Celestion Ditton 44 Refurb [Tweeter repair / Cab Resto etc]

[istari_knight]

Well, as some know I picked up a pair of Celestion Ditton 44's last week courtesy of eBay... I tested them at the sellers house all okay, wired them in at home everything was fine then that evening one tweeter decided to suddenly go open circuit :scratch:

A quick dissection showed the actual voice coil was black & crumbled to dust when touched so repair was off the cards ! After some hunting around the net it seems others have had similar problem & the suggested replacement is the Seas 19TFF1. Some clever chap over on diyaudio has calculated the necessary changes to the crossover making the Seas a proper replacement instead of a bodge.

Anyway, I've just ordered the parts so will update when they're here & installed - I thought I might as well do a thread on it as its a common problem & lots of people seem to give up & flog the speakers without working tweeters which is a shame.

This is the original crossover:

http://farm4.staticflickr.com/3713/10038925016_53b0d09c0b_b.jpg (http://www.flickr.com/photos/87920837@N06/10038925016/)

And this is the revised crossover :

http://farm4.staticflickr.com/3773/10039000313_1a37a8973c_b.jpg (http://www.flickr.com/photos/87920837@N06/10039000313/)

Its also worth noting this is compatible with both Ditton 44 & Ditton 66 as they share the same HF crossover & 4ohm HF2000 tweeter... The Seas 19TFF1 is a direct replacement for the HF2000 whereas the Hiquphon OW1 would be a major upgrade in sound quality but thats not my goal ;)

[istari_knight]

Fantastic service from Audio-components.co.uk as always, I placed the order at 2pm yesterday & they arrived 10am this morning ! Unfortunately the tweeters haven't arrived from Falcon yet :(

Anyway this is what convinced me to go for the Seas as apposed to finding another HF2000:

http://farm6.staticflickr.com/5528/10054062284_702db5a815_b.jpg (http://www.flickr.com/photos/87920837@N06/10054062284/)

Thats a Vifa D20 I nicked out of a Rega Kyte, its not a drop in replacement & its not even fitted properly and yet it sounds indistinguishable from the HF2000 in the other speaker :eyebrows:

That gunk on the roll surrounds is indeed glue as Geoff guessed... I've tried isopropyl alcohol but its been there for 40 years and intends to stay... Anyone got a bright idea how to remove it ? I can only think of using "back to black" rubber paint to cover it but not sure how that will look :hmm:

[istari_knight]

http://i26.photobucket.com/albums/c129/istari_knight9/tumble_zps9be5952d.gif

[Marco]

Piccy no worky!

Marco.

[istari_knight]

Piccy no worky!

Marco.

How about now ?

S'ok, nothing important just a tumbleweed smilie as the new tweeters still haven't arrived :(

[Reffc]

Great refurb project James. Personally I wouldn't use any solvent based liquid near the drivers. If they sound ok, perhaps just leave them? If you need any help with crossover values/advice, I'd be glad to help, just ping me a PM.

[Reffc]

..

[istari_knight]

Great refurb project James. Personally I wouldn't use any solvent based liquid near the drivers. If they sound ok, perhaps just leave them? If you need any help with crossover values/advice, I'd be glad to help, just ping me a PM.

Thanks for that Paul, your probably right about leaving the surrounds as they are... I always leave grilles in situ so they wont be seen anyway just me being fussy ! I've read about using silicon spray to bring them back like new but who knows the long term effects ? As for the crossovers I'm hoping the chap on diyaudio knows what he's on about as I've followed his advice to the word :lol: I'm sure he does... Its all been calculated on LspCAD & several others have reported positive results.

One thing I am going to do is add a foam rubber ring to the tweeter faceplates [like Royd minstrels] we can say its for diffraction purposes but really its because the Seas faceplate is 5mm smaller in diameter than the HF2000, that way I can hide the 2.5mm gap & still use the original mounting method with 3 screw down clamps... Possibly with tweeter grilles too if they don't interfere with the sound too much they should look much closer to original then :eyebrows:

[Reffc]

Thanks for that Paul, your probably right about leaving the surrounds as they are... I always leave grilles in situ so they wont be seen anyway just me being fussy ! I've read about using silicon spray to bring them back like new but who knows the long term effects ? As for the crossovers I'm hoping the chap on diyaudio knows what he's on about as I've followed his advice to the word :lol: I'm sure he does... Its all been calculated on LspCAD & several others have reported positive results.

One thing I am going to do is add a foam rubber ring to the tweeter faceplates [like Royd minstrels] we can say its for diffraction purposes but really its because the Seas faceplate is 5mm smaller in diameter than the HF2000, that way I can hide the 2.5mm gap & still use the original mounting method with 3 screw down clamps... Possibly with tweeter grilles too if they don't interfere with the sound too much they should look much closer to original then :eyebrows:

Good plan James, but I'd be tempted to use (black coloured) felt in place of rubber hard edged rings and make sure that they don't protrude beyond the faceplates.

[Marco]

How about now ?

S'ok, nothing important just a tumbleweed smilie as the new tweeters still haven't arrived :(

Yup, working now - and it was worth the wait! :lol:

Marco.

[istari_knight]

That's a very good idea :thumbsup: ... Cheaper too !

[istari_knight]

Delivery from Falcon Acoustics arrived today ! :yay:

http://farm8.staticflickr.com/7434/10086657145_139f1f61cc_b.jpg (http://www.flickr.com/photos/87920837@N06/10086657145/)

Just awaiting the tweeter surround felt & some better speaker cable for the rewire :)

[istari_knight]

Spent the afternoon recapping the crossovers...

This is one of the original crossovers:

http://farm6.staticflickr.com/5534/10104588123_25fc0337e7_b.jpg (http://www.flickr.com/photos/87920837@N06/10104588123/)

Check out the production date on that cap :eyebrows:

http://farm8.staticflickr.com/7432/10104529106_c2a0cde68d_b.jpg (http://www.flickr.com/photos/87920837@N06/10104529106/)

After the recap with added resistors for the HF... Just needs a cleanup to get rid of the flux:

http://farm3.staticflickr.com/2815/10104467504_bc2ce17911_b.jpg (http://www.flickr.com/photos/87920837@N06/10104467504/)

Pair:

http://farm8.staticflickr.com/7341/10104465495_2dfae030d9_b.jpg (http://www.flickr.com/photos/87920837@N06/10104465495/)

I measured the original caps after removal & every single one was still within the 10% tolerance... No idea of ESR though as my meter doesn't have that function. I'll probably have a go at fitting the new tweeters tomorrow, the cutout hole needs slightly enlarging, with an additional cut-out to clear the terminals on the Seas tweeter so I'll have some fun with a rasp :)

[Firebottle]

I measured the original caps after removal & every single one was still within the 10% tolerance...

That's pretty impressive, but should be excellent with the new caps.
Dielectric films have come on a long way since '73,

:cool: Alan

[Reffc]

Nice neat job. Originals may still be fine even after 40 years. Any reason for choosing electrolytics to go back in over polyprops?

[istari_knight]

Nice neat job. Originals may still be fine even after 40 years. Any reason for choosing electrolytics to go back in over polyprops?

I've recapped 10 pairs of speakers now & every time I've replaced 'lytics with PP's the resulting sound has been worse... Much worse in some cases [always bright & brittle sounding.]

I'm pretty sure its due to the PP's having lower ESR than 'lytics the crossover was designed for, the chap over on diyaudio that calculated the adjustments for the Seas tweeters has also reworked the entire crossover should one like to replace the 'lytics with PP's - There is an additional 5 resistors to mimic the 'lytics ESR.

So nowadays I only replace like for like unless adding ESR compensation.. Which I couldn't be arsed with in this case :)

[Reffc]

Good point RE ESR. Aluminium electrolytics can have very high ESR values compared with poly's, but polys remain far more stable over time. Still, easier to design for like for like replacements using electrolytics.

[User211]

If I didn't spend time and money on messing with Apogees I'd be spending it on trying to get the best out of a pair of 66s. My brother used to run 25s for years until they got nicked.

Let's have a look at them then... or are the cabs so knackered it isn't a good idea? If they are then surely the speakers are worth doing something about that? No?

[istari_knight]

If I didn't spend time and money on messing with Apogees I'd be spending it on trying to get the best out of a pair of 66s. My brother used to run 25s for years until they got nicked.

Let's have a look at them then... or are the cabs so knackered it isn't a good idea? If they are then surely the speakers are worth doing something about that? No?

Patience grasshopper... All will be revealed :)

The seller told me they were her brothers, he bought them shortly after joining the RAF in the early 70's. They were his pride & joy along with the rest of his hifi which he only used on Saturday mornings... As a result they are in very good condition & only need some minor TLC to the cabinets.

[istari_knight]

One dodgy looking tweeter template :lol:

http://farm6.staticflickr.com/5331/10141098896_833d5a7109_b.jpg (http://www.flickr.com/photos/87920837@N06/10141098896/)

Cut out

http://farm8.staticflickr.com/7316/10140893874_92a8bd6063_b.jpg (http://www.flickr.com/photos/87920837@N06/10140893874/)

Crossover in

http://farm6.staticflickr.com/5548/10141050626_314c759ef5_b.jpg (http://www.flickr.com/photos/87920837@N06/10141050626/)

Tweeter in

http://farm6.staticflickr.com/5548/10141065093_bd7213b859_b.jpg (http://www.flickr.com/photos/87920837@N06/10141065093/)

Gold binders fitted :eek:

http://farm8.staticflickr.com/7397/10141027653_57ec53a88f_b.jpg (http://www.flickr.com/photos/87920837@N06/10141027653/)

The felts still on order so I'll have to remove the tweeters again to do that bit :cool:

[istari_knight]

These sound goood :wow: Tweeters sound spot on perfect & the new caps have really improved the mids... Bass is pretty much the same which is no bad thing ! 12" in a sealed cab = very nice :eyebrows:

[istari_knight]

Well I did say better pictures would come along at some point so here you go...

http://farm4.staticflickr.com/3831/10188794846_42b040be14_b.jpg (http://www.flickr.com/photos/87920837@N06/10188794846/)

http://farm4.staticflickr.com/3671/10188821933_02c9f2a5f4_b.jpg (http://www.flickr.com/photos/87920837@N06/10188821933/)

I've reluctantly had to put them on eBay due to some silly bills dropping on the doormat :rolleyes: but I really hope no one buys them ! ;)