The tweeter caps
Hi picpic,
you will not need to change the green caps if the sound is OK through them to the tweeters,
because those caps are not electrolytic but are polyester and have very long life.
They can be damaged by heat, but if sufficient power went through them in a 66 to damage them the tweeters would have been damaged also.
They are an older plastic type which is more sensitive to heat from soldering than modern metalized polypropylene caps,
thus if you do de-solder them be careful to not leave the iron heating them for too long.
With the old green caps and the new Alcaps the sound should be close to the original 66 when-new sound, but it won't be absolutely identical
... not that any of us will know, because its a long time since anyone heard a NEW 66 !
I recommend that you do not change the inductors unless you want greater bass and low midrange output,
and for that only change the two inductors in the woofer filter.
If you change the inductors in the midrange filter the sound can easily be ruined.
The midrange and tweeter filter inductors are very good as they are if they have not been damaged.
Hi picpic,
you will not need to change the green caps if the sound is OK through them to the tweeters,
because those caps are not electrolytic but are polyester and have very long life.
They can be damaged by heat, but if sufficient power went through them in a 66 to damage them the tweeters would have been damaged also.
They are an older plastic type which is more sensitive to heat from soldering than modern metalized polypropylene caps,
thus if you do de-solder them be careful to not leave the iron heating them for too long.
With the old green caps and the new Alcaps the sound should be close to the original 66 when-new sound, but it won't be absolutely identical
... not that any of us will know, because its a long time since anyone heard a NEW 66 !
I recommend that you do not change the inductors unless you want greater bass and low midrange output,
and for that only change the two inductors in the woofer filter.
If you change the inductors in the midrange filter the sound can easily be ruined.
The midrange and tweeter filter inductors are very good as they are if they have not been damaged.
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TNT tripleT cable, {and interim to sba}
Hi DennyG,
I have previously read some things on the tnt-audio web-site,
and I have now read their TNT tripleT diy cable project.
It is similar to an idea which I have, but which I have not yet had time to make and try.
I will likely not copy the TNT design, because I am not convinced that is the optimum way to combine CAT 5 {or CAT 6, etc ... cables},
but I cannot state their design is not good.
One would have to try it and listen.
In general I like the TNT site, not only because it contains diy, but because that diy seems well thought out,
thus do continue reading there for ideas.
Both TNT's and my design are derived from Kimber's plaited cable ideas.
I like Kimber cable, and am not claiming here that I can improve on their idea,
but hey, this is diy !
For Kimber's speaker cables, the cheapest series - 4PR may have Polyethylene insulation {which is good},
or may have PVC which is not good, but if one can only afford PVC then with Kimber's plaited wires the 4PR is likely better than most other PVC insulated cables.
Next up in price is their 4VS, which does have Polyethylene insulation, and a slightly higher grade of copper wire.
Next up is 4TC, which has Teflon insulation, and that one I like, but some listeners prefer the PE insulated 4VS which I have not heard.
***************
Where are you up to with your mods ?
I apologise that I have not yet posted about absorbent treatment of the baffle panel to allow more accurate measurements, {and clearer sound}.
I intend to get to that soon.
***************
Hi sba,
you have been fortunate to find those good condition MFs !
I will get back to those when I have time available.
I have to go now.
Hi DennyG,
I have previously read some things on the tnt-audio web-site,
and I have now read their TNT tripleT diy cable project.
It is similar to an idea which I have, but which I have not yet had time to make and try.
I will likely not copy the TNT design, because I am not convinced that is the optimum way to combine CAT 5 {or CAT 6, etc ... cables},
but I cannot state their design is not good.
One would have to try it and listen.
In general I like the TNT site, not only because it contains diy, but because that diy seems well thought out,
thus do continue reading there for ideas.
Both TNT's and my design are derived from Kimber's plaited cable ideas.
I like Kimber cable, and am not claiming here that I can improve on their idea,
but hey, this is diy !
For Kimber's speaker cables, the cheapest series - 4PR may have Polyethylene insulation {which is good},
or may have PVC which is not good, but if one can only afford PVC then with Kimber's plaited wires the 4PR is likely better than most other PVC insulated cables.
Next up in price is their 4VS, which does have Polyethylene insulation, and a slightly higher grade of copper wire.
Next up is 4TC, which has Teflon insulation, and that one I like, but some listeners prefer the PE insulated 4VS which I have not heard.
***************
Where are you up to with your mods ?
I apologise that I have not yet posted about absorbent treatment of the baffle panel to allow more accurate measurements, {and clearer sound}.
I intend to get to that soon.
***************
Hi sba,
you have been fortunate to find those good condition MFs !
I will get back to those when I have time available.
I have to go now.
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No problem, to, avoid confusion you can use the private messaging system ;-)
Hello, thanks for the answer. A friend who is an electronic engineer told me the same thing: the value of those green caps should not have changed at this point in their life.
I have received the Alcaps and I will test them. I will first measure the actual Elcaps to see if a change is needed.
The sound may change compared to the originals... but honestly if you look at all the revisions of the original 66 crossovers, i don't think Celestion was THAT careful to regarding the influence of the crossovers to the sound quality... for example you will notice that Celestion themselves has made numerous changes in the design of the crossover, maybe simply related to components availability... for example they put 2 caps in // to obtain certain values then a few month later they put 4 caps in // to obtain exactly an approaching value (sometimes even a bit different !). Sometimes they put polyester caps in tweeter section, and then in another crossover revision they put Elcaps... I don't know if all these modifications even made a change to the final sound of the loudspeakers ? If they did, then every revision of the 66 has a different sound ?
So, honestly, I don't thinks it's a big deal to put Alcaps in there. I will do before & after listening sessions and post a review here !
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attachments to private messages
I don't seem to be able to attach files to private messages, Do you a way to?
Regards
Wayne
Hi,
I don't seem to be able to attach files to private messages, Do you a way to?
Regards
Wayne
Woops no, never tried. I tought it was possible. Howerver there's many website out there to upload files for free (megaupload, rapidshare...) and then share them by sharing their URL
attachments to private messages
Ok thanks, I will try using those.
Regards
Wayne
Hi,Woops no, never tried. I tought it was possible. Howerver there's many website out there to upload files for free (megaupload, rapidshare...) and then share them by sharing their URL
Ok thanks, I will try using those.
Regards
Wayne
DC resistances of all drivers
Hi Alan,
I've started on the next stage and carefully measured the DCR's of the drivers in the 66's and the two MF500's in the PTB speakers. Results are given below. Note that the meter used had a resolution of 0.1 ohm. Readings were corrected using 3.3 ohm Mills MRA05F and 8 ohm Mills MRA12F.
I also took out the drivers from both 66 cabinets and discovered the two mid units are of different series - one is an MD500 the other an MF500. Strange? One speaker went back to the dealer for repairs many years ago for repair of the bass driver. I can't recall them billing me for a new mid driver. Maybe the factory used both when they manufactured mine. Or the local dealer did a swap.
Do any other 66 owners have one MD and one MF?
PTB.MF500.L 6.3 ohm
PTB.MF500.R 6.4 ohm
66.MF500.L 7.3 ohm
66.MD500.R 6.3 ohm
66.HF2000.L 4.3 ohm
66.HF2000.R 5.2 ohm
66.FC12.L 4.0 ohm
66.FC12.R 4.0 ohm
_____________________
I'll measure the impedance/freq curves for all drivers as soon as I can setup the equipment.
_____________________
I also noticed the similarity of the 'TNT' cable to the design of Kimber cable. I have a couple of 2m lengths of their black/grey cable (= current 4VS?) from 20 years ago I can experiment with later.
Hi Alan,
I've started on the next stage and carefully measured the DCR's of the drivers in the 66's and the two MF500's in the PTB speakers. Results are given below. Note that the meter used had a resolution of 0.1 ohm. Readings were corrected using 3.3 ohm Mills MRA05F and 8 ohm Mills MRA12F.
I also took out the drivers from both 66 cabinets and discovered the two mid units are of different series - one is an MD500 the other an MF500. Strange? One speaker went back to the dealer for repairs many years ago for repair of the bass driver. I can't recall them billing me for a new mid driver. Maybe the factory used both when they manufactured mine. Or the local dealer did a swap.
Do any other 66 owners have one MD and one MF?
PTB.MF500.L 6.3 ohm
PTB.MF500.R 6.4 ohm
66.MF500.L 7.3 ohm
66.MD500.R 6.3 ohm
66.HF2000.L 4.3 ohm
66.HF2000.R 5.2 ohm
66.FC12.L 4.0 ohm
66.FC12.R 4.0 ohm
_____________________
I'll measure the impedance/freq curves for all drivers as soon as I can setup the equipment.
_____________________
I also noticed the similarity of the 'TNT' cable to the design of Kimber cable. I have a couple of 2m lengths of their black/grey cable (= current 4VS?) from 20 years ago I can experiment with later.
Hi.
Just changed the old Elcaps on the mid & bass section of the crossover on my 66's (PCB crossover).
While the 24µF & 72µF caps measured quite good after all those years, both 4µF caps were totally out of specs (both below 1µF).
I changed all the caps for good measure. 72µF & 4µF were replaced by equivalents (Alcaps 50V/2% from Falcon Acoustics). 24µF were replaced by two 12µF Alcaps in //. (didn' touch the tweeter/green caps section or the inductors). The operation was quite easy, approx 10 minutes per speaker.
I only did a short listening so far, but I must say I immediately noticed an improvement in the medium section which is now really more detailed and have a better presence than before. Beside that, I didn't noticed a loss of quality in the overall sound. I would say it's much better than with the old caps.
According to the crossovers diagram, the faulty 4µF (C5) is located in the MD500 part of the crossover. The improvement i'm hearing is probably related to the fact that C5 value is now correct.
Just changed the old Elcaps on the mid & bass section of the crossover on my 66's (PCB crossover).
While the 24µF & 72µF caps measured quite good after all those years, both 4µF caps were totally out of specs (both below 1µF).
I changed all the caps for good measure. 72µF & 4µF were replaced by equivalents (Alcaps 50V/2% from Falcon Acoustics). 24µF were replaced by two 12µF Alcaps in //. (didn' touch the tweeter/green caps section or the inductors). The operation was quite easy, approx 10 minutes per speaker.
I only did a short listening so far, but I must say I immediately noticed an improvement in the medium section which is now really more detailed and have a better presence than before. Beside that, I didn't noticed a loss of quality in the overall sound. I would say it's much better than with the old caps.
According to the crossovers diagram, the faulty 4µF (C5) is located in the MD500 part of the crossover. The improvement i'm hearing is probably related to the fact that C5 value is now correct.
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MIDS IMPEDANCE AND NEARFIELD
Hi Alan,
Following on from the previous post of the DCR’s I’ve measured the impedances and nearfields of the mid drivers as shown in the charts below.
The nearfield measurements were done in two runs at different sound levels to check the repeatability of the test method. Results showed the same trends for the individual drivers for both runs so repeatability was considered acceptable. Only one run is shown here.
For the record, the tests were done using Speaker Workshop, calibrated jig and an un-calibrated mic (ECM8000+MIC100). Nearfields were done at a mic distance of about ½ inch with the individual drivers on their normal enclosure baffle ie the 66 mids on the 66 baffle and the PTB mids on their small triangular baffle and sitting on top of and flush with the front of the PTB woofer enclosure.
I’ve also measured the Impedance of the complete speakers and will post these later.
Hi Alan,
Following on from the previous post of the DCR’s I’ve measured the impedances and nearfields of the mid drivers as shown in the charts below.
The nearfield measurements were done in two runs at different sound levels to check the repeatability of the test method. Results showed the same trends for the individual drivers for both runs so repeatability was considered acceptable. Only one run is shown here.
For the record, the tests were done using Speaker Workshop, calibrated jig and an un-calibrated mic (ECM8000+MIC100). Nearfields were done at a mic distance of about ½ inch with the individual drivers on their normal enclosure baffle ie the 66 mids on the 66 baffle and the PTB mids on their small triangular baffle and sitting on top of and flush with the front of the PTB woofer enclosure.
I’ve also measured the Impedance of the complete speakers and will post these later.
66 - OVERALL IMPEDANCE AND PHASE
Hi again Alan,
I measured this after I reassembled the speakers with the Sonicaps installed and with the old Solen 6uF added to one of the 68uF’s in each crossover.
The 6uF was added to the 68uF that runs off the connection between the two inductors. Is this the correct one? What effect should I expect with this additional 6uF in place?
Do the Impedance/Phase charts indicate they will be difficult to drive?
Hi again Alan,
I measured this after I reassembled the speakers with the Sonicaps installed and with the old Solen 6uF added to one of the 68uF’s in each crossover.
The 6uF was added to the 68uF that runs off the connection between the two inductors. Is this the correct one? What effect should I expect with this additional 6uF in place?
Do the Impedance/Phase charts indicate they will be difficult to drive?
hi Alan and everyone.
I have just seen a very interesting add on ebay where someone has added great photos of Celestion 66 brochures. I have copied them for my collection.
They are selling some of the best looking 66 I have ever seen on ebay though far too far away for me!
here is the link, i am not connected to the seller as its a US sale: Celestion Ditton 66 Studio Monitor Loudspeakers ...Pair on eBay (end time 15-Feb-11 00:01:27 GMT)
enjoy!
I have just seen a very interesting add on ebay where someone has added great photos of Celestion 66 brochures. I have copied them for my collection.
They are selling some of the best looking 66 I have ever seen on ebay though far too far away for me!
here is the link, i am not connected to the seller as its a US sale: Celestion Ditton 66 Studio Monitor Loudspeakers ...Pair on eBay (end time 15-Feb-11 00:01:27 GMT)
enjoy!
The man just left my place with his *new 66's*. At half the cost of above link. Alan, I also threw in the original HF 2000's. He brought his own disk & was very happy with what he heard. He thought he might convert the xovers back to as close to original as he can versus what you had worked out for my particular case. I'm gonna miss my girls.
Your updated crossovers
Hi,
I bet the man left you in a very good mood indeed. If you have seen any of my posts regarding updating my 66's crossovers. You may have noticed the controversy over the new crossover design. Unfortunately I went into the process feet first without the necessary knowledge to verify the competence of the designer and the ultimate design itself, and without taking the advice I had been given by those who new better. Impatience can turn out to be a very expensive trait to have!
I am now very grateful to Alan for helping me to try and resolve the situation, or at least have a damage limitation plan in place.
I was just wondering what your design you had adopted for the 66's you have just sold? Am I right in thinking you also changed the tweeters? it's probably here amongst this or other Threads.
Also could I ask why the new owner wanted to return to the original crossover design?
Regards
Wayne
Hi,
I bet the man left you in a very good mood indeed. If you have seen any of my posts regarding updating my 66's crossovers. You may have noticed the controversy over the new crossover design. Unfortunately I went into the process feet first without the necessary knowledge to verify the competence of the designer and the ultimate design itself, and without taking the advice I had been given by those who new better. Impatience can turn out to be a very expensive trait to have!
I am now very grateful to Alan for helping me to try and resolve the situation, or at least have a damage limitation plan in place.
I was just wondering what your design you had adopted for the 66's you have just sold? Am I right in thinking you also changed the tweeters? it's probably here amongst this or other Threads.
Also could I ask why the new owner wanted to return to the original crossover design?
Regards
Wayne
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uh oh just got email from unhappy customer. someone telling him my (his)66's are MK 1, not Mk 2 like he wanted. He said try's to keep things he buys as close to original as possible. I even substituted the HF 2000's back in & let him keep the new Seas tweets.
My final version of the xover is somewhere in this thread. It was customized to bring out high freq's, as my old ears couldnt hear them
page 66 post 659 is my final xover schematic
My final version of the xover is somewhere in this thread. It was customized to bring out high freq's, as my old ears couldnt hear them
page 66 post 659 is my final xover schematic
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why did you sell ?
Hi Doug,
I am very surprised !
After all the work you did getting the 66s to a sound you like,
why did you sell them ?
*** *** *** *** ***
Hi DennyG, picpic, ittf, Wayne, {and sba if you are lurking unseen !},
I see in the Link ittf posted that the MkII 66 have "UL 12" designated as the bass driver, and not FC12.
sba posted long ago about small visual differences between his pairs of bass drivers, thus perhaps this FC versus UL ...
I see on sba's Frequency Response plots that all 4 of his measure very similarly, thus difference may be only the dust caps,
and perhaps the type of rubber used in the suspension ..?
The Ditton 25's woofer may be the same as the earlier 66 and 44 woofer, but possibly not same as the MkII woofer ...
any comments sba ?
I'll get back to here as soon as I have time available to comment on other matters raised, including your queries Denny.
Hi Doug,
I am very surprised !
After all the work you did getting the 66s to a sound you like,
why did you sell them ?
*** *** *** *** ***
Hi DennyG, picpic, ittf, Wayne, {and sba if you are lurking unseen !},
I see in the Link ittf posted that the MkII 66 have "UL 12" designated as the bass driver, and not FC12.
sba posted long ago about small visual differences between his pairs of bass drivers, thus perhaps this FC versus UL ...
I see on sba's Frequency Response plots that all 4 of his measure very similarly, thus difference may be only the dust caps,
and perhaps the type of rubber used in the suspension ..?
The Ditton 25's woofer may be the same as the earlier 66 and 44 woofer, but possibly not same as the MkII woofer ...
any comments sba ?
I'll get back to here as soon as I have time available to comment on other matters raised, including your queries Denny.
Alan: Reducing all my audio. Kids wont want it, dont want to move it. Re the bass on the above link, I saw it listed as FC-12. In all the 78 pgs here, was /has it ever been uncategorically determined what constitutes MK I vs MkII ? My understanding, MkI were essentially *blackies* with MF 500 mid, MkII had MD 500 & teak fronts. Am I wrong? Wondering if my buyer was thinking of a set of 662's.
after further research: Ditton66 (various versions), Ditton 662, Ditton 66 MarkII. This sometime in 1980's with the ABR at the back of the cabinet.
Know anything about these Alan? Have to eat a little crow & my girls are coming back home. Have a spare MD5oo but 2 different meters showdifferent ohms. 2.5 vs 4.6 how to believe which?
Hi Alan,
There are a pair of 12" bass units on eBay #290532982987. I was assuming that although they were taken from Ditton 25s they were the same as 66's 12" bass drivers. They are both designated T1600, with the same patent number '1 321 581'. Where does the UL 12 come into play?
Best Regards
Wayne
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