IMF TLS-50MkII's - Time to operate!

SimplySound

Kent Engineering & Fondry
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OK, the patient has been properly anesthetized... the required organ donors have submitted their body parts and I think we are ready to dig in! :thmbsp:

First order of business will be to open 'er up! I already have noted the following conditions. I have a mid-range surround that will need to be repaired. I am going to call in a specialist for that! Orange County Speaker is my preferred doctor but maybe someone has some alternatives to consider for a second opinion.

I know that the Coles 4001g Super-tweeter is not performing up to spec, so I intend to replace it with a new and improved version (grown from stem-cells harvested from the original designs) rather than relying on an organ donor for that.

However, I have found a matched set of Audax Tweeters to use as replacement for the "odd" unit that is currently in this cabinet. I believe it will be good to have a matched set to voice these as accurately as possible. Measurments will be taken to verify that they are fully functional and equivilent.

Any other suggestions before we get started? :scratch2:

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Looks like an interesting rebuild. How long did it take to get parts from Falcon? Also, do you have a pic of the back of the mid and who will supply the surrounds for the mids?
 
Looks like an interesting rebuild. How long did it take to get parts from Falcon? Also, do you have a pic of the back of the mid and who will supply the surrounds for the mids?

Took about a week to get the parts from Falcon after ordering. The Coles and the Caps cost me about $180US delivered. I was lucky to snag the Audax Tweets off daBay for about $60US.

So considering I "overpaid" 7-Benji's for these to begin with (actually $350 for the speakers and $350 for shipping :tears:), I'm looking at about $1000 by the time I have them singing right. But even singing "wrong" these things have been phenominal! All I can say is if you ever stumble upon a set of IMF's, ANY IMF's! They are well worth working with! :thmbsp:
 
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Ok, seems I've run into the first complication in this surgery. I have the six screws out of the front baffle, but it doesn't seem to want to come up off the cabinet. Is it glued? I hate to put too much force into this. Am I missing something? Where's Canucker when we need him?

EDIT: It seems like the baffle may be glued to the metal surround. I may need to take a box cutter to this, but I'll wait for Canucker to chime in! :yes:

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You may have to take off the aluminum trim, but I'm not sure of that.

What woofers do you have?
 
Well ain't this the damnest thang... did the Audax have a fuse on them? Mine does! And it looks like some dang wire is flopping around in there. Gee, wonder if it goes to the Coles? :scratch2:

Also, what is a TW/1500? This does say IMF on the front, but not sure if this is a replacement?

Mech... I'll let you know what the woofers are when I get that far! :thmbsp:

EDIT: It looks like the Coles was completely disconnected (glad it didn't short)! I think this may have happened during shipping but not sure. It seems I had some high frequencies from it for a while, but then it stopped. I thought maybe I blew it up feeding it 260WPC from my old Yammie M-85! ;)

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Well ain't this the damnest thang... did the Audax have a fuse on them? Mine does! And it looks like some dang wire is flopping around in there. Gee, wonder if it goes to the Coles? :scratch2:

Also, what is a TW/1500? This does say IMF on the front, but not sure if this is a replacement?

Mech... I'll let you know what the woofers are when I get that far! :thmbsp:

EDIT: It looks like the Coles was completely disconnected (glad it didn't short)! I think this may have happened during shipping but not sure. It seems I had some high frequencies from it for a while, but then it stopped. I thought maybe I blew it up feeding it 260WPC from my old Yammie M-85! ;)

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Well, you might have been lucky - time to check the fuse and see if that is the problem, otherwise, unsolder and test the tweeter and supertweeters for voice coil DC resistance. If you get a good reading, you may have gotten lucky.

The TW/1500 is an Audax number for a later version of the silk dome tweeter, so I think its just a later one Audax supplied to IMF or replacement unit. IMO, it looks like the Coles tweeter solder tab broke off with the wire - could have been from shipping or possibly moved around too many times.

Looks like some of the MDF came off with the sealant material on the Coles?
 
I recapped without removing the baffle - just removed the woofer and took the crossover board out thru the woofer hole. I didn't even desolder the board - just recapped it while still connected with the wire going to all the drivers.
 
Well, you might have been lucky - time to check the fuse and see if that is the problem, otherwise, unsolder and test the tweeter and supertweeters for voice coil DC resistance. If you get a good reading, you may have gotten lucky.

Yeah, I'll meter everything once I get stuff apart. I think I need to get the Baffle off to get to the Crossover, but maybe Canuck will tell me different. I had hoped to completely re-do the wiring in these so I would like to get them open, but I don't want to mess anything up... these are WAY too nice to butcher! Even though it looks like someone kinda started that process already! ;)

I recapped without removing the baffle - just removed the woofer and took the crossover board out thru the woofer hole. I didn't even desolder the board - just recapped it while still connected with the wire going to all the drivers.

Thanks Captouch... that's maybe what I'll end up doing!
 
It was Canucker's suggestion that I try it without removing the baffle - worked out well!

As he also reminded me, don't forget the 2 caps on the small board where the speaker wires and selector switch are.
 
It was Canucker's suggestion that I try it without removing the baffle - worked out well!

As he also reminded me, don't forget the 2 caps on the small board where the speaker wires and selector switch are.

Got it... guess that's the way it is! Back to the patient! ;)
 
Very nice speakers!

I generally make a habit covering the other drivers when doing this sort of thing, with a piece of wood or even a towel, just in the extremely unlikely event something might, say um, SLIP, and maybe puncture something.

Not that I've ever had that happen or anything.
 
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How's the patient doing?

I've had to transfer them to the ICU to await getting time in the operating room again. It's Valentines "week" ya know and the girlfriend doesn't want to hear about playing with speakers (I think she has something else in mind). ;)

I hope to dig back in again this weekend! :thmbsp:

Stay tuned!
 
Looks like I was late to this party!

Not sure how an IMF thread snuck by me.

Anyways, it looks like you've got most of the advice you need. :thmbsp:

As for the fuse being on the tweeter, that's new to me! Looks like they added that as a way to protect it in later models - good thing. And you got matching tweeters, well hey if one ever dies you now have a back-up in case the fuse is the problem. :)

As captouch said, don't forget to do the two caps sitting on the board at the speaker terminal where the attenuator is situated.

Other then that, it's a fairly straightforward job. Very much looking forward to hearing how it turns out. Keep us posted!

Edit:

Just noticed you asked about the TW/1500. That is a custom made driver for IMF - not an Audax, but very close to it. It was used later on in the TLS 50 IIa which had all Elac parts in it. I'm guessing the previous owner sourced a tweeter on eBay. If you got the Audax tweeters of eBay, those are the right ones for that model. Either one would be fine though, the crossovers as far as I remember are the same.

Just some more thinking here.. about that midrange, could you take a shot of the magnet? I'm wondering what that driver is - all the mids I've seen in those IMF's have dope on them, whereas those don't. I'm wondering about that - they sure look like the original, but just a plain paper cone. Not that this is a bad thing but it interests me. For the surrounds, I can fill you in on where to get them. It's a very simple job - no need to worry about taking them in anywhere, the surrounds will cost you $20 and a little bit of time and fun. :thmbsp:
 
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Mid basket looks correct for the elac midrange, wonder if it was reconed or a replacement Elac but non-coated was used?
 
That's possible, it's also possible they bought some stock and just didn't dope the cones. Who knows. An email to Jerry would likely resolve that question.
 
Mid basket looks correct for the elac midrange, wonder if it was reconed or a replacement Elac but non-coated was used?

Both mids are the same, un-doped paper! They are glued onto the baffle pretty well so I think they are original. I will pull the one this weekend and let you guys know what I find! Thanks for all of the support guys. daKarma's daBest! :thmbsp:
 
The good, the bad and the ugly....

...and man is this ugly! :tears:

Well first the good! The bass units are KEF B200 SP1039's! The big motors! :thmbsp: I was real happy when I saw those!

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