Ditton 66 "Legend filter

[Depaj]

I have been using these speakers for a while and I'm quite pleased with them but one of them started sounding a bit "messy". I checked the filter and discovered one of the two resistors started melting and damaged a nearby electrolytic (the only one in the whole filter). the resistor reads 3.8R, the 2.2R resistor measures 3.4R with the same multimeter. Does anyone have an idea what its value should be ? I can't find any schematics for this model (it seems to be the first version). Also now that I've got it out anyway I would maybe change the caps (the electrolytic has to go for sure but also the rest of them if that could improve things). I don't have a huge budget so if it's better to leave them alone and just swap out the 47µF non polar (would nichicon muse ES be a good idea here ??) and the burnt resistor that's ok with me.


Thanks 😀

 

[Wieslaw Lipowsk]

Here you are

 

[Depaj]

Thank You but That doesn't look like the legend version, probably the studio monitor.

 

[Wieslaw Lipowsk]

Here you are again. Can you see the details?

 

[Depaj]

Sorry, still not the right version, I think this is the second version of the studio monitor 😀.
Mine is this version :

The filter has one 2.2µF, one 3.3µFone 22µF and one electrolytic non-polar 47µF. there are also three resistors, one of 2.2Ohm, a 10Ohm and the other one has melted but I think it's around 3Ohms (I can check on the second filter, it also got hot but I might be able to read the inscription.

 

[Wieslaw Lipowsk]

I think the original Celestion Ditton 66 looked like this: (no Audax tweeter, that's for sure)

 

[Depaj]

Yes it does, the "legend" version came out a little later and the filter is different.

 

[Wieslaw Lipowsk]

The crossover parts:

 

[Wieslaw Lipowsk]

I've found another schematic on my HD. I don't recall its origin

 

[Depaj]

None of those are what I'm looking for but thank you for the effort 😉.

The values and components are on the picture I posted.

 

[Depaj]

It looks like s*** but here's what I made up from what I can see on the board.

 

[Wieslaw Lipowsk]

Just look at the other xover and measure the parts on it. Are you sure your 66's are stock, and not DiY ?

 

[Depaj]

That's what I did, the resistor is actually fine, but the caps definitely need changing.

How do you mean DIY ?!!! Of course they are Stock, you've got the 66 studio monitor that came out in 1977


Later they made the 662 version in 1979



Last but not least, the ones I have The 66 Legend in 1989 and a second version in 1990.



All three versions were made by celestion in England.

 

[Depaj]

BTW there was a mistake in my drawing, here's what it should be (again sorry for my pour skills with Paint) :

 

[Wieslaw Lipowsk]

Did you pull the parts out before measuring them?

 

[Depaj]

Yes, the burnt resistor measures 3.3R and exactly the same on the other filter. I think I will go ahead and replace them anyway with some higher wattage non inductive resistors. both electrolytic caps measure 9nF instead of 47µF. I don't know if my meter is faulty or if these caps are just completely dead but replacing them can only do good.

 

[Wieslaw Lipowsk]

You can replace them with Mundorf Ecaps 47uF/100V PLAIN or RAW. Make sure they are the same kind (LL or generic).

 

[Depaj]

That's exactly what I ordered (Raw I think) , the rest I'm going to replace with mundorf Mcap Evo.

 

[Depaj]

Wow and I who thought they were good before, I hadn't heard half of it.

Finally got to finished the crossovers, I went with Mundorf Ecap for the 47µF, Mcap EVO for the others and Mundorf 10W non inductive resistors. I also changed the internal wiring from the binding posts to the filter and from the filter to the woofer.
The first listen just blew me away, I keep discovering little details in some songs I have been listening to for ages and it feels like the band is actually playing in my room !!!

 

[Wieslaw Lipowsk]

Good for you 🙂