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IMF pro monitors 3 refurb

W

whistler

Member
Hi

After many years I managed again to acquire a pair of pro monitors 3 (reference?) which have needed very serious refurbishment, which I have now almost completed. I am now left with the problem of tweeters.

The speakers at times in their lives have been modified on many occasions with different drivers and xovers. When I got them they even had two different makes and types of tweeters which I have at least managed to change to a pair of the same type from an earlier incarnation of the speakers but they really need replacement as they are definitely not the correct fitments .

Originally I believe they may have had T27s or like a previous pair that I had in the 70s HF1300s. Now rather than go looking for a pair of thirty year old tweeters, I intend to replace/upgrade but trying to retain the overall nature of the beasts.

From recommendations I am considering the Morel CAT308 as a candidate, I believe the MDT30 was considered a good replacement for the HF1300, and the CAT308 is its successor. I contacted Wimslow but he seems enamored with the Morel Cat298 saying its an excellent replacement for the T27 needing no mods. But does not seem to want to say too much about the 308.

Here is the problem I have never heard either the 298 or 308, and I was wondering if anyone has any opinions on which would be better, as I said I am leaning more towards the 308 as they are supposed to be a smoother better driver. I am aware that I would have to tweak the xover for sensitivity with the 308 . And as I said I did some years ago have what was a later pair of pro monitors with the HF1300s which I found very satisfying.

Incidentally does anyone know what were the differences between the reference pro monitor and pro monitor mk3s if any. These present ones though having the formica rear panel differ from the other pair I had in several ways and trying to get info on the earlier versions is rather difficult, even the sites dedicated to the IMFs have a lack of info on the earlier versions.

I have found a picture on the net of a identical pair to mine (a dealer) which he identified as a TDL IMF Reference pro monitor (yup I know) I am not sure if it would be ok to post the link to the pic but I do have it If anyone is interested.

Any comments much appreciated.
 
Not familiar with IMF, but I would try and stick with original type tweeters. If it was HF1300's they are pretty robust and good examples should be around. Super tweeter is less critical (I think) all seem to do the job, Coles 4001, KEF T27 and Celestion HF2000.

The combination of HF1300/ supertweeter is a very good one.
 
Thanks for that, If you think that the HF1300 do hold up well then I will put them back on the shopping list. IME I have found that some tweeters do not last very well and so am a bit hesitant on buying old tweeters..

My original intention was just to bring them up to standard, but found difficulty in even finding out what was standard for this box. Including the xovers (thats another story???)

But having played (fitted) with various different types/makes of tweeters that I had 'borrowed' from other speakers that either I or friends own, for curiosity sake and in the hope of finding a suitable one. Closest was I think a Seas (?) taken from an old Rogers but was not quite right nor would I like to lose the use of the Rogers.

While experimenting, I must admit that one pair (a friends) were absolutely stunning on a couple of passages of music. Problem is that they would require a lot of juggling with the xover to blend with the other drivers, and I am not sure that I am able enough to successfully complete the task, the other is the cost which over £240 a driver.

Having heard the possibilities of a high class tweeter, I was hoping, having been told that the CAT308 was a good match for the HF1300 that they would ,without requiring too much work on the xovers give a result that would be an improvement over a standard setup. But like most things that I seem to need info on, very little is written about the 308, that again I can find. Anyway many thanks for the input and info..
 
Are these anything like yours?

http://images.google.co.uk/imgres?i...q=imf+professional+monitors+3&hl=en&sa=N&um=1

KEF B139, KEF B110, Celestion HF1300, Celestion HF2000.

In case you were not aware there are several types of HF1300, basically big magnet, small magnet, high and low impedance.

The B&W's, Spendor and I believe the IMF's use the large magnet 15 Ohm ones.

Small magnet ones are used in things like Celestion Ditton 10, 15, County. In my experience, they seem to be less robust (still pretty good though)
 
Both the HF1300 and coles super tweeter are still made by Coles today.if you google them you can get new replcements.
I have the site somewhere if you cant find.
Geoff
 
GWM said:
Both the HF1300 and coles super tweeter are still made by Coles today.if you google them you can get new replcements.
I have the site somewhere if you cant find.
Geoff
Click to expand...

I thought the Coles did not do the 1300, but did a similar tweeter, the 3000.
 
I am no expert on IMF's, certainly the ones I remember seeing years ago had the KEF, B139, B110, 1300, 2000. But I may be mixing up, the big elliptical Elac may have been used when the company took the TDL name.
 
Radfordman said:
I am no expert on IMF's, certainly the ones I remember seeing years ago had the KEF, B139, B110, 1300, 2000. But I may be mixing up, the big elliptical Elac may have been used when the company took the TDL name.
Click to expand...

I've seen a fair few pairs go through on eBay where the mid unit surround is cracked in many places and a kind of off-brown colour. This is very clearly not a B110 as the surround is not black rubber. I'll see if I can google-up a pic...

Tony.
 
Tony L said:
I've seen a fair few pairs go through on eBay where the mid unit surround is cracked in many places and a kind of off-brown colour. This is very clearly not a B110 as the surround is not black rubber. I'll see if I can google-up a pic...

Tony.
Click to expand...


Yes other mids were used, one was the EMI paper coned unit (was heavily doped). I have some here as my friend at EMI used to supply IMF. Think it may have been in IMF Super Compact (and possibly others)
 
Coles make a HF1300 replacement from the original Design I believe.
There some good stuff on Troels site in the Spendor BC1 section on the HF1300.
Geoff
 
lexi said:
Having said all this the Racetrack B139 does rot at the surround.....eventually!
Click to expand...

Very early ones were foam surrounds, they did rot in the usual way.

Strange, my very early Celestes, (B139 +T15) probably about 1964 are not foam and are in perfect condition. So are the B139's from 1971 Concertos that I have.
 
Thanks for all the info, as luck would have it one of the 139s was U/s open circuit and they were different anyway but the surrounds were excellent, I managed to get a matched pair as replacements. The 110s were perfect.

Radfordman said:
Are these anything like yours?

http://images.google.co.uk/imgres?i...q=imf+professional+monitors+3&hl=en&sa=N&um=1

KEF B139, KEF B110, Celestion HF1300, Celestion HF2000.

In case you were not aware there are several types of HF1300, basically big magnet, small magnet, high and low impedance.

The B&W's, Spendor and I believe the IMF's use the large magnet 15 Ohm ones.

Small magnet ones are used in things like Celestion Ditton 10, 15, County. In my experience, they seem to be less robust (still pretty good though)
Click to expand...

Thanks for that, I passed a pair of 15ohm ones thinking that they should be the 8ohm ones.... should have asked earlier... Will now add that to the I should know file.

No the ones in the pic are the the later ones, more controlled bass and they came with stands and not casters. I personally think the best of all the IMFs.
I hope with some work to get mine to that level. I have recently heard a pair of mkV11s that had the caps replaced with poly and the owner thought they were too clinical so sold them to a studio. I personally would have just gone back to 'litics. But they were very clinical. (Bit OT but he also had a pair of Atkinsons which were nothing like I expected from reports on the net).

Here is a link to a pair that are like mine but with the I believe correct tweeters.

http://www.zenn.com.sg/TDL_IMF_Reference_Standard_Professional_Monitor_Mk_3.JPG


GWM said:
Both the HF1300 and coles super tweeter are still made by Coles today.if you google them you can get new replcements.
I have the site somewhere if you cant find.
Geoff
Click to expand...

I did hear that they still made the 3000 the Coles version of the HF1300 but when I tried to find a source I was told they had stopped making them. Of course I could have been given duff info :(

If you do have an address for a site that still sells them I would be very grateful for the URL. And thanks for the heads up on Troels site, been there before but lost the address and could not find it again.
 
Just to confuse even further, the B&W DM3 uses a tweeter that looks almost identical to the big magnet Celestion HF1300 except the magnet is slightly deeper. This is the Celestion HF1400, quite rare.
 
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