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08-17-2009 Post mapped to one branch of Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,327
Joined on 05-28-2004

Post #: 1
Post ID: 11449
Reply to: 11449
The African compression electromagnet drivers?
fiogf49gjkf0d

I know very little about this company.

http://www.kilimanjaro-series.com

It called after an African mountain but the guy sells his drivers out of French ebay.

http://shop.ebay.fr/merchant/chlorophyllin

So, I presume that he is from French Equatorial Africa - had to say – a half of North-Western Africa speak French.

What I wonder if the Kilimanjaro company.  Are the same as the German “Great Vintage Loudspeakers”.

http://www.romythecat.com/Forums/ShowPost.aspx?postID=10467#10467

The drivers look similar but in the Kilimanjaro site there is no mentioning of “Great Vintage Loudspeakers” affiliation.

I think it might be a sign of two things. Ether they just try to crates different companies to promote these drivers at different locations with different flavor. Or the company was spit and somebody started his own venture with the similar products. Both cases are fine by me.

That is still do not answer the most interesting question: how those drivers sound. The $3.5K for a pair of converted JBL375 drivers is expensive but not the end of the world.  I would like them to write the critical review what they do NOT like in the sound of standard JBL375/2440 and what they feel their electromagnetic driver does better. But it would be too rational thing to wish….

The caT


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
08-31-2009 Post does not mapped to Knowledge Tree
twogoodears


Italy
Posts 115
Joined on 03-26-2008

Post #: 2
Post ID: 11603
Reply to: 11449
Southern Germany, not French speaking Africa
fiogf49gjkf0d
Herr Wolf von Langa is a gentleman from Southern Germany (look at the link here http://twogoodears.blogspot.com/2009/03/great-site-from-germany-field-coils.html).
He and his sister are dealing in modding vintage speakers, speakers woodworking and vintage audio dealing... I purchase from them some old, N.O.S. Altec's 15 inchers, few months ago.


"Use your ears as your eyes" - Gertrude Stein

Stefano
08-31-2009 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,327
Joined on 05-28-2004

Post #: 3
Post ID: 11616
Reply to: 11603
The most exclusive audio circles? Oh, please…
fiogf49gjkf0d
 twogoodears wrote:

Christine and Wolf Von Langa deal in nice mods, restorations and rebuilding from scratch of classic Altec's drivers, adding the sought-after "field-coils" feature instead using permanent magnets... a snobbish, yet highly considered practice in most exclusive audio circles worldwide to reach better frequencies control and overall better performance...

Thanks, Stefano.  Do you feel that the field-coil version of this diver and particularly with plastic cone offer more advanced sound then the default 375/2440? Did you try on this 2440 the contemporary production aftermarket aluminum cones?  BTW, I do not think that there are ANY evidence that field-coil has ANY connection with “better frequencies control”. If would be very interesting if you have the Herr Wolf von Langa’s drivers right next to the original 375/2440 with new cones. It would be fascinating to learn what Wolf was trying to accomplish.

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
09-01-2009 Post does not mapped to Knowledge Tree
twogoodears


Italy
Posts 115
Joined on 03-26-2008

Post #: 4
Post ID: 11620
Reply to: 11616
Field-coils vs. permanent magnets
fiogf49gjkf0d
Unfortunately I cannot reply to your question, Roman, as I purchased from herr Von Langa a N.O.S. pair of Altec 416-8B 15" woofers.

BTW: while in Berlin, last May, Frank Schroeder performed an interesting, provoking "blind-test" using '50s and '60 Telefunken's midrange loudspeakers (22 cm diam.), comparing FC vs. PM:
almost everyone in the listening panel better ranked and appreciated the FC's - smoother, more natural, less beamy.

Will read with interest any (informed) opinion concerning field-coils vs. permanent magnets comparisons.


"Use your ears as your eyes" - Gertrude Stein

Stefano
09-01-2009 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,327
Joined on 05-28-2004

Post #: 5
Post ID: 11622
Reply to: 11620
The invitation to Wolf von Langa
fiogf49gjkf0d

 twogoodears wrote:
BTW: while in Berlin, last May, Frank Schroeder performed an interesting, provoking "blind-test" using '50s and '60 Telefunken's midrange loudspeakers (22 cm diam.), comparing FC vs. PM:
almost everyone in the listening panel better ranked and appreciated the FC's - smoother, more natural, less beamy.

Will read with interest any (informed) opinion concerning field-coils vs. permanent magnets comparisons.

The subject of field-coils vs. permanent magnets is well beaten at my site. I generally am not pleased how people out there cover this subject. The Frank Schroeder experiment in my view was interning but not conclusive. There was not comment how much that “50s and 60 Telefunken's midrange” driver sound off from what it shell. What it initially badly sounding driver, then what the Schroeder’s excrement would shows? Nothing in my view. The whole point is to take a good sounding driver, change the manger and to see what happen. This Von Langa guy looks like did with JBL 375 and his result  are very interesting because the 375/2440 is a very good driver with very well know performing parameters.

BTW. I did the similar experiments with my S2 driver; you might read the dairies:

http://www.romythecat.com/Forums/ShowPost.aspx?postID=1929#1929

Do not miss the linked threads from there if you want more about the field-coils and I have this subject spread all over the site. In my case I did not find the direction perspective for myself without a very substantial re-research the subject at very different level of commitment and dedication. I was not going to do it. I also do not do see anybody else do the field-coils at serious level of objectives. People out there just wind coils (thankfully it is cheaper then fix magnet), get “ANY sound” and then run and screams like idiots that because it was field-coil then the random crap that they got was the god-send Sound. Well, there is a reason why I consider that most of audio people out there are morons….

BTW, the most intelligent analysis in my view about the subject of the field-coils was exes by a “be” from Denmark. Her is his post:

http://www.RomyTheCat.com/TreeItem.aspx?PostID=10659

I feel that he is on something with it…. If you wish then bring the Wolf von Langa to the table and let him to express his view about the default 2440 vs. the 2440 with electromagnet.

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
08-06-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,327
Joined on 05-28-2004

Post #: 6
Post ID: 14191
Reply to: 11449
New production of RCA 1428 from Wolf von Langa.
fiogf49gjkf0d

In the thread “Vitavox S2 with Electromagnets.” there was plenty of discussion about RCA 1428 driver. Here is more to it:  the Great Vintage Loudspeakers made a new production of the RCA 1428 driver.

http://www.kilimanjaro-series.com/kilimanjaro-series/a1428wvl/

… they call it A1428WVL.

I am not well familiar with RCA 1428, so it difficult to analyze what is being done in there. It looks like the driver is driven by 30V – a bit too low. Considering the later high voltage discovers I would rather to have 100-200V field coil. The site said that the driver uses “composite cone”. I have no idea what it is. Anyhow, it is second attempt to remake the RCA 1428 after the Cogent. Sure it needs to be heard to see what they are trying to do.

What is very interesting to me is who the customers of Wolf von Langa’s products are. I am sure that the production of those things is expensive but there is dozen or so derange people around the world who curiosity in those things. I am sure to wish Mr. von Langa a prospers business venture but I just do not see it.

Anyhow,  a new Kilimanjaro-Series driver is out. I have no point of reference how good or bad they are and I do not see people talk about Kilimanjaro. It is sad as it would be interesting to hear from Kilimanjaro users.

The caT


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
08-06-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,327
Joined on 05-28-2004

Post #: 7
Post ID: 14192
Reply to: 14191
Kilimanjaro's RCA
fiogf49gjkf0d

In fact I posted a question to Wolf and he replied that he can produce the coil of any voltage the customer would like to have. That is good. The below is data by Wolf von Langa:

MI-1428 - original version of the RCA 1428 - especially made for Manhatten Opera House (AKA MI-1437) - 100V field-coil motor, 8 section phasing cap and fibrous cone material (may have been hemp paper).
MI-1428A - second version of MI-1428 w/same 8 section phase plug but a new phenolic cone. 13V/1.7A (about 18 Watt) field-coil motor, 8.4 Ohm DCR, voice coil: about 4 Ohm DCR
MI-1428B - the phasing plug was changed to 15 sections. Same phenolic coated silk cone, except modified with cloth suspension and felt damping rings (replacement cone is RCA Stock No. 26414)
MI-1443 - same loudspeaker as the 1428B except the field-coil volatge is about 115 Volt
MI-1429 - 15" woofer made by Lansing Manufacturing Co. (Model 15X29) - 110V field supply (used in RCA Shearer/Photophone systems with Lansing 285 high-frequency driver)
MI-1434 - same as MI-1429 except field-coil motor is 13V
MI-1435 - same as 1428 except painted black and built to MGM specs for use in Shearer systems (13V, about 26 Watt)
MI-1437 - formerly known as MI-1428 prototype 100V field-coil driver - made for Manhatten Opera House
MI-1438 - formerly known as MI-1432 - companion 100V field-coil 15" woofer to the original 1428, also made for Manhatten Opera House
MI-1443 - same as 1428B except 115V field-coil

Parameter A1428WVL 8 Ohm 
Frequency response = 340 Hz – 16 kHz (w/2350 horn)
Power handling = 75 Watt
Sensitivity = 110 dB @1W/1m
Minimum impedance = 8.3 Ohm
Diaphragm = composite paper cone driven by a 2" voice coil
Flux density = up to 23 kGauss (measured in the gap)
Net weight = 15 kG
Diameter = 178 mm
Horn throat diameter = 2"

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
08-10-2010 Post does not mapped to Knowledge Tree
audiofilofine
Posts 29
Joined on 02-26-2010

Post #: 8
Post ID: 14212
Reply to: 14192
Field coil
fiogf49gjkf0d
to reel from 7 volts or 700 volts is equal to the reel. should rather ask why or why 7 or  700 volts. should be asked how you intend to use the horn driver, you should ask graphs of frequency response and power handling. build a field coil driver is easy , it is not easy calculate voltages, impedances and which trumpets used to equalize the driver .. I do not see any of this work in Kilimanjaro.
I do not understand how we can provide a driver that works in 7 or 115 volts only changing the solenoid, but can not play sounds good in both cases, changing too many parameters.

part of rca driver are like this?  :     http://voltiaudio.com/midrangedrivers.shtml


http://www.toutlehautparleur.com/bms/bms-diaph-4591-p-3116.html
08-11-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,327
Joined on 05-28-2004

Post #: 9
Post ID: 14217
Reply to: 14212
The new Kilimanjaro driver.
fiogf49gjkf0d

 audiofilofine wrote:
to reel from 7 volts or 700 volts is equal to the reel. should rather ask why or why 7 or  700 volts. should be asked how you intend to use the horn driver, you should ask graphs of frequency response and power handling. build a field coil driver is easy , it is not easy calculate voltages, impedances and which trumpets used to equalize the driver .. I do not see any of this work in Kilimanjaro.
I do not understand how we can provide a driver that works in 7 or 115 volts only changing the solenoid, but can not play sounds good in both cases, changing too many parameters.

part of rca driver are like this?  :     http://voltiaudio.com/midrangedrivers.shtml


http://www.toutlehautparleur.com/bms/bms-diaph-4591-p-3116.html

Audiofilofine, they all valid points. I agree that to build a field coil drivers is very easy, in fact  much easier then perm magnet and I did wrote before that field coils mast be less expensive then permanent magnet drivers. To calculate voltages and impedances is also VERY simple. A bit more difficult to get the core mass for core built only in case of conversion. If one build a new driver then it is very easy. Again, what does it mean difficult? A qualified engineer shall give you the specification for core mass and coil parameters with an hour of work. It is how long it took for my engineer when I converted my S2 driver to field coil. So, is it difficult? I do not think so.

In my short exchange with Wolf von Langa he told me that he coil build any voltage, even 5000V field coil. I do not know if he said it juts to be nice or he has no idea what take to build 5000V coil. To have a magnetizing coil to be over 5000V rates it shell be VERY different winding and anti-corona isolation employed – it very different then 12-100 coils. Still his opines to do higher voltage coils is a nice fact.
It was mentioned and discussed at this site that higher magnetizing voltage is beneficial as it offsets the sound softening that is comes with coil heating.  It was not my idea but I find it extremely well noted and I am very enthusiastically support the concept. I did not try it personally (I have enough projects on my table for now) but I am absolutely certain that the concept will work perfectly fine.

The biggest question is what else will change if the voltage of solenoid goes up with all other equal conditions? Sure, the different coil impedance but would it be it? I did post the question to Wolf von Langa but he did not reply. I asked him is T/S parameters of the driver change with voltage change – it got to be in my view. Frankly I do not think he have answer to this question. I do not think a lot of people out there do. Audio people generally do not question too much own actions or own thinking. specifically the field coil tend to be absolutely immune to any cognitive sensibility. For whatever reason a typical audio Morons when he see a field coil label he collapse any brain faction and approach the driver banded, backward and with his pants down.

Yes, I do feel that change voltage from 12 V to 120 or to 240V will make a driver to be a different driver. It is possible that the diaphragm and it’s suspension need to be modified to optimize it for higher voltage and working with more energized magnetic field. But where did you see the field coil people ever talk about specifics not to mention to talk about the actual results. Did you even see anybody from the field coil clan to talk about sound of the divers? Never! At least I did hear/see it. Funny, but if they are trying to show off that they talk about sound then they avoidably copy each other words. So, I pretty much discard the field coil experience of others as I did not find it credible. My own experience with electromagnets made me do not want to go there - my perm mans drivers were clearly better. Still I would like to try the high voltage electromagnets as I do feel that there is a lot of promise in there.

About Wolf von Langa’s new RCA drivers. I do not know. To ignite interest of public, at least he public of my level of understanding he need come up with something more than historical essay and a few pictures. I do not care about history and I do not stupidly assume that it was vintage then it shall be good. Wolf von Langa made his own new driver and it need to be treated as a new driver. The fact that it uses the RCA architecture is fine - it make it no better or worse. It is a new driver and it need to be treated as a new driver. It’s it.

Rgs, Romy the Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
08-11-2010 Post does not mapped to Knowledge Tree
audiofilofine
Posts 29
Joined on 02-26-2010

Post #: 10
Post ID: 14218
Reply to: 11622
Rca field coil
fiogf49gjkf0d
for me is not new driver , is only a mechanic  puzzle without research .
is beautiful  work if make for personal game but is fake if make for business.
08-11-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,327
Joined on 05-28-2004

Post #: 11
Post ID: 14219
Reply to: 14218
Forget about RCA, look at what von Langa is.
fiogf49gjkf0d
 audiofilofine wrote:
for me is not new driver , is only a mechanic  puzzle without research .
is beautiful  work if make for personal game but is fake if make for business.

Audiofilofine, possible, if you have any more information or familiar with it. I do not. I do not know Kilimanjaro drivers generally and I do not know what is in the head of Wolf von Langa’s to make any assumptions of guesses. Any driver is in away a mechanical puzzle the key is what are the objective of the person who navigate and administer this puzzle. The fact that Kilimanjaro RCA driver might look a bit different then RCA driver does not bother me at all.  The Wolf’s drivers are made in 70 year, so they by default are very different drivers. I hope the guy who make them would say more about their sound and the application of the drivers. I usually can get any more or less predictable pictures if I see person critiques of other brands. So if Wolf would express how his driver behave it relation to other driers in different applications then it would be know where he stay in his thinking, and consequential implementations .

The caT


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
08-11-2010 Post does not mapped to Knowledge Tree
be
Copenhagen, Denmark
Posts 86
Joined on 02-12-2007

Post #: 12
Post ID: 14223
Reply to: 14217
Fieldcoil parameters and coil voltage.
fiogf49gjkf0d
Hi!
Let me point out that two field coil magnets with identical iron parts, but different field coil wire thiknesses, will at the same field coil power dissipation produce exactly the same magnetic field and the loudspeaker will hence have same parameters.
Naturally since the impedance of the field coils are different the required voltage applied will differ.
Therefore if fieldcoil drivers with higher voltage ratings tend to sounds better, it must be due to other indirect factors like difference in power suplies or maybe different mechanical or heat conducting characteristics of thin and thick wires.

Regards
be
08-11-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,327
Joined on 05-28-2004

Post #: 13
Post ID: 14225
Reply to: 14223
It will be different magnetic field.
fiogf49gjkf0d
 be wrote:
Hi!
Let me point out that two field coil magnets with identical iron parts, but different field coil wire thiknesses, will at the same field coil power dissipation produce exactly the same magnetic field and the loudspeaker will hence have same parameters.
Naturally since the impedance of the field coils are different the required voltage applied will differ.
Therefore if fieldcoil drivers with higher voltage ratings tend to sounds better, it must be due to other indirect factors like difference in power suplies or maybe different mechanical or heat conducting characteristics of thin and thick wires.

Actually, be, you are incorrect. What I was pitched with idea of high voltage filed coil I spoke with people who consult me and they explained to me that with same amount of flux but with higher voltage in coil the result will be different magnetic field. It is not the power supplies, or mechanics or heat but internal changes in the field itself. I do not remember exactly all details and do not insist they are write but the explanations I got sounded very reasonable to me.

Rgs, Romy the Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
08-12-2010 Post does not mapped to Knowledge Tree
be
Copenhagen, Denmark
Posts 86
Joined on 02-12-2007

Post #: 14
Post ID: 14227
Reply to: 14225
Field will (in a way) be the same.
fiogf49gjkf0d



I agree that the total flux will be the same but therefor in the same iron structure, the field in the gap will be the same, at least in the statical case.

If the system is modulated by the speach coil, a simpel measure of how well the system resists this modulation, is the ratio of resistance to inductance of the field coil, lets call it Fc.
If the  insulation thickness of the field coil wire is negligable, this ratio is unchanged and therefor the dynamic behavior will be the same as well.

Real insulations have a thickness and this inperfection will tend to upset the ballance, so that higher voltage coils by unchaged statical flux will tend to be softer (higher Fc) or more easy to modulate and therefore the unit will have higher distortion due to the magnetic nonlinearities of the pole pieces.

Higher distortion might be beneficial for the sound, I dont know.

The point to make is that it should be possible to get the same result if you put a resistor in series with the field coil voltage source, keeping the voltage over the coil the same by increasing the suply voltage.
Or even using a current source (maximum distortion)

This could, if the speculations are right, open up for tuning the sound by simple means. 
Have anybody experimented with this?

Regards
Erik

 

08-12-2010 Post does not mapped to Knowledge Tree
be
Copenhagen, Denmark
Posts 86
Joined on 02-12-2007

Post #: 15
Post ID: 14228
Reply to: 14227
Forgot to mention..
fiogf49gjkf0d
that the high voltage coil will at the same flux have higher dissipation, this could mean that it will run at a higher temperature and thereby softening the mooving parts more.
If this is the case and is benneficial, the resistor mentionned in the post above could be mounted at the back plate of the electromagnet or the magnet could be insulated to run at a higher temperature!
08-12-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,327
Joined on 05-28-2004

Post #: 16
Post ID: 14229
Reply to: 14228
Statical flux vs. move vivid flux?
fiogf49gjkf0d
Erik, I do not think a resistor in series would do as it will burn on itself some voltage and the coil will be driven by the same voltages. It would be good to put in place of the resistor a rheostat and to slide it up and down while slide up and down the voltage of power supply and maintaining the same voltage on the field coil. This would indicate how the PS distortions might affect sound, at least hypothetically.

I think to conduct any more or less methodologically cleaner experiment the best would be to have the field coil with multiple taps. Make the coil standard 600V rated and to design the coil to have let say 4 taps that identically fill the bobbin. Let say it would be 12-48-96 and 192V. Then driving the coil from a powerful PS that has a lot of buffer it would be possible to switch taps on the field coil and adjusting the PS to maintain the same faux. I have such a PS – a vintage Fluke 409. It is a large PS that out puts up to 500V and up to .5A, the unit is all tubes and tube-regulated. I think I will make this experiment in future with my S2 driver, after I finish with what I am going through now. I have spoken a few month back with my coil guy and he agreed to wider the coil like this.

I think in your post above the key was “the field in the gap will be the same, at least in the statical case.” The statical flux is the same but dynamic characteristics of flux at higher voltage have to be different. I think because they will be different the resulting sound will be different.

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
08-12-2010 Post does not mapped to Knowledge Tree
haralanov


Bulgaria
Posts 130
Joined on 05-20-2008

Post #: 17
Post ID: 14230
Reply to: 14229
FCs again.......
fiogf49gjkf0d
 Romy the Cat wrote:
I think to conduct any more or less methodologically cleaner experiment the best would be to have the field coil with multiple taps. Make the coil standard 600V rated and to design the coil to have let say 4 taps that identically fill the bobbin. Let say it would be 12-48-96 and 192V. Then driving the coil from a powerful PS that has a lot of buffer it would be possible to switch taps on the field coil and adjusting the PS to maintain the same faux.

Unfortunately this method is not going to have success, simply because you can't mantain the same flux in gap using the low voltage taps (compared to the 192V tap) because you need substantially more current (192/12=16 times more) flowing through the wire and you are going to melt it.


 be wrote:
I agree that the total flux will be the same but therefor in the same iron structure, the field in the gap will be the same, at least in the statical case.

Yes, that's right. But only in statical case.


 be wrote:
If the system is modulated by the speach coil, a simpel measure of how well the system resists this modulation, is the ratio of resistance to inductance of the field coil, lets call it Fc.
If the  insulation thickness of the field coil wire is negligable, this ratio is unchanged and therefor the dynamic behavior will be the same as well.

Real insulations have a thickness and this inperfection will tend to upset the ballance, so that higher voltage coils by unchaged statical flux will tend to be softer (higher Fc) or more easy to modulate and therefore the unit will have higher distortion due to the magnetic nonlinearities of the pole pieces.

the high voltage coil will at the same flux have higher dissipation, this could mean that it will run at a higher temperature and thereby softening the mooving parts more.
If this is the case and is benneficial, the resistor mentionned in the post above could be mounted at the back plate of the electromagnet or the magnet could be insulated to run at a higher temperature!

Be, is that your own thoughts or you had read it somewhere?  




"If you can't explain it simply, you don't understand it well enough." -A.E.
08-12-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,327
Joined on 05-28-2004

Post #: 18
Post ID: 14231
Reply to: 14230
An experimental coil
fiogf49gjkf0d
 haralanov wrote:
Unfortunately this method is not going to have success, simply because you can't mantain the same flux in gap using the low voltage taps (compared to the 192V tap) because you need substantially more current (192/12=16 times more) flowing through the wire and you are going to melt it.

 
Yes, I knew that I was dreaming when I wrote it as 12V-192V coil would be impractical. Still, it is not an operation coil but an experiment coil to prove the concept. I do not remember specifically but I think I was requested from my coil guy 50-100-150-200V coil. It might be different voltages, it is not the point. The point is that no matter what kind taped coil you would make then it would be thermal compromise anyhow as the unused turns will slow down the cooling of the under-laying turns. So, a taped coil is an experimental coil anyhow and it meant to be abused or even melted.


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
08-12-2010 Post does not mapped to Knowledge Tree
be
Copenhagen, Denmark
Posts 86
Joined on 02-12-2007

Post #: 19
Post ID: 14232
Reply to: 14229
Statical flux vs. move vivid flux?
fiogf49gjkf0d
Hi, it is a bit unclear what you mean.

If it is what normaly is called a tapped coil it will be dead wrong and the results probably invalid since different parts of the coil volume in the iron structure would be without current, depending of the tapps used.

A better way to do it , would be to have many sections that could be either parallel or serially conected in different combinations.
This would at least ensure that some current but not necesarilly equal current flows in all coils.

With four equal sections stacked from bottom to top of the central polepiece you could have three combinations of them where the current would be the same in each one. and the whole thing would act as one homogeneous coil.
But maybe this is what you meant?

Loking forward to hear about your results! 

Regards
Erik

08-12-2010 Post does not mapped to Knowledge Tree
be
Copenhagen, Denmark
Posts 86
Joined on 02-12-2007

Post #: 20
Post ID: 14233
Reply to: 14230
FCs again.......
fiogf49gjkf0d
They are based on some simple coil calculations on paper and a bit of qualitative mind modelling.

The claimed observation that the higher temperature makes a difference comes from sombody else.

Regards
Erik
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