IMF owners thread!

[Frequency295]

Hello IMF owners, I somewhat recently became part of the family. A family friend gave me a set of IMF Studio speakers. I'm sorry to jump in and ask likely a dumb question but is there a good way to tell if i need the 8 or 16 ohm coles super tweeter? Mine are not functioning in either unit. I made a post in speakers with the details so I'll just drop the link below. I didn't know there was a British Audio forum until someone posted on my thread. Thanks for looking!
https://audiokarma.org/forums/index.php?threads/imf-studio-rebuild.1058452/

 

[AmbisonicGuy]

Hello IMF owners, I somewhat recently became part of the family. A family friend gave me a set of IMF Studio speakers. I'm sorry to jump in and ask likely a dumb question but is there a good way to tell if i need the 8 or 16 ohm coles super tweeter? Mine are not functioning in either unit. I made a post in speakers with the details so I'll just drop the link below. I didn't know there was a British Audio forum until someone posted on my thread. Thanks for looking!
https://audiokarma.org/forums/index.php?threads/imf-studio-rebuild.1058452/

The Coles supertweeter to replace the original KEF HF2000s in both the TLS-80s and the RSPM mkiv(s) should be 8 ohms. To my knowledge, IMF UK and IMF U.S. never used 16 ohm drivers, period. The Coles drivers work very well as replacements for these two models.

 

[quadmatrix82]

In both my tls8mk2 and rspm iv improved they measured about 6.5 ohm all original fyi

 

[AmbisonicGuy]

In both my tls8mk2 and rspm iv improved they measured about 6.5 ohm all original fyi

Then the drivers should be an overall 8 ohms “impedance”. You measured “D.C. resistance”. When an audio signal passes through a driver’s voice coil, the higher frequencies will be subject to the effect of higher impedance than the 6.5 ohms you measured. So using an ohmmeter to test as you did only gives you part of the actual total impedance but is usually an adequate test to determine: 1) Is the driver good at all, and 2) A rough estimate of what the driver’s total impedance is. Rounding 6.5 ohms to the nearest standard driver impedance value gets you to 8 ohms. IMF was one of the only speaker manufacturers ever to provide frequency/impedance graphs in their published specifications. The point of this is to show impedance stability across the driver’s actual operating frequency range. Falconacoustics.co.uk is my source for “anything IMF”. The owner Jerry Bloomfield hired Malcom Jones, the original KEF driver engineer to create updated versions of the original B139 bass, B110 midrange, and the T-27 tweeter drivers not used in IMFs, but were used in the legendary BBC LS3/5a studio monitors made by several very good speaker manufacturers. Falcon also has pre-packaged re-cap (capacitor) kits for your 80’s and others.

 

[quadmatrix82]

Thanks for explaining I did a check and misspoke before the originals were 4.5 ohm with a dc resistance check do you think they would still be 8ohms or 4 ohms?

 

[AmbisonicGuy]

Then the drivers should be an overall 8 ohms “impedance”. You measured “D.C. resistance”. When an audio signal passes through a driver’s voice coil, the higher frequencies will be subject to the effect of higher impedance than the 6.5 ohms you measured. So using an ohmmeter to test as you did only gives you part of the actual total impedance but is usually an adequate test to determine: 1) Is the driver good at all, and 2) A rough estimate of what the driver’s total impedance is. Rounding 6.5 ohms to the nearest standard driver impedance value gets you to 8 ohms. IMF was one of the only speaker manufacturers ever to provide frequency/impedance graphs in their published specifications. The point of this is to show impedance stability across the driver’s actual operating frequency range. Falconacoustics.co.uk is my source for “anything IMF”. The owner Jerry Bloomfield hired Malcom Jones, the original KEF driver engineer to create updated versions of the original B139 bass, B110 midrange, and the T-27 tweeter drivers not used in IMFs, but were used in the legendary BBC LS3/5a studio monitors made by several very good speaker manufacturers. Falcon also has pre-packaged re-cap (capacitor) kits for your 80’s and others.

I think I have a new Coles driver that I can check for you. Check back for an update from me later today. There can be variances in D.C. resistance but that sounds a bit too far off for an 8 ohm. Let me check though.

 

[Frequency295]

Thanks all, it sounds like I should go for the 8 ohm units. One more question if you don't mind. Looking at my crossover there is a silver component that looks like a capacitor but I'm not following the printed text on it. Can anyone confirm what this is?
Studio Crossover - Silver capacitor looking thing looks like it says M6M 0,5 MK +-10% 250B IV 71r

 

[Frequency295]

Nevermind on that question, I found out its a russian capacitor. 0.5uf 250v. I'm confused why its on my boards but not in the schematic. Any thoughts?

 

[AmbisonicGuy]

Was the previous owner Russian? It would seem so. Here is what it looks like to me, but I can’t verify. The person replaced that original cap with a .5mf cap. The “250” in the number should represent the max voltage which in caps is typically 125v or 250v. But that is not the right replacement value. Look in the component list for the coils (inductors). There is a “.5 mh” value for one. If they got the .5 part right, they must have assumed that the original bad capacitor was that .5mh inductor. That’s all that would make sense. I do not have a Studio xover board to look at. Again, only guessing, I think that you need to swap out that silver cap with the correct value. Given where it is located on the board, it is likely that the original was a 100mfd cap. Use an audio grade cap like an Alcap with no more than 10% tolerance. To be absolutely sure on this new replacement, you should find another Studio model owner who is willing to get to their xover board and identify that cap value for you. Unless they have one as a spare, or are very familiar with the board, then they will need to pull a B139 woofer out to get to the xover.

 

[zibi079]

Hello, I have a question: Have any of you compared the IMF tls 50/50mk2 with the imf studio monitor? The studio monitor model is probably the successor of the tls 50. Studio monitor belongs to the reference series.

 

[IMF_Pioneer]

Hello, I have a question: Have any of you compared the IMF tls 50/50mk2 with the imf studio monitor? The studio monitor model is probably the successor of the tls 50. Studio monitor belongs to the reference series.

Not quite sure how you come to the conclusion that the SM belongs to the Reference line ??

 

[zibi079]

Nie do końca pewien, jak dochodzisz do wniosku, że SM należy do linii RefReference

Byłem sprawdzany

IMF electronics - IMF Electronics

IMF stands for Irving "Bud" M. Fried. IMF is the name of the company. You can read some company data here, select categories page, choose a quick link from the table below, or go to any subpage of this one (see list at bottom of this page).

www.imf-electronics.com

Imf studio monitor is in the rerefence series

 

[Mikvdm]

Hey guys!

Ive been reading this thread for a while, and it has made me whole lot wiser! I started out with a pair of super compact 2 with the original mids burned out so i replaced them with the Monacors (MSH-115). I got curious so i started hunting for a "cheap" pair of imf tls50mk2 which i found. The filter was messed up (with blown caps!) and the super tweeters where unoriginal. The normal tweeters also didnt seem original. So i did the alcap recap, got new coles 4001g 16ohm and got the tweeters from my super compact II. Also i placed the Monacors in the tls50 bacause i didn't have the time nor money to refoam them. They sound great! Now while writing the glue of the re-foamed 4em/101's is drying. I will try and listen to the differences, because the Monacor is the go to replacement but does it really sound the same? I really enjoyed the restoration process so i'm sad to see it coming to a end. But i still have one thing to do (maybe 2 if i want to build tls80 inspired stands), re-finishing the cabinets. But i really do not know where to start, do you guys have advice? I know i should sand them carefully, but what oil do i use (i would like them to be as original as possible)? how many layers? Should i even try re-finishing them? What do you guys think/have to tell?

Greetings,
Mik

 

[IMF_Pioneer]

Byłem sprawdzany

IMF electronics - IMF Electronics

IMF stands for Irving "Bud" M. Fried. IMF is the name of the company. You can read some company data here, select categories page, choose a quick link from the table below, or go to any subpage of this one (see list at bottom of this page).

www.imf-electronics.com

Imf studio monitor is in the rerefence series

Yes that's because the person that put that page together many years ago thought that was the case. The "True References" are the RSPM, SACM and to a lesser degree the HPCM. The TLS-50 and 80 are just domestic speakers and the SM and PM were their later replacements.

 

[IMF_Pioneer]

Hey guys!

Ive been reading this thread for a while, and it has made me whole lot wiser! I started out with a pair of super compact 2 with the original mids burned out so i replaced them with the Monacors (MSH-115). I got curious so i started hunting for a "cheap" pair of imf tls50mk2 which i found. The filter was messed up (with blown caps!) and the super tweeters where unoriginal. The normal tweeters also didnt seem original. So i did the alcap recap, got new coles 4001g 16ohm and got the tweeters from my super compact II. Also i placed the Monacors in the tls50 bacause i didn't have the time nor money to refoam them. They sound great! Now while writing the glue of the re-foamed 4em/101's is drying. I will try and listen to the differences, because the Monacor is the go to replacement but does it really sound the same? I really enjoyed the restoration process so i'm sad to see it coming to a end. But i still have one thing to do (maybe 2 if i want to build tls80 inspired stands), re-finishing the cabinets. But i really do not know where to start, do you guys have advice? I know i should sand them carefully, but what oil do i use (i would like them to be as original as possible)? how many layers? Should i even try re-finishing them? What do you guys think/have to tell?

Greetings,
Mik

If you want to keep things as original as possible then you should be using a clear acrylic lacquer opposed to timber oils as that's what the cabinet makers that were making these were using. Later on in the timeline IMF bought the cabinet makers so they had full control of the building process.

 

[Athers-Aud]

I had these in for crossover recap
TLS50's ... I personally find them a bit coloured. a bit flabby in the bottom end. ... Well I'm that way too and we're about the same age.

 

[montrecott]

Hey guys!

Ive been reading this thread for a while, and it has made me whole lot wiser! I started out with a pair of super compact 2 with the original mids burned out so i replaced them with the Monacors (MSH-115). I got curious so i started hunting for a "cheap" pair of imf tls50mk2 which i found. The filter was messed up (with blown caps!) and the super tweeters where unoriginal. The normal tweeters also didnt seem original. So i did the alcap recap, got new coles 4001g 16ohm and got the tweeters from my super compact II. Also i placed the Monacors in the tls50 bacause i didn't have the time nor money to refoam them. They sound great! Now while writing the glue of the re-foamed 4em/101's is drying. I will try and listen to the differences, because the Monacor is the go to replacement but does it really sound the same? I really enjoyed the restoration process so i'm sad to see it coming to a end. But i still have one thing to do (maybe 2 if i want to build tls80 inspired stands), re-finishing the cabinets. But i really do not know where to start, do you guys have advice? I know i should sand them carefully, but what oil do i use (i would like them to be as original as possible)? how many layers? Should i even try re-finishing them? What do you guys think/have to tell?

Greetings,
Mik

Congrats on restoring another pair of IMF speakers. Re: the cabinets, I've had good luck with both Watco Danish Oil and Howard's Restore-a-Finish. Using steel wool can help with rough areas, if you have some of those. How many coats? As many as it takes to make them look good! If the veneer is bad enough to need replacing, well, that's out of my league.

 

[WFM333]

The only thing that im having trouble with the tls80s is the mid bass , especially at lower listening levels. I use eq but that can muddy things up a bit. This is mostly an issue with heavy rock and metal music. They can lack a bit of slam, attack and mid bass grip / clarity.
Would adding a sub to cover the 100 hz to 200hz attack be worth trying? Or should i look at new speakers . Im running a luxman cl34 preamp into a 200 watt mosfet ss poweramp. ( maya200 aksa).
Many thanks

 

[drbiggles]

Hey,
Even with the subwoofer, the tls80s are screwing up more than just your mid bass slam. Those fancy crossovers are filtering out all the character of your recordings. Pass them along, find something a little more rowdy.

Biggles

 

[Woodwind]

Hey,
Even with the subwoofer, the tls80s are screwing up more than just your mid bass slam. Those fancy crossovers are filtering out all the character of your recordings. Pass them along, find something a little more rowdy.

Biggles

That is a bit unfair! They are lovely speakers with great clarity - at least the pair I have feel that way. I can compare them with Ditton 66, 662 and 25s, as well as Pacific Ev0 30s and three other classic speakers. At the moment I run the IMFs together with the Ditton 66s, though I prefer the 662s and will use them again once they have a slight cross-over issue sorted. That said, the TLS80s might look "big"as a speaker unit, but even with the TLS set-up they cannot compare with a 12in or 15inch bass driver in terms of sheer "oomph". So if that is your main music of choice, then I would agree that you might prefer something able to provide the heavy-duty sound that you are perhaps looking for.
P.S. I also have Luxman as my main set-up.