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Post by firebottle on Mar 14, 2022 16:21:34 GMT
Thought I would take a look at updating the crossovers in the Thiel speakers I recently bought, they are now 30 years old. I've looked on the inteweb thingy and found a picture of the crossover, it has 8 film capacitors and 6 10W resistors on it all ripe for replacement.  Lets work out the access shall we?  Right that's the speaker out, well damped directly behind.  OMG, there are two crossover boards, not one. Will take a little while to study these before removal, to see just how many components I am going to need. More to follow as I progress. |
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Bigman80
Grandmaster
The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,398
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Post by Bigman80 on Mar 14, 2022 16:51:52 GMT
Crikey, thats gonna get expensive, especially with the rewire they need too!
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Post by macca on Mar 14, 2022 17:11:16 GMT
Half of the RS catalogue in there. Will keep you out of trouble for a while.
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Post by misterc on Mar 14, 2022 17:29:06 GMT
You see that's the beauty of discovering an old piece of elecronics or speakers you really like, purchase them for not so much outlay and the bulk of the funds can go on bring them back and beyond they new conditioner, why pay more for a piece of kit that is not going to keep you satisfiled when you can make a decent job of getting rather good imho
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Post by electronumpty on Mar 14, 2022 18:05:42 GMT
Nice little birthday project there Alan🙂
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Post by sq225917 on Mar 14, 2022 19:06:13 GMT
2 xo boards, my old kef ref 203.2 laugh in your general direction with 3 boards and over 100 parts. God, they did bland really well....
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Post by rexton on Mar 14, 2022 19:45:36 GMT
2 xo boards, my old kef ref 203.2 laugh in your general direction with 3 boards and over 100 parts. God, they did bland really well....  excellent sarcasm! |
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Post by antonio on Mar 15, 2022 5:51:17 GMT
Can't leave bloody well alone  Should keep you out of mischief for a little while, will you remove some of that dampening material? |
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Post by firebottle on Mar 15, 2022 7:27:59 GMT
I have decided not to go the foo route, or the expense is going to be as much as I paid for the speakers  . I have ordered modern low loss polypropylene capacitors for most, I have tested a couple of samples in the BBu and am quite happy with the performance. The three largest electrolytic caps I shall measure and assess when the boards are out and replace if necessary. I shall be replacing the resistors with non inductive Jantzen Metal Oxide 5%, which is as good or better than those fitted. I will rewire with Zaphino1877 OCC as I have some I can use. Copper binding post are essential as well. |
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Post by jimbo on Mar 15, 2022 7:32:39 GMT
They will sound different after you have worked on them, hopefully better?
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Post by firebottle on Mar 15, 2022 10:03:25 GMT
They do sound good already but hopefully a bit more 'open' when finished.
The copper posts and OCC wiring should help facilitate that.
I shall be measuring the old components to see if any were out of spec, I fully expect the old film caps to not be up to modern low loss specifications.
A chap with extensive Theil experience reckons the caps weren't that great to begin with, having loosely wound construction by modern standards.
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Post by firebottle on Mar 18, 2022 13:23:24 GMT
New parts are here.  |
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Post by jimbo on Mar 18, 2022 13:52:39 GMT
You didn't get those from China.
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Bigman80
Grandmaster
The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,398
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Post by Bigman80 on Mar 18, 2022 14:21:39 GMT
New parts are here. Finished it yet? |
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Post by firebottle on Mar 19, 2022 10:43:47 GMT
Not a good start, one of the tweeters is blown. I checked the other one, that is OK. Fortunately replacement soft dome diaphragm/coil replacements are available, I think I'd better get two on order. Blown metal dome tweeter:  Second problem is the strength of the glue used to hold the internal wires. Each crossover section is wired separately down to the terminals, with slots in the wood to hold the wires.  I've managed to pull some out but a bit of leverage is now required for the rest. |
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Post by macca on Mar 19, 2022 11:19:00 GMT
shame about the tweeter. I guess it was already blown when you got them?
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Post by electronumpty on Mar 19, 2022 12:35:45 GMT
Well, they well definitely sound better when you fix them up now.
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Bigman80
Grandmaster
The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,398
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Post by Bigman80 on Mar 19, 2022 12:39:23 GMT
shame about the tweeter. I guess it was already blown when you got them? I'd say so. They sounded a bit veiled to Me, but a tweeter out may have a bit to do with that? |
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Post by firebottle on Mar 19, 2022 12:43:51 GMT
Yes I guess so Martin. Anyone with experience of Ferro Fluid? I have removed the diaphragm of the blown tweeter and there is brown gunk as shown in the photo.  Is ferrofluid normally this brown colour? I need advice on its replacement as well. I have now removed the two Xover assemblies, here is a closer look. Bass crossover:  Mid and tweeter crossover:  There is a small blown resistor under the 1.5uF capacitor, I will have to look in the second speaker to find out its value. |
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Post by macca on Mar 19, 2022 12:59:41 GMT
You can run them without the ferrofluid just reduces the power handling a bit. Some say it will sound brighter without it but I doubt it will actually be any different, not in a three-way speaker anyway.
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Bigman80
Grandmaster
The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,398
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Post by Bigman80 on Mar 19, 2022 13:31:22 GMT
Yes I guess so Martin. Anyone with experience of Ferro Fluid? I have removed the diaphragm of the blown tweeter and there is brown gunk as shown in the photo. Is ferrofluid normally this brown colour? I need advice on its replacement as well. I have now removed the two Xover assemblies, here is a closer look. Bass crossover: Mid and tweeter crossover: There is a small blown resistor under the 1.5uF capacitor, I will have to look in the second speaker to find out its value. Bin those tweeters and get replacements. No point in trying to repair them is a pure pain and rarely restores them to their full glory. Looks to me like these are a potential money pit Al. Any recompense From the seller? I find it hard to imagine he didn't know? |
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Post by firebottle on Mar 19, 2022 13:43:31 GMT
It's only the tweeters that are done in. I don't think there are any direct replacements available, after a quick search anyway.
I have messaged the seller, we shall see.
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Post by pete on Mar 19, 2022 14:00:34 GMT
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Post by firebottle on Mar 19, 2022 14:19:15 GMT
Thanks but wrong one. That's a D28, I need D26.
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Post by jimbo on Mar 19, 2022 15:48:03 GMT
If your Ferrofluid has dried out you can scrape it out and replace with new stuff but better just to replace both tweeters. There must be something equivalent out there?
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Post by antonio on Mar 19, 2022 16:25:43 GMT
Sorry about your blown tweeter, hope you can get this sorted Alan.
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Post by electronumpty on Mar 21, 2022 10:11:55 GMT
Replacement ferrofluid is quite cheap if you want to try and replace it.
ferrofluid |
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Post by macca on Mar 21, 2022 11:38:36 GMT
If the tweeter is damaged beyond repair then there's no point messing with ferrofluid.
Getting replacements shouldn't be too hard if you know the spec of the originals. As long as sensitivity is a match or close and they will fit in the holes they'll be fine. The crossover is dictating everything else, and it's not like this is a two-way speaker where the tweeter has to do some heavy lifting.
I have some Audax metal domes somewhere, very high quality tweeters, probably better than what was in there before. I can dig them out and see if they might be of any use if you want.
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Post by firebottle on Mar 21, 2022 17:50:37 GMT
First Xover board done:  |
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Bigman80
Grandmaster
The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,398
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Post by Bigman80 on Mar 21, 2022 18:07:10 GMT
First Xover board done: Very tidy Al. |
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excellent sarcasm! 
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