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IMF tls 80

I notice the super tweeter in the original design is run wide open on top...no low pass filter.

Hate to say it, but I've got a feeling that that ring radiator would actually sound a lot better than the pair of Celestions. Tweeter technology has moved on a lot, and the HF1300 isn't a great driver compared to modern tweeters IMO - that phase plug knocks off the high end.

I would advise how to modify the crossover but I have no idea about series crossovers. Time to do a bit of reading me thinks...
 
Munkey Q, what do you think about the idea of staying with the original 4 way crossover, leaving the vifa ring radiator in place (it sounds great to me) and just finding another modern tweeter to play the part of the HF 2000, work with the Vifa and capture the higher stuff? That way I might be able save my self a few bucks short term and still keep the crossover as-is for a future original conversion should I collect the parts. I think the original conversion would still be the way to go from a value standpoint...but I don't want to spend 2-300 bucks right now to revert.

Any thoughts?
 
Cdfac did a complete rebuild of the IMF-80 crossover I believe, perhaps you can get him involved in this discussion.
 
RichmondMark said:
Munkey Q, what do you think about the idea of staying with the original 4 way crossover, leaving the vifa ring radiator in place (it sounds great to me) and just finding another modern tweeter to play the part of the HF 2000, work with the Vifa and capture the higher stuff? That way I might be able save my self a few bucks short term and still keep the crossover as-is for a future original conversion should I collect the parts. I think the original conversion would still be the way to go from a value standpoint...but I don't want to spend 2-300 bucks right now to revert.

Any thoughts?
Click to expand...
To be honest, that Vifa covers the range from the B110 upwards (3.5khz and up) without a problem - you don't need a supertweeter. It's a rather good modern unit with a decent sized back chamber and low mass diaphragm. The HF1300 naturally (and somewhat messily I might add) rolls off at about the crossover point, hence the need for a supertweeter. The HF2000 doesn't like being fed much power below about 5khz from what I've heard from various people. It's also rather fragile, and I'd expect they were blown by someone down the line, hence the modern replacements.

If it were my speakers, I'd work on keeping the Vifa as it's an upgrade sonically, and it's easier on your wallet to boot. However, it'll hurt the resale value if that's your intention.
 
Taking a look at the crossover schematic... :scratch2: If that's accurate, then it's not a series crossover- If it were drawn in a more conventional manner, I think we'd see it's second order LP for the woofer, third-order bandpass for the mid, and third-order HP for the tweeters. Since there was no LP filter for the "low-tweeter", you could, conceivably keep the ring-radiators in there (provided they're connected to the "low-tweeter" terminals) without modifying the crossover at all (I would, however, still recap it).

MonkeyQ is correct in that the ring-radiator you currently have is generally superior to the originals; however, I would qualify that by insisting that some experimentation is in order. When I tried to eliminate the super-tweeter from my 50's (I replaced the original low-tweeter with a Polk SL2000, which possessed the sort of extended response the original lacked, and re-worked the crossover for it), the speaker did not perform the same, lacking the same depth as it did in the previous 4-way configuration. I ended up, in the end, re-installing the super tweeter and putting the crossover back into its original configuration. I did keep the Polk tweeter in there, however, and managed to donate the originals to another set of 50's.
 
Well, I guess if I'm keeping them (that's my intention) then it shouldn't matter...Right? I just guess the OCD in me likes original stuff for some reason I can't put my finger on. And I've also seen some bigger price tags on original units.

You're right...the specs on the vifa indicate it reproducing frequencies well beyond audibility. And without the crossover point I guess it would do it more smoothly. So, maybe I will look into modifying the crossover...but try to do it without screwing it up too bad. Maybe I can keep the components associated with the super tweeter crossover point and keep them for the future should I want to go back.

I'll look into this as an alternative. Jimreeves said another member did a mod on this make (thanks Jim). I guess I'll shoot him a message.

It's great having this forum to bounce this stuff around.
 
So Mike...

Are you saying you think the crossover point/crossover for the low tweeter provides eveything above the midrange to the low tweeter? In other words, if the Vifa is attached to the low tweeter leads I'm covered for everything above the midrange with nothing being shaved off for a nonexistent super tweeter?

It would be fantastic if I could just recap and enjoy these for a while...and only worry about trying an original restoration should I want to in the future. I just don't want to be losing the upper end.
 
RichmondMark said:
So Mike...

Are you saying you think the crossover point/crossover for the low tweeter provides eveything above the midrange to the low tweeter? In other words, if the Vifa is attached to the low tweeter leads I'm covered for everything above the midrange with nothing being shaved off for a nonexistent super tweeter?

It would be fantastic if I could just recap and enjoy these for a while...and only worry about trying an original restoration should I want to in the future. I just don't want to be losing the upper end.
Click to expand...
Yep, as he said there's no low pass filter on the low tweeter originally - it's just left to roll off naturally. That new Vifa is getting everything from 3.5khz up...recapping the xover would be all you need to do to have a working speaker.

Depending on efficiency, you might want to play around with padding it down.
 
RichmondMark said:
So Mike...

Are you saying you think the crossover point/crossover for the low tweeter provides eveything above the midrange to the low tweeter? In other words, if the Vifa is attached to the low tweeter leads I'm covered for everything above the midrange with nothing being shaved off for a nonexistent super tweeter?

It would be fantastic if I could just recap and enjoy these for a while...and only worry about trying an original restoration should I want to in the future. I just don't want to be losing the upper end.
Click to expand...

Yep. The super tweeter just had it's own 1st order HP filter- From the schematic, there is nothing limiting the HF extension to the tweeter (as MonkeyQ said, the original low-tweeter had a natural roll-off characteristic). If you intend to keep them in this configuration, though, I would remove C10, just to be on the safe-side; there is a possibility, albeit very remote, that leaving it there could create a tuned resonant circuit, and with the leads acting as an antenna, make the speakers subject to RFI. Strange, but possible (had the same thing happen in a set of AR speakers, where I removed disconnected the tweeter to use them as a sub-woofer). Or, install a 10-watt, 8-ohm non-inductive resistor across the leads.
 
hi

just sold my IMF TLS80 II for 1100GBP (about 2k USD) so yes i would say buy them for 200USD.

tweeter should be a Celestion HF1300 and a super tweeter Celestion HF2000 which regularly turn up on UK ebay. look to pay about 50USD for a pair of HF1300 and 150USD for a pair of HF2000.

IMF used a unusual mounting for the HF2000 so i recommend you buy a pair and accept they will look different.

there were very many versions of each tweeter, be careful you get the right ones!

that said, the HF1300 tweeters are probably the weak link and the replacement vifa tweeter is highly respected. so if they have not done a good job on the crossover modification it maybe easier, cheaper and better simply to get the crossover modification done correctly.

enjoy the bass, those IMFs produce the best bass i have heard from a speaker.
 
Congrats on that sale price. Did you sell those on Ebay? I saw a couple go for that price within the last week on a UK listing...and that listing was one of the main reasons for me taking the drive to pick them up at over 2 hrs away but only 200 bucks. So if so, I guess I owe you...

You are absolutely right about the base...and these speakers have breathed new life into my old vinyl. Not having the stands I do need to get some carpet spikes or do something to get them off the floor/carpet to tighten the base up. I'll keep tweaking but I'm definitely excited about this purchase.

Thanks for the input...
 
IMF used a unusual mounting for the HF2000 so i recommend you buy a pair and accept they will look different.
Click to expand...

No you don't..

IMF Celestion HF2000 are rear mounts.

Non-IMF Celestion HF2000 are all rear mount units held in a cup by a single set screw to make them front mounts.

You just need to be mechanically competent to convert one type to the other.


:music:


This post or any other information supplied to this website or any other by myself is not available as sales and marketing material for sleezeBay or Audiodogging pimps and the like.
 
Perfect. I had seen 2000's on ebay with that cup/flange on the front so it is good to know they can still be mounted on the rear. I guess the other question is that it appears the 1300's or 2000's may have come with different impedance ratings (???) so I guess I'll have to figure that out as well if I want to go that route.

Looks like I have a lot of options with these already good sounding speakers. Everyone has been a big help.
 
You'll probably find that the already good bass will tighten up with the addition of new capacitors - the big 100uF electrolytic capacitor which forms the 2nd order filter for the B139 will have lowered in value, making a mess of things.

Anyway, as MJarve said, play around with things. Keeping the Vifa will probably lose the English-sounding top end and in my opinion improve things, but it's all down to what music you listen to and your preferences.

The Coles 4001 is another British supertweeter similar to the Celestion HF2000 and may make a good replacement if you can't find a decent priced HF2000. The Coles 3000 is pretty much sonically identical to the HF1300 too, but it rolls off better.

I think your TLS80s use the big magnet 8 ohm version of the HF1300. B&W used the 15 ohm variant so those tend to be more common though.

Radfordman knows his British speakers very well, so hopefully he might chip in if he's around.
 
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