TDL Studio 3 restoration

droeftoeter · 25th September 2011, 02:37 AM

It's about time i post something after 7 years of lurking on diyaudio.

A couple of weeks ago i adopted a pair of TDL Studio 3 transmission line speakers from a good friend of mine. They had been stored in a slightly moist basement that smells of oil and they weren't improving on it.. I was more than happy to offer them a new home although at nearly 30kg each it was quite an effort to get them moved!

Now that i've listened to them for a while on an Accuphase amp from the same 80s era, i must say that i'm pleasantly surprised by the sound of these units. The drivers are of absolute high build quality and implemented in a d'appolito layout powered by a 2-way filter. Sadly the cabinet had been painted over in the past and was dented and scratched from storage. I'm currently working on a new coating.

Not sure what's going on with the pritex here..

Removing the old paint which was loose already in some places.

The wood veneer underneath the black paint didn't come out good enough to restore it so i put it in primer. Now i'm applying a nice white finish. Bottom side and the foot are black so it won't look that "dirty" over time.

Next on my list are upgrading the internal wiring and giving the filter a proper upgrade with high quality components. Since i don't have the exact values of the original components i have to measure them individually. The caps have been replaced in the past and are confirmed to have slightly different values due to availability. Current reverse-engineering put into a drawing below. L1 still unmeasured. More on this later!

David Gatti · 25th September 2011, 02:42 PM

Nice find ! Certainly looks like an excellent design and your refinishing looks great.
They look like Seas woofers.
How's the quality of the crossover components?

droeftoeter · 25th September 2011, 03:50 PM

All drivers are TDL branded, the woofers have "electric acoustic industries ltd" imbued in their frames. As for the original filter components, they were basic cement resistors and a small air coil inductor with ~0.7mm wiring. It measures 0.9ohms which is a bit high i guess. The caps have been replaced by MKP ones, i'm sure they weren't that high grade originally.

My goal is proper quality series components, MKP+ for the high along with a MOX and a good low resistance air coil for the low frequencies, depending on its mH value i still have to get measured. Parallel part in low can remain MKP cap and a cement resistor.

David Gatti · 25th September 2011, 10:08 PM

Here's the Seas CA15RLY I was thinking of, which has an excellent reputation.
The TDL may be a rebadged version of this.

H1216-08 CA15RLY

droeftoeter · 25th September 2011, 11:06 PM

Not sure, it's hard to find any good information about these speakers! Also there appear to be multiple versions of the Studio's. Made a typo in my last post; it's Electro not Electric.

Originally known as Transducer Developments Ltd., TDL was founded in the 1970s as a joint venture between IMF Electronics Ltd. - famous for its transmission line speaker systems, and Electro Acoustic Industries Ltd., - ELAC - one of the UK's leading commercial loudspeaker drive unit manufacturers.

droeftoeter · 9th October 2011, 01:54 AM

Updated the filter image in the first post for those looking for the original values. The project is finished and i can finally enjoy my music again

25th September 2011, 02:37 AM	#1
droeftoeter diyAudio Member Join Date: Jun 2004 Location: NL	TDL Studio 3 restoration It's about time i post something after 7 years of lurking on diyaudio. A couple of weeks ago i adopted a pair of TDL Studio 3 transmission line speakers from a good friend of mine. They had been stored in a slightly moist basement that smells of oil and they weren't improving on it.. I was more than happy to offer them a new home although at nearly 30kg each it was quite an effort to get them moved! Now that i've listened to them for a while on an Accuphase amp from the same 80s era, i must say that i'm pleasantly surprised by the sound of these units. The drivers are of absolute high build quality and implemented in a d'appolito layout powered by a 2-way filter. Sadly the cabinet had been painted over in the past and was dented and scratched from storage. I'm currently working on a new coating. Not sure what's going on with the pritex here.. Removing the old paint which was loose already in some places. The wood veneer underneath the black paint didn't come out good enough to restore it so i put it in primer. Now i'm applying a nice white finish. Bottom side and the foot are black so it won't look that "dirty" over time. Next on my list are upgrading the internal wiring and giving the filter a proper upgrade with high quality components. Since i don't have the exact values of the original components i have to measure them individually. The caps have been replaced in the past and are confirmed to have slightly different values due to availability. Current reverse-engineering put into a drawing below. L1 still unmeasured. More on this later!

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25th September 2011, 02:42 PM	#2
David Gatti diyAudio Member Join Date: Mar 2004 Location: Melbourne, Australia	Nice find ! Certainly looks like an excellent design and your refinishing looks great. They look like Seas woofers. How's the quality of the crossover components?

25th September 2011, 03:50 PM	#3
droeftoeter diyAudio Member Join Date: Jun 2004 Location: NL	All drivers are TDL branded, the woofers have "electric acoustic industries ltd" imbued in their frames. As for the original filter components, they were basic cement resistors and a small air coil inductor with ~0.7mm wiring. It measures 0.9ohms which is a bit high i guess. The caps have been replaced by MKP ones, i'm sure they weren't that high grade originally. My goal is proper quality series components, MKP+ for the high along with a MOX and a good low resistance air coil for the low frequencies, depending on its mH value i still have to get measured. Parallel part in low can remain MKP cap and a cement resistor.

25th September 2011, 10:08 PM	#4
David Gatti diyAudio Member Join Date: Mar 2004 Location: Melbourne, Australia	Here's the Seas CA15RLY I was thinking of, which has an excellent reputation. The TDL may be a rebadged version of this. H1216-08 CA15RLY

25th September 2011, 11:06 PM	#5
droeftoeter diyAudio Member Join Date: Jun 2004 Location: NL	Not sure, it's hard to find any good information about these speakers! Also there appear to be multiple versions of the Studio's. Made a typo in my last post; it's Electro not Electric. Originally known as Transducer Developments Ltd., TDL was founded in the 1970s as a joint venture between IMF Electronics Ltd. - famous for its transmission line speaker systems, and Electro Acoustic Industries Ltd., - ELAC - one of the UK's leading commercial loudspeaker drive unit manufacturers.

9th October 2011, 01:54 AM	#6
droeftoeter diyAudio Member Join Date: Jun 2004 Location: NL	Updated the filter image in the first post for those looking for the original values. The project is finished and i can finally enjoy my music again

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