 degrees so they start to hang in the opposite direction than they've been for the last 30+ years. The surrounds on the small mid-range are still healthy on my speakers; if you touch them they are soft and slightly sticky. I did notice the top surround and cardboard ring on one mid had pulled loose from the frame ever so slightly. After pushing the surround / ring back in place is seems to have stuck OK. I think the driver rotation will also assist with that sort of thing.

I did get a pic of the back of the mid w/ the white surround, see attached. I don't know if the info will help you track some down or not.

I also found the x-over board right behind the white surround mid, it has the following values:

4 MFD 50v
4 MFD 50v
60 MFD 50v
60 MFD 50v

Unfortunately there is just about zero speaker wire slack on the board, so it's going to be a serious PITA to remove this boards for the re-cap. I suspect I'll end up gutting all the wires and replacing them with something better. I also noticed discovered some more components on a board which is on the back of the terminal cup. It has was appears to be:

16 MFD 50v (it looks like the 1 was partially scraped off)
12 MFD 50v
Click to expand...

Awesome thanks, I don't know if it'll help me out either but I appreciate it all the same! I have another pair of the Kef B200 SP1014s and I'm thinking of using those, but don't know if they're suitable so I want to see if I can find out the specs of that driver somehow (the front baffle is cut out to fit the Kef B200 so that's one reason I'm considering it).

Those caps on the speaker terminal are for the attenuator which increases or minuses 1dB at a certain frequency range. Can't recall which exactly off the top of my head - you could probably find out from imfelectronics.com which should have the manual or description from the manual on the site there.

Also, rotating the drivers should help and isn't a bad idea at all. The cones aren't really heavy or anything but after all these years who knows if the spider is sagging yet or not.
 
canuckaudiog said:
One last thing - those Audax tweeters, the domes seem to dry out. From what I've researched the domes have some sort of a pliable material that when dried out, will reduce the SPL of the tweeter. You may find the highs to be a bit reticent, even after the recap. If so, I recommend replacing with the Audax replacements available on http://www.falconacoustics.co.uk. Also, see the first page of this thread for some information on restoring the speakers.\
Click to expand...

Do you know what exactly dries out with these tweeters? Could it just be the ferrofluid inside the voicecoil gap? It's usually pretty easy to clean the old stuff out and add fresh fluid.

As for the xovers...I had look at some of schematics online for other IMF models, and it's a safe bet that the two 4uf caps are for the tweeter, so I think I'll buy something a little spiffy for those, and probably just get more modest film caps for the other positions.
 
tmarx said:
Do you know what exactly dries out with these tweeters? Could it just be the ferrofluid inside the voicecoil gap? It's usually pretty easy to clean the old stuff out and add fresh fluid.



As for the xovers...I had look at some of schematics online for other IMF models, and it's a safe bet that the two 4uf caps are for the tweeter, so I think I'll buy something a little spiffy for those, and probably just get more modest film caps for the other positions.
Click to expand...


I think it's some sort of doping that goes over top of the dome itself. I'm not 100% sure on this, it's just a guess, but other Audax tweeters use this doping material and I can't find any other reason why these tweeters drop in SPL. elnaldo here at AK tipped me off on it with a thread of his.


Sent from my iPhone using Tapatalk
 
I understood that ferrofluid helped with power efficiency and power handling. This company's website says as much:

https://www.ferrotec.com/products/ferrofluid/audio/

Ferrofluid does dry over time, so it could explain attenuated output.

I had a speaker Tech show me how easy it is to refresh a set of tweeters with new fluid a few years ago, I'll add this to my list of things to try.
 
tmarx said:
I understood that ferrofluid helped with power efficiency and power handling. This company's website says as much:



https://www.ferrotec.com/products/ferrofluid/audio/



Ferrofluid does dry over time, so it could explain attenuated output.



I had a speaker Tech show me how easy it is to refresh a set of tweeters with new fluid a few years ago, I'll add this to my list of things to try.
Click to expand...


Yeah I know what you mean, these Audax tweeters don't use ferro fluid though. I wish it was that simple - I've refreshed many tweeters with new fluid and it's true, it's not that tough to do.


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With this talk of tweeter swapping, makes me think about my hiquphons I have that are in a set of LINN's and putting them in my studios.

Here are the specs for the current production drop in replacement, figured, they are as good as anything. What I wonder is, would I replace the KEF 1.5" dome tweeter, which I think crosses over at 13Khz. The super would be left in place.

What I like about the hiquphon, is that it is incredibly 3 dimensional to the point that it sounded great next to Carver Ribbons, I was honestly floored by it. So why not just use them? meh, no fun in that.

What i don't know and hopefully one of you can comment, is would this even work........well.

Thanks
 

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c-atle-79bay said:
With this talk of tweeter swapping, makes me think about my hiquphons I have that are in a set of LINN's and putting them in my studios.


What I like about the hiquphon, is that it is incredibly 3 dimensional to the point that it sounded great next to Carver Ribbons, I was honestly floored by it.

Thanks
Click to expand...

I have been listening to Hiquphon tweeters for almost 20 years now and enjoy them for all my critical listening.
 
reched said:
Is there a source in the US for Falcon midrange drivers? Thanks.
Click to expand...

Welcome to AK!

Are you referring to the Falcon FB110 KEF B110 remakes? If so, so far no, only available from Falcon directly.

The Monacor MSH-115 is a replacement for the IMF 4/200 and later midrange but is only available in England and Europe. I haven't found anyone in the US or Canada who imports this driver. Falcon and possibly Wilmslow Audio can source this driver, as well as a couple of other British and European vendors. But many of us would prefer to support Falcon as they also provide a lot of information and OEM parts for crossovers.
 
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Thanks very much for the photos!

I have a set of ALS 40 IIs that are missing bits and pieces - that's really helpful because my ALS 40 IIs are identical to yours. Now I know exactly what parts to get. Thanks!!

I'd also like to report on something I stumbled upon! I've been trying out different receivers, amps, pre amps, etc. with my IMF RSPM Mk IVs. Basically, I have two set-ups. One consists my all modern, small room set-up with my Kef LS50s. Then I have the big IMFs in my living room which also contains my analog rig. I have recently fallen in love with vinyl and so, lately I've been mucking around with my turntable and the phono in different amps and receivers. I recently fell into an amazing combination - I picked up a Kenwood Model Eleven II receiver. Not having experienced Kenwood before, I wasn't sure what to really expect, but wow what a stellar combination this is! I've actually heard of Kenwood being run with IMFs before, but I haven't heard it. I highly recommend it - I'm not sure if all Kenwoods have this character sound, but it matches very well with the IMFs. The sound is amazing - I wasn't expecting such an amazing performance from a receiver. I can only imagine what their separates or even integrated amps might sound like.

So if you get the chance, try out a Kenwood with your IMFs. I think it will work out pretty well!
 
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Thanks for the pix POZiTRON. It's well documented that IMF changed some of the components during production runs, but it's interesting to note that the crossover boards are quite different if you compare your photos to mine on the previous page. It appears the cap values are the same.

I've been scouring the web for a schematic of the ALS-40mkII crossover, and haven't been able to find anything. I attempted to join the Yahoo IMF Group hoping to find it here, but there's no response to the request I submitted to join, or subsequent emails. I can only assume that group, or at least it's Admin, is no longer active.
 
canuckaudiog said:
Thanks very much for the photos!

I'd also like to report on something I stumbled upon! I've been trying out different receivers, amps, pre amps, etc. with my IMF RSPM Mk IVs ...

... I recently fell into an amazing combination - I picked up a Kenwood Model Eleven II receiver. Not having experienced Kenwood before, I wasn't sure what to really expect, but wow what a stellar combination this is! I've actually heard of Kenwood being run with IMFs before, but I haven't heard it. I highly recommend it - ...

... So if you get the chance, try out a Kenwood with your IMFs. I think it will work out pretty well!
Click to expand...

Awesome:banana: Thanks for the tip! I have been looking for a good amp to compliment my TLS50's, but weren't able to find any decent info on what would be good combinations. I like Kenwood - Now I must just find one. I am thinking an old integrated stereo amp from the 80's should be fairly easy to find :)
 
So you all know about the history of IMF and Ambisonics, right?

For quite some time I have had an Ambisonics decoder which is on loan to me just to see what Ambisonics is all about. I have yet to give it a shot in true surround - you require two power amps in order to do it and of course two pairs of speakers, preferably the power amps be matched and the speakers as well so the phasing is all congruent.

Anyway, I've kind of had it sitting off to the side but I forgot about one thing. You can still take the UHJ encoded IMF Electronics Ambisonics LPs and run them through this decoder and engage the UHJ decoder circuit without running Ambisonics.

What a treat it is sonically. I have all 3 of the IMF Ambisonics LPs and these are some of the best sounding LPs I have - they sound excellent and anyone who owns them I am sure can attest to that. Anyhow, I hooked up the Minim AD7 decoder I have here and decided to give it a shot.

Easily some of the most natural and true-to-the-recording sound I've heard. What I like about the Ambisonics LPs is they retain the atmosphere of the recording. With the decoder it enhanced that atmosphere a lot. I won't try to go into specifics like imaging or anything like that but the experience is you really get a much stronger feel of being there in the same place the recording was taken. Much more so than just running the LP without any decoding whatsoever.

Really cool!! If you own any UHJ encoded LPs and don't have the proper decoder, I really implore you to try and find one (they are rare unfortunately) and give it a shot. It's an awesome experience. :thmbsp:

Next step is to get another power amp and another pair of speakers and really try out Ambisonics instead of just the UHJ decoder.

Edit:

Whudja lookit dat, I hit 5000 posts. :smoke:
 
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canuckaudiog said:
So you all know about the history of IMF and Ambisonics, right?

For quite some time I have had an Ambisonics decoder which is on loan to me just to see what Ambisonics is all about. I have yet to give it a shot in true surround - you require two power amps in order to do it and of course two pairs of speakers, preferably the power amps be matched and the speakers as well so the phasing is all congruent.

Anyway, I've kind of had it sitting off to the side but I forgot about one thing. You can still take the UHJ encoded IMF Electronics Ambisonics LPs and run them through this decoder and engage the UHJ decoder circuit without running Ambisonics.

What a treat it is sonically. I have all 3 of the IMF Ambisonics LPs and these are some of the best sounding LPs I have - they sound excellent and anyone who owns them I am sure can attest to that. Anyhow, I hooked up the Minim AD7 decoder I have here and decided to give it a shot.

Easily some of the most natural and true-to-the-recording sound I've heard. What I like about the Ambisonics LPs is they retain the atmosphere of the recording. With the decoder it enhanced that atmosphere a lot. I won't try to go into specifics like imaging or anything like that but the experience is you really get a much stronger feel of being there in the same place the recording was taken. Much more so than just running the LP without any decoding whatsoever.

Really cool!! If you own any UHJ encoded LPs and don't have the proper decoder, I really implore you to try and find one (they are rare unfortunately) and give it a shot. It's an awesome experience. :thmbsp:

Next step is to get another power amp and another pair of speakers and really try out Ambisonics instead of just the UHJ decoder.

Edit:

Whudja lookit dat, I hit 5000 posts. :smoke:
Click to expand...



Always learning on this sight.
 
Does anyone know how a NAD C356BEE amplifier will pair up with the IMF TLS50's? (or Nad, in general, for that matter)
 
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