TDL Studio 1 : need replacement drivers

Difficult to say from looking at the image, even when magnified.

I can see 1 inductor coil and three probably original bipolar capacitors plus a two resistors, or 1 resistor and a label.

It could be unmodified.

Just posted and seen your new images.

I still think unmodified, but the wire links are an unknown to me, are they original or replacing an earlier fitted component.

I suspect others will know better than I
 
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Thanks raymondj. Yes, the speakers were "repaired" once and different drivers installed. This was quite a few years ago and the person who did the job says he can't remember whether he modified the crossovers but doesn't think so : "maybe a tweak in the wiring here and there" I think he just doesn't remember but he sais it would've been unusual for him to modify them.
 
Here are some pictures of the holes
 

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I think people are interested in the hole dimensions to consider suitable replacement drivers for you. I am not sure where we are in the repair process?
If you haven't already posted this people will be interested in the diameter of the large whole where the bass driver lives, and the dimensions of the tweeter cut out, as it is not circular or symmetrical maybe min and max dimensions of the cut out.

Assuming the crossover has not been modified, replacement old drivers from eBay could be a possibility. But this will be dependent on price and non rotted foams or replacement foams being fitted.
 
OK, thanks very much. I've already measured the holes and I think it'll be on the thread (I'll check) Up to now I'm just trying to work out what to order and would like to get it right as I'm in France and postage would be expensive (and maybe unreliable) if I need to return them and order different ones. I'm in touch with a company called Wilmslow Audio. I don't know if you've heard of them?
 
Having mulled this over, I quite like the look of this Wilmslow Audio WA-165 polycone bass:

WA -165 Bass-mid Diameter 165mm

With a 147mm cutout, it'll fit. Whether the mounting holes, which might have convenient T-Nuts, might line up, remains to be seen. But easy to make 4 new mounting holes for screws.

Lots of bits at wilmslow for modifications:

Components and accessories

The replacement 104mm Vifa XT25SC-30 (4 ohms) is a slight worry. Not a great choice IMO. Just about covers the tweeter cutout. And needs an attenuator to control a big impedance peak around (guesses) 800Hz.

Crossover looks unmodified:

843893d1589440727-tdl-studio-1-replacement-drivers-crossover-tdls-3-jpg


I'm not sure what it does exactly. 1 coil, two resistors and 3 capacitors. Some values might help. Some people added an attenuator to similar designs:
TDL RTL Rebuild - Crossover and Measurements

I could make a good guess on tweeter polarity with more detail there. But 90% of the time, positive. The crossover is connected to a 4 terminal biwire input by 4 bolts. These ought to undo and the whole thing will lift off, possibly with washers falling off in the process. Not unknown to find extra components on the back. Positive is usually red or brown in crossovers. Negative is usually black or blue.

I have a pair of unwanted rectangular frame Elac 180NS10 paper woofers. These are 180mm wide. 143mm cutout. Mounting holes on a 183mm diameter circle known as PCD to the technical.

307484d1350776343-upgrading-mordaunt-short-ms15-bookshelves-mordaunt_short_ms15_disassembled-jpg


They probably would do.
 
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According to the review in Stereophile, the crossover was at 3KHz, 1st order high pass and 2nd order low pass.


Referring to the photo, the resistor by the coil is 10ohms and the other one is 2.2ohms. The caps are 12uF, 4uF and 5uF but I don't know which one is which.



I got this info from another thread somewhere where the owner was doing a recap. Unfortunately the poster didn't trace out a schematic.


I would take a guess that the coil and 5uF are the 12db to the woofer. The 12uF and 10ohm are probably in series across the woofer. The 2.2ohm and 4uF probably feeding the tweeter.


My 2 pence.
 
Hah! After my last post I decided to re-read the whole Stereophile review and it's right there.
"The crossover is relatively simple, a series non-polarized electrolytic capacitor in the tweeter feed providing a first-pass high-pass slope, with a series resistor to lower the tweeter level; the woofer filter is basically second-order low-pass, with a series air-cored coil and a shunt electrolytic capacitor. There is also an RC Zobel network shunting the drive-unit terminals."


Pat on back.
 
Hi raymondj. Yes, I'll be ordering the replacement drivers this week. Neil at Wilmslow Audio, after many conversations in which I spoke to them about all the advice I'd received on the forum suggests the following :

Monacor SPH-165CP Size 165x165mm
Monacor DT-100 Size 116x80mm
which seems to fit with what many of you have been suggesting. For the crossovers, it seems they may need replacing (do I wait and see what the sound's like with the ones I've already got or is it better just to replace them anyway?)
cm2s find of the description of the original specs looks great but for the uninitiated reads like something straight out of The Hitchiker's Guide to the Galaxy! I'm wondering whether to ask Wilmslow Audio whether they could assemble them for me and send them with the drivers. A sort of "plug-in-and-go".

Any thoughts anybody?
 
Things have moved on a fair bit then.

Can you solder and do you have the soldering iron?
Do you have a friend who can do this for you? I think you are going to need some further help with this the final stage. There will be somebody in the local community who fixes electrical things I am sure.

Your idea about "plug in and go" is very sensible. Wilmslow hopefully have read this thread and may already know about the crossover design, so it would be nice if they came up with a similar specified crossover for the new drive units.

If they are not aware of this thread you could point out to them to it and the linked Stereophile review. That should get them on the right path. They will of course charge for this design work, I think they have a fixed fee for Xover design.

If the repair is getting a bit expensive, you could take the slightly less technical approach and just replace the original capacitors. CM6 has told us the original capacitor values of 12, 4 and 5 microfarad, you could go ahead and order two of each value, Wilmslow will understand what to supply. This is where you will need the soldering skills to replace the caps.

Monday is a bank holiday in UK, maybe somebody will be kind and do a quick sim for the new drivers, but ideally we need some more data.

Does anybody have the frd and zma files for these two drivers, monacor-dt-100 and monacor-dt-250 ?

We know from stereophile that the studio 1 baffle dimensions are 72.4cm by 23cm (H x W)
Original crossover frequency was at 3kHz, with a first-order, high-pass; second-order, low-pass. Sensitivity: 86dB/W/m. Nominal impedance: 8 ohms.

CM6's thoughts on the crossover are very sensible and are functional i.e the coil and 5uF are the 12db to the woofer. The 12uF and 10ohm are probably in series across the woofer. The 2.2ohm and 4uF probably feeding the tweeter.

Without measurements we will have to react to your comments on how they sound and advise as needed.
 
To answer the question, if either the front or rear panels are screwed in place and not secured with glue as well, it should be relatively simple to unscrew the screws and ease the panel out. Even without being glued it will have sat down to the sealing gasket and may need a fair effort to remove it. Preferably a new sealing foam gasket should be fitted when you start re assembling everything.

If the insides are not easily accessible, you may have to be creative with smaller pieces of foam inserted in the immediate area around the woofer cut out, a bit of a pain.

I take it the foam has started to break up?