Hey Qwin,
Thanks for the offer, I may take you up on that. There's a local hobby shop that sells a kit to make your own PCB, and I am thinking I will go that route but we'll see how far I get with all of this. Currently I just fitted a bunch of components onto some cardboard to see how it might fit/work out. Seems OK.
As for the caps I am going with the later PCB version crossover which uses the 24uF LL and not an additional 6uF. My thinking is that for some reason they thought it was better than the original crossover and, I did some research and found that there are MD500s in the 66s with the tagged board so I don't think it has any correlation to do with the MF500 vs. MD500. So, with that thinking I am going to go with the 24uF. As it is, that is how I have them wired up now and I am pleased with the sound so I am not going to change it. I snagged an 8uF + 16uF. Like you say not ideal, but it's better than the old aging Elcaps.
And yes, the Elcaps are definitely way past their prime. I have recapped many speakers (over a dozen, using Alcaps) that use Elcaps and all of them made significant improvements. The biggest one was a pair of Celestion Ditton 25s that had the black baffle and were from the early 70s. The older they are, the bigger the difference it makes. I am 100% confident that when I swap out the Elcaps for the Alcaps the midrange is going to snap in place as I still detect a veil over the midrange that is holding them back somewhat.
Anyway, I think you should stick with your passive crossovers, but if it were me I would use Alcap lytics on the midrange filter without any resistors and just keep it to the original design. Messing with polypropylene capacitors is deviating from the original design and, while it may make improvements in some areas, I think it will detract in others. Separating the inductors onto a larger board on its own should be a good improvement over the original design, as well as using the Seas tweeters, so going any further then that, in my opinion, is an exercise in simply experimenting.
Of course, YMMV with all that said. I'll be sure to report on my findings when the Alcaps come in and let you know how it goes. I am pretty confident at that point I will be done working on these, and will finally have a satisfying, original and fresh sounding pair of Ditton 66s that I can sit back, relax and enjoy.
Thanks for the offer, I may take you up on that. There's a local hobby shop that sells a kit to make your own PCB, and I am thinking I will go that route but we'll see how far I get with all of this. Currently I just fitted a bunch of components onto some cardboard to see how it might fit/work out. Seems OK.
As for the caps I am going with the later PCB version crossover which uses the 24uF LL and not an additional 6uF. My thinking is that for some reason they thought it was better than the original crossover and, I did some research and found that there are MD500s in the 66s with the tagged board so I don't think it has any correlation to do with the MF500 vs. MD500. So, with that thinking I am going to go with the 24uF. As it is, that is how I have them wired up now and I am pleased with the sound so I am not going to change it. I snagged an 8uF + 16uF. Like you say not ideal, but it's better than the old aging Elcaps.
And yes, the Elcaps are definitely way past their prime. I have recapped many speakers (over a dozen, using Alcaps) that use Elcaps and all of them made significant improvements. The biggest one was a pair of Celestion Ditton 25s that had the black baffle and were from the early 70s. The older they are, the bigger the difference it makes. I am 100% confident that when I swap out the Elcaps for the Alcaps the midrange is going to snap in place as I still detect a veil over the midrange that is holding them back somewhat.
Anyway, I think you should stick with your passive crossovers, but if it were me I would use Alcap lytics on the midrange filter without any resistors and just keep it to the original design. Messing with polypropylene capacitors is deviating from the original design and, while it may make improvements in some areas, I think it will detract in others. Separating the inductors onto a larger board on its own should be a good improvement over the original design, as well as using the Seas tweeters, so going any further then that, in my opinion, is an exercise in simply experimenting.
Of course, YMMV with all that said. I'll be sure to report on my findings when the Alcaps come in and let you know how it goes. I am pretty confident at that point I will be done working on these, and will finally have a satisfying, original and fresh sounding pair of Ditton 66s that I can sit back, relax and enjoy.
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Hi Jeffrey
When it comes to 66's I compiled a brief history on another site as there are so many errors and wrong statements early in this thread.
There were two basic tag board variants on early 66's using MF drivers and 30uf.
PCB boards were for MD drivers. As was 24uf.
There may have been some cross over as old stock was run down at the point of change.
One thing that keeps cropping up is that there was a definitive change over point, that at the time Blackies became Woodies that the mid driver changed and PCB was introduced. Not so, the product changed gradualy over several years.
Early woodies had tag board crossovers for instance. But I would say that if you have an MD driver you should have a PCB but I know there are exceptions.
Just as an aside, I have tried 7 variations of caps in the mid range this afternoon including putting originals back in. Single 30uf normal Alcap for a start. Then 25uf LL+5uf normal Alcap. Then Solen 25uf PP+5uf normal Alcap. Then two 15uf LL Mundorf Lytics. All without any resistors or L-Pads. then back to original CCL/Elcap combo and on to Ansar PP with L-Pad.
This is a typical listening day for me - all caps have many hours on them before use, 80hrs min.
Going to the Alcaps over old Elcaps in the mids will give a brighter more transparent presentation (slightly) but is harsher in the upper mids. So its win/looze.
Unfortunately, going to Alcaps is deviating from the original design as they behave differently. The much talked about ESR element and disipation which acts as a damping factor varies from make to make, more so ESR. I've tried three different Lytics today and they all sound different and have different effects on audible resonance.
Any cap make/type other than the original type is going to be a compromise. Its whether you can find one you can live with, I haven't.
A friend in the trade recons it could be inductor interaction causing all the problems, he's not a big fan of 66's, guess I will find out soon enough with the new boards.
If you go active you take the cap differences out of the equation. You introduce a whole new can of worms but that is another story.
I recently heard an active set of Maggies, the guy said he would never go back to passive. They did sound good.
He offered to bring his DSP to mine and dial in my x-over values and see how the 66's sound. If I get the 6 channel amp he could do that. Most active x-overs are at line level and sit between the Pre amp and 6 channels of power amp needed for a three way pair of speakers. That is one of the down sides, your budget for power amp has to be spread accross three stereo amps or 6 mono's. I am looking at putting a foot in the water by getting a 6 channel AV amp with gain adjustment on each channel. No L-Pad type of attenuation is needed, if a driver is too forward, just turn the gain down to integrate with the others. This also means drivers of different impedance and sensitivity are easily catered for. There are some compelling points to draw you in.
If the new inductor placement does sort things out, the 6 channel amp won't be redundent as I could use it to Tri-Amp the passive crossover.
When it comes to 66's I compiled a brief history on another site as there are so many errors and wrong statements early in this thread.
There were two basic tag board variants on early 66's using MF drivers and 30uf.
PCB boards were for MD drivers. As was 24uf.
There may have been some cross over as old stock was run down at the point of change.
One thing that keeps cropping up is that there was a definitive change over point, that at the time Blackies became Woodies that the mid driver changed and PCB was introduced. Not so, the product changed gradualy over several years.
Early woodies had tag board crossovers for instance. But I would say that if you have an MD driver you should have a PCB but I know there are exceptions.
Just as an aside, I have tried 7 variations of caps in the mid range this afternoon including putting originals back in. Single 30uf normal Alcap for a start. Then 25uf LL+5uf normal Alcap. Then Solen 25uf PP+5uf normal Alcap. Then two 15uf LL Mundorf Lytics. All without any resistors or L-Pads. then back to original CCL/Elcap combo and on to Ansar PP with L-Pad.
This is a typical listening day for me - all caps have many hours on them before use, 80hrs min.
Going to the Alcaps over old Elcaps in the mids will give a brighter more transparent presentation (slightly) but is harsher in the upper mids. So its win/looze.
Unfortunately, going to Alcaps is deviating from the original design as they behave differently. The much talked about ESR element and disipation which acts as a damping factor varies from make to make, more so ESR. I've tried three different Lytics today and they all sound different and have different effects on audible resonance.
Any cap make/type other than the original type is going to be a compromise. Its whether you can find one you can live with, I haven't.
A friend in the trade recons it could be inductor interaction causing all the problems, he's not a big fan of 66's, guess I will find out soon enough with the new boards.
If you go active you take the cap differences out of the equation. You introduce a whole new can of worms but that is another story.
I recently heard an active set of Maggies, the guy said he would never go back to passive. They did sound good.
He offered to bring his DSP to mine and dial in my x-over values and see how the 66's sound. If I get the 6 channel amp he could do that. Most active x-overs are at line level and sit between the Pre amp and 6 channels of power amp needed for a three way pair of speakers. That is one of the down sides, your budget for power amp has to be spread accross three stereo amps or 6 mono's. I am looking at putting a foot in the water by getting a 6 channel AV amp with gain adjustment on each channel. No L-Pad type of attenuation is needed, if a driver is too forward, just turn the gain down to integrate with the others. This also means drivers of different impedance and sensitivity are easily catered for. There are some compelling points to draw you in.
If the new inductor placement does sort things out, the 6 channel amp won't be redundent as I could use it to Tri-Amp the passive crossover.
Where did you get the information that the MF was the earlier driver, and the MD was the later driver? And that it changed from the black baffle, TBC board, to the wood fronted, PCB board?
Not to discount what you're saying, but unless you worked at Celestion, it's really just speculation at best. They were the only ones that knew what happened with this model and why. I'd like to know what the changes were, but with all my digging on the internet, I have yet to find any definitive information. Heck, we don't even know the real difference between the MF500 and MD500. Only that one has a higher and lower rated power rating and for some reason they sound different. What that reason is, who knows.
Anyway, I question everything, and with regard to your experiment with the Elcaps I am still apprehensive about your findings. Especially since I have recapped many British speakers (IMF, Kef, Celestion) that used these capacitors and they always sounded worse before recapping with Alcaps. I can't imagine that the 66s are a special case in this regard. Especially since I recapped a pair of 25s and they made a huge improvement - it went from, these are OK speakers - to, wow, these are great to listen to.
Again, I'm sure that what you're saying is what you've found, but it doesn't line up with my previous experiences, of which I've had many. I am beginning to wonder if this is something related to location, perhaps the dry air here affects the capacitors negatively over the years. Or something like that? I have no idea.
Anyway, I am curious about where you found this information about the MD vs. MF500 because I have yet to find anything really concrete in that regard.
Not to discount what you're saying, but unless you worked at Celestion, it's really just speculation at best. They were the only ones that knew what happened with this model and why. I'd like to know what the changes were, but with all my digging on the internet, I have yet to find any definitive information. Heck, we don't even know the real difference between the MF500 and MD500. Only that one has a higher and lower rated power rating and for some reason they sound different. What that reason is, who knows.
Anyway, I question everything, and with regard to your experiment with the Elcaps I am still apprehensive about your findings. Especially since I have recapped many British speakers (IMF, Kef, Celestion) that used these capacitors and they always sounded worse before recapping with Alcaps. I can't imagine that the 66s are a special case in this regard. Especially since I recapped a pair of 25s and they made a huge improvement - it went from, these are OK speakers - to, wow, these are great to listen to.
Again, I'm sure that what you're saying is what you've found, but it doesn't line up with my previous experiences, of which I've had many. I am beginning to wonder if this is something related to location, perhaps the dry air here affects the capacitors negatively over the years. Or something like that? I have no idea.
Anyway, I am curious about where you found this information about the MD vs. MF500 because I have yet to find anything really concrete in that regard.
This DIY stuff eats up a lot of time and money
I refurbished my two pairs some years back. At the time Alan had not yet come up with his ESR compensation values for Poly caps. I replaced all of my caps with Solens because the Solen store in Canada was almost giving away their stock of non-RoHS PP caps in order to make room for the new supply of RoHS (environmental) ones. Had I instead used mostly new electrolytic caps, the results would probably have been just as satisfactory.
Having previously played around with adding different resistor values to crossovers , I've never been confident that those low resistor values for the ESR compensation would actually be audible and worth the trouble of redoing the circuit board a second time. I did measure the values on the original electrolytics and they were way out of spec, putting the mids and tweeters in jeopardy.
If I were starting a recap project today I would do two additional things. I would put a variable Lpad on the tweeter. This facilitates fine tuning in the room, as well as providing attenuation for alternate tweeters. The other thing I would do is fabricate an external crossover. It's a harsh environment inside the speaker and the caps can easily become microphonic.
Good luck with your projects Jeffrey and Qwin.
I refurbished my two pairs some years back. At the time Alan had not yet come up with his ESR compensation values for Poly caps. I replaced all of my caps with Solens because the Solen store in Canada was almost giving away their stock of non-RoHS PP caps in order to make room for the new supply of RoHS (environmental) ones. Had I instead used mostly new electrolytic caps, the results would probably have been just as satisfactory.
Having previously played around with adding different resistor values to crossovers , I've never been confident that those low resistor values for the ESR compensation would actually be audible and worth the trouble of redoing the circuit board a second time. I did measure the values on the original electrolytics and they were way out of spec, putting the mids and tweeters in jeopardy.
If I were starting a recap project today I would do two additional things. I would put a variable Lpad on the tweeter. This facilitates fine tuning in the room, as well as providing attenuation for alternate tweeters. The other thing I would do is fabricate an external crossover. It's a harsh environment inside the speaker and the caps can easily become microphonic.
Good luck with your projects Jeffrey and Qwin.
Jeffery, Jeffrey, it is not speculation at all, if you read some of what I have posted on the subject you will have seen that blackies were produced for the first two years. All of this is common knowledge. I have posted Cellestion documentation including circuit diagrams, parts lists and photographs for the tag board and PCB x-overs and the brochure for the launch of the wood fronted version. Note also that some caps (CCL) had dates on them and some, not all cabinets had the date of manufacture stamped inside, this has all helped date the sequence of events. I have early and late drivers, and some from B&O products. So I have done a fair bit of digging to come up with what I say.
The MF500 was the original and world famous mid driver that gave the Celestion 66's their reputation, the tweeter was state of the art as well, Google it and you will find reference to this in press articicles when the product was launched. The MD500 was introduced later with a higher power rating, again well documented. The MF500 is in my opinion the better driver and remains flat to 7kHz, the later driver, while having a higher power rating, falls off a cliff at 4.5kHz and loozes 7dB by the 5kHz cross over point. The MF rolls off slowly from 7kHz and is only 7dB down by 10kHz. This is why B&O continued using the early driver in their Beovox 5700 model speakers, which were crossed over at 6kHz. These figures are on the web and even in plots earlier in this thread. I just prefere the sound of the earlier MF driver, the MD is a bit bolder, more forward and some would say more dynamic, but it depends what you listen too and personal preferences, if out and out power is not an issue.
For what its worth, my old Elcaps are in remarkably good phisical condition and measure well, I posted the measurements, earlier on and only the big 72uf were a good way off spec. I just don't trust parts of this age, not to fail on me.
SBA - Thanks, three way x-overs are never easy to restore. Give me a two way anytime.
The MF500 was the original and world famous mid driver that gave the Celestion 66's their reputation, the tweeter was state of the art as well, Google it and you will find reference to this in press articicles when the product was launched. The MD500 was introduced later with a higher power rating, again well documented. The MF500 is in my opinion the better driver and remains flat to 7kHz, the later driver, while having a higher power rating, falls off a cliff at 4.5kHz and loozes 7dB by the 5kHz cross over point. The MF rolls off slowly from 7kHz and is only 7dB down by 10kHz. This is why B&O continued using the early driver in their Beovox 5700 model speakers, which were crossed over at 6kHz. These figures are on the web and even in plots earlier in this thread. I just prefere the sound of the earlier MF driver, the MD is a bit bolder, more forward and some would say more dynamic, but it depends what you listen too and personal preferences, if out and out power is not an issue.
For what its worth, my old Elcaps are in remarkably good phisical condition and measure well, I posted the measurements, earlier on and only the big 72uf were a good way off spec. I just don't trust parts of this age, not to fail on me.
SBA - Thanks, three way x-overs are never easy to restore. Give me a two way anytime.
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These are the circuit boards I made from "Paxolin" sheet.
Brass eyelets with 3mm through holes have been fitted for use as point to point solder contacts. The six large holes just off centre line up with the six binding posts I have already fitted to the cabinet. The boards will be secured using 16mm M4 stand off's, this will position them just above the block of wood on the rear face of the lower compartment, that Celestion added for mounting the binding posts. Plus give additional clearance to accommodate the plastic spacer bar that each pair of binding posts I have fitted is secured by.
Hey Ken,
I did some more digging and found your post on The Art Of Sound forums.
There is some interesting information in there. While what you say seems logical, I still can't help but feel like we really don't know for sure. I admit your experimenting is a lot greater than mine when it comes to the 66, so I'm sure you know some things more than I do when it comes to these. Have you taken apart the MD500 and MF500 and been able to see any differences in the construction? I'm wary of taking mine apart but I think I read that you took yours apart and cleaned them up.
One thing that came to mind while we are discussing this is I had forgotten I've been running my crossovers with the inductors spread apart since the beginning. If this is making as significant a difference as it seems it would, then this could account for the differences in our findings. I'll be very interested to read your findings when you put the new crossovers in and see how you feel about their sound afterwards. I haven't put the all original crossovers in mine to compare side by side because the capacitors would be different and I can't ascertain a clear difference between the two. That and I don't feel like rewiring one of the speakers just to use the old crossover.
Also I have to say you are doing a splendid job on the restoration of your 66s. I'm most impressed by your custom plinths that you created as well as the label with the tri-amp capability. It looks really nice, and I hope you get to a point where you are totally satisfied with these as you've put a ton of work into them. Maybe together we can figure these bloody speakers out!
Anyway, keep me posted about your findings on the crossovers Ken.
Jeffrey
I did some more digging and found your post on The Art Of Sound forums.
There is some interesting information in there. While what you say seems logical, I still can't help but feel like we really don't know for sure. I admit your experimenting is a lot greater than mine when it comes to the 66, so I'm sure you know some things more than I do when it comes to these. Have you taken apart the MD500 and MF500 and been able to see any differences in the construction? I'm wary of taking mine apart but I think I read that you took yours apart and cleaned them up.
One thing that came to mind while we are discussing this is I had forgotten I've been running my crossovers with the inductors spread apart since the beginning. If this is making as significant a difference as it seems it would, then this could account for the differences in our findings. I'll be very interested to read your findings when you put the new crossovers in and see how you feel about their sound afterwards. I haven't put the all original crossovers in mine to compare side by side because the capacitors would be different and I can't ascertain a clear difference between the two. That and I don't feel like rewiring one of the speakers just to use the old crossover.
Also I have to say you are doing a splendid job on the restoration of your 66s. I'm most impressed by your custom plinths that you created as well as the label with the tri-amp capability. It looks really nice, and I hope you get to a point where you are totally satisfied with these as you've put a ton of work into them. Maybe together we can figure these bloody speakers out!
Anyway, keep me posted about your findings on the crossovers Ken.
Jeffrey
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Another update.
I just finished putting together another crossover on cardboard so that both speakers are exactly the same. No, this is not permanent, just a test to see if I like the way they sound in this configuration.
I am currently using the following on the crossovers:
Speaker 1 - Left
Celestion Ditton 66 "Blackies" Inductors (original)
Alcap 72uF 100V x2
Elcap 24uF LL (original)
Elcap 4uF (original)
3.6uF 430V Solen
11uF 430V Solen
30ohm Resistor (parallel with tweeter)
Speaker 2 - Right
Celestion Ditton 66 "Woodies" Inductors (original)
Alcap 72uF 100V x2
Elcap 24uF LL (original)
Elcap 4uF (original)
3.6uF 430V Solen
11uF 430V Solen
30ohm Resistor (parallel with tweeter)
So now they are identical, except I have used the later, P.C.C. inductors in one and the original T.B.C. inductors in the other. Ken, you had mentioned that you were curious if perhaps the old inductors on the "Blackies" due to the way they were made might have been causing issues, so I decided to take the more tightly wound and better made inductors from the later P.C.C. crossover and put them in one just to see.
First of all, now that the crossovers are essentially identical, I noticed an improvement in the midrange. It became smoother and richer. This is likely a result of replacing the mylar film capacitors in the one I redid back to the 4uF Elcap so that now the capacitors match between the two. I think in part though, some of this may be due to the better layout of the crossover as well as I fastened the parts to the cardboard so they are not loose anymore. I'm impressed, these continue to improve so this is beginning to become a fun project again.
I will add more once I have done some A/Bing against each one to see if the later inductors improved the sound or not.
I just finished putting together another crossover on cardboard so that both speakers are exactly the same. No, this is not permanent, just a test to see if I like the way they sound in this configuration.
I am currently using the following on the crossovers:
Speaker 1 - Left
Celestion Ditton 66 "Blackies" Inductors (original)
Alcap 72uF 100V x2
Elcap 24uF LL (original)
Elcap 4uF (original)
3.6uF 430V Solen
11uF 430V Solen
30ohm Resistor (parallel with tweeter)
Speaker 2 - Right
Celestion Ditton 66 "Woodies" Inductors (original)
Alcap 72uF 100V x2
Elcap 24uF LL (original)
Elcap 4uF (original)
3.6uF 430V Solen
11uF 430V Solen
30ohm Resistor (parallel with tweeter)
So now they are identical, except I have used the later, P.C.C. inductors in one and the original T.B.C. inductors in the other. Ken, you had mentioned that you were curious if perhaps the old inductors on the "Blackies" due to the way they were made might have been causing issues, so I decided to take the more tightly wound and better made inductors from the later P.C.C. crossover and put them in one just to see.
First of all, now that the crossovers are essentially identical, I noticed an improvement in the midrange. It became smoother and richer. This is likely a result of replacing the mylar film capacitors in the one I redid back to the 4uF Elcap so that now the capacitors match between the two. I think in part though, some of this may be due to the better layout of the crossover as well as I fastened the parts to the cardboard so they are not loose anymore. I'm impressed, these continue to improve so this is beginning to become a fun project again.
I will add more once I have done some A/Bing against each one to see if the later inductors improved the sound or not.
OK, so I did some A/Bing of both speakers.
There is a difference between the two! This surprised me. And not a subtle difference, either, it was fairly noticeable. The speaker with the "blackies" inductors sounded more closed in and less natural. It had a veil over the midrange (I imagine this must have been what I was hearing before). The speaker with the "woodies" inductors had a more open sound to it. more compelling and more balanced.
However, I thought, this could be a result of the capacitors as well - maybe one of the Elcaps is on its last legs causing the difference. But to sort this out, I decided to just put the "woodies" inductors in the other speaker and see if the difference remained.
I just finished wiring it back up, and sure enough the gap decreased quite a bit. There's a very, very subtle difference between the two, but not like before.
It would appear that the inductors on the TBC crossovers are maybe not as good as the inductors on the later PCC crossovers. They appear to be the same in terms of gauge of wiring and of course their mH rating. And as inductors don't really age, I can't think of any other reason.
There is a difference between the two! This surprised me. And not a subtle difference, either, it was fairly noticeable. The speaker with the "blackies" inductors sounded more closed in and less natural. It had a veil over the midrange (I imagine this must have been what I was hearing before). The speaker with the "woodies" inductors had a more open sound to it. more compelling and more balanced.
However, I thought, this could be a result of the capacitors as well - maybe one of the Elcaps is on its last legs causing the difference. But to sort this out, I decided to just put the "woodies" inductors in the other speaker and see if the difference remained.
I just finished wiring it back up, and sure enough the gap decreased quite a bit. There's a very, very subtle difference between the two, but not like before.
It would appear that the inductors on the TBC crossovers are maybe not as good as the inductors on the later PCC crossovers. They appear to be the same in terms of gauge of wiring and of course their mH rating. And as inductors don't really age, I can't think of any other reason.
Hey Jeffrey
You made some interesting points.
First, if you have moved the inductors appart you might be getting better results than me. "Reffc" on AoS thinks this might be part of my problems. The early tag board coils were air core without a bobin and loosely wound with no varnish etc to bond the windings. He thinks interaction of my closely located coils may be causing microphonics on loose windings. Its a distinct possibility and I value his input, he designs/makes/sells loudspeakers for a living.
I am not a big fan of Solen especially in HF filters. I didn't even like one in the midrange, thought the Alcap sounded as good and didn't need any resistors. The capacitor tests done on humblehomemadehifi.com said similar to my findings and if I am remembering correctly said they can be a touch forward for mids and nazzle. I see you used the cap values recomended earlier on this thread, I tried that and didn't like it at all, couldn't get the values to compute on an on line calculator either, not even close.
If I were you I would keep identical parts on the two boards. If you have the later tighter wound coils for the second x-over I would use them for both boards. - Which I think you say you have done.
Am I understanding correctly, that you thought the later coils on plastc bobbins sounded slightly better?
As for MF/MD500 I have not seen anyone comment on the physical differences and I have not taken mine appart, just removed the face plate and cleaned the domes. It would be something like the windings being different and maybe on a different, higher temperature material for the former, like capton, something like that. So nothing dramatic but capable of withstanding the higher temperatures the increased output would generate. The two types of driver produce very different frequency plots and also impedance plots and as I said earlier sound subtley different.
You made some interesting points.
First, if you have moved the inductors appart you might be getting better results than me. "Reffc" on AoS thinks this might be part of my problems. The early tag board coils were air core without a bobin and loosely wound with no varnish etc to bond the windings. He thinks interaction of my closely located coils may be causing microphonics on loose windings. Its a distinct possibility and I value his input, he designs/makes/sells loudspeakers for a living.
I am not a big fan of Solen especially in HF filters. I didn't even like one in the midrange, thought the Alcap sounded as good and didn't need any resistors. The capacitor tests done on humblehomemadehifi.com said similar to my findings and if I am remembering correctly said they can be a touch forward for mids and nazzle. I see you used the cap values recomended earlier on this thread, I tried that and didn't like it at all, couldn't get the values to compute on an on line calculator either, not even close.
If I were you I would keep identical parts on the two boards. If you have the later tighter wound coils for the second x-over I would use them for both boards. - Which I think you say you have done.
Am I understanding correctly, that you thought the later coils on plastc bobbins sounded slightly better?
As for MF/MD500 I have not seen anyone comment on the physical differences and I have not taken mine appart, just removed the face plate and cleaned the domes. It would be something like the windings being different and maybe on a different, higher temperature material for the former, like capton, something like that. So nothing dramatic but capable of withstanding the higher temperatures the increased output would generate. The two types of driver produce very different frequency plots and also impedance plots and as I said earlier sound subtley different.
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Jeffrey - Do you have your x-overs external?
I have mine external for development and due to having the three sets of binding posts have them Tri - wired back to the amp. This does tighten things up a little, but nothing dramatic.
Best place to see my progress is on my website, I allways update that first as its where I host the pictures that are linked to on the forums.
Check out some of my other DIY stuff in the projects tab on:
Artist
I have mine external for development and due to having the three sets of binding posts have them Tri - wired back to the amp. This does tighten things up a little, but nothing dramatic.
Best place to see my progress is on my website, I allways update that first as its where I host the pictures that are linked to on the forums.
Check out some of my other DIY stuff in the projects tab on:
Artist
Hey Ken,
I agree with you about the findings on Solen caps. I may change those out later on. In the treble filter they are sounding OK, but I admit they could be better. In the midrange filter they were terrible, just as you said they had this awful nasal sound to them. What's odd though, is I recall using this same series of capacitors in a friends pair of Polk Audio LSi9s and they sounded excellent! Those were a 2-way, though, so maybe that's why (that and the caps they replaced were polypropylene already).
Anyhow, I may end up trying 30uF later on just to see. I originally found 30uF to be better over 24uF, but this was with the Solens and ESR compensating resistors so I don't count that experience.
As for the coils on plastic bobbins, yes, absolutely, they are better.
Regarding the MD/MF500, that was what I thought too, that the coil must be wound differently. I wonder what the reason was to develop the MD500? Maybe too many people were burning them out? In the brochure you posted they do extensively talk about the power rating of the speakers. I can't imagine why they would talk about that if there wasn't some sort of problem with the conception of the power rating of their speakers. I don't recall many other manufacturers going to the extent they did, and especially putting it on one of the first pages of the brochure. It's also interesting how much of a difference in frequency response it created between the two drivers. In a sense, I'm glad I got the MF500s and not the MD500s.
And finally I don't have my crossovers external. I wish I did. I need to fashion something to make this happen. How do you have yours wired up? With the tri-amp capability I can see that would be much easier to do. I am not very handy with doing modifications like that, although it would be nice if I could. Perhaps if I had a drill with the right drill bit size I could do it.
Oh and I decided I am going to try one more thing before the Alcaps. I have the later Ditton 66 12" bass driver (as indicated earlier in this thread) and I would like to try to use these if I can. I found that one had a much higher resistance than the other, about 7ohms DCR vs. 4ohms DCR. I am going to do some experimenting and see if I add some resistance in parallel with the higher resistance driver that perhaps I can balance the two. If I can do this, I can see if the later 12" bass drivers are superior. I have to admit, I like the look of them over the originals, so it would be nice if they did sound better!
I'll keep you guys posted on how things turn out.
I agree with you about the findings on Solen caps. I may change those out later on. In the treble filter they are sounding OK, but I admit they could be better. In the midrange filter they were terrible, just as you said they had this awful nasal sound to them. What's odd though, is I recall using this same series of capacitors in a friends pair of Polk Audio LSi9s and they sounded excellent! Those were a 2-way, though, so maybe that's why (that and the caps they replaced were polypropylene already).
Anyhow, I may end up trying 30uF later on just to see. I originally found 30uF to be better over 24uF, but this was with the Solens and ESR compensating resistors so I don't count that experience.
As for the coils on plastic bobbins, yes, absolutely, they are better.
Regarding the MD/MF500, that was what I thought too, that the coil must be wound differently. I wonder what the reason was to develop the MD500? Maybe too many people were burning them out? In the brochure you posted they do extensively talk about the power rating of the speakers. I can't imagine why they would talk about that if there wasn't some sort of problem with the conception of the power rating of their speakers. I don't recall many other manufacturers going to the extent they did, and especially putting it on one of the first pages of the brochure. It's also interesting how much of a difference in frequency response it created between the two drivers. In a sense, I'm glad I got the MF500s and not the MD500s.
And finally I don't have my crossovers external. I wish I did. I need to fashion something to make this happen. How do you have yours wired up? With the tri-amp capability I can see that would be much easier to do. I am not very handy with doing modifications like that, although it would be nice if I could. Perhaps if I had a drill with the right drill bit size I could do it.
Oh and I decided I am going to try one more thing before the Alcaps. I have the later Ditton 66 12" bass driver (as indicated earlier in this thread) and I would like to try to use these if I can. I found that one had a much higher resistance than the other, about 7ohms DCR vs. 4ohms DCR. I am going to do some experimenting and see if I add some resistance in parallel with the higher resistance driver that perhaps I can balance the two. If I can do this, I can see if the later 12" bass drivers are superior. I have to admit, I like the look of them over the originals, so it would be nice if they did sound better!
I'll keep you guys posted on how things turn out.
All right, I put in one of the T2619 12" drivers.
Unfortunately, with the other measuring roughly 7 ohms (minus the resistance of the DMM), it didn't work. I added 15 ohms in parallel but that's too much, I think I need to put more like 10 ohms.
However, the other one worked just fine. I did some comparisons against the other Celestion with the old FC-12 in place.
Immediately I noticed a difference in the midrange overall. The Celestion with the newer T2619 bass driver seemed to have a cleaner midrange up to its crossover point. Bass was tighter, not as sloppy. It did seem in some way that the driver was playing a bit louder. It was hard to tell though because deep bass was the same - maybe the clarity was giving off the impression that it was louder but really wasn't? I measured the DC resistance of both the FC-12 and T2619 and both measured exactly the same.
Unfortunately because I don't have a stereo pair of the T2619 bass drivers I can't hook both of them up with this driver and hear it in stereo, which would have told me the rest of the story. I'm considering looking for another T2619 just to give it a try - my impressions based on the A/B between the two was that the T2619 was better in every way, but I couldn't be sure if it messed with the balance of the speaker or not.
Unfortunately, with the other measuring roughly 7 ohms (minus the resistance of the DMM), it didn't work. I added 15 ohms in parallel but that's too much, I think I need to put more like 10 ohms.
However, the other one worked just fine. I did some comparisons against the other Celestion with the old FC-12 in place.
Immediately I noticed a difference in the midrange overall. The Celestion with the newer T2619 bass driver seemed to have a cleaner midrange up to its crossover point. Bass was tighter, not as sloppy. It did seem in some way that the driver was playing a bit louder. It was hard to tell though because deep bass was the same - maybe the clarity was giving off the impression that it was louder but really wasn't? I measured the DC resistance of both the FC-12 and T2619 and both measured exactly the same.
Unfortunately because I don't have a stereo pair of the T2619 bass drivers I can't hook both of them up with this driver and hear it in stereo, which would have told me the rest of the story. I'm considering looking for another T2619 just to give it a try - my impressions based on the A/B between the two was that the T2619 was better in every way, but I couldn't be sure if it messed with the balance of the speaker or not.
I decided to go back through the thread and pull out some choice posts - mostly these are measurements taken by sba and DennyG (mostly sba).
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-13.html#post1300077
ESR/uF measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-23.html#post1412692
Celestion 66 Ad
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-36.html#post2018065
Mid Dome Impedance measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-36.html#post2018066
12" Bass Impedance measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-36.html#post2018067
HF2000 Impedance measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-49.html#post2234593
FR measreuments
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-49.html#post2234599
Mid dome FR measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-49.html#post2235313
HF2000 FR measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-49.html#post2235343
Mid dome FR measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-50.html#post2236068
FC-12 FR measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-50.html#post2236168
THD measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-50.html#post2240738
FR measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-50.html#post2240764
Total system measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-50.html#post2240830
Mid dome measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-50.html#post2240837
HF2000 measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-51.html#post2241312
Woofer plots
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-51.html#post2273225
IR Plots
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-64.html#post2349165
MF500 FR measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-65.html#post2349167
MD500 FR measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-65.html#post2349170
Woofer FR measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-65.html#post2349470
System plots
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-66.html#post2368242
Crossover schematic with polypropylene caps + Seas tweeter
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-73.html#post2417223
Celestion 66 brochure
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-74.html#post2433589
Seas 19tff1 measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-76.html#post2445926
Additional MF500 data
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-77.html#post2458015
Mid dome measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-78.html#post2458052
Overall impedance and phase
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-79.html#post2473220
Ditton 66 PCC with variations
I am going to go through them and see about the impedance of the MD500 vs. MF500, should be enough data here to get an idea.
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-13.html#post1300077
ESR/uF measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-23.html#post1412692
Celestion 66 Ad
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-36.html#post2018065
Mid Dome Impedance measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-36.html#post2018066
12" Bass Impedance measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-36.html#post2018067
HF2000 Impedance measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-49.html#post2234593
FR measreuments
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-49.html#post2234599
Mid dome FR measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-49.html#post2235313
HF2000 FR measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-49.html#post2235343
Mid dome FR measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-50.html#post2236068
FC-12 FR measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-50.html#post2236168
THD measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-50.html#post2240738
FR measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-50.html#post2240764
Total system measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-50.html#post2240830
Mid dome measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-50.html#post2240837
HF2000 measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-51.html#post2241312
Woofer plots
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-51.html#post2273225
IR Plots
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-64.html#post2349165
MF500 FR measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-65.html#post2349167
MD500 FR measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-65.html#post2349170
Woofer FR measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-65.html#post2349470
System plots
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-66.html#post2368242
Crossover schematic with polypropylene caps + Seas tweeter
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-73.html#post2417223
Celestion 66 brochure
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-74.html#post2433589
Seas 19tff1 measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-76.html#post2445926
Additional MF500 data
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-77.html#post2458015
Mid dome measurements
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-78.html#post2458052
Overall impedance and phase
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-79.html#post2473220
Ditton 66 PCC with variations
I am going to go through them and see about the impedance of the MD500 vs. MF500, should be enough data here to get an idea.
All my frequency response / impulse response plots prior to post # 600 were contaminated by some unkown agent.
I ended up switching to a different computer and sound card.
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-13.html#post2332060
My FR / IR plots from the #600s up, are good.
The impedance plots were made with Dayton Woofer tester and are all good.
I ended up switching to a different computer and sound card.
http://www.diyaudio.com/forums/multi-way/93055-celestion-66-needs-mid-range-13.html#post2332060
My FR / IR plots from the #600s up, are good.
The impedance plots were made with Dayton Woofer tester and are all good.
Last edited:
Jeffrey - I thought more about this Mid range series cap.
Lets face it, the rest of the circuit works well, the other Lytics are just shunting to ground and normal Alcaps work here and any other decent brand would work just as well in my opinion. The HF is fine with PP's as they work similar to the original film caps that Celestion used. Its only this 30uf value in the mids, which crucially is in series with the signal path, that causes problems. PP's with or without ESR simulating resistors just don't work here, sound inferior to my ancient Elcaps and screw up driver integration.
Celestion used a combination of 24uf LL Lytic which has fairly low ESR content, more than a PP but a lot less than a normal Lytic. They topped this off with a normal Lytic of 6uf which has a high ESR value to get to the required 30uf. Note also that the disipation in a Lytic acts as a damping factor, making another way in which they differ from PP's.
I think this combination, is what fine tunes the midrange, in terms of tone and x-over point/slope. This is what we (and anyone else here) just hasn't been able to achieve so far in all that has been tried.
I have not tried using a combination of Alcap LL/Normal in the same ratio as the originals, because I am shying away from Alcaps due to supplies running out. If a viable solution is to be found for us and anyone else wanting to follow our lead, I think Alcaps should be avoided. You will have to renew them a few years down the line anyway, what then? This is what got me looking at Mundorf LL Lytics.
I tried a combination of 25uf PP and 5uf normal Alcap Lytic but this didn't sound good, I think this was more about the Solen PP than anything else as we are in agreement that the brand just does not work in this position.
I hunted through my parts bin to see what other options were available, but I don't have many large value PP's going spare. I did find a pair of 15uf Sonicaps so I tried a 15uf Sonicap paralled with 15uf Mundorf LL Lytic.
In theory this should not be very good as Sonicaps do not like being mixed with other brands in a parallel pair. This was the findings on Humblehomemadehifi.com in the cap tests and having used many Sonicaps over the years I can confirm this to be the case.
However........
This pairing sounds good, at least better than it should, no resistors used anywhere in the MId range circuit, just this cap combination. Tone and driver integration are great and I sat and listened to quite a lot of music last night, note I say I listened to the music not the speakers. That was the most noticable attribute over other things I have tried here, in many ways it just felt right. There was a slight echoey effect that you get with Sonicaps/Another combined, humble said it was like listening to two different caps at the same time, which is about right.
I think this is worth persuing further with other brands, a combination of the trancparency of the PP and ESR/damping of the Lytic could be the dream ticket. I will look at this further, but we are getting close to the hollidays so time for dabbling is in short supply. Maybe an Ansar Supersound PP of 18uf and a mixture of normal/LL Lytics to make up to 30uf, who knows, I will post any findings.
As to why Celestion felt the need to up the power handling of the mid driver, I would hazard a guess that it was due to them being used in recording studios a lot and those guys tend to do loud. Plus the competion in that area were offering higher power handling. My units came from a small recording studio.
Let's not forget, the Original Blackies were labeled "66 Studio Monitors" Only when revamped as Woodies to match the rest of the range was the term "Ditton 66" applied, again this was to fit in with all the other product names in the range, so a bit of tidying up for the catalogue and brand offerings there.
Lets face it, the rest of the circuit works well, the other Lytics are just shunting to ground and normal Alcaps work here and any other decent brand would work just as well in my opinion. The HF is fine with PP's as they work similar to the original film caps that Celestion used. Its only this 30uf value in the mids, which crucially is in series with the signal path, that causes problems. PP's with or without ESR simulating resistors just don't work here, sound inferior to my ancient Elcaps and screw up driver integration.
Celestion used a combination of 24uf LL Lytic which has fairly low ESR content, more than a PP but a lot less than a normal Lytic. They topped this off with a normal Lytic of 6uf which has a high ESR value to get to the required 30uf. Note also that the disipation in a Lytic acts as a damping factor, making another way in which they differ from PP's.
I think this combination, is what fine tunes the midrange, in terms of tone and x-over point/slope. This is what we (and anyone else here) just hasn't been able to achieve so far in all that has been tried.
I have not tried using a combination of Alcap LL/Normal in the same ratio as the originals, because I am shying away from Alcaps due to supplies running out. If a viable solution is to be found for us and anyone else wanting to follow our lead, I think Alcaps should be avoided. You will have to renew them a few years down the line anyway, what then? This is what got me looking at Mundorf LL Lytics.
I tried a combination of 25uf PP and 5uf normal Alcap Lytic but this didn't sound good, I think this was more about the Solen PP than anything else as we are in agreement that the brand just does not work in this position.
I hunted through my parts bin to see what other options were available, but I don't have many large value PP's going spare. I did find a pair of 15uf Sonicaps so I tried a 15uf Sonicap paralled with 15uf Mundorf LL Lytic.
In theory this should not be very good as Sonicaps do not like being mixed with other brands in a parallel pair. This was the findings on Humblehomemadehifi.com in the cap tests and having used many Sonicaps over the years I can confirm this to be the case.
However........
This pairing sounds good, at least better than it should, no resistors used anywhere in the MId range circuit, just this cap combination. Tone and driver integration are great and I sat and listened to quite a lot of music last night, note I say I listened to the music not the speakers. That was the most noticable attribute over other things I have tried here, in many ways it just felt right. There was a slight echoey effect that you get with Sonicaps/Another combined, humble said it was like listening to two different caps at the same time, which is about right.
I think this is worth persuing further with other brands, a combination of the trancparency of the PP and ESR/damping of the Lytic could be the dream ticket. I will look at this further, but we are getting close to the hollidays so time for dabbling is in short supply. Maybe an Ansar Supersound PP of 18uf and a mixture of normal/LL Lytics to make up to 30uf, who knows, I will post any findings.
As to why Celestion felt the need to up the power handling of the mid driver, I would hazard a guess that it was due to them being used in recording studios a lot and those guys tend to do loud. Plus the competion in that area were offering higher power handling. My units came from a small recording studio.
Let's not forget, the Original Blackies were labeled "66 Studio Monitors" Only when revamped as Woodies to match the rest of the range was the term "Ditton 66" applied, again this was to fit in with all the other product names in the range, so a bit of tidying up for the catalogue and brand offerings there.
Jeffrey - Just noticed I did not reply to your question on tri-wiring.
Each crossover element High/Mid/Low frequency has its own filter and these can be quite easily seperated in the circuit.
I think the easiest way to follow this is to forget the layout on the circuit board and look at the Celestion circuit schematic I posted on my website.
On there the three seperate elements can be seen quite clearly from left to right the Bass/Mid/treble filters and drivers are shown.
These are fed by a common + rail at the top and - rail at the bottom, representing the signal imputs from the binding posts.
For tri-wiring simply seperate the three elements and give them each their own +/- terminals.
I hope I've not insulted you by dumbing it down, but I was not sure which bit you are asking about, and hopefully that explanation will help others too.
For external experimenting I simply attached the drivers direct to the three sets of binding posts and then used banana plug/leads from these posts to my x-over boards. Banana plug/leads from the amp to the crossover board, to which I fitted banana sockets on small flexible leads as input terminals.
I only have a stereo amp with one set of output posts at present, so I made a pair of tri-wire leads up, both positive and negative going from one to three connections by joining the three wires together at one end (6 wires).
I did this for both left and right channels, each using a six core cable. I used Van Damme "Black" Tour grade cable for this as it is reasonable price and one of the few companies making six core. You can see a picture of the cable on my website.
Hopefully somewhere in there is the answer to your question.
Each crossover element High/Mid/Low frequency has its own filter and these can be quite easily seperated in the circuit.
I think the easiest way to follow this is to forget the layout on the circuit board and look at the Celestion circuit schematic I posted on my website.
On there the three seperate elements can be seen quite clearly from left to right the Bass/Mid/treble filters and drivers are shown.
These are fed by a common + rail at the top and - rail at the bottom, representing the signal imputs from the binding posts.
For tri-wiring simply seperate the three elements and give them each their own +/- terminals.
I hope I've not insulted you by dumbing it down, but I was not sure which bit you are asking about, and hopefully that explanation will help others too.
For external experimenting I simply attached the drivers direct to the three sets of binding posts and then used banana plug/leads from these posts to my x-over boards. Banana plug/leads from the amp to the crossover board, to which I fitted banana sockets on small flexible leads as input terminals.
I only have a stereo amp with one set of output posts at present, so I made a pair of tri-wire leads up, both positive and negative going from one to three connections by joining the three wires together at one end (6 wires).
I did this for both left and right channels, each using a six core cable. I used Van Damme "Black" Tour grade cable for this as it is reasonable price and one of the few companies making six core. You can see a picture of the cable on my website.
Hopefully somewhere in there is the answer to your question.
Hey Ken,
Good observations there. I agree with what you've said.
Regarding the 24uF capacitor, upon doing some looking over the impedance charts listed earlier in this thread, it would appear that the MD and MF500 measure differently. I think you are right that the change on the crossover most likely correlated with the change to the MD500 to accomodate this difference. Unfortunately since it is nearly some 40 years later we do not have perfect working examples, but based on the data we have here this is a fairly logical conclusion. Although, I imagine the 6uF difference is not necessarily substantial, but I am sure it is enough to be worthwhile. I have some 7uF Alcap capacitors lying around (non-LL) that I will try with the Alcap LL caps when I put them in and do an A/B just like I have been so far.
You are absolutely right that this is the critical area in the crossover of this speaker and makes the most difference. Interesting that combination you found.. I agree, the transparency of a PP combined with the ESR of an electrolytic may make for the best combination. I have 24uF Solen caps I could experiment with but I think there's no point as you and I have discovered these are not good caps to use in the midrange filter. I think the amount of capacitance used by the PP cap and the electrolytic capacitor is going to make a difference in the combination as well. I am not sure at all what ratio would be best, but this sounds promising.
Thanks for your answer about the tri-wire/external crossover. No, no insult at all - I am a simple person and I appreciate the explanation Some of this stuff goes over my head so more information is always better. Thanks for taking the time to answer that. I don't have the resources to give that a shot but I may pick up some parts to make it happen.
Although, I am still not sure how far I am willing to take these Celestions. Last night I decided to take them out into my living room and have a listen to them there. This is where I can be conclusive about what I am hearing since it's the best room in the house acoustically. They sounded far better than they ever have, which is great, up until I turned on my IMFs. Oops. It reminded me of the shortcomings of the Celestions, which is how colored and unnatural in the bass/midbass they are. But, this isn't exactly a bad thing, it's more preferential. It did however show me that even though I have made all of these modifications, there is going to be no changing the overall sound of the speaker unless I start to modify the speakers further and that would require substantial changes.
I do wonder, though, if there may be some way to make these speakers sound more natural. I started to play around with the stuffing inside the cabinet and came to the conclusion that Celestion knew what they were doing, as putting more polyfill inside the cabinet while it did improve the coloration some, it mucked with the balance of the speaker and made it sound worse overall. I think the real trouble here is the 12" driver doing some of the lower midrange and then carrying up to the dome. The only real way to deal with this would be to find a new mid dome. Which is now going to be a completely different speaker - so, hence my comment about how far I want to take these. I would like to continue experimenting, but I am slowly discovering that I am not going to be able to turn these into something they are not.
With all that said, however, I am very impressed with how things are progressing and how they are sounding. They are a nice sounding speaker - not, in my opinion, what you would want if you are particular about timbres or something that sounds realistic, but they are warm and pleasing and have a lovely sound to them that makes music sound good, and they are forgiving. They don't stand a chance against my IMFs, but that's a little unfair considering the IMFs were over double their price when sold new.
Good observations there. I agree with what you've said.
Regarding the 24uF capacitor, upon doing some looking over the impedance charts listed earlier in this thread, it would appear that the MD and MF500 measure differently. I think you are right that the change on the crossover most likely correlated with the change to the MD500 to accomodate this difference. Unfortunately since it is nearly some 40 years later we do not have perfect working examples, but based on the data we have here this is a fairly logical conclusion. Although, I imagine the 6uF difference is not necessarily substantial, but I am sure it is enough to be worthwhile. I have some 7uF Alcap capacitors lying around (non-LL) that I will try with the Alcap LL caps when I put them in and do an A/B just like I have been so far.
You are absolutely right that this is the critical area in the crossover of this speaker and makes the most difference. Interesting that combination you found.. I agree, the transparency of a PP combined with the ESR of an electrolytic may make for the best combination. I have 24uF Solen caps I could experiment with but I think there's no point as you and I have discovered these are not good caps to use in the midrange filter. I think the amount of capacitance used by the PP cap and the electrolytic capacitor is going to make a difference in the combination as well. I am not sure at all what ratio would be best, but this sounds promising.
Thanks for your answer about the tri-wire/external crossover. No, no insult at all - I am a simple person and I appreciate the explanation
Some of this stuff goes over my head so more information is always better. Thanks for taking the time to answer that. I don't have the resources to give that a shot but I may pick up some parts to make it happen.Although, I am still not sure how far I am willing to take these Celestions. Last night I decided to take them out into my living room and have a listen to them there. This is where I can be conclusive about what I am hearing since it's the best room in the house acoustically. They sounded far better than they ever have, which is great, up until I turned on my IMFs. Oops. It reminded me of the shortcomings of the Celestions, which is how colored and unnatural in the bass/midbass they are. But, this isn't exactly a bad thing, it's more preferential. It did however show me that even though I have made all of these modifications, there is going to be no changing the overall sound of the speaker unless I start to modify the speakers further and that would require substantial changes.
I do wonder, though, if there may be some way to make these speakers sound more natural. I started to play around with the stuffing inside the cabinet and came to the conclusion that Celestion knew what they were doing, as putting more polyfill inside the cabinet while it did improve the coloration some, it mucked with the balance of the speaker and made it sound worse overall. I think the real trouble here is the 12" driver doing some of the lower midrange and then carrying up to the dome. The only real way to deal with this would be to find a new mid dome. Which is now going to be a completely different speaker - so, hence my comment about how far I want to take these. I would like to continue experimenting, but I am slowly discovering that I am not going to be able to turn these into something they are not.
With all that said, however, I am very impressed with how things are progressing and how they are sounding. They are a nice sounding speaker - not, in my opinion, what you would want if you are particular about timbres or something that sounds realistic, but they are warm and pleasing and have a lovely sound to them that makes music sound good, and they are forgiving. They don't stand a chance against my IMFs, but that's a little unfair considering the IMFs were over double their price when sold new.
Hi Jeffrey
Tried some more variations this afternoon 21uf Sonicap / 9uf normal Alcap. Didn’t like it as it was showing signs of the faults associated with PP’s.
The 15uf Sonicap/ 15uf Mundorf LL Lytic was better, regardless of the fact that Sonicaps don’t like being mixed with other brands/types.
I think the balance is going to lie somewhere between 30-50% PP with the remainder being made up of a good quality LL Lytic.
A fellow diyaudio poster has put me on to Visaton LL Lytics, he rates them better than Alcap for the mid range. As they are only a couple of quid each I will give them a go when I get the chance.
I will also consider Ansar Supersound for the 30-50% PP element. They are a good all rounder that excels in midrange applications.
It’s times like this I wonder if the tweaking will ever stop.
I would say that whether the mids sound warm and cosy or stark and bright is in the main down to this large series cap and using a single PP brings great detail and timber but at the expense of introducing distortion. The LL Lytics sound clean in terms of lack of distortion but the presentation is bright, with subdued bass and has veiled detail in my opinion.
Maybe I am just chasing rainbows but I’m not finished yet.
Going active keeps rearing it’s head, the idea of taking the caps out of the equation and having the opportunity to integrate a sub with a Linkwitz Riley 24dB/Octave filter applied to the main bass driver and crossing over at say 46Hz is worth considering (approx -6dB point).
I don’t know if you read Celestions own performance figures in the “Woodies” catalogue but they roll off very early, -4dB at 50Hz and down to -10dB at 40Hz.
I have confirmed this in a fashion by playing test tones and the volume drops off considerably as you go down the range. 30Hz is virtually non existent. A good quality 12” sealed box Sub in a downward firing configuration could give -3db of 20Hz but integration is key. I’ve heard so many that were badly done, the owners proud of the depth/slam/SPL they can create, but they just sounded detached to me and were competing for the 50 to 40Hz region as the main speakers were just rolling off naturally, making the whole thing sound muddy.
Well at least I’ve not run out of things to try, that would be worrying!
Cheers
Tried some more variations this afternoon 21uf Sonicap / 9uf normal Alcap. Didn’t like it as it was showing signs of the faults associated with PP’s.
The 15uf Sonicap/ 15uf Mundorf LL Lytic was better, regardless of the fact that Sonicaps don’t like being mixed with other brands/types.
I think the balance is going to lie somewhere between 30-50% PP with the remainder being made up of a good quality LL Lytic.
A fellow diyaudio poster has put me on to Visaton LL Lytics, he rates them better than Alcap for the mid range. As they are only a couple of quid each I will give them a go when I get the chance.
I will also consider Ansar Supersound for the 30-50% PP element. They are a good all rounder that excels in midrange applications.
It’s times like this I wonder if the tweaking will ever stop.
I would say that whether the mids sound warm and cosy or stark and bright is in the main down to this large series cap and using a single PP brings great detail and timber but at the expense of introducing distortion. The LL Lytics sound clean in terms of lack of distortion but the presentation is bright, with subdued bass and has veiled detail in my opinion.
Maybe I am just chasing rainbows but I’m not finished yet.
Going active keeps rearing it’s head, the idea of taking the caps out of the equation and having the opportunity to integrate a sub with a Linkwitz Riley 24dB/Octave filter applied to the main bass driver and crossing over at say 46Hz is worth considering (approx -6dB point).
I don’t know if you read Celestions own performance figures in the “Woodies” catalogue but they roll off very early, -4dB at 50Hz and down to -10dB at 40Hz.
I have confirmed this in a fashion by playing test tones and the volume drops off considerably as you go down the range. 30Hz is virtually non existent. A good quality 12” sealed box Sub in a downward firing configuration could give -3db of 20Hz but integration is key. I’ve heard so many that were badly done, the owners proud of the depth/slam/SPL they can create, but they just sounded detached to me and were competing for the 50 to 40Hz region as the main speakers were just rolling off naturally, making the whole thing sound muddy.
Well at least I’ve not run out of things to try, that would be worrying!
Cheers
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