SpeakerTalk

[T.O. Chef]

Greeting all.
I've been away from the forum a while, but keeping tabs occasionally. Here's my first post since acquiring IMF tls80's. Currently these are my main speakers being enjoyed every singlr day for both 2 channel and Home Theater.
Sorry speaker guru ... I'm seriously bitten by the TL bug

Now coming to me are some Cambridge TL-200's. Something I've held a fascination towards for many years, but never been fortunate enough to find here in Canada. Until now.
It was our dear friend Colin (R-50's) and member TL-200 here who have spoken so highly of them that tweaked my deep interest. The fact that these have a narrower profile makes room placement and aesthetics very appealing.

I have not yet viewed or heard this pair yet, but have committed to buy. I know I have a challenge ahead as these have been "upgraded" by the owner with All New Polypropylene cap's. Not exactly a selling point IMHO. Jerry (Falcon) ... here I come!
Before deciding how far to go with them I'm hoping someone can provide a bit of advise.
Questions are:
* Has anyone any opinions on how the TL-200's compare in sound to the IMF 80's?
* If going the route of a complete filter replacement from Falcon, which version would be the best bet? (High Power ones of course, I'll be using an Aragon 4004mkII amp at 200 wpc). Should I select the the aB circuit modification, the 18dB slope (mid / HF) mod, or all out top of the line, all inclusive, very expensive package?
* Do I need to be concerned with the wool stuffing? Will it have shifted, or need adjustments? If so, How?
* Is it advisable or of sonic value to swap out the Cole's super tweeter for 8ohm HF-2000's (making crossover cap & inductor changes of course). I do have HF-2000's to put in place.

I expect these will be the last speakers I ever buy for main system use. So I don't mind doing whatever, spending whatever, to make them perfectly "right".
The Boss of the household has long said "Those IMF's are here forever", and I have happily agreed with her to now.
Interestingly, she's quite supportive of this purchase though, appreciates the looks and is fine as long as they are as musical as what we have now.

No ... sorry everyone. The wife's a keeper Blessed I am!
Thanks for any advise or comments on these everyone!
Robert
_________________
Music is food for the soul.

[speakerguru]

[T.O. Chef]

Speakerguru .... Would the following description properly summarize the true effect of a so named TL loudspeaker design, In your opinion?

" A theoretically perfect TL would absorb all frequencies entering the line from the rear of the drive unit but remains theoretical, as it would have to be infinitely long. The physical constraints of the real world, demand that the length of the line must often be less than 4 meters before the cabinet becomes too large for any practical applications, so not all the rear energy can be absorbed by the line. In a realized TL, only the upper bass is TL loaded in the true sense of the term (i.e. fully absorbed); the low bass is allowed to freely radiate from the vent in the cabinet. The line therefore effectively works as a low pass filter, another crossover point in fact, achieved acoustically by the line and its absorbent filling. Below this “crossover point” the low bass is loaded by the column of air formed by the length of the line. The length is specified to reverse the phase of the rear output of the drive unit as it exits the vent. This energy combines with the output of the bass unit, extending its response and effectively creating a second driver. "
(Quoted from a Wikipedia article)

I have often wondered exactly why you refer to the TL as an impossibility, but this seems to explain that position. A true TL exists only in theory.
So I stand corrected
But I LOVE the sound!
_________________
Music is food for the soul.

[speakerguru]

Yes, I would broadly agree with that if I had to generalize. I think it better to look at specific alignments and use a combination of experimental results and maths to describe what is really going on. All practical "TL" designs I have come across, have used a quarter wavelength pipe resonance to increase the low end (with an increased cut-off slope below resonance as in a reflex).

I'm not sure about the "reverse phase" bit the the Wikipedia entry. I suspect a quadrature relationship between the driving force and the "TL" output is more likely, again just like a reflex, but I haven't done the maths.

[T.O. Chef]

Math was never my strong point I'm afraid. Thanks Speakerguru, your comments are very appreciated. Don't go to great efforts to crunch numbers on my behalf though, Please.

Regardless of what's physically going on I have not heard a reflex speaker (ported or resonator) that's as satisfying in the low end like the 1/4 wavelength pipes of the IMF 80's and RSPM's.

The KEF 104aB's that served me well for 25 + years were very enjoyable (if a bit slow), and the Celestion Ditton 66's could plumb down pretty deep (and pin you to the wall at high SPL's). But it wasn't 'til I heard the Big Boys that I realized what's really down in the depths and had been missing.

Here's hoping someone can chime in who knows these TL-200's and perhaps can offer some comparative information on other TL named designs
_________________
Music is food for the soul.

[TL 200]

Hello Chef,
sorry for my late reaction. Even in the Netherlands it's a busy time of year.
My TL's have been completely restored by my audiodealer before i bought them.
All caps are replaced with Audyn-caps, the filling had to be placed properly again, it wasn't stiffend but it sank out-of position through the years. They also got new cableconnectors on the backside (gold-plated good quality).
My drivers are all original, mine were build in 1976 as far i know. In that year they were also tested by A J van den Hul, a famous dutch audiodesigner who makes several turntable cartridges, cabels etc. (google his name).
he tested them and concluded it was the best pair of speakers in that time with the technology available.
I do have a copy of the results but they are written in dutch.....
Before i had these i played with a pair of self-build Baily transmission-line with a B200 woofer and an Audax tweeter. I don't think you have to change the filters or the Coles, they play loud enough, in spite of the 50 W power handling. I use a Cyrus 2 amp with external power supply wich delivers 70 watts continue per channel. That's more tahn enough, volumeknob never comes above 4 at scale from one to ten.
I can only advise to get them as soon as possible, they won't dissapoint you.
Good luck and let us know if you have them.
_________________
Without music, life would be a mistake.

Friedrich Wilhelm Nietzsche,
The Twilight of the Idols, 1889

[T.O. Chef]

The TL-200's have landed in my basement.
They are in good company down there amongst the KEF collection (Cantata's, R.104aB's, CS-1's).

The cabinets are salvageable with some stripping and refinishing, though if I found myself over the moon with their sound when finished I would consider a re-veneer job.

But I'm a bit baffled by what's inside. Read On:.
It's difficult to assess them given the "upgrade" made by a well intentioned but misguided hobbyist who replaced all the mid-range electrolytic cap's with no-name Polypropylene ones from Parts Express. 20 minutes of listening gave me a splitting headache. Glaringly Bright, Forward and totally unbalanced.

Opening them up to examine in detail I find only a small shred of the expected long hair wool stuffing, and that one was tucked behind a wad of polyester fill in the B-110 chamber. The upper portion of that chamber, behind a mesh grill is completely empty. Nada Fiber of anything.
Down Below, Behind the B-139 there's only Wide Open Space above a thin strip if yellow ridged foam that lines the bottom and goes up the back panel and out of sight.
The line above the void is packed with more of the white "pillow stuffing" found in the B-110 chamber. There's another wad of the stuff plugging the line exit at the top. Of course I cannot tell what's in the line center portions, but I assume no one's altered that unless they have multi-jointed pencil thin arms!

So ... I'm not at all sure about these. They don't look like any pictures I've seen of others. I'm wondering if someone's made a stuffing change for some reason. Or, is it possible that some TL-200's were made this way?

I've ordered high power crossover kits (Falcon) and will be at least getting the drivers properly fed. Only then will I know if the bass is correct, or close to what I expect it should be.

What would be WONDERFUL is if someone could tell me exactly what's supposed to be in this line, both in terms of material, quantity (weight), and placement.
I'd be eternally grateful !
_________________
Music is food for the soul.

[TL 200]

I hope you can find some info here http://www.diyaudio.com/forums/multi-way/224412-cambridge-audio-r50-rogers-monitor-repair-3.html

Or here http://www.lencoheaven.net/forum/index.php?topic=14674.0
Good luck TL 200

just to tease youa little bit a picture of my set. My veneer is nearly as good as new, thank the Lord. I must say i have been very lucky because i am the second owner of them. The previous owner was a schoolteacher. They always have been taken good care off and that shows.

_________________
Without music, life would be a mistake.

Friedrich Wilhelm Nietzsche,
The Twilight of the Idols, 1889

[T.O. Chef]

Thank You Tl !
Great looking cabinets ... for sure! And I love your taste in TT's also. Looks like mine ... is it a Thorens TD-160mkII ?

Yes. I had seen that post, and have since registered with the DIY forum (as member RC in TO). I have posted some questions there, specifically where to source this Long Haired Wool and exactly how much should be used in the areas where it's obviously lacking in mine. But the question remains, Will I ever find something the same after 40 odd years!?!?
Mine are stamped inside with a 1976 build date btw.

I have fired a digital camera up the first part of the line and discovered that there is original fiber up at the end of it. So that's a relief, knowing that the interior sections of the line are still properly damped.

R-50 Crossover kits from Falcon have been ordered. I'll start with that project while I await what I hope is good news from somewhere on the stuffing dilemma. I suppose I could take a sample of the wool fiber to a good yarn shop and ask opinions on matching it. There's still the question of quantity and placement to figure out. Don't really want to do that by ear. That could take a while! I'd have to pay a flight over for Profski to help!!! IF he wouldn't mind.

I'll keep you posted!
_________________
Music is food for the soul.

[TL 200]

The original wool used is dr. Bailey's long hair.
Don't know if it's available in Canada though. I'll see if i can find something about the place and amount of the fillings.
And yes it's a TD-166 mkII, prettty modified too.
_________________
Without music, life would be a mistake.

Friedrich Wilhelm Nietzsche,
The Twilight of the Idols, 1889

[TL 200]

Chef, i think i found what you need:https://dl.dropboxusercontent.com/u/7577946/Cambridge%20R50/Webb%20R50%20Construction.pdf
It is all there i guess.
Good luck.
_________________
Without music, life would be a mistake.

Friedrich Wilhelm Nietzsche,
The Twilight of the Idols, 1889

[T.O. Chef]

Good stuff TL !!! It's greatly appreciated
I do recal seeing and reading this through once years ago when studying up on the TRansmission Line concept.
I think it was our dear friend Colin who sent me the link, but I didn't save the file at the time.
Well, now I know the quantity at least, 2 pounds per side. Think that includes the B-110 chamber?
The wool source will still be a challenge as I doubt that Falcon still has any supply of it. Interestingly, They were the supplier back in the 70's to the DIY community as mentioned in the article.

I will take a sample to the local craft supplier, see what they can recommend.
Also, I will have to guess at the amount still in the inaccessible part of the line, so some "trial be ear" is undoubtably going to be part of the restoration process.

However ..... The information here is invaluable, and I'm brimming with gratitude to you!
Many, many Thanks.
_________________
Music is food for the soul.

[Garethwatkins]

Try these guys.
http://www.qtasystems.co.uk/loudspeaker-components/damping-materials.htm

[T.O. Chef]

That too is quite helpful Garethwatkins.
Thank you!I've sent a request for information to them.

I'm also awaiting a response from Jerry at Falcon, seeing if he still has any tucked away somewhere. A few years ago before Jerry partnered up to puchase Falcon Acoustics he was kind enough to send me some of this original wool fiber for another project i was working on.
The fiber he sent was identical to what is remaining in the TL-200 cabinets I work on today. The material from the shop linked here looks quite different. However, i'll take what I can get
_________________
Music is food for the soul.

[TL 200]

No thanks Chef, i'm glad i can help you.
The wool also has to be put in the B-110's chamber, 6-8oz. per cubic foot, two pounds per cabinet, look next to image 11a. Distribute it evenly through the whole cabinet/ labyrinth.
_________________
Without music, life would be a mistake.

Friedrich Wilhelm Nietzsche,
The Twilight of the Idols, 1889