options of Capacitors for Woofer filter section of 66 crossover
'ullo Pete , and to who-ever else may be following this ,
I have checked the various capacitors' sellers web-sites again ,
and will here describe more options for capacitors for the woofer filter of the 66 crossover.
Previously I described using Parallel pairs of 36uF to sum to 72uF ,
and 33uF and 39uF in Parallel to sum to 72uF ,
and using 68uF instead of 72 for the output cap with 75uF instead of 72 for the centre cap.
I also described to "reggie" how to use his 68uF caps including his 8.2uF cap in Parallel with the centre cap ,
which then sums to 76.2uF there , which is close enough to work well when 68uF is used for the output cap.
I refer readers here to #946 on Page 95 :- open the file there and see the Schematic that reggie drew.
The 4uF cap is missing from the mid-range filter , and this schematic is for a different tweeter than the HF2000 ,
however the woofer filter is correct for the caps and resistors.
{ DennyG has 6uF instead of 8.2uF in his version , and that is also close enough to work well.}
Another option is to use three 24uF caps connected in Parallel in both cap postions to sum to 72uF in both.
That was in some of the original 66 crossovers instead of a single 72uF caps.
I mention this option now , because there is now a smaller physical sized 24uF Polypropylene cap available than previously when in this thread I listed the 250 volt sized 24uF cap.
Now there is a 160 volt rated 24uF which is Oval shape , in the ClarityCap PWA series.
It has a 27mm/32mm oval cross-section and is 47mm long.
The oval cross-section allows the 3 caps to be tied or glued together in either a 3 caps vertical stack , or in a 2 under/1 over triangle cross-section stack.
Do whichever you can fit onto the board in between the inductors.
The PWA series will not be quite as good for sound as the ClarityCap PX series I have been recommending for the midrange and tweeter filters ,
but will be quite adequate in the woofer filter , and likely no lesser sound quality than the AXON and Solen 250 volt rated caps I previously recommended for the woofer filter ,
and with the advantage that the ClarityCap PWA are smaller size than AXON and Solen.
In ClarityCap PWA there is also a 68uF cap of size 46mm Diameter x 46mm Length.
That is smaller than AXON and Solen 68uF/250 volt of 43mm x 60mm.
There is no PWA in 75uF , however there is an Oval shaped 8.2uF of 19mm/24mm cross-section x 34mm length.
This can be tied or glued to the central 68uF cap , and the two resistors connected separately to each cap , as in the Schematic in #946.
{ ClarityCap PX 8.2uF is 22mm/26mm x 45mm , and could be used there , though the PWA is adequate.}
The ClarityCap PWA series are available from the German seller I mentioned in #957 on Page 96 ,
as are the PX series for the midrange and tweeter filters.
If you want to buy all caps in the UK :-
There is a large 400 volt rated 70uF Solen cap which is 50mm x 65mm ,
however there is a Mundorf 250 volt rated 68uF which is 43mm x 61mm.
There is no Mundorf 75uF cap , however there is a Mundorf 250 volt 8.2uF which is 22mm X 30mm ,
which can be tied or glued on top of the 68uF cap to fit more easily than the Solen 70uF cap.
There are no Mundorf caps in 6uf or 24uF or 25uF , for the other positions of the crossover ,
however the Mundorf seller has the ClarityCap ESA series with 3.9uF { suitable for 4uF } and 25uF in the 250 volt sizes.
These are more expensive than the PX series , which this seller does not stock ,
however for UK residents the Postage will be lower than from overseas from PX sellers.
But a compromise is needed if buy from this seller ,
because for the 6uF tweeter filter cap there is only the large 630 volt rated ClarityCap SA series which is 35mm x 45mm.
Its price is moderate at 6.85 GBP , thus if it can be fitted on the board then all needed can be bought from this seller ,
who also stocks the Mills MRA-5 resistors.
If you want to use a 250 volt 75uF cap you will have to buy from either of two Canadian sellers.
It measures 44mm x 60mm.
Pete ,
I recommend you measure the spaces between the inductors in the 66 crossover , then decide which caps' option for the woofer and tweeter filters.
You could make a new larger board for the crossover , or do as thread contributor sba did ,
which is put a new larger board under the old board with the new one extending out around the edges of the old board far enough to fit the large capacitors onto.
sba posted a photo of his new + old boards' combination with the large capacitors in #155 on Page 16 of this thread.
You will have to Log In to be able to see the photo.
The largest size caps there are 400 volt rated Solen , but if you buy 250 volt caps you will not need quite as large board.
As your friend's meter measures capacitance to only 20uF ,
then to check twelve 24uF PWA caps so as to be able to group them in sets of 3 he will have to connect each 24uF cap in Series to a Reference cap that he has measured ,
and then measure the combination and then calculate the actual capacitance of each 24uF sample.
This is easy to do - I have done it using an Alligator clip to connect the unknown cap and the reference cap in Series.
The Reference cap can be any capacitance lower than 20uF ,
however the final calculation will be more accurate if a large capacitance is used than if a small capacitance ,
thus for the Reference cap I would use a standard 15uF or 16uF cap , but if he has only a standard 10uF cap that will suffice.
Yes , you can use the new 6uF tweeter cap for the Reference - less accuracy in final calculation , but adequate for a useable result.
The reason I state the above is because ALL capacitors have a Tolerance ,
which is a spread of actual capacitances each sample may measure.
For a 24uF +/- 5% tolerance cap , some may measure as large as 25.2 and some as low as 22.8.
When three are connected in Parallel for the filter , if by co-incidence one set happens to be all 22.8 and another set happens to be all 25.2 ,
then you will have effectively one 68.4uF and one 75.6uF.
Ideally one measures each sample and then combines them to sum to the same Total for BOTH output cap positions and another Total for BOTH centre cap positions of the filter.
If your friend does not want to measure and calculate , then you can pay the German seller 2.60 EURO for each PAIR measured ,
and ask him to mark the pairs so that I can advise you how to use one from each pair to combine to make your 4 sets of 3 capacitors each.
'ullo Pete , and to who-ever else may be following this ,
I have checked the various capacitors' sellers web-sites again ,
and will here describe more options for capacitors for the woofer filter of the 66 crossover.
Previously I described using Parallel pairs of 36uF to sum to 72uF ,
and 33uF and 39uF in Parallel to sum to 72uF ,
and using 68uF instead of 72 for the output cap with 75uF instead of 72 for the centre cap.
I also described to "reggie" how to use his 68uF caps including his 8.2uF cap in Parallel with the centre cap ,
which then sums to 76.2uF there , which is close enough to work well when 68uF is used for the output cap.
I refer readers here to #946 on Page 95 :- open the file there and see the Schematic that reggie drew.
The 4uF cap is missing from the mid-range filter , and this schematic is for a different tweeter than the HF2000 ,
however the woofer filter is correct for the caps and resistors.
{ DennyG has 6uF instead of 8.2uF in his version , and that is also close enough to work well.}
Another option is to use three 24uF caps connected in Parallel in both cap postions to sum to 72uF in both.
That was in some of the original 66 crossovers instead of a single 72uF caps.
I mention this option now , because there is now a smaller physical sized 24uF Polypropylene cap available than previously when in this thread I listed the 250 volt sized 24uF cap.
Now there is a 160 volt rated 24uF which is Oval shape , in the ClarityCap PWA series.
It has a 27mm/32mm oval cross-section and is 47mm long.
The oval cross-section allows the 3 caps to be tied or glued together in either a 3 caps vertical stack , or in a 2 under/1 over triangle cross-section stack.
Do whichever you can fit onto the board in between the inductors.
The PWA series will not be quite as good for sound as the ClarityCap PX series I have been recommending for the midrange and tweeter filters ,
but will be quite adequate in the woofer filter , and likely no lesser sound quality than the AXON and Solen 250 volt rated caps I previously recommended for the woofer filter ,
and with the advantage that the ClarityCap PWA are smaller size than AXON and Solen.
In ClarityCap PWA there is also a 68uF cap of size 46mm Diameter x 46mm Length.
That is smaller than AXON and Solen 68uF/250 volt of 43mm x 60mm.
There is no PWA in 75uF , however there is an Oval shaped 8.2uF of 19mm/24mm cross-section x 34mm length.
This can be tied or glued to the central 68uF cap , and the two resistors connected separately to each cap , as in the Schematic in #946.
{ ClarityCap PX 8.2uF is 22mm/26mm x 45mm , and could be used there , though the PWA is adequate.}
The ClarityCap PWA series are available from the German seller I mentioned in #957 on Page 96 ,
as are the PX series for the midrange and tweeter filters.
If you want to buy all caps in the UK :-
There is a large 400 volt rated 70uF Solen cap which is 50mm x 65mm ,
however there is a Mundorf 250 volt rated 68uF which is 43mm x 61mm.
There is no Mundorf 75uF cap , however there is a Mundorf 250 volt 8.2uF which is 22mm X 30mm ,
which can be tied or glued on top of the 68uF cap to fit more easily than the Solen 70uF cap.
There are no Mundorf caps in 6uf or 24uF or 25uF , for the other positions of the crossover ,
however the Mundorf seller has the ClarityCap ESA series with 3.9uF { suitable for 4uF } and 25uF in the 250 volt sizes.
These are more expensive than the PX series , which this seller does not stock ,
however for UK residents the Postage will be lower than from overseas from PX sellers.
But a compromise is needed if buy from this seller ,
because for the 6uF tweeter filter cap there is only the large 630 volt rated ClarityCap SA series which is 35mm x 45mm.
Its price is moderate at 6.85 GBP , thus if it can be fitted on the board then all needed can be bought from this seller ,
who also stocks the Mills MRA-5 resistors.
If you want to use a 250 volt 75uF cap you will have to buy from either of two Canadian sellers.
It measures 44mm x 60mm.
Pete ,
I recommend you measure the spaces between the inductors in the 66 crossover , then decide which caps' option for the woofer and tweeter filters.
You could make a new larger board for the crossover , or do as thread contributor sba did ,
which is put a new larger board under the old board with the new one extending out around the edges of the old board far enough to fit the large capacitors onto.
sba posted a photo of his new + old boards' combination with the large capacitors in #155 on Page 16 of this thread.
You will have to Log In to be able to see the photo.
The largest size caps there are 400 volt rated Solen , but if you buy 250 volt caps you will not need quite as large board.
As your friend's meter measures capacitance to only 20uF ,
then to check twelve 24uF PWA caps so as to be able to group them in sets of 3 he will have to connect each 24uF cap in Series to a Reference cap that he has measured ,
and then measure the combination and then calculate the actual capacitance of each 24uF sample.
This is easy to do - I have done it using an Alligator clip to connect the unknown cap and the reference cap in Series.
The Reference cap can be any capacitance lower than 20uF ,
however the final calculation will be more accurate if a large capacitance is used than if a small capacitance ,
thus for the Reference cap I would use a standard 15uF or 16uF cap , but if he has only a standard 10uF cap that will suffice.
Yes , you can use the new 6uF tweeter cap for the Reference - less accuracy in final calculation , but adequate for a useable result.
The reason I state the above is because ALL capacitors have a Tolerance ,
which is a spread of actual capacitances each sample may measure.
For a 24uF +/- 5% tolerance cap , some may measure as large as 25.2 and some as low as 22.8.
When three are connected in Parallel for the filter , if by co-incidence one set happens to be all 22.8 and another set happens to be all 25.2 ,
then you will have effectively one 68.4uF and one 75.6uF.
Ideally one measures each sample and then combines them to sum to the same Total for BOTH output cap positions and another Total for BOTH centre cap positions of the filter.
If your friend does not want to measure and calculate , then you can pay the German seller 2.60 EURO for each PAIR measured ,
and ask him to mark the pairs so that I can advise you how to use one from each pair to combine to make your 4 sets of 3 capacitors each.
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Hi Alan,
I am very happy with my Celestion Ditton 44s with the Seas 19mm tweeters and rebuilt crossovers you helped me with. The sound is awesome, but as is the way for us DIY-ers, I am always looking to squeeze out imperfections. Recently, because of the Pass Labs F5 I built (incredible amp by the way - mind - blowingly good!) I had to put Neutrik Speakon connectors on my speakers to insure against short circuiting, and whilst inside the speaker I found myself looking at that upholstery foam that the tractor boys over Ipswich decided was hi-fi grade speaker damping material. No, I'm sure they were very notable speaker designers of course, but really, this stuff has got to go, right? What do you think? Have you done any experiments with speaker filling materials in sealed designs like the 44s and 66s? I'm interested to hear your experiences!
Thanks
Lucas
I am very happy with my Celestion Ditton 44s with the Seas 19mm tweeters and rebuilt crossovers you helped me with. The sound is awesome, but as is the way for us DIY-ers, I am always looking to squeeze out imperfections. Recently, because of the Pass Labs F5 I built (incredible amp by the way - mind - blowingly good!) I had to put Neutrik Speakon connectors on my speakers to insure against short circuiting, and whilst inside the speaker I found myself looking at that upholstery foam that the tractor boys over Ipswich decided was hi-fi grade speaker damping material. No, I'm sure they were very notable speaker designers of course, but really, this stuff has got to go, right? What do you think? Have you done any experiments with speaker filling materials in sealed designs like the 44s and 66s? I'm interested to hear your experiences!
Thanks
Lucas
Absorption inside loudspeaker enclosures , and other modifications
'ullo Lucas ,
It is good that you are still here , albeit in the 66 thread instead of the 44 thread ,
however some of what you have been , and currently are , interested in is being discussed here ,
and more is to follow when I have time to get to it.
Do you think the Celestion designers were also "Tractor Boys" ?
{ Perhaps some of them were ! }
*** *** ***
The 44 and 66 are NOT the same type of "sealed design".
Any internal sound absorbing materials need to be relevant to the requirement in the 66 of not reducing the effectiveness of its ABR.
The 44 is a true Closed Box , and several things can be achieved inside it with sound absorbing materials ,
some of which are relevant to the 66 , such as reducing midrange and upper bass resonances ,
and one different , which is to fine-tune its low bass range response
without slowing its Transient Response as would occur in the 66 if completely filled with a sound absorbing substance.
Lucas ,
I recommend you read some of my recent posts in this thread which in whole or part contain information about sound absorbing materials ,
as follows:
Page 93 , #929 on Felt ;
Page 94 , #931 and #935 to distinguish between two different uses for Felts - internal and external to enclosures ;
Page 95 , #948 about plastic Foam ;
Page 96 , #951 about Foam , { and also about Inductors as you were previously interested in } ,
and #955 about on-baffle Felt , and Foam.
Then next as follows :-
Open a 44 enclosure and inspect very closely the surface of the Foam.
Use a magnifying glass.
Is the surface mostly Open-cell or is it mostly Closed-cell ?
That is , can you see holes that go into the foam , or tiny circles that look sealed with thin foam ?
If both types are visible , then which type is there more of ?
Please post descriptions , and/or a largely magnified photo of the surface if you have equipment able to do that.
Acoustic foam for sound absorption was not always egg-crate type contoured as in recent years ,
but once was flat surfaced.
A well designed and manufactured contour surface foam will outperform a flat surface foam for sound absorption ,
however , some contour surface foams are not sound absorbing , but are impact absorbing packaging foam ,
which some sellers do not realize will not absorb sound ,
and some other sellers know but realize that many DIYers do not know ,
so they sell the lower price packaging foam and state it as egg-crate acoustic foam , etc ...
Thus the old Celestion foam may be OK , so do inspect and describe here.
In a 44 one can place an additional sound absorber between the foam and the backs of the drivers
which if carefully done can extend the bass response to reproduce more of the lowest frequencies with very little compromising of anything else in the bass range ,
if the old foam is an absorptive type.
If the old foam is not a good absorptive type , then if removed better can be achieved for low bass extension with a suitable grade of any of :-
real Wool , Rock/Mineral wool , Fibreglass batt.
*** *** ***
Other improvements to the Bass response , of both the 44 and the 66 ,
which should be Priority as both will exceed the benefits of additional internal sound absorption are :
(1)- moving the Crossover away from the back of the woofer , if it is not already.
This has been reported favourably in the middle of this thread with description of imrovement to the sound , { though I have forgotten by whom }.
The crossover can be placed on the inside bottom of the 66 , or on back panel behind the ABR , or higher up behind mid-dome or tweeter.
For the 44 the bottom and lower back are a bit too close to the woofer magnet , so move the crossover up higher.
(2)- installing significantly lower DCR Inductors in the woofer filter section only of the crossover for the 66 ,
and replacing the cored inductors in the 44 with low DCR air-cores as above , but with a medium DCR air-core in the midrange filter.
This I will be posting more about as soon as I have time available to do it comprehensively.
*** *** ***
Lucas ,
I'm pleased to learn that you are happy with the tweeter upgrade and aspects of the crossover !
Inform me , did you install your 10uF MKP capacitors in the tweeter filter ,
and if so , did you hear any further improvement ?
If I'm remembering correctly you initially installed 3.9uF for the input cap of the tweeter filter ,
and a lower than 10uF cap as the output cap.
Thank you for your comments about the Pass Labs amplifier.
I was hoping to study its circuit to consider whether to make one , however I have not yet had time to.
'ullo Lucas ,
It is good that you are still here , albeit in the 66 thread instead of the 44 thread ,
however some of what you have been , and currently are , interested in is being discussed here ,
and more is to follow when I have time to get to it.
Do you think the Celestion designers were also "Tractor Boys" ?
{ Perhaps some of them were ! }
*** *** ***
The 44 and 66 are NOT the same type of "sealed design".
Any internal sound absorbing materials need to be relevant to the requirement in the 66 of not reducing the effectiveness of its ABR.
The 44 is a true Closed Box , and several things can be achieved inside it with sound absorbing materials ,
some of which are relevant to the 66 , such as reducing midrange and upper bass resonances ,
and one different , which is to fine-tune its low bass range response
without slowing its Transient Response as would occur in the 66 if completely filled with a sound absorbing substance.
Lucas ,
I recommend you read some of my recent posts in this thread which in whole or part contain information about sound absorbing materials ,
as follows:
Page 93 , #929 on Felt ;
Page 94 , #931 and #935 to distinguish between two different uses for Felts - internal and external to enclosures ;
Page 95 , #948 about plastic Foam ;
Page 96 , #951 about Foam , { and also about Inductors as you were previously interested in } ,
and #955 about on-baffle Felt , and Foam.
Then next as follows :-
Open a 44 enclosure and inspect very closely the surface of the Foam.
Use a magnifying glass.
Is the surface mostly Open-cell or is it mostly Closed-cell ?
That is , can you see holes that go into the foam , or tiny circles that look sealed with thin foam ?
If both types are visible , then which type is there more of ?
Please post descriptions , and/or a largely magnified photo of the surface if you have equipment able to do that.
Acoustic foam for sound absorption was not always egg-crate type contoured as in recent years ,
but once was flat surfaced.
A well designed and manufactured contour surface foam will outperform a flat surface foam for sound absorption ,
however , some contour surface foams are not sound absorbing , but are impact absorbing packaging foam ,
which some sellers do not realize will not absorb sound ,
and some other sellers know but realize that many DIYers do not know ,
so they sell the lower price packaging foam and state it as egg-crate acoustic foam , etc ...
Thus the old Celestion foam may be OK , so do inspect and describe here.
In a 44 one can place an additional sound absorber between the foam and the backs of the drivers
which if carefully done can extend the bass response to reproduce more of the lowest frequencies with very little compromising of anything else in the bass range ,
if the old foam is an absorptive type.
If the old foam is not a good absorptive type , then if removed better can be achieved for low bass extension with a suitable grade of any of :-
real Wool , Rock/Mineral wool , Fibreglass batt.
*** *** ***
Other improvements to the Bass response , of both the 44 and the 66 ,
which should be Priority as both will exceed the benefits of additional internal sound absorption are :
(1)- moving the Crossover away from the back of the woofer , if it is not already.
This has been reported favourably in the middle of this thread with description of imrovement to the sound , { though I have forgotten by whom }.
The crossover can be placed on the inside bottom of the 66 , or on back panel behind the ABR , or higher up behind mid-dome or tweeter.
For the 44 the bottom and lower back are a bit too close to the woofer magnet , so move the crossover up higher.
(2)- installing significantly lower DCR Inductors in the woofer filter section only of the crossover for the 66 ,
and replacing the cored inductors in the 44 with low DCR air-cores as above , but with a medium DCR air-core in the midrange filter.
This I will be posting more about as soon as I have time available to do it comprehensively.
*** *** ***
Lucas ,
I'm pleased to learn that you are happy with the tweeter upgrade and aspects of the crossover !
Inform me , did you install your 10uF MKP capacitors in the tweeter filter ,
and if so , did you hear any further improvement ?
If I'm remembering correctly you initially installed 3.9uF for the input cap of the tweeter filter ,
and a lower than 10uF cap as the output cap.
Thank you for your comments about the Pass Labs amplifier.
I was hoping to study its circuit to consider whether to make one , however I have not yet had time to.
Last edited:
a Correction to #963 - placement of Crossover inside cabinet
I saw later that the woofer in the 44 is sufficiently high above the base of the cabinet for its magnet to not substantially affect the magnetic field
of the Inductors in the crossover if the crossover is placed on the inside bottom of the cabinet as close to the back panel as possible.
Cut away some of the foam wadding so that it does not touch any resistors in the crossover.
It does not matter if the foam touches capacitors or inductors , because those will not become hot , however the resistors will warm up a bit during music ,
thus need air around them for that heat to dissipate and so more heat is not built up as the music continues.
I saw later that the woofer in the 44 is sufficiently high above the base of the cabinet for its magnet to not substantially affect the magnetic field
of the Inductors in the crossover if the crossover is placed on the inside bottom of the cabinet as close to the back panel as possible.
Cut away some of the foam wadding so that it does not touch any resistors in the crossover.
It does not matter if the foam touches capacitors or inductors , because those will not become hot , however the resistors will warm up a bit during music ,
thus need air around them for that heat to dissipate and so more heat is not built up as the music continues.
New Inductors for the woofer filter
In follow-up to my previous posts about the Inductors in the woofer filter of the 66 crossover:
The Celestion woofer is a nominal 4 ohm driver , thus with the moderately high DCR -{ DC Resistance }-
of the two Series connected inductors there is significant waste of low frequencies' signal dissipated in the inductors.
Allowing for one , likely inadvertent , mistake earlier in this thread ,
the largest inductor of 3.5mH has a DCR of 1.5 ohms ,
and the following 2.2mH inductor has a DCR of 1.3 ohms ,
which together add to 2.8 ohms versus the 4 ohms woofer , thus the ratio of loss of signal in the inductors is significant.
To achieve significantly less loss the DCRs will need to be at least half of their current ohms ,
and better can be achieved by getting down to a quarter or less of the current DCRs ,
BUT , to do so requires the use of thicker wire ,
which means the inductors will be larger in diameter , thus will not fit on the old crossover board.
A new board can be made of suitable size to fit the 2 inductors and the capacitors for the woofer filter ,
and that can be placed down low in the cabinet , either on the back behind the ABR ,
or on the bottom , which will mean putting it under the foam damping , and that will not be a problem ,
because lower DCR inductors will not get hot , because less signal is dissipated in them.
The original crossover board can be retained for the mid-range and tweeter filters ,
and the inductors for those do not need to be changed , as no wanted signal is wasted in those.
AWG is a Specification number for thickness of wire , that is the wire's Guage.
It is an Inverse specification , that is the Thicker the wire the lower the AWG number.
The old Celestion wire is probably AWG 20 , or possibly AWG 18.
Thicker wire is AWG 16 , thicker again is AWG 15 , etc ...
Unfortunately simply using thicker wire does NOT always result in lower DCR.
To achieve the lowest possible DCR the physical Dimensions of the Coil need to be optimised ,
those are the Inner Diameter of the coil , and the Height of the coil.
{ Height is the height when the coil is lying flat on its side - some people think of this as the Thickness of the coil , but Thickness is better kept as a term for the wire guage.}
When the Diameter and Height are not optimum , and not within a particular Ratio of each other , a larger quantity of wire is need to achieve the same Inductance ,
because Inductance is relevant to the Magnetic Field through the centre of the coil.
Ideally one wants a small Inner diameter , and a Height that is equal to or slightly less than the Inner diameter.
BUT , small inner diameter is not easy to wind thick wire onto ,
thus unless one winds one's own inductors one will have to make do with whatever diameters , and heights , the various Manufacturers use ,
AND remember that to have Cost-effective manufacture , they will not have an optimum winding bobbin for every possible inductance , but will compromise ,
hopefully towards the best average for a range of inductors ,
and then another bobbin size for the next range , etc ...
If the Inner diameter is too large , there is lower Magnetic Field generated thus lower inductance until more wire is used.
More wire = higher DCR ; higher weight to ship to buyer and thus higher price to buy.
If the Height of the coil exceeds the Inner diameter the Magnetic Field again is lower until more windings are put on ... thus again as above.
In IDEAL dimensions 16AWG will get down to about half the DCR of Celestion's inductors , and that includes if the wire is efficiently wound to have minimal gaps/spaces around it.
Of the published data I have found on the web-sites of the various major retailers of inductors , none have the lowest possible DCR ,
thus for most with their manufacturing compromises 15AWG will have to be the minimum guage to buy in.
The exception is Solen in Canada , whose 16AWG inductors achieve about half the DCR of Celestion's.
Solen achieve significantly lower DCR with their 14AWG inductors , however they are large size:
3.6mH 14AWG is about 4 inches in Outer diameter { 102mm },
versus in 16AWG it is about 3 inches { 89mm }.
The 14 AWG 3.6mH will weigh about 1 kilo , so to DennyG and Reggie , you will be paying a lot to ship to Australia for 2 of those
plus for two of 2.2mH at about three-quarters the weight of the 3.6mH.
Jantzen Audio manufacture in 14AWG , and again those are large and heavy ,
and also in 15AWG which results in not quite as large or heavy.
Their 16AWG are not sufficiently low in DCR , so for Jantzen the 15AWG is the minimum it is worth buying or really you will not achieve sufficient improvement for the money you spend.
You will have to pay to ship the Jantzen from Europe ,
though I see the Australian distributer of Jantzen has the 14AWG in 2.2mH , but not the 3.4mH 14AWG nor the 3.5mH 15AWG ,
however he may order them in for you , but then I doubt the price would be any lower than if you buy direct yourself from Europe.
Jantzen use a different manufacturing method than Solen , and I think as result the Jantzens will be better audio quality inductors ,
however the Solens will not be poor quality.
Other brands:
Some manufacturers do not make a 3.5mH or close to , so I am not listing those ,
and some other manufacturers' inductors are reported in some audio forums to be of lower audio quality and/or not wound to close enough to their claimed Inductance ,
so I am not listing those.
Falcon Components in the UK is a specialist inductor manufacturer ,
but the thickest wire they have is not sufficiently thick for the required low DCR to significantly better the old Celestion inductors.
Wimslow Audio do not publish the DCRs of their inductors ,
and as they did not reply to my email to inform me , let us assume they are not low enough and Wimslow are not interested.
North Creek Music in the USA manufacture with very thick wire , 12AWG and thicker ,
but these are very expensive and very heavy ,
thus will cost a small fortune to ship to Australia.
I have read a thread on this web-site about inductor sellers in Australia.
One manufacturer has 1.8mm wire , and that is between 13AWG and 14AWG so will have low DCR , as indeed his stated resistances show for his 3.6mH and 2.1mH:
3.6mH has 0.415 ohms ; 2.1mH has 0.311 ohms.
Those are not the absolute lowest DCR that can be obtained with 1.8mm , but are more than low enough.
If using 3.6mH instead of the Celestion 3.5 , and 2.1mH instead of the Celestion 2.2 ,
the two opposite differences will compensate for each other and the filter will be very little different than if same values that Celestion used , so do not worry about this.
You can expect his 1.8mm 3.6mH to weigh more than 1 kilo , but our two Australians here have only to pay local Postage.
{ That seller has also 1.32mm wire , but that is not thick enough for sufficiently low DCR , so do not buy those.}
His method of manufacture is lesser quality than Jantzen and Solen , { but don't expect him to agree with that } ,
however do remember that he is winding small quantities to order , and will not have the large scale automated equipment that Jantzen and Solen have.
If you decide to buy his inductors you can improve their audio quality if you obtain some Wax - candle wax or similar that is easy to melt.
Find an old saucepan , such as an Aluminium one that I hope none of you are still using to cook food in ,
and use that to heat the wax on the stove until it is sufficiently liquid to allow an inductor be submerged in it.
{ Do NOT heat an inductor on a stove when the wax is not liquid.}
You will need sufficient wax to cover the inductor when it is submerged.
Next , keep the heat low enough that the wax does not boil - a few bubbles will be OK , but not smoke , etc ...
I will describe more about doing this if anyone wants to try it , because there is more you will need to do.
I think his inductors will work in the condition he supplies them , but may be a bit microphonic ,
that is if loose windings those will vibrate with the resonant energy inside the speaker box.
Vibrating wire of an inductor causes a changing magnetic field , thus changing signal through the inductor to the woofer ,
which if it is bass or low midrange you will hear because the capacitors are allowing filtering of only the upper mids and treble.
Melted wax will penetrate through the gaps/spaces between the semi-loose windings , and when it cools to solid the the inductor will be solid ,
thus no significant vibration within the coil , thus no error audio generation.
As I stated in earlier posts , with lower DCR inductors there will be louder bass , and tighter bass quality ,
and the woofer will be able to control the ABR better , thus less overhang of the lowest bass notes.
As result the Series resistor in the midrange filter , at the 24uF capacitor , can be reduced or perhaps ommitted ,
and as result of all that you will have a more efficient loudspeaker that is easier to drive with a moderately powered amplifier ,
hence not be driving your amplifiers into compression or overload conditions when the music peaks.
So , DennyG and Reggie ,
post here what you want to do and I will post more that is relevant to the choices you have made.
Any USA and Canadian readers , I recommend you consider the Solen from Canada , or the North Creek Music if you want to buy the best.
Any UK and European readers I recommend you buy Jantzen Audio , but post here and I will list the particular part numbers ,
because Jantzen manufacture several in each Inductance , and some of those will NOT sufficiently improve on the original Celestion inductors.
All the above is about Air-core inductors.
Ferrite cored inductors are a waste of time , because they saturate when the music peaks and the sound compresses as result ,
and when very loud sound you may hear distortion as well as a lot of compression.
Jantzen also manufacture what they call P-core inductors - P = Permite , or similar.
This will undoubtably allow a lower saturation inductor than Ferrite , but ALL solid core inductors with cores made of any affordable substance will saturate to some degree.
I have not tried the P-cores , and I do not intend to , because I wind my own air-core.
If you want to try the P-core for their smaller size/lower shipping cost , etc ... that is for you to decide , but I am not here now recommending them.
In follow-up to my previous posts about the Inductors in the woofer filter of the 66 crossover:
The Celestion woofer is a nominal 4 ohm driver , thus with the moderately high DCR -{ DC Resistance }-
of the two Series connected inductors there is significant waste of low frequencies' signal dissipated in the inductors.
Allowing for one , likely inadvertent , mistake earlier in this thread ,
the largest inductor of 3.5mH has a DCR of 1.5 ohms ,
and the following 2.2mH inductor has a DCR of 1.3 ohms ,
which together add to 2.8 ohms versus the 4 ohms woofer , thus the ratio of loss of signal in the inductors is significant.
To achieve significantly less loss the DCRs will need to be at least half of their current ohms ,
and better can be achieved by getting down to a quarter or less of the current DCRs ,
BUT , to do so requires the use of thicker wire ,
which means the inductors will be larger in diameter , thus will not fit on the old crossover board.
A new board can be made of suitable size to fit the 2 inductors and the capacitors for the woofer filter ,
and that can be placed down low in the cabinet , either on the back behind the ABR ,
or on the bottom , which will mean putting it under the foam damping , and that will not be a problem ,
because lower DCR inductors will not get hot , because less signal is dissipated in them.
The original crossover board can be retained for the mid-range and tweeter filters ,
and the inductors for those do not need to be changed , as no wanted signal is wasted in those.
AWG is a Specification number for thickness of wire , that is the wire's Guage.
It is an Inverse specification , that is the Thicker the wire the lower the AWG number.
The old Celestion wire is probably AWG 20 , or possibly AWG 18.
Thicker wire is AWG 16 , thicker again is AWG 15 , etc ...
Unfortunately simply using thicker wire does NOT always result in lower DCR.
To achieve the lowest possible DCR the physical Dimensions of the Coil need to be optimised ,
those are the Inner Diameter of the coil , and the Height of the coil.
{ Height is the height when the coil is lying flat on its side - some people think of this as the Thickness of the coil , but Thickness is better kept as a term for the wire guage.}
When the Diameter and Height are not optimum , and not within a particular Ratio of each other , a larger quantity of wire is need to achieve the same Inductance ,
because Inductance is relevant to the Magnetic Field through the centre of the coil.
Ideally one wants a small Inner diameter , and a Height that is equal to or slightly less than the Inner diameter.
BUT , small inner diameter is not easy to wind thick wire onto ,
thus unless one winds one's own inductors one will have to make do with whatever diameters , and heights , the various Manufacturers use ,
AND remember that to have Cost-effective manufacture , they will not have an optimum winding bobbin for every possible inductance , but will compromise ,
hopefully towards the best average for a range of inductors ,
and then another bobbin size for the next range , etc ...
If the Inner diameter is too large , there is lower Magnetic Field generated thus lower inductance until more wire is used.
More wire = higher DCR ; higher weight to ship to buyer and thus higher price to buy.
If the Height of the coil exceeds the Inner diameter the Magnetic Field again is lower until more windings are put on ... thus again as above.
In IDEAL dimensions 16AWG will get down to about half the DCR of Celestion's inductors , and that includes if the wire is efficiently wound to have minimal gaps/spaces around it.
Of the published data I have found on the web-sites of the various major retailers of inductors , none have the lowest possible DCR ,
thus for most with their manufacturing compromises 15AWG will have to be the minimum guage to buy in.
The exception is Solen in Canada , whose 16AWG inductors achieve about half the DCR of Celestion's.
Solen achieve significantly lower DCR with their 14AWG inductors , however they are large size:
3.6mH 14AWG is about 4 inches in Outer diameter { 102mm },
versus in 16AWG it is about 3 inches { 89mm }.
The 14 AWG 3.6mH will weigh about 1 kilo , so to DennyG and Reggie , you will be paying a lot to ship to Australia for 2 of those
plus for two of 2.2mH at about three-quarters the weight of the 3.6mH.
Jantzen Audio manufacture in 14AWG , and again those are large and heavy ,
and also in 15AWG which results in not quite as large or heavy.
Their 16AWG are not sufficiently low in DCR , so for Jantzen the 15AWG is the minimum it is worth buying or really you will not achieve sufficient improvement for the money you spend.
You will have to pay to ship the Jantzen from Europe ,
though I see the Australian distributer of Jantzen has the 14AWG in 2.2mH , but not the 3.4mH 14AWG nor the 3.5mH 15AWG ,
however he may order them in for you , but then I doubt the price would be any lower than if you buy direct yourself from Europe.
Jantzen use a different manufacturing method than Solen , and I think as result the Jantzens will be better audio quality inductors ,
however the Solens will not be poor quality.
Other brands:
Some manufacturers do not make a 3.5mH or close to , so I am not listing those ,
and some other manufacturers' inductors are reported in some audio forums to be of lower audio quality and/or not wound to close enough to their claimed Inductance ,
so I am not listing those.
Falcon Components in the UK is a specialist inductor manufacturer ,
but the thickest wire they have is not sufficiently thick for the required low DCR to significantly better the old Celestion inductors.
Wimslow Audio do not publish the DCRs of their inductors ,
and as they did not reply to my email to inform me , let us assume they are not low enough and Wimslow are not interested.
North Creek Music in the USA manufacture with very thick wire , 12AWG and thicker ,
but these are very expensive and very heavy ,
thus will cost a small fortune to ship to Australia.
I have read a thread on this web-site about inductor sellers in Australia.
One manufacturer has 1.8mm wire , and that is between 13AWG and 14AWG so will have low DCR , as indeed his stated resistances show for his 3.6mH and 2.1mH:
3.6mH has 0.415 ohms ; 2.1mH has 0.311 ohms.
Those are not the absolute lowest DCR that can be obtained with 1.8mm , but are more than low enough.
If using 3.6mH instead of the Celestion 3.5 , and 2.1mH instead of the Celestion 2.2 ,
the two opposite differences will compensate for each other and the filter will be very little different than if same values that Celestion used , so do not worry about this.
You can expect his 1.8mm 3.6mH to weigh more than 1 kilo , but our two Australians here have only to pay local Postage.
{ That seller has also 1.32mm wire , but that is not thick enough for sufficiently low DCR , so do not buy those.}
His method of manufacture is lesser quality than Jantzen and Solen , { but don't expect him to agree with that } ,
however do remember that he is winding small quantities to order , and will not have the large scale automated equipment that Jantzen and Solen have.
If you decide to buy his inductors you can improve their audio quality if you obtain some Wax - candle wax or similar that is easy to melt.
Find an old saucepan , such as an Aluminium one that I hope none of you are still using to cook food in ,
and use that to heat the wax on the stove until it is sufficiently liquid to allow an inductor be submerged in it.
{ Do NOT heat an inductor on a stove when the wax is not liquid.}
You will need sufficient wax to cover the inductor when it is submerged.
Next , keep the heat low enough that the wax does not boil - a few bubbles will be OK , but not smoke , etc ...
I will describe more about doing this if anyone wants to try it , because there is more you will need to do.
I think his inductors will work in the condition he supplies them , but may be a bit microphonic ,
that is if loose windings those will vibrate with the resonant energy inside the speaker box.
Vibrating wire of an inductor causes a changing magnetic field , thus changing signal through the inductor to the woofer ,
which if it is bass or low midrange you will hear because the capacitors are allowing filtering of only the upper mids and treble.
Melted wax will penetrate through the gaps/spaces between the semi-loose windings , and when it cools to solid the the inductor will be solid ,
thus no significant vibration within the coil , thus no error audio generation.
As I stated in earlier posts , with lower DCR inductors there will be louder bass , and tighter bass quality ,
and the woofer will be able to control the ABR better , thus less overhang of the lowest bass notes.
As result the Series resistor in the midrange filter , at the 24uF capacitor , can be reduced or perhaps ommitted ,
and as result of all that you will have a more efficient loudspeaker that is easier to drive with a moderately powered amplifier ,
hence not be driving your amplifiers into compression or overload conditions when the music peaks.
So , DennyG and Reggie ,
post here what you want to do and I will post more that is relevant to the choices you have made.
Any USA and Canadian readers , I recommend you consider the Solen from Canada , or the North Creek Music if you want to buy the best.
Any UK and European readers I recommend you buy Jantzen Audio , but post here and I will list the particular part numbers ,
because Jantzen manufacture several in each Inductance , and some of those will NOT sufficiently improve on the original Celestion inductors.
All the above is about Air-core inductors.
Ferrite cored inductors are a waste of time , because they saturate when the music peaks and the sound compresses as result ,
and when very loud sound you may hear distortion as well as a lot of compression.
Jantzen also manufacture what they call P-core inductors - P = Permite , or similar.
This will undoubtably allow a lower saturation inductor than Ferrite , but ALL solid core inductors with cores made of any affordable substance will saturate to some degree.
I have not tried the P-cores , and I do not intend to , because I wind my own air-core.
If you want to try the P-core for their smaller size/lower shipping cost , etc ... that is for you to decide , but I am not here now recommending them.
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Hi Alan
I am in the UK and would be very interested in the Jantzen part numbers.
I have already followed your advice and re-capped the crossovers (with load resistors), including relocating the boards to behind the ABR and the results were superb. So many thanks for taking the time to post all this information.
Many thanks
Val
I am in the UK and would be very interested in the Jantzen part numbers.
I have already followed your advice and re-capped the crossovers (with load resistors), including relocating the boards to behind the ABR and the results were superb. So many thanks for taking the time to post all this information.
Many thanks
Val
I have been looking for the best supplier to use for the Jantzen Inductors to the UK and have found Kamm Lautsprecher ( ehighend.de ) to be the most competitive and with easy methods of payment, including PayPal.
They do not list the 3.5mH in 15awg, so I emailed an enquiry and was swiftly replied to by Frank. He tells me that he can get Jantzen to custom wind the 3.5mH in 14awg for €36.00ea. Lead time, about one week. Their delivery charge to the UK for four Inductors is €12.50 via DHL.
This makes the total for the four inductors, 2 x 2.2mH and 2 x 3.5mH all air core and all in 14AWG, €128.30 including VAT and delivery (that's about £114.50).
Seems a reasonable deal to me, so thought that others may be interested.
I've placed an order and will report back on the delivery and of course, the sound once fitted.
Val
They do not list the 3.5mH in 15awg, so I emailed an enquiry and was swiftly replied to by Frank. He tells me that he can get Jantzen to custom wind the 3.5mH in 14awg for €36.00ea. Lead time, about one week. Their delivery charge to the UK for four Inductors is €12.50 via DHL.
This makes the total for the four inductors, 2 x 2.2mH and 2 x 3.5mH all air core and all in 14AWG, €128.30 including VAT and delivery (that's about £114.50).
Seems a reasonable deal to me, so thought that others may be interested.
I've placed an order and will report back on the delivery and of course, the sound once fitted.
Val
Hello Alan,
I've just spoken to Stephen at Speakerbug. He has 14AWG 2.2mh, 0.39ohm air cored Jantzen coils (#28) for $40 each and 14AWG 3.3mh, .48ohm air cored Jantzen coil (No.34) for $48 each (old stock - new stock now $58 with increased copper prices). He can order 14AWG 3.5mh air core for $68 each OR I can try the Jantzen 15AWG .215ohm permite cored coil for $27. He tells me that saturation wouldn't occur until very high voltage (500?) so probably ok in the 66. However, I guess that if I did use them I would always be wondering, what if. So. I'll probably go for the special order Jantzen 3.5mh air core (unless the 3.3 will do???).
Reggie
I've just spoken to Stephen at Speakerbug. He has 14AWG 2.2mh, 0.39ohm air cored Jantzen coils (#28) for $40 each and 14AWG 3.3mh, .48ohm air cored Jantzen coil (No.34) for $48 each (old stock - new stock now $58 with increased copper prices). He can order 14AWG 3.5mh air core for $68 each OR I can try the Jantzen 15AWG .215ohm permite cored coil for $27. He tells me that saturation wouldn't occur until very high voltage (500?) so probably ok in the 66. However, I guess that if I did use them I would always be wondering, what if. So. I'll probably go for the special order Jantzen 3.5mh air core (unless the 3.3 will do???).
Reggie
an addition to my #965 + about Jantzen Audio inductors
I should have included with the above from my previous post
that the woofer will control the ABR better because with less DCR in the inductors the woofer will respond faster to the signal from the amplifier ,
AND , the back-EMF from the woofer will faster return to the amplifier , thus better Damping ,{less overhang }, of Transients.
The woofer drives the ABR with the Input signal , however the ABR drives the woofer with the effects of the Inertia of the ABR ,
thus the faster the woofer can respond to the amplifier , the faster it can drive and respond to the Inertia effects from the ABR.
*** *** ***
Jantzen Audio inductors:
For the 2.2mH , my primary recommendation is: Coil No.28 , 14AWG, 0.385 ohm.
My secondary recommendation is: Coil No.1246 , 15AWG , 0.473 ohm ,
and if no stock of that then: Coil No.1314 , 15AWG , is 0.490 ohm because it has a larger inner diameter , { and it will occupy more space on the board }.
My primary recommendation for the 3.5mH is 3.4mH: Coil No.35 , 14AWG , 0.488 ohm.
3.4mH will work here because with lower DCR in the circuit there does not need to be as high inductance for the same filtering ,
however , Reggie , I think dropping to 3.3mH is likely to be too low , thus I do not recommend that option.
My secondary recommendation is: 3.5mH , Coil No.1493 , 15AWG , 0.690 ohm ,
however as that is only about half the DCR of Celestion's inductor I strongly recommend the more expensive Coil No.34
so as to get as low as possible DCR in this circuit position where there is no benefit to having any DCR.
If you are constrained by Budget , then buy the 15AWG option for the 2.2mH ,
because a small amount of DCR is partially useful there to damp the resonances caused by the capacitors around it in the circuit.
With these low DCR inductors the resistors I specified to add in Series with the polypropylene caps are even more critical , so as to dampen resonance in the circuit.
This type of filter is a Trade-Off - a Compromise - however for best bass control I recommend the lowest possible DCRs for both inductors.
If any additional resonance becomes audible , then the middle resistor in Series with the middle cap can be increased , ie: the 1 ohm to 1.2 ohm , or even to 1.5 ohm ,
however listen first , the sound may be fine with no need to increase the resistances in Series with that cap.
In the UK:
Loudspeaker Design| Loudspeaker Drive Units| Loudspeaker Measurement, Restoration, Repair Services
has listed stock of all the above inductors , thus if his prices are not higher than the German seller , it will be cheaper because of lower Shipping within the UK ,
BUT , if you buy from Audio Components , above Link , I strongly recommend you simply buy the inductors , and do not buy any of the proprietor's advice ,
because to date he has ruined the crossovers in at least 2 pairs of Celestion 66 , { 2 different owners have corresponded with me } ,
because he convinced both that alternate options would work better ,
however neither worked better , and proprietor refuses to exchange the non-optimum parts or refund.
He seems to not understand how crossover components interact with the Impedance characteristics of drivers ,
and relies on his computer program to design crossovers.
Computer programs cannot design anything !
Intelligent design has to be done by Humans who understand the limitations of what they are designing for and with.
Computer programs are useful only to assist in speeding up the evaluation of options ,
but one needs to understand what the computer programs cannot effectively evaluate.
'ullo Val33 ,
thankyou for your report about the audible benefit of the crossover modifications and placement.
That will be helpful to other owners who may be unsure about my recommendations.
Jantzen specify their Air-core inductors to +/- 3% Tolerance ,
and a 3.4mH + 3% is almost exactly 3.5mH , thus not likely any problem for Jantzen to achieve with their machine settings for that coil's winding.
Jantzen did similar for a KEF loudspeaker owner I have corresponded with for an inductor very close to the design optimum he wanted.
As the German seller is willing to arrange that service for you , then I recommend you , and others reading here , buy from him ,
because the UK seller above did not reply to the email from the KEF owner when he requested a + Tolerance selected inductor.
As you have ordered all in 14AWG , we will all here be interested in your later report about the resultant sound !
G'day Reggie ,
yes , buy the Coil No.28 for 2.2mH if the price is right for you , and for the 3.5mH I recommend that you order Coil No.35
AND with the order ask your Stephen to request Jantzen measure and select two from their stock that measure in the +ive side of the Tolerance.
That will ensure you receive slightly larger than 3.4mH and not slightly lower ...
... and which could measure as low as 3.3 if in -3% side of Tolerance.
As above , I do not recommend the 3.3mH option.
The P-core is likely to work better at low frequencies than at high frequencies ,
thus would work better in a Bass circuit than in an Upper Midrange or Treble circuit ,
however as I have not used P-core , nor know of any in loudspeakers I have heard , I cannot recommend them.
I mentioned them because I know that some DIYers will find the listings of them ,
but I would only suggest their use if one has to fit a woofer filter into a very small space ,
and then only if the owner was intending to buy Ferrite cored inductors , those being small size.
To all readers:
These large inductors must be placed at least 4 inches apart to reduce magnetic field cross-coupling which will affect the filter ,
and better will be if 6 inches apart - not a problem as you will be making a new board to fit them ,
and the capacitors can be placed in between the spaced inductors on the board.
Yes , I know Celestion put their inductors closer together , however that was a compromise.
The Celestion bass filter inductors can be left on the old board if the capacitors are removed ,
because then there will be no short-circuit through them ,
and also at least one end of the old inductor chain must be disconnected ,
either the 3.5mH at its Input end , and/or the 2.2mH at its Output end. I would disconnect the Output at least.
I should have included with the above from my previous post
that the woofer will control the ABR better because with less DCR in the inductors the woofer will respond faster to the signal from the amplifier ,
AND , the back-EMF from the woofer will faster return to the amplifier , thus better Damping ,{less overhang }, of Transients.
The woofer drives the ABR with the Input signal , however the ABR drives the woofer with the effects of the Inertia of the ABR ,
thus the faster the woofer can respond to the amplifier , the faster it can drive and respond to the Inertia effects from the ABR.
*** *** ***
Jantzen Audio inductors:
For the 2.2mH , my primary recommendation is: Coil No.28 , 14AWG, 0.385 ohm.
My secondary recommendation is: Coil No.1246 , 15AWG , 0.473 ohm ,
and if no stock of that then: Coil No.1314 , 15AWG , is 0.490 ohm because it has a larger inner diameter , { and it will occupy more space on the board }.
My primary recommendation for the 3.5mH is 3.4mH: Coil No.35 , 14AWG , 0.488 ohm.
3.4mH will work here because with lower DCR in the circuit there does not need to be as high inductance for the same filtering ,
however , Reggie , I think dropping to 3.3mH is likely to be too low , thus I do not recommend that option.
My secondary recommendation is: 3.5mH , Coil No.1493 , 15AWG , 0.690 ohm ,
however as that is only about half the DCR of Celestion's inductor I strongly recommend the more expensive Coil No.34
so as to get as low as possible DCR in this circuit position where there is no benefit to having any DCR.
If you are constrained by Budget , then buy the 15AWG option for the 2.2mH ,
because a small amount of DCR is partially useful there to damp the resonances caused by the capacitors around it in the circuit.
With these low DCR inductors the resistors I specified to add in Series with the polypropylene caps are even more critical , so as to dampen resonance in the circuit.
This type of filter is a Trade-Off - a Compromise - however for best bass control I recommend the lowest possible DCRs for both inductors.
If any additional resonance becomes audible , then the middle resistor in Series with the middle cap can be increased , ie: the 1 ohm to 1.2 ohm , or even to 1.5 ohm ,
however listen first , the sound may be fine with no need to increase the resistances in Series with that cap.
In the UK:
Loudspeaker Design| Loudspeaker Drive Units| Loudspeaker Measurement, Restoration, Repair Services
has listed stock of all the above inductors , thus if his prices are not higher than the German seller , it will be cheaper because of lower Shipping within the UK ,
BUT , if you buy from Audio Components , above Link , I strongly recommend you simply buy the inductors , and do not buy any of the proprietor's advice ,
because to date he has ruined the crossovers in at least 2 pairs of Celestion 66 , { 2 different owners have corresponded with me } ,
because he convinced both that alternate options would work better ,
however neither worked better , and proprietor refuses to exchange the non-optimum parts or refund.
He seems to not understand how crossover components interact with the Impedance characteristics of drivers ,
and relies on his computer program to design crossovers.
Computer programs cannot design anything !
Intelligent design has to be done by Humans who understand the limitations of what they are designing for and with.
Computer programs are useful only to assist in speeding up the evaluation of options ,
but one needs to understand what the computer programs cannot effectively evaluate.
'ullo Val33 ,
thankyou for your report about the audible benefit of the crossover modifications and placement.
That will be helpful to other owners who may be unsure about my recommendations.
Jantzen specify their Air-core inductors to +/- 3% Tolerance ,
and a 3.4mH + 3% is almost exactly 3.5mH , thus not likely any problem for Jantzen to achieve with their machine settings for that coil's winding.
Jantzen did similar for a KEF loudspeaker owner I have corresponded with for an inductor very close to the design optimum he wanted.
As the German seller is willing to arrange that service for you , then I recommend you , and others reading here , buy from him ,
because the UK seller above did not reply to the email from the KEF owner when he requested a + Tolerance selected inductor.
As you have ordered all in 14AWG , we will all here be interested in your later report about the resultant sound !
G'day Reggie ,
yes , buy the Coil No.28 for 2.2mH if the price is right for you , and for the 3.5mH I recommend that you order Coil No.35
AND with the order ask your Stephen to request Jantzen measure and select two from their stock that measure in the +ive side of the Tolerance.
That will ensure you receive slightly larger than 3.4mH and not slightly lower ...
... and which could measure as low as 3.3 if in -3% side of Tolerance.
As above , I do not recommend the 3.3mH option.
The P-core is likely to work better at low frequencies than at high frequencies ,
thus would work better in a Bass circuit than in an Upper Midrange or Treble circuit ,
however as I have not used P-core , nor know of any in loudspeakers I have heard , I cannot recommend them.
I mentioned them because I know that some DIYers will find the listings of them ,
but I would only suggest their use if one has to fit a woofer filter into a very small space ,
and then only if the owner was intending to buy Ferrite cored inductors , those being small size.
To all readers:
These large inductors must be placed at least 4 inches apart to reduce magnetic field cross-coupling which will affect the filter ,
and better will be if 6 inches apart - not a problem as you will be making a new board to fit them ,
and the capacitors can be placed in between the spaced inductors on the board.
Yes , I know Celestion put their inductors closer together , however that was a compromise.
The Celestion bass filter inductors can be left on the old board if the capacitors are removed ,
because then there will be no short-circuit through them ,
and also at least one end of the old inductor chain must be disconnected ,
either the 3.5mH at its Input end , and/or the 2.2mH at its Output end. I would disconnect the Output at least.
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Is there any difficulty in building an inductor ? At the bass end a plastic coil of wire as sold might be what I would need . I plan a speaker cutting off at 600 Hz . I can do it actively so probably will do that . If the speakers end up as a gift I might do a passive crossover . If active the bass from a NAD 3020 ( active ) . The rest bespoke using NAD as preamp . The speaker mimics a Bose / Magneplanar hybrid . Cheap as chips . 50 Hz to 15 kHz open baffle . Adapted to he OK on MP3 .
Keep magnets away from inductors . If you put the crossover outside a speaker it often sounds different . Vibration is one reason . The other is proximity to magnets . It isn't always an upgrade . Also the seemingly nasty electrolytic caps are often rather nice . They are special types made for the job , excellent in pre amps where large values required ( MC pick up ) . Compared with polypropylene they seem softer yet open . They are especailly good up to 0.4 V and often better than Audiophile types . In low level circuits they excel . 1000 uF 16 V can be used for MC . Perhaps the sweetness is the sub 0.4 V range . Above that diode effects come in .
Keep magnets away from inductors . If you put the crossover outside a speaker it often sounds different . Vibration is one reason . The other is proximity to magnets . It isn't always an upgrade . Also the seemingly nasty electrolytic caps are often rather nice . They are special types made for the job , excellent in pre amps where large values required ( MC pick up ) . Compared with polypropylene they seem softer yet open . They are especailly good up to 0.4 V and often better than Audiophile types . In low level circuits they excel . 1000 uF 16 V can be used for MC . Perhaps the sweetness is the sub 0.4 V range . Above that diode effects come in .
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winding Inductors , and other about Inductors ; Electrolytic caps ; Turntable motors
'ullo Nigel ,
no , there is no difficulty "in building and inductor" if one understands the particular application the inductor is to be used in ,
that is , R.F. tuning versus Power Supply Regulation and Filtering versus Passive Loudspeaker Crossovers , all require a somewhat different allocation of priorities.
I have been posting about choices in buying ready made here , because that is what Reggie prefers to do , and perhaps DennyG ? ,
though LucasAdamson was originally intending to wind his own , but now ?
If one understands the inevitable trade-offs when using finite materials in combinations for a complex mechanical + magnetic + electrical application ,
and if one has the manual dexterity to control the winding , together with the patience to endure the time it takes to wind many many turns ,
then one can make one's own , as I do.
It would be useful to have 3 hands , and for my next attempt to wind I intend to engage the assistance of another person so that a suitable adhesive can be applied to the wire whilst I am winding ,
because I want a coil that will have no internal localized vibration , and there-by has no modulated magnetic field other than that caused by the music signal.
As I have been posting in this thread , for Series connected inductors in woofer filters one needs low DCR with respect to the DCR of the woofer , ideally a 1:10 ratio or higher ,
though for a 4 ohm woofer as Celestion's crossing in the low midrange , the physical size of the coil plus the cost of the wire renders that ratio impractical for many DIYers ,
so we are making do with a 1:5 ratio that includes the Total DCR of both the Series connected coils.
Ideally this Total DCR should include that of the loudspeaker cable also , thus the users here will likely have reduced to 1:4 or lower ...
and really I consider 1:4 including the cable's loop DCR to be the minimum for reasonably well controlled bass.
Inductors in Parallel arms of midrange and tweeter filters do not need very low DCR , and often are more useful in the circuit if have some DCR of up to 20% of the DCR of the driver
IF the driver's peak-to-peak voice-coil excursion is sufficient to tolerate a small reduction in the filtering of low frequencies at the maximum sound output level required of the driver.
For your 600 Hz application you will need 16AWG or thicker wire for a woofer filter , depending on the inductance required ,
and 20AWG or thinner wire for the Parallel connected inductor in the 600 Hz Highpass filter filter.
I think Active filtering is better for crossing over at low midrange and mid-bass frequencies , and that includes up to at least 400 Hz ,
but also to your 600 Hz depending on the drivers , available amplifier quality , and your budget.
My preference is to cross in the upper bass , between 120Hz <---> 160Hz , to a midrange driver that will tolerate playing that low ,
and for that I will be designing an Active crossover -{ if I stop spending my available time posting in Forums ! }.
*** *** ***
Electrolytic capacitors:
as with types of Inductors , their application to quality audio depends on the type of circuit they are to be used in.
In a circuit where the caps are included in a entirely Electrical Feedback loop , electrolytic caps can be got to deliver closer to transparent audio
than in circuits that include mechanical to magnetic to electrical Back-EMF , which is what passive crossovers have to cope with.
Nigel's reported favourable results with electro caps are in the circuit types they can be got to work well in ,
AND , where a poor quality polypropylene cap , such as one that is some-what microphonic , would cause the sound to be much worse.
*** *** ***
Nigel ,
as I read in your Profile on this web-site that you are a Turntable designer , I think it likely you will know more than a little about motors ...
I have two NOS samples of a Papst motor of the type that was apparently used in the Mark II version of the Oracle turntable years ago.
It is a DC Servo type , and one which can be got to work across a wide range of speeds.
I have forgotten its Model Number , but I will look later , and post it in a suitable thread in a suitable Forum of diyaudio.
I will need to design for a speed that will provide sufficient Torque via the pulley to belt to sub-platter diameter to start and maintain steady speed of a likely heavy platter.
I prefer to use a heavy platter so as to achieve high rotational Inertia , and there-by as low as possible slowing under load whilst an LP is playing ,
because I cannot stand listening to any wow&flutter , as that not only wobbles the Pitch of notes ,
but also it reduces the impact of Transients , that is it causes dynamics' related compression of a sort albeit via the effect on the stylus' cantilever.
As you will know , in any mechanical system there is a fundamental Resonant frequency of vibration.
My concern here is that the motor assembley itself will have a resonant frequency which will be excited when the motor is operated at a speed very close to that frequency ,
and that resonance will then interfere with the stability of the motor speed , and particually so with the Servo which will be then constantly causing changes to the induced speed errors ,
thus I will have to find that Resonant frequency and not use the motor at that speed.
The resonant frequency of the motor assembley will change to some degree when the motor is bolted to the turntable plinth , depending on the tightness of the coupling ,
thus there will be a second Resonance generated if the motor is operated at a speed near to that frequency ,
hence I am going to have to find a speed I can operate the motor at which does not excite two or more resonant frequencies , and which provides sufficient Torque ...
all before I can decide on a pulley diameter for a Gear Ratio to a subplatter.
Now , if you have grappled with this predicament , please can you post the Titles and Authors of any Threads in diyaudio or elsewhere where this is discussed ?
... and similarly for Papst DC Servo motors ?
Yes , motors cause vibration regardless of the speeds they are operated at.
I can find some ways to minimize the effects of some vibration.
What I want to do is avoid speeds which coincide with resonant frequencies in the related mechanical structures ,
because those will cause greater amounts of vibration than other speeds.
Lower speed is only lower vibration when no resonance is excited ,
and lower speed does not necessarily provide sufficient Torque ...
assuming I have understood the Torque requirements for audio turntables , though I may not have ..?
'ullo Nigel ,
no , there is no difficulty "in building and inductor" if one understands the particular application the inductor is to be used in ,
that is , R.F. tuning versus Power Supply Regulation and Filtering versus Passive Loudspeaker Crossovers , all require a somewhat different allocation of priorities.
I have been posting about choices in buying ready made here , because that is what Reggie prefers to do , and perhaps DennyG ? ,
though LucasAdamson was originally intending to wind his own , but now ?
If one understands the inevitable trade-offs when using finite materials in combinations for a complex mechanical + magnetic + electrical application ,
and if one has the manual dexterity to control the winding , together with the patience to endure the time it takes to wind many many turns ,
then one can make one's own , as I do.
It would be useful to have 3 hands , and for my next attempt to wind I intend to engage the assistance of another person so that a suitable adhesive can be applied to the wire whilst I am winding ,
because I want a coil that will have no internal localized vibration , and there-by has no modulated magnetic field other than that caused by the music signal.
As I have been posting in this thread , for Series connected inductors in woofer filters one needs low DCR with respect to the DCR of the woofer , ideally a 1:10 ratio or higher ,
though for a 4 ohm woofer as Celestion's crossing in the low midrange , the physical size of the coil plus the cost of the wire renders that ratio impractical for many DIYers ,
so we are making do with a 1:5 ratio that includes the Total DCR of both the Series connected coils.
Ideally this Total DCR should include that of the loudspeaker cable also , thus the users here will likely have reduced to 1:4 or lower ...
and really I consider 1:4 including the cable's loop DCR to be the minimum for reasonably well controlled bass.
Inductors in Parallel arms of midrange and tweeter filters do not need very low DCR , and often are more useful in the circuit if have some DCR of up to 20% of the DCR of the driver
IF the driver's peak-to-peak voice-coil excursion is sufficient to tolerate a small reduction in the filtering of low frequencies at the maximum sound output level required of the driver.
For your 600 Hz application you will need 16AWG or thicker wire for a woofer filter , depending on the inductance required ,
and 20AWG or thinner wire for the Parallel connected inductor in the 600 Hz Highpass filter filter.
I think Active filtering is better for crossing over at low midrange and mid-bass frequencies , and that includes up to at least 400 Hz ,
but also to your 600 Hz depending on the drivers , available amplifier quality , and your budget.
My preference is to cross in the upper bass , between 120Hz <---> 160Hz , to a midrange driver that will tolerate playing that low ,
and for that I will be designing an Active crossover -{ if I stop spending my available time posting in Forums ! }.
*** *** ***
Electrolytic capacitors:
as with types of Inductors , their application to quality audio depends on the type of circuit they are to be used in.
In a circuit where the caps are included in a entirely Electrical Feedback loop , electrolytic caps can be got to deliver closer to transparent audio
than in circuits that include mechanical to magnetic to electrical Back-EMF , which is what passive crossovers have to cope with.
Nigel's reported favourable results with electro caps are in the circuit types they can be got to work well in ,
AND , where a poor quality polypropylene cap , such as one that is some-what microphonic , would cause the sound to be much worse.
*** *** ***
Nigel ,
as I read in your Profile on this web-site that you are a Turntable designer , I think it likely you will know more than a little about motors ...
I have two NOS samples of a Papst motor of the type that was apparently used in the Mark II version of the Oracle turntable years ago.
It is a DC Servo type , and one which can be got to work across a wide range of speeds.
I have forgotten its Model Number , but I will look later , and post it in a suitable thread in a suitable Forum of diyaudio.
I will need to design for a speed that will provide sufficient Torque via the pulley to belt to sub-platter diameter to start and maintain steady speed of a likely heavy platter.
I prefer to use a heavy platter so as to achieve high rotational Inertia , and there-by as low as possible slowing under load whilst an LP is playing ,
because I cannot stand listening to any wow&flutter , as that not only wobbles the Pitch of notes ,
but also it reduces the impact of Transients , that is it causes dynamics' related compression of a sort albeit via the effect on the stylus' cantilever.
As you will know , in any mechanical system there is a fundamental Resonant frequency of vibration.
My concern here is that the motor assembley itself will have a resonant frequency which will be excited when the motor is operated at a speed very close to that frequency ,
and that resonance will then interfere with the stability of the motor speed , and particually so with the Servo which will be then constantly causing changes to the induced speed errors ,
thus I will have to find that Resonant frequency and not use the motor at that speed.
The resonant frequency of the motor assembley will change to some degree when the motor is bolted to the turntable plinth , depending on the tightness of the coupling ,
thus there will be a second Resonance generated if the motor is operated at a speed near to that frequency ,
hence I am going to have to find a speed I can operate the motor at which does not excite two or more resonant frequencies , and which provides sufficient Torque ...
all before I can decide on a pulley diameter for a Gear Ratio to a subplatter.
Now , if you have grappled with this predicament , please can you post the Titles and Authors of any Threads in diyaudio or elsewhere where this is discussed ?
... and similarly for Papst DC Servo motors ?
Yes , motors cause vibration regardless of the speeds they are operated at.
I can find some ways to minimize the effects of some vibration.
What I want to do is avoid speeds which coincide with resonant frequencies in the related mechanical structures ,
because those will cause greater amounts of vibration than other speeds.
Lower speed is only lower vibration when no resonance is excited ,
and lower speed does not necessarily provide sufficient Torque ...
assuming I have understood the Torque requirements for audio turntables , though I may not have ..?
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Hi Alan . If it is allowed a discussion about motors . There is one great fly in the ointment and also saving grace of belt drives . They reduce the transmission of vibration . The idea was to make very cheap transcription turntables when AR did the first commersial design . Very simple tests will show that in a typical belt drive only power output of the motor matters . The belt is almost like an osmotic barrier . The only problem is the vibration of the stylus gets absorbed . One must be honest and say the trade off is excellent . There comes a point when the trade off is the limiting factor .
Stiffening the belt is the answer . The leader tape of old works well .
The remote location of the motor seems a reasonable thing to do . Also twin motors or a tentioner ( like motorcycle valve chain adjuster ) .
Platter mass might be ideal at 3 kg . I do not place much faith in the mass route . Having said that some sound fine . Verdier seems an excellent design . I know all the maths etc . Still am not convinced . Bakelite is a great material . Acrylic also . Bronze outer perhaps ?
Tom Fletcher I think found the motor to be the least important component as long as the power output is high and vibration low . A speeded up direct drive via a stiff belt seems ideal ( as yours ? ) . Garrard used 1500 rpm ( ish ) = 25 Hz . Linn of old 250 rpm = 4.2 Hz . I have a feeling 25 Hz is more OK although can be heard . It is away from other problems like Fo of pick up ( one hopes ) .
My observation is the power output of most motors is too low by a factor of 10 ( LP12 of old ) . One that contradicted that was a turntable using a tape recorder capstan motor . It had an internal speed regulator . My guess is it could mimic a larger motor torque wise . The internal servo being very nice in operation . As the guy said it is the only place where a servo might work . FG servo if memory is correct .
I am 90% convinced the resonance of the motor is a smaller factor than having a belt . I am 90% convinced high platter mass is risky . Dancing with divers boots I call it ( why it matters I don't know ) . I suspect the problem is bearing related . If magnetic levitation is used it should be OK . Still begs the question about doing it .
Optimum use of mass is critical .
I recently bought a JVC direct drive for my girl friend . It is the piece of junk it would be . However it sounds decent . Then I looked again . Very clever engineering . The pick up arm although minimal has made that a virtue in the mass . The motor is powerful and cog free ( within it's concept that is , reduced cog effects ) . The horrible plastic is just wall paper . The chassis is substantial . If it has a defect it masks detail . It is almost good enough for broadcast . I will miss it as it is easy to use . L-E3 . Would love the MC pick up it could have .
The old Lenco 75 was annoyingly good .
Stiffening the belt is the answer . The leader tape of old works well .
The remote location of the motor seems a reasonable thing to do . Also twin motors or a tentioner ( like motorcycle valve chain adjuster ) .
Platter mass might be ideal at 3 kg . I do not place much faith in the mass route . Having said that some sound fine . Verdier seems an excellent design . I know all the maths etc . Still am not convinced . Bakelite is a great material . Acrylic also . Bronze outer perhaps ?
Tom Fletcher I think found the motor to be the least important component as long as the power output is high and vibration low . A speeded up direct drive via a stiff belt seems ideal ( as yours ? ) . Garrard used 1500 rpm ( ish ) = 25 Hz . Linn of old 250 rpm = 4.2 Hz . I have a feeling 25 Hz is more OK although can be heard . It is away from other problems like Fo of pick up ( one hopes ) .
My observation is the power output of most motors is too low by a factor of 10 ( LP12 of old ) . One that contradicted that was a turntable using a tape recorder capstan motor . It had an internal speed regulator . My guess is it could mimic a larger motor torque wise . The internal servo being very nice in operation . As the guy said it is the only place where a servo might work . FG servo if memory is correct .
I am 90% convinced the resonance of the motor is a smaller factor than having a belt . I am 90% convinced high platter mass is risky . Dancing with divers boots I call it ( why it matters I don't know ) . I suspect the problem is bearing related . If magnetic levitation is used it should be OK . Still begs the question about doing it .
Optimum use of mass is critical .
I recently bought a JVC direct drive for my girl friend . It is the piece of junk it would be . However it sounds decent . Then I looked again . Very clever engineering . The pick up arm although minimal has made that a virtue in the mass . The motor is powerful and cog free ( within it's concept that is , reduced cog effects ) . The horrible plastic is just wall paper . The chassis is substantial . If it has a defect it masks detail . It is almost good enough for broadcast . I will miss it as it is easy to use . L-E3 . Would love the MC pick up it could have .
The old Lenco 75 was annoyingly good .
The platter mass issue is interesting . Many turntables that have it are as interesting as a funeral . Now that could be because they are doing nothing wrong .
Cutting lathes sound great for playback . They sound nothing like high mass turntables . However they do sound like the master tape ( exceedingly ) .
I had a bronze platter made for a Garrard 301 . An exact replica . It worked fine . It just sounded pedestrian . The bearing is uniquely able to allow this on a 301 . Later much bronze was removed and special plastics used to fill the portholes machined away .That worked nicely ( like Thorens reference designs , thanks Kurt ) .
Cutting lathes sound great for playback . They sound nothing like high mass turntables . However they do sound like the master tape ( exceedingly ) .
I had a bronze platter made for a Garrard 301 . An exact replica . It worked fine . It just sounded pedestrian . The bearing is uniquely able to allow this on a 301 . Later much bronze was removed and special plastics used to fill the portholes machined away .That worked nicely ( like Thorens reference designs , thanks Kurt ) .
Hi Alan. A quick question please. In your post #969 under your heading Jantzen Audio Inductors at para 2 you say "my primary recommendation for the 3.5mh coil is the 3.4mh coil #35.." But then, in the last sentence of that para you say "..I strongly recommend the more expensive coil #34.." As I am a very literal person (as in I find ambiguity troubling) could you confirm for me please that it is a 3.4mh coil #35 I should be purchasing. Then, if I may, could I post a list of the items I intend to purchase before I actually do it?
Reggie
Reggie
a Correction to my #969 on Page 97 , about a Jantzen inductor
In my Post #969 on Page 97 is a mistake.
It is in the section I posted again as a Quote in the above box where I stated:
"however as that is only about half the DCR of Celestion's inductor I strongly recommend the more expensive Coil No.34 ... "
I do NOT recommend Coil No.34 , I recommend Coil No.35 ,
and for the reasons I stated in #969.
Despite proof-reading my post I failed to see the error , perhaps because too much 3.4mH thinking in my brain I typed #34 instead of #35.
Coil No.34 is the 3.3mH which I advised Reggie to not buy.
It would be a good buy for owners of Celestion 44 , as that model had a 3.3mH inductor in the woofer filter.
I apologize for whatever confusion this mistake may have caused to readers.
As I have on several occasions during this thread later posted Corrections to earlier posts I advise here that readers look always before doing anything
to see if I later posted a Correction , particually after my long posts because there it is easy for me to miss a typo as my brain is focussing on the subject more than on my spelling ...
and this latter is a weakness of mine also.
Thankyou Reggie for drawing my attention to the mistake ,
and hey , after me catching you with a schematic mistake a while ago , now you have caught me !
Well , this type of thing is common , and a substantially more experienced designer of integrated circuits , etc , than I am of loudspeaker systems ,
made the point in his book about the use of having one's collegues proof-read one's work before it is published ,
and that included for them to check his circuit designs at work , and each others' also.
Yes , do post a complete Parts List here , and if you are prefering a once only Order ,
then consider including the 24uF or 25uF caps for the midrange filter in either SoniCap or ClarityCap
in case your Mundorf 22uF cap filters off a little too much of the lower midrange - that being a central part of the Male vocals' range.
Cost of later mailing two caps from overseas may be excessive versus the possible no extra mailing cost if bought now with other parts.
*** *** ***
'ullo Nigel ,
Thankyou indeed for all that you posted about Turntable design - I am grateful !
I will post a bit of follow-up to that when I next return to here.
I have little time available today - I posted primarily today to correct my earlier Inductor part number mistake.
In my Post #969 on Page 97 is a mistake.
It is in the section I posted again as a Quote in the above box where I stated:
"however as that is only about half the DCR of Celestion's inductor I strongly recommend the more expensive Coil No.34 ... "
I do NOT recommend Coil No.34 , I recommend Coil No.35 ,
and for the reasons I stated in #969.
Despite proof-reading my post I failed to see the error , perhaps because too much 3.4mH thinking in my brain I typed #34 instead of #35.
Coil No.34 is the 3.3mH which I advised Reggie to not buy.
It would be a good buy for owners of Celestion 44 , as that model had a 3.3mH inductor in the woofer filter.
I apologize for whatever confusion this mistake may have caused to readers.
As I have on several occasions during this thread later posted Corrections to earlier posts I advise here that readers look always before doing anything
to see if I later posted a Correction , particually after my long posts because there it is easy for me to miss a typo as my brain is focussing on the subject more than on my spelling ...
and this latter is a weakness of mine also.
Thankyou Reggie for drawing my attention to the mistake ,
and hey , after me catching you with a schematic mistake a while ago , now you have caught me !
Well , this type of thing is common , and a substantially more experienced designer of integrated circuits , etc , than I am of loudspeaker systems ,
made the point in his book about the use of having one's collegues proof-read one's work before it is published ,
and that included for them to check his circuit designs at work , and each others' also.
Yes , do post a complete Parts List here , and if you are prefering a once only Order ,
then consider including the 24uF or 25uF caps for the midrange filter in either SoniCap or ClarityCap
in case your Mundorf 22uF cap filters off a little too much of the lower midrange - that being a central part of the Male vocals' range.
Cost of later mailing two caps from overseas may be excessive versus the possible no extra mailing cost if bought now with other parts.
*** *** ***
'ullo Nigel ,
Thankyou indeed for all that you posted about Turntable design - I am grateful !
I will post a bit of follow-up to that when I next return to here.
I have little time available today - I posted primarily today to correct my earlier Inductor part number mistake.
Seeing as someone might know . Is there a simple way to modify a standard drive unit for open baffle use ?The Celestion 44 might make an interesting design if having a spare bit of MDF . I have no idea of Qts of a 44 , might be 0.7 . About 1.3 is what the OB people choose
Here is one I fancy using if it will adapt . No problem building a current drive amplifier if that is what it needs .
LS00430 - PRO SIGNAL - WOOFER, POLYPROP CONE, 8OHM, 8 | Farnell United Kingdom
Here is one I fancy using if it will adapt . No problem building a current drive amplifier if that is what it needs .
LS00430 - PRO SIGNAL - WOOFER, POLYPROP CONE, 8OHM, 8 | Farnell United Kingdom
Hi (once again) Alan.
I’ve made my list of parts (and some extra questions).
Woofer:
Caps: Utilise existing 2 x 68uf caps with additional 1 x 8.2uf cap from tweeter
Coils: Jantzen Air-Cored - 1 x 3.4mh, 14awg No.35 and
1 x 2.2mh, 14awg No.28
Resistors: Mills MRA5 - 1 x 1ohm, 1 x 1.5ohm, 1 x 8.2ohm(i)
Mid:
Caps: Jantzen Superior Z caps - 1 x 3.9uf, 1 x 22uf(ii)
Coils: Jantzen Air-Cored – 1 x 2.2mh 14awg No.28(iii) and
1 x 0.35mh 18awg 0.27ohm(iv)
Resistors: Mills MRA5 - 1 x 1.8ohm, 1 x 3.9ohm
Tweeter:
Caps Jantzen Superior Z caps - 2 x 1.8uf(v) and
2 x 5.6uf(vi)
Coils: Jantzen Air-Cored – 1 x 0.15mh 20awg 0.23ohm(vii)
Resistors: Mills MRA5 – 1 x 1.2ohm, 1 x 15ohm(viii)
Questions:
(i) If, in the future I change the 8.2uf capacitor, will this resistor also change?
(ii) Note that you have suggested I may need to use a 24 or 25uf capacitor here. (Although I liked the change to the 22uf from the 30 odd uf I had in there before.)
(iii) Should this coil be the same awg as the coil in the woofer. Jantzen do make 2.2mh coils in other wire gauges?
(iv) Again, we haven’t discussed replacement of these mid-range inductors. Is this an appropriate coil?
(v) Cross-over calls for 1 x 3.6uf but Jantzen doesn’t have one. Their closest is 3.3uf or 3.9uf.
(vi) Again, Jantzen’s closest is 10uf
(vii) Alan, at your post #902 you recommended a 0.15mh, 20awg coil for the tweeter. Which is good because Jantzen don’t make a 0.15mh. (actually, I have taken your post out of text). Is this size coil ok with these capacitors?
(viii) Your recommendation for the LPad was for either a 1.1ohm and a 15ohm resistor, or a 1.2ohm and an 18ohm. Should I order both formats?
I know this is going to cost me (relatively) big dollars but, will be the last time, surely??
Thank you Alan
I’ve made my list of parts (and some extra questions).
Woofer:
Caps: Utilise existing 2 x 68uf caps with additional 1 x 8.2uf cap from tweeter
Coils: Jantzen Air-Cored - 1 x 3.4mh, 14awg No.35 and
1 x 2.2mh, 14awg No.28
Resistors: Mills MRA5 - 1 x 1ohm, 1 x 1.5ohm, 1 x 8.2ohm(i)
Mid:
Caps: Jantzen Superior Z caps - 1 x 3.9uf, 1 x 22uf(ii)
Coils: Jantzen Air-Cored – 1 x 2.2mh 14awg No.28(iii) and
1 x 0.35mh 18awg 0.27ohm(iv)
Resistors: Mills MRA5 - 1 x 1.8ohm, 1 x 3.9ohm
Tweeter:
Caps Jantzen Superior Z caps - 2 x 1.8uf(v) and
2 x 5.6uf(vi)
Coils: Jantzen Air-Cored – 1 x 0.15mh 20awg 0.23ohm(vii)
Resistors: Mills MRA5 – 1 x 1.2ohm, 1 x 15ohm(viii)
Questions:
(i) If, in the future I change the 8.2uf capacitor, will this resistor also change?
(ii) Note that you have suggested I may need to use a 24 or 25uf capacitor here. (Although I liked the change to the 22uf from the 30 odd uf I had in there before.)
(iii) Should this coil be the same awg as the coil in the woofer. Jantzen do make 2.2mh coils in other wire gauges?
(iv) Again, we haven’t discussed replacement of these mid-range inductors. Is this an appropriate coil?
(v) Cross-over calls for 1 x 3.6uf but Jantzen doesn’t have one. Their closest is 3.3uf or 3.9uf.
(vi) Again, Jantzen’s closest is 10uf
(vii) Alan, at your post #902 you recommended a 0.15mh, 20awg coil for the tweeter. Which is good because Jantzen don’t make a 0.15mh. (actually, I have taken your post out of text). Is this size coil ok with these capacitors?
(viii) Your recommendation for the LPad was for either a 1.1ohm and a 15ohm resistor, or a 1.2ohm and an 18ohm. Should I order both formats?
I know this is going to cost me (relatively) big dollars but, will be the last time, surely??
Thank you Alan
Replies to posts since my #975
'ullo Nigel ,
the short answer is I recommend you do not buy that LS00430 woofer from Farnell , for several reasons ,
and there is better for what you may be designing , for little higher in price.
I will reply more about this below.
*** *** ***
Hi Doug ,
well , you know one person who could afford 66s in North America -
- the guy you sold your new caps' 66s to for too low a price ...
and now realize what he may on-sell them for if he sees that Vietnam advertisment !
What loudspeakers are you listening through now ?
*** *** ***
G'day Reggie ,
Your "Woofer" list is correct , but as for the other drivers !?!
To reply to your questions:
(i) - No
(ii) - the 22uF reduced the excess lower mids , however after you upgrade the woofer filter and note that the woofer had been reproducing some excess of the lower mids also ,
you may hear that the lower mids are a little too much reduced with 22uF.
Ideally I think you should listen with the 22uF Mundorf in circuit after the woofer and tweeter circuit upgrades , and decide then ,
especially as you may be wasting money on that expensive Jantzen 22uF cap.
If you are determined to buy Jantzen caps , then buy three of 8.2uF and connect them in Parallel to sum to 24.6uF ,
but really that is both a waste of space and money when a 24uF SoniCap or 25uF ClarityCap will do the job just as well for less money and in less space ,
and with less trouble than having to neatly solder a 3 caps' bundle into the circuit.
(iii) - No ! - this coil , as in Parallel , needs some DCR to reduce Resonance in the filter.
I have posted several times about this , especially for Bandpass filters , which a midrange filter in a 3-way crossover is.
There is nothing wrong with using Celestion's inductor there.
Do your samples of those seem to have any faults , such as loose windings ?
(iv) - there is no need to replace this coil , as it seems low enough in DCR.
Let us wait till we see what DennyG may find when he does an LTSpice simulation of the actual Impedance of the MD-500 at 5kHz ,
because a higher Inductance there may cause a better result , particually with the tweeter upgrade you have that adds more output.
Celestion seem to have balanced the upper mids' output in a way to complement the lower output of their tweeter.
(v) and (vi) - you are the fellow who wants to buy Jantzen caps !
I have been recommending ClarityCap and SoniCap - what is it about those you do not favour ?
Also , connecting caps in Parallel pairs in a circuit for treble requires one to solder very neatly and with the pairs of cap leads in such way as to not cause Series Inductance
or other losses ... if one really wants to be fussy ... and that would be the only sensible reason to want those large size and expensive caps.
(vii) - Celestion's tweeter inductor is OK , unless your samples have loose windings .?.
There is only one other reason to change it - that is if one does not want to buy 3.6uF and 11uF or 12uF caps.
If you want to buy 3.3uF and 10uF , then change the inductor to 0.15mH ,
but post here about that so I can find one that is not too low in DCR , because for a Parallel circuit position cap some DCR is beneficial.
The one I saw on the Speakerbug list is slightly too low , and Jantzen do have a few that seem closer to optimum ,
thus as you are having a Jantzen inductor special ordered for the woofer filter you may as well for the tweeter filter also ,
if you are determined to change that inductor so as to use 3.3uF and 10uF caps.
(viii) you may have read my #902 again , but it seems you may not have read my #937 and #938 again ,
as I calculated the L-Pad resistor values for an Impedance that used the 0.14mH Celestion inductor in circuit.
If you want to use 0.15mH I will re-calculate the L-Pad resistor values for the different circuit Impedance.
Please post which option ?
QUOTE:
"I know this is going to cost me (relatively) big dollars but, will be the last time, surely??"
The Last Time was a song by the Rolling Stones , which I think you may know ,
but as for when will be "the last time" for High-Roller Reggie ... ?
Before I speculate more about your crossover components , please inform me ,
do you intend to make a new board for the woofer filter only , and use the old Celestion board for the mid and tweeter filters ,
or do you intend to make one new board for the entire crossover ?
I ask the latter part , because if you are planning to put sensitive inductors for mids and treble
on the same board as the new large Magnetic Field radiating woofer inductors you will need a much larger board ...
... which may not fit through the woofer cut-out into the cabinet ... though you could make two new boards ...
*** *** ***
'ullo again Nigel ,
'oi , geezers like wot we are being Engineers of a sort wind our own Inductors ,
and really we do not ask about prices without specifying a target DCR , or the particular location and application in the Circuit ...
I'll take a guess as you want 10mH that it is for Series to a woofer ..?
and thus if you want to not lose signal and ruin Damping you will need low DCR wrt the woofer Impedance ...
Well , to get about 10% of a typical woofer's DCR in 10mH you will likely need a 12AWG wire inductor if air-core.
That may be about 5 inches or larger in Diameter , depending on its Height ,
and may weigh about 4 Kilo or more ...
thus maybe you will prefer to chance what can be achieved with Jantzen's P-core inductors ... which will not saturate as badly as Ferrite cored ,
but whether close enough to performance of an Air-core to suit your hearing I do not know ,
however if you are intending to use that cheap Farnell 8 inch woofer it will not matter , because you won't get much bass from it in an open baffle.
You will need to use at least two per channel if 8" to even hear much bass in a Small room , and even then it will be fairly low volume.
Two 10" per channel would be better , but one 10" may suffice if you intend only an experimental project and don't expect a lot of bass SPL.
Before I post more , what is you room size and the result you hope to achieve ?
'ullo Nigel ,
the short answer is I recommend you do not buy that LS00430 woofer from Farnell , for several reasons ,
and there is better for what you may be designing , for little higher in price.
I will reply more about this below.
*** *** ***
Hi Doug ,
well , you know one person who could afford 66s in North America -
- the guy you sold your new caps' 66s to for too low a price ...
and now realize what he may on-sell them for if he sees that Vietnam advertisment !
What loudspeakers are you listening through now ?
*** *** ***
G'day Reggie ,
Your "Woofer" list is correct , but as for the other drivers !?!
To reply to your questions:
(i) - No
(ii) - the 22uF reduced the excess lower mids , however after you upgrade the woofer filter and note that the woofer had been reproducing some excess of the lower mids also ,
you may hear that the lower mids are a little too much reduced with 22uF.
Ideally I think you should listen with the 22uF Mundorf in circuit after the woofer and tweeter circuit upgrades , and decide then ,
especially as you may be wasting money on that expensive Jantzen 22uF cap.
If you are determined to buy Jantzen caps , then buy three of 8.2uF and connect them in Parallel to sum to 24.6uF ,
but really that is both a waste of space and money when a 24uF SoniCap or 25uF ClarityCap will do the job just as well for less money and in less space ,
and with less trouble than having to neatly solder a 3 caps' bundle into the circuit.
(iii) - No ! - this coil , as in Parallel , needs some DCR to reduce Resonance in the filter.
I have posted several times about this , especially for Bandpass filters , which a midrange filter in a 3-way crossover is.
There is nothing wrong with using Celestion's inductor there.
Do your samples of those seem to have any faults , such as loose windings ?
(iv) - there is no need to replace this coil , as it seems low enough in DCR.
Let us wait till we see what DennyG may find when he does an LTSpice simulation of the actual Impedance of the MD-500 at 5kHz ,
because a higher Inductance there may cause a better result , particually with the tweeter upgrade you have that adds more output.
Celestion seem to have balanced the upper mids' output in a way to complement the lower output of their tweeter.
(v) and (vi) - you are the fellow who wants to buy Jantzen caps !
I have been recommending ClarityCap and SoniCap - what is it about those you do not favour ?
Also , connecting caps in Parallel pairs in a circuit for treble requires one to solder very neatly and with the pairs of cap leads in such way as to not cause Series Inductance
or other losses ... if one really wants to be fussy ... and that would be the only sensible reason to want those large size and expensive caps.
(vii) - Celestion's tweeter inductor is OK , unless your samples have loose windings .?.
There is only one other reason to change it - that is if one does not want to buy 3.6uF and 11uF or 12uF caps.
If you want to buy 3.3uF and 10uF , then change the inductor to 0.15mH ,
but post here about that so I can find one that is not too low in DCR , because for a Parallel circuit position cap some DCR is beneficial.
The one I saw on the Speakerbug list is slightly too low , and Jantzen do have a few that seem closer to optimum ,
thus as you are having a Jantzen inductor special ordered for the woofer filter you may as well for the tweeter filter also ,
if you are determined to change that inductor so as to use 3.3uF and 10uF caps.
(viii) you may have read my #902 again , but it seems you may not have read my #937 and #938 again ,
as I calculated the L-Pad resistor values for an Impedance that used the 0.14mH Celestion inductor in circuit.
If you want to use 0.15mH I will re-calculate the L-Pad resistor values for the different circuit Impedance.
Please post which option ?
QUOTE:
"I know this is going to cost me (relatively) big dollars but, will be the last time, surely??"
The Last Time was a song by the Rolling Stones , which I think you may know ,
but as for when will be "the last time" for High-Roller Reggie ... ?
Before I speculate more about your crossover components , please inform me ,
do you intend to make a new board for the woofer filter only , and use the old Celestion board for the mid and tweeter filters ,
or do you intend to make one new board for the entire crossover ?
I ask the latter part , because if you are planning to put sensitive inductors for mids and treble
on the same board as the new large Magnetic Field radiating woofer inductors you will need a much larger board ...
... which may not fit through the woofer cut-out into the cabinet ... though you could make two new boards ...
*** *** ***
'ullo again Nigel ,
'oi , geezers like wot we are being Engineers of a sort wind our own Inductors ,
and really we do not ask about prices without specifying a target DCR , or the particular location and application in the Circuit ...
I'll take a guess as you want 10mH that it is for Series to a woofer ..?
and thus if you want to not lose signal and ruin Damping you will need low DCR wrt the woofer Impedance ...
Well , to get about 10% of a typical woofer's DCR in 10mH you will likely need a 12AWG wire inductor if air-core.
That may be about 5 inches or larger in Diameter , depending on its Height ,
and may weigh about 4 Kilo or more ...
thus maybe you will prefer to chance what can be achieved with Jantzen's P-core inductors ... which will not saturate as badly as Ferrite cored ,
but whether close enough to performance of an Air-core to suit your hearing I do not know ,
however if you are intending to use that cheap Farnell 8 inch woofer it will not matter , because you won't get much bass from it in an open baffle.
You will need to use at least two per channel if 8" to even hear much bass in a Small room , and even then it will be fairly low volume.
Two 10" per channel would be better , but one 10" may suffice if you intend only an experimental project and don't expect a lot of bass SPL.
Before I post more , what is you room size and the result you hope to achieve ?
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