Hey all,
I just picked up a pair of Ditton 44s super cheap as a project. The cabs are a bit rough, the grilles are currently covered in a thick velvet curtain material and the tweeters have been replaced by some truly horrible Motorola things, so I have my work cut out!
I've ordered some Seas 19TFF1, speaker cloth and some wool felt for the front baffles, next up is the crossover.
I've heard mention in all the usual places of an upgraded crossover design by Istari_knight, but the posts are fairly old and the images are dead. I don't suppose anyone has a crossover schematic for the Ditton 44s with a Seas tweeter?
Thanks!
I just picked up a pair of Ditton 44s super cheap as a project. The cabs are a bit rough, the grilles are currently covered in a thick velvet curtain material and the tweeters have been replaced by some truly horrible Motorola things, so I have my work cut out!
I've ordered some Seas 19TFF1, speaker cloth and some wool felt for the front baffles, next up is the crossover.
I've heard mention in all the usual places of an upgraded crossover design by Istari_knight, but the posts are fairly old and the images are dead. I don't suppose anyone has a crossover schematic for the Ditton 44s with a Seas tweeter?
Thanks!
There are some schematics:
post #54
Celestion Ditton 44 sounding muddy
post#12
Custom Celestion Ditton project - need expert opinions
post #54
Celestion Ditton 44 sounding muddy
post#12
Custom Celestion Ditton project - need expert opinions
Last edited:
Thanks for the reply. I'm attempting to make a Frankenstein crossover from the original and an updated crossover for the 66 with a Seas tweeter. I have a very limited knowledge of electronics so I could use a little help! From what I read the 44 and 66 are supposed to be very similar in the mid/high, but as far as I can tell they're totally different. Am I right in thinking I can just replace the originals like-for-like in everything but the tweeter path, or does this new design change the crossover point, therefore requiring changes to the mid? I've attached the version I'm looking at, as well as the original. Thanks!
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Also, there's no mention of the value of L1, I'm assuming that stays the same? I don't usually bother replacing inductors, as a long piece of wire is a long piece of wire no matter how old it is!
I am afraid I won't be able to help you in this matter in the days to come, perhaps later but I can not promise anything.
I totally understand. Perhaps it is time I actually learned how a crossover works - I've been a professional audio engineer for nearly 10 years, it's about time!
There are a couple of threads on here that dealt extensively with the 44 crossover with the addition of the Seas tweeter, so check those for info.
I have done the crossovers, and been inside the cabinets, and to be blunt, the cabinets are crap. If you're not up to making well braced, solid, replacements, be prepared to add a lot of bracing as there is nothing from the front to rear baffle (the mid boxes don't go back that far). You can make some triangular pieces of wood and bond them with construction adhesive from the baffles to the sides. Also, check the midrange boxes to ensure they are actually sealed - mine were not.
I have done the crossovers, and been inside the cabinets, and to be blunt, the cabinets are crap. If you're not up to making well braced, solid, replacements, be prepared to add a lot of bracing as there is nothing from the front to rear baffle (the mid boxes don't go back that far). You can make some triangular pieces of wood and bond them with construction adhesive from the baffles to the sides. Also, check the midrange boxes to ensure they are actually sealed - mine were not.
Mine are sealed as far as I can tell, but bracing sounds like a very good idea, tapping on the box creates all sorts of resonances.
So my Seas tweeters arrived, and the dittons sound surprisingly good without any modification! However, I have a question regarding tweeter polarity. As someone who does critical listening as a trade, I was expecting to immediately clock whether it's right or not, but I'm actually really struggling.
So I have a red and black wire, but I don't know for sure if the red is actually the real positive or the negative (which is supposed to connect to the positive on the driver). The issue is the speaker actually sounds pretty good both ways. Red - Positive results in a fairly upper-mid voiced speaker (which I would assume to be the result of the crossover point being in phase, but isn't what I expected from what I've read of these speakers). Red - Negative is a slightly more scooped sound, with more top end. I definitely prefer the Red-Red sound.
So the question is, is the tweeter polarity reversed to reduce the upper mids in the original design, or is it just to bring them in phase?
So my Seas tweeters arrived, and the dittons sound surprisingly good without any modification! However, I have a question regarding tweeter polarity. As someone who does critical listening as a trade, I was expecting to immediately clock whether it's right or not, but I'm actually really struggling.
So I have a red and black wire, but I don't know for sure if the red is actually the real positive or the negative (which is supposed to connect to the positive on the driver). The issue is the speaker actually sounds pretty good both ways. Red - Positive results in a fairly upper-mid voiced speaker (which I would assume to be the result of the crossover point being in phase, but isn't what I expected from what I've read of these speakers). Red - Negative is a slightly more scooped sound, with more top end. I definitely prefer the Red-Red sound.
So the question is, is the tweeter polarity reversed to reduce the upper mids in the original design, or is it just to bring them in phase?
Fantastic, this was exactly what I needed! I've been trawling through 50+ page arguments on which capacitor brands sound better looking for this exact information. So by the looks of it, it's exactly the same but with a couple of resistors to adjust for the different impedance?
No I'm going to do a recap (I was going to do that anyway, but I've just hooked up the other speaker and there are some discrepancies between left/right) but I was just planning on replacing the electrolytics and leaving any poly caps.
A couple of photos just for fun. For the record, the tweeter wires were swapped at the crossover end so red-positive was correct.
I've always considered "burn-in" a psychoacoustic phenomenon, but after leaving these running for about half an hour they're sounding noticeably more balanced and the low end has definitely loosened up. I'm guessing they've been sat unused for a long time so they just needed to blast out some dust! I'm wondering if the bass drivers would benefit from being rotated, I do that every couple of years with my Leak 3090s to avoid them sagging.
The bracing doesn't look as terrible as I thought, there's a bit of wood bracing the sides, and the front-back is effectively being braced by the mid-range enclosure. I wouldn't describe them as particularly "fast", especially for a sealed box but I don't hate that. My daily listening speakers are PMC TB2s which are extremely quick, the Dittons are now my reggae/blues speakers :-D
I've always considered "burn-in" a psychoacoustic phenomenon, but after leaving these running for about half an hour they're sounding noticeably more balanced and the low end has definitely loosened up. I'm guessing they've been sat unused for a long time so they just needed to blast out some dust! I'm wondering if the bass drivers would benefit from being rotated, I do that every couple of years with my Leak 3090s to avoid them sagging.
The bracing doesn't look as terrible as I thought, there's a bit of wood bracing the sides, and the front-back is effectively being braced by the mid-range enclosure. I wouldn't describe them as particularly "fast", especially for a sealed box but I don't hate that. My daily listening speakers are PMC TB2s which are extremely quick, the Dittons are now my reggae/blues speakers :-D
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How does this look? I don't want to go crazy with it, just want to replace them with reasonable quality caps. I couldn't find any 24uf so I'm going for two 100v 12uf. I'm guessing I want to avoid the low-loss caps because of the lower ESR?
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Check the midrange boxes again, mine did not contact that big, unbraced, chipboard back panel. It was easy to bond (construction adhesive) a batten to the bottom of the midrange box and to the back panel.
Use whatever you're comfortable with. I tend to use Solens because I'm not willing to pay crazy prices for 'elite' caps, and being in Canada Solen is easy to order from.
Just a quick update on these. Did a recap and replaced the useless terminals. Someone had really done a number on the soldering in there - none of the components had been replaced, but there was definitely evidence of some repair to wiring. I checked the midrange enclosures and they were well sealed - haven't looked at bracing yet.
They're sounding much more balanced. The tweeters are at the perfect level and left and right are matching much better now, I think maybe the crossover points had drifted somewhere along the way. The imaging still isn't great if I'm honest, there's a real lack of centre image. It could just be a positioning thing, or maybe I'm expecting too much from a 50 year old speaker?
Huge thanks to prairieboy, your schematics and advice were invaluable!
That big, detracting, lip doesn't help. I don't think that line was ever truly outstanding. Celestion's 2 series - 442, 662, 551 - were all much better, and other than being power hungry, I liked the UL series.
You'll do better sawing it. It's a bit of real wood, and then chipboard, so it won't leave a presentable surface (there was quite a gap if I remember correctly). I cut the lip off, routed a rabbet, and put in a solid teak strip. I have a complete wood working shop, so I had the tools, and wood. You may not be so fortunate.