TDL RTL3 Blown Mid Bass unit

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Hello,

Just checked my pair of TDL RTL3 loudspeakers and one of the mid bass units is open circuit.

It has written on it 172-NS-06 and has squared off corners.

I beleive it is a Monacor drive unit and someone mentioned it may be a variant of a SPH 175 available.

Can I use one of these instead ?

Or does anyone have a original Mid/Bass for sale?

Any help appreciatted
 
Hello,

Thanks guys for the help. Yeah, I will probably pick up a pair of ebay!! as you say get a cheap pair of RTL2's and it will give me some spares.

The major problem with these speakers is there low impedance presented to underpowered amps (with a lack of current rather than voltage) causes clipping etc.

Vikash, I was wondering what tweeters you would recommend. ?

Have recently upgraded the crossover. Had burn't out resistors and caps and I put in decent film polyprops. Air core inductors etc may be an improvement also. Might do that later.

May have to hand draw (reverse engineer) the Xover schematic. Anyone got it ?

Thanks again.
 
You could try Speakerbits in Melbourne Australia

From their website-
TDL 5" magnetically shielded bass / midrange. These are genuine TDL spare parts - no data available though. The cones are a very nice coated paper / surround design. Uses would include centre speakers and small shielded monitors.
Stock code : ST115

They are in their Clearance pages $22 Australian

http://www.speakerbits.com

John
 
The bass drivers on the rtl3 come in two types the one with the code 172-ns-XX are about 14 ohms impedance not the more usual 8ohm.These are actualy vifa units and are no longer made or available!they have rounded corners and look like the moral ones everyone keeps going on about but they are not the same..
If you put a multimeter onto the bass driver plugs on the rear both together will be about 5.7ohms (RE dc resistance) if one as blown it will read about 10.3 ohms.(give or take)

The drivers from RTL 2 look the same but they are not... they are 8ohm. you might get away with changing one on each of the pairs to keep the sound balanced but this will cirtainly mess your crossover up.
You could try and get a 2nd hand pair and take out the bits you need. You could also by four of the moral drivers but bare a couple of things in mind. 1/ they are very slightly smaller.(170mm not 172) 2/They are 8 ohms impedance so if you wire them back too standard you will have 4ohm bass midrange and 8 ohm tweeter. 3/ You would need to correct this with a custom crossover.Not as hard as it sounds to make one yourself. You could get hold of four hi fi quality 4ohm drivers (3Xhz -4khz) and wire them in series instead and this would give about the right electrical propertys for the cross over and present a normal impedance to your amp. But I cannot say what it would sound like. I would still want to build a new crossover to get it all back to being balanced.

And while we are on the subject the cross over diagram posted for RTL3 is always wrong... The bass set up has a resistor 10ohms in series with a capacitor. This is a zobel impedance correction circuit not part of the cross over. The cross over for the bass drivers is one inductor in series with the bass drivers. (6db slope)Leave it alone in standard set up you cannot mess with this cap or resistor values!
 
TDL RTL3s in need of some TLC!

Hello,

I'm new to this forum. I read with interest the posts by MrMardy and System7.

I already have '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 repaired them. They 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:

https://www.youtube.com/watch?v=PJEYvSxBWjQ

Does anybody have any suggestions of budget drive units I can use to do a quick repair?

Thanks!

Heathcliff
 
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