Vintage TDL RTL3 repair - need a bass driver!

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I'm new to this forum. I came in search of advice and found threads a decade or more old and still going strong.

I own slightly 'custom' TDL RTL3 speakers. I bought them 20 years ago and they're my pride and joy.

A few years ago, one of the mid-bass cones blew. Richer Sounds replaced one driver in each speaker with a unit that was similar... but different. Instead of 8 edges, the new drivers have 4. They look similar to the ones used in the TDL RTL3 Special Edition.

Now one of the remaining original (8 sided) drivers has blown. It sounds like someone playing a comb through greaseproof paper. Bzzzzz, Bzzzzzzz, Bzzzzzzzzzz! I'm gutted. I need a replacement driver. I don't think I can afford to buy a matching pair.

I've unscrewed the drivers to have a look. They're unbranded. The 8 sided one is marked 172-NS-06 and the 4 sided one is marked 172-NS-08. They're both polypropylene.

From what I've read, these units are 14 ohm. Or 10 ohm. Nobody actually knows. My scary ex has my multimeter, so I can't find out.

Here's a guided tour. Sorry about the sound quality:

Does anybody have any suggestions of budget drive units I can use to do a quick repair? Does anybody have a working driver lying around the workshop?


could I also suggest that you remove the the binding post plate on the back of the speakers

then take photo's and upload them here.

the crossovers are prone to burning out (overdriven too loud/not enough amplification)

I am no expert but do have a pair of these in bits

the tweeters were none originals and the crossovers were burnt out

check out this link on here
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Yes, I saw that thread earlier today and read the whole thing. It was amusing to see how old the thread was but, I must admit, I was lost. I'm a newbie to speaker repairs and mods. The most I've ever done is swap out speaker cones for straight replacements. This is the first time I've tried to find a replacement for a unit that has been discontinued.

I've uploaded an inspection video. I'll publish it down below. Meanwhile, I was wondering if there were any other tests I can do without my equipment? My soldering kit is with my multimeter, still over at my scary ex's. When I feel brave enough to fetch it I was thinking of desoldering the matching driver from the other speaker and swapping it for this one. This way, if it's the crossover at fault, I'll know. Right now I can't do anything except disconnect the biwire shorts.

As you can see you maybe or not be aware the two drivers are in parallel, meaning they both receive the same frequency signals,

if the crossover was buggered then both drivers would exhibit the same problem.

your video shows no obvious problems with crossover been burntout.

maybe try and put the drivers back in the cabinet (but the faulty one rotate it 180 degrees) the bit that was at the top should now be at the bottom , cone rub could be a problem (the speaker cone sagging ) after storage.

Try pushing on the driver lightly and evenly to see if it is rubbing (google you tube)

an example
Ahh, parallel drivers. That makes sense. I did the tests you recommended. Hmmm. The cone is definitely rubbing at the bottom. Tapping it sounds like a drum. Gentle pressing makes a rubbing noise. At the bottom. You're dead right. All of the other cones sound just fine. Tight and drum like. But they've been standing for more than a couple of years. When I think about it, I packed the speakers away in 2009. I left them standing in their boxes in the corner of my loft for... 6 years. Crikey.

I just turned the driver through 180 degrees. Screwed it back in firmly. Still some distortion, although not quite so bad. Does this mean I have to play music through the speakers for 6 years in order for the sag to go in the opposite direction? Should I still try to find a replacement? Should I rotate all the drivers in order to prevent this happening to the others?

Thank you, by the way. That advice was very helpful. : )
Well, everything seems to be fine on the front. I'll have a look at the back over the next few days. The driver has been upside down for 24 hours now, and it still rubs when I press it. I guess the rubber must have been very tired. A forum member has PM'd me with a generous spare parts offer, and I've accepted. With a bit of luck, I'll have these speakers restored to their former glory before too long.

Meanwhile, I'm still curious as to what, if anything, I could have replaced them driver with. Surely the Monacor SPH-175 (with paper cone) isn't the only thing on the market that is remotely like it?

I have another project I want to do, and that's to repair an elderly subwoofer. I might need some more help from you guys with that. I've never taken an active sub apart before, and I'm a complete newbie. : )

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