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The tweeter caps are already film [the one's bundled together] the rest are all 'lytics.
Having been there & done it with a pair of 44 [near identical crossover] I would advise replacing the tweeter capacitors with decent modern polypropylene's & replacing the rest with Alcap low loss 'lytics from Falcon acoustics. In other words: get them back to "as intended" by Celestion first and then see how you feel about mods.
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Have a look on diyaudio.com with regards restoration threads for the 66's I think this may help you;)
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Update
:lol: Rexton - have a read of my previous posting.
istari_knight - Thanks for the tip.
http://www.jkwynn.co.uk/Project_Images/66/66_07.jpg
Word has it that the 66's need to be up off the floor and well isolated for the bass to perform properly. I am fitting 3 of these "Soundcare" feet to each speaker base. They are like a spike which caries round its own floor cup/shoe, the big stainless washer is to prevent the fairly small diameter neck from biting into the veneer.
These will then stand on a custom made concrete plinth with a profile that matches the cabinet. This will have 4 adjustable spiked feet and a spirit bubble set into the centre, allowing the plinth to be levelled before putting the speakers in place.
http://www.jkwynn.co.uk/Project_Images/66/66_08.jpg
The Midrange Driver had its front plate removed and the crud cleaned from the inside and from the dome. This was then reassembled and tested, given a final polish and is ready to install.
http://www.jkwynn.co.uk/Project_Images/66/66_09.jpg
The ABR has been cleaned and is also ready to go back into the cabinet.
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Looking good! What did you use to clean the ABR?
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Those drivers look brand new now. You can't beat a speaker restoration thread especially when it's a good big 'un being restored.
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Darren - I leveled the worst of the blobs in the gunk on the ABR face with some 400 grade abrasive, carefully as its only made from Polystyrene. Then applied a light coat of water based satin black paint (Acrylic Wilko own brand) some paints will disolve the styrene but acrylic is safe. This gave the styrene and glue an even colour just paint this, not the rubber or centre disc. The rubber and bittumen centre disc was given a coat of black trim wax and buffed with a clean cloth when dry, this cleans and feeds the rubber and helps protect it from drying out and cracking, oh and it looks good too. :D
UPDATE:
http://www.jkwynn.co.uk/Project_Images/66/66_10.jpg
The replacement bass drivers arrived. The seller mounted them on plywood boards with spacers so the rubber surrounds wouldn't be under pressure. Then he wedged them face to face, diagonally in a thick polystyrene box, which was then in a stout cardboard box. I think the delivery guy could have dropped them from the van and kicked them to the door and they would have been undamaged - but I'm glad he didn't. They measure well and play music through the x-over so will just have a light clean up before being installed. Many of these drivers have had after market cone treatments applied these look original and unmolested.
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Update
Found out the tweeters are both blown, open circuit between contacts, I suspected they may have been so it's no biggie.
I've purchased a matched pair in pristine condition from a guy in California. When I say matched I mean they both measure exactly the same resistance. The base drivers are pretty close as well with only 0.1 Ohm difference between them.
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Update
http://www.jkwynn.co.uk/Project_Images/66/66_11.jpg
This is one of the x-over boards from my “Blackies”.
The values may be useful to some folks.
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Thanks for sharing that, Ken. Love the fact that all the components are hard-wired, point to point - when done properly it's so much better than using PCBs.
I've not touched the crossovers yet on my 66s, but would quite like to upgrade the electrolytic capacitors with high-quality polys of the same value.
Which ones are the electrolytics? :)
Marco.
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Marco - All bar the Tweeter caps are electrolytics.
I will be replacing them all with Polyprops.
When you replace the electrolytics you have to add a resistor in series with the Polyprop replacement.
These are ESR simulating resistors to bring the replacements (low ESR) up to the original values of the Electrolytics (high ESR).
If you don't do this the circuit will behave differently to the original.
The Tweeter caps, on mine anyway, are film caps with low ESR so no resistors required when these are replaced, they used a variety of makes and qtys bundled in parallel to make the total value required.
The bass coils and caps are a weak area regarding quality, apparently upgrading the coils with same value (mH) but approx half the dcR and changing lytics to props in this area will give tighter faster bass. The existing parts smear the sound.
There is lots about this on diyaudio.
I will be doing all this to mine but I am not touching the original x-overs. I am keeping these original and building new boards as every part will be changed and possibly a better layout on a bigger board. One point was raised over at diyaudio about coil interaction due to close proximity, the Celestion engineers were not fools and the circuits when new performed well, so maybe there was some interaction and was accounted for in values. If that was the case then giving better locations with similar values might produce worse results? It's a thought - if it ain’t broke don't fix it comes into mind here? Without building both versions and doing comparisons, it would be hard to guess about the outcome and who has the time for that amount of experimenting.
I will be drawing up a circuit with values and parts to use soon, need to clarify one or two things first with the 66 guru on diyaudio. “Alan-1-b” seems to have a handle on what makes these things tick. ;)