Well .... there's the obvious stamped number on the basket. (Sorry, couldn't resist) I'd have to look at the numbers but there was a marked difference in Fa and Vas. Some of that could be a function of the surround, as the rubber on the one pair was quite deteriorated compared to the other.
""I found the attached view of the Ditton 66 crossover board on The Art of Sound forum. Renovation of Celestion 66 Studio Monitors - Page 2""
Thanks Galu ... I read the 1st 12 pages of this blog .. I'd not seen it befor ...
It sort of worried me about changing the voice of the speakers when I do the caps ... The author of the blog certainly seems knowledgable .. and I'm hoping ..slightly over obsessed ... he talks of recapping with mixed caps and then finding he has pushed the mid into the background a bit .. this might be due to his mixing of the types .. I don't know .. .. so this has left me cautious .. and so far I've not ordered the new caps as I'm still thinking on what sort... Ive added a pic of the 2 xovers .. as u can see thay are not identical .. so maybe I should just go for poly caps .. thru out ?
looking at the date stamps I think my pair are from late 73 made 3 days apart ..
27th nov and 1st Dec .. the drivers are the T1600 .. Ive not checked the donor 25's yet .. but from what Prairieboy says I think they are the T2619 with the thicker rubber surround Are these 2 types totally interchangeable ?
I've put glue blocks in .. 3 on the back and 2 on the front to sure up the bracing as I think the front chipboard probably has relaxed a little after nearly 50 years of vibrations ( there is befor and after pic ) But this has still not made it 100% air tight .. I'm hoping a little silicone bead at the point where the drivers meet the cabs will sort this when I do the caps ..
Thanks Galu ... I read the 1st 12 pages of this blog .. I'd not seen it befor ...
It sort of worried me about changing the voice of the speakers when I do the caps ... The author of the blog certainly seems knowledgable .. and I'm hoping ..slightly over obsessed ... he talks of recapping with mixed caps and then finding he has pushed the mid into the background a bit .. this might be due to his mixing of the types .. I don't know .. .. so this has left me cautious .. and so far I've not ordered the new caps as I'm still thinking on what sort... Ive added a pic of the 2 xovers .. as u can see thay are not identical .. so maybe I should just go for poly caps .. thru out ?
looking at the date stamps I think my pair are from late 73 made 3 days apart ..
27th nov and 1st Dec .. the drivers are the T1600 .. Ive not checked the donor 25's yet .. but from what Prairieboy says I think they are the T2619 with the thicker rubber surround Are these 2 types totally interchangeable ?
I've put glue blocks in .. 3 on the back and 2 on the front to sure up the bracing as I think the front chipboard probably has relaxed a little after nearly 50 years of vibrations ( there is befor and after pic ) But this has still not made it 100% air tight .. I'm hoping a little silicone bead at the point where the drivers meet the cabs will sort this when I do the caps ..
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What does Fa and Vas mean ?
And you talked of different measurements in another post .. ?
thanks for your help .. Dom
I would go for poly caps throughout. You don't know what these speakers sounded like when the original capacitors were new, so why anguish over what difference poly caps might make to the sound now?
Re interchangeability of bass drivers - seems you'll have to do it anyway as continuing to use drivers with cracked and brittle surrounds is not an option.
There's lots of information out there on Theile/Small parameters such as Vas, for example:
Thiele/Small Parameters Explained. A beginner's guide.
Understanding Loudspeaker Data | Eminence Speaker
Re interchangeability of bass drivers - seems you'll have to do it anyway as continuing to use drivers with cracked and brittle surrounds is not an option.
There's lots of information out there on Theile/Small parameters such as Vas, for example:
Thiele/Small Parameters Explained. A beginner's guide.
Understanding Loudspeaker Data | Eminence Speaker
see : celestion 66 needs midrange , started by Mr. White, all 128 pages worth
started in 2006 last post in 2019 get ready for a very long read
started in 2006 last post in 2019 get ready for a very long read
I've finally ordered the caps today ... 🙂
Falcon Acoustics have just managed to restock thier suppy of alcaps ..... so as it goes my procrastination paid off 🙂
After reading more of the blog Galu linked in this thread I went with this .. using Solen 400v for the polyprop and the 30uf is not LL...
Falcon Acoustics have just managed to restock thier suppy of alcaps ..... so as it goes my procrastination paid off 🙂
After reading more of the blog Galu linked in this thread I went with this .. using Solen 400v for the polyprop and the 30uf is not LL...
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Looks good!
By the way, I don't know why I said poly caps throughout - the larger value caps call out for electrolytics!
I await your report on how the renovated speakers perform.
By the way, I don't know why I said poly caps throughout - the larger value caps call out for electrolytics!
I await your report on how the renovated speakers perform.
So, Dom, you think the problem lies with one of your crossover boards.
All I can suggest at the moment is to (a) carefully compare the wiring on the suspect board with that on the good board, and, (b) check for a dry solder joint or joints on the suspect board.
There is unlikely to be a component (capacitor/inductor) fault.
All I can suggest at the moment is to (a) carefully compare the wiring on the suspect board with that on the good board, and, (b) check for a dry solder joint or joints on the suspect board.
There is unlikely to be a component (capacitor/inductor) fault.
Hi Galu Thanks for your much needed help. 🙂
I've numbered the solder joints on the diagram .
So after a long day last week ,(so not at my best ) I redid the joins at 2 and 3 and added a bit more solder at 8 ... with no change 🙁
Any other suggestions ?
I was wondering what logic steps I could take to isolate the possible dry join ...
Would it damage any thing ??????
If i was to say .... disconect the driver at 2 and temporary connect it to say 5 or 12 ??
T.I.A Dom
I've numbered the solder joints on the diagram .
So after a long day last week ,(so not at my best ) I redid the joins at 2 and 3 and added a bit more solder at 8 ... with no change 🙁
Any other suggestions ?
I was wondering what logic steps I could take to isolate the possible dry join ...
Would it damage any thing ??????
If i was to say .... disconect the driver at 2 and temporary connect it to say 5 or 12 ??
T.I.A Dom
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EDIT
""So after a long day last week ,(so not at my best ) I redid the joins at 2 and 3 and added a bit more solder at 8 ... with no change""
I just redid the driver leads at 2 and 3 not redoing the caps at 2 and 3 ... they appeared to be sound at the time ... but I was tired
""So after a long day last week ,(so not at my best ) I redid the joins at 2 and 3 and added a bit more solder at 8 ... with no change""
I just redid the driver leads at 2 and 3 not redoing the caps at 2 and 3 ... they appeared to be sound at the time ... but I was tired
As for the crossover fix, it may be helpful if you attach photos of your upgraded crossovers.
I would reflow ALL solder joints on the suspect board.
Are you absolutely sure that both mids work perfectly when connected to the 'good' crossover?
I would reflow ALL solder joints on the suspect board.
Are you absolutely sure that both mids work perfectly when connected to the 'good' crossover?
Hi ..
Yeah I swopped them over this morning .. just to make sure again .. Ive now put connector blocks between the drivers and the PCB to avoid any unnessercery .soldering
The problem board is the board marked B bottom left of board on right
Here is a pic of the recapped Xover taken befor I redid joints 2 and 3.
Thanks for the link to the thread 🙂 gonna be a long read 🙁
Yeah I swopped them over this morning .. just to make sure again .. Ive now put connector blocks between the drivers and the PCB to avoid any unnessercery .soldering
The problem board is the board marked B bottom left of board on right
Here is a pic of the recapped Xover taken befor I redid joints 2 and 3.
Thanks for the link to the thread 🙂 gonna be a long read 🙁
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Look at the ALCAP at the very bottom of the board B.
Its left hand lead doesn't connect to the inductor above like the one on the good board.
Its left hand lead doesn't connect to the inductor above like the one on the good board.
I'm not sure thats not a short coming in the photo.. I will have a look this week ... fingers crossed 🙂 thanks for your help .. .
Any other logic steps I can take while Ive got them open ?? ..
Any other logic steps I can take while Ive got them open ?? ..
That 30uF ALCAP is not connected to point 11 as per the circuit diagram.
It's easy to make a wiring mistake like this.
Continue to compare the boards for any other errors in the wiring.
It's easy to make a wiring mistake like this.
Continue to compare the boards for any other errors in the wiring.
After thinking about it ... I'm more hopefull you might be on the money .. There is some sound about 10 or 20 % from the driver .. As a total novice looking at the diagram this join "11" is in the right place for the symptoms 🙂 .. but I'm in above my pay grade 🙂